Title of Invention	AN ENGINE STARTER FOR A VEHICLE
Abstract	An engine starter for a vehicle, which includes a starter motor for cranking an engine in response to a specific engine-starting operation, and an ignitor for igniting said engine at a specific rotational angle in response to said engine-starting operation, said engine starter being characterized by including ignition prohibiting means for .prohibiting an ignition operation of said ignitor in an engine-stopping process from an operational state to a stopping state; and wherein said ignition prohibiting means prohibits ignition operation of said ignitor if an engine speed is equal to or less than a first engine speed in an engine-stopping process from an operational state to a stopping state, and prohibits the ignition operation of said ignitor if the engine speed is equal to or less than a second engine speed in an engine-starting process form a stopping state, wherein said first engine speed is higher than said second speed. 20 APR 2006

Title of Invention

AN ENGINE STARTER FOR A VEHICLE

Abstract

An engine starter for a vehicle, which includes a starter motor for cranking an engine in response to a specific engine-starting operation, and an ignitor for igniting said engine at a specific rotational angle in response to said engine-starting operation, said engine starter being characterized by including ignition prohibiting means for .prohibiting an ignition operation of said ignitor in an engine-stopping process from an operational state to a stopping state; and wherein said ignition prohibiting means prohibits ignition operation of said ignitor if an engine speed is equal to or less than a first engine speed in an engine-stopping process from an operational state to a stopping state, and prohibits the ignition operation of said ignitor if the engine speed is equal to or less than a second engine speed in an engine-starting process form a stopping state, wherein said first engine speed is higher than said second speed. 20 APR 2006

Full Text	FORM 2 THE PATENTS ACT 1970 [39 OF 1970] & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See Section 10; rule 13] "AN ENGINE STARTER FOR A VEHICLE" HONDA MOTOR CO., LTD., a corporation of Japan, of 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan, The following specification particularly describes the invention and the manner in which it is to be performed: GRANTED 20-4-2006 The present invention relates to an engine starter for a vehicle. The present invention relates to an engine starter for a vehicle, which is for starting the engine by making use of a starter motor, and particularly to an engine starter for a vehicle, which is suitable for a vehicle including an engine automatic stopping/starting system for automatically stopping the engine in response to a specific vehicle-stopping condition during running of the vehicle and restarting the engine in response to a specific vehicle-starting condition after stopping the engine. [0002] [Prior Art] In the case of starting an engine, an ignitor starts its ignition operation simultaneously with an operation of starting a starter motor. Accordingly, in this case, if the ignition operation is performed in an initial state of drive of the engine, that is, at a point of time when an engine speed is very low, the piston of the engine is pushed down- with an exploded force caused by the ignition operation before it reaches the top dead center, with a result that a load is applied to the 2 starter motor and simultaneously noise occurs. Such a phenomenon is generally called "back-kick". [0003] To reduce noise due to such back-kick occurring at the time of starting the engine, a technique for prohibiting an operation of an ignitor until an engine speed reaches a specific value has been proposed, for example, in Japanese Patent Laid-open No. Sho 60-187766 oryJLei 2-1473. [Problem to be Solved by the Invention] According to the above-described prior art, an engine speed is measured when a starting operation is detected, and if the engine speed is equal to or more than a specific value, the operation of the ignitor is permitted. In this prior art, since it is assumed that the engine is usually started from its stopping state, the engine speed is gradually increased along with cranking by a starter motor. Accordingly, if the measured engine speed is equal to or more than the specific value, the engine speed at the subsequent actual ignition timing is usually higher than the specific value, with a result that it is possible to effectively prevent occurrence of back-kick. 3 [0005] On the contrary, if the engine-starting operation is performed in an engine-stopping process from the operational state to the stopping state, the ignition operation is permitted because the engine speed at the measurement timing is equal to or more than the specific value; however, since the engine speed may be often lower than the specific value at the subsequent actual ignition timing, there may occur back-kick. [0006] On the other hand, from the viewpoints of environment protection and energy-saving, vehicles including engine automatic stopping/starting systems have been developed and put on the market. The engine automatic stopping/starting system is operated to stop an ignition operation of an engine ignitor in response to a specific vehicle-stopping condition during running of a vehicle and to restart the ignition operation in response to a specific vehicle-starting operation after interruption of the ignition operation. In the vehicle including such an engine automatic stopping/starting system, since an engine-starting operation may be sometimes performed in an engine-stopping process from the operational state to the stopping state, there is a possibility of occurrence of back-kick. [0007] An object of the present invention is to solve the above-described problem of the prior art, and to provide an engine starter capable of preventing occurrence of back-kick at the time of starting an engine, thereby suppressing noise occurring at the time of starting the engine at a low value. [0008] [Means for Solving the Problem] To achieve the above object, according to the present invention, there is provided ah engine starter for a vehicle, which includes a starter motor for cranking an engine in response to a specific engine-starting operation, and an ignitor for igniting the engine at a specific rotational angle in response to the engine-starting operation. The engine starter is characterized as follows: [0009] (1) The engine starter includes ignition prohibiting means for prohibiting an ignition operation of the ignitor in an engine-stopping process from an operational state to a stopping state. [0010] (2) The engine starter includes ignition prohibiting means for prohibiting an ignition operation of the ignitor if an engine speed is equal to or less than a first engine speed in an engine-stopping process from an operational state to a stopping state, and prohibiting the ignition operation of the ignitor if the engine speed is equal to or less than a second engine speed in an engine-starting process from a stopping state, wherein the first engine speed is higher than the second engine speed. [0011] With the above-described feature (1), since the operation of the ignitor is prohibited in the engine-stopping process from the operational state to the stopping state, even if the engine-starting operation is performed in the engine-stopping process and the piston of the engine reaches an ignition position immediately before the top dead center at a low speed, the engine is not ignited, to thereby prevent occurrence of back-kick. [0012] With the above-described feature (2), since the upper limit of the engine speed, at which the ignition operation of the ignitor is prohibited, in the engine-stopping process is set to be higher than that in the engine-starting process, it is possible to positively prevent occurrence of back-kick not only in the engine-starting process but also in the engine-stopping process while suppressing the prohibiting number of the ignition operation at minimum. The present invention relates to an engine starter for a vehicle, which includes a starter motor for cranking an engine in response to a specific engine-starting operation, and an ignitor for igniting said engine at a specific rotational angle in response to said engine-starting operation, said engine starter being characterized by including ignition prohibiting means for prohibiting an ignition operation of said ignitor in an engine-stopping process from an operational state to a stopping state; and wherein said ignition prohibiting means prohibits ignition operation of said ignitor if an engine speed is equal to or less than a first engine speed in an engine-stopping process from an operational state to a stopping state, and prohibits the ignition operation of said ignitor if the engine speed is equal to or less than a second engine speed in an engine-starting process form a stopping state, wherein said first engine speed is higher than said second speed. [Brief Description of the Drawings] [FIG. 1] FIG. 1 is a sectional view of a first embodiment of a swing unit of a vehicle including an engine automatic stopping/starting system. [FIG. 2] FIG. 2 is a sectional view, taken on a plane perpendicular to a crankshaft, showing the swing unit of the first embodiment. [FIG. 3] FIG. 3 is a sectional view of a second embodiment of a swing unit of a vehicle including an engine automatic stopping/starting system. [FIG. 4] FIG. 4 is a sectional view of a third embodiment of a swing unit of a vehicle including an engine automatic stopping/starting system. [FIG. 5] FIG. 5 is a side view of a motorcycle on which an engine automatic stopping/starting system is mounted. [FIG. 6] FIG. 6 is a sectional view of a fourth embodiment of a swing unit of a vehicle including an engine automatic stopping/starting system. 8 [FIG. 7] FIG. 7 is a sectional view, taken on a plane perpendicular to a crankshaft, showing the swing unit of the fourth embodiment. [FIG. 8] FIG. 8 is a block diagram showing an engine automatic stopping/starting system according to one embodiment of the present invention. [FIG. 9] FIG. 9 is a block diagram showing the function of a main control unit (part 1). [FIG. 10] FIG. 10 is a block diagram showing the function of the main control unit (part 2) . [FIG. 11] FIG. 11 is a block diagram showing the function of the main control unit (part 3). [FIG. 12] FIG. 12 is a block diagram showing the function of the main control unit (part 4). [FIG. 13] FIG. 13 is a list of main operations of the main control unit (part 1). [FIG. 14] FIG. 14 is a list of the main operations of the main control unit (part 2). [FIG. 15] FIG. 15 is a diagram showing conditions for switching operational modes from each other. [FIG. 16] Fig. 16 is a diagram showing a relationship between an engine speed Ne and a throttle opening degree 6 , and a standard ignition timing. [FIG. 17] Fig. 17 is a graph showing a relationship between an engine speed and an ignition timing. [FIG. 18] FIG. 18 is a timing chart showing an operation of a starting signal extending unit shown in FIG. 9. [FIG. 19] FIG. 19 is a diagram showing a method of determining an extension of a starting time by the starting signal extending unit shown in FIG. 9. [FIG. 20] FIG. 20 is a flowchart showing an operation of an ignition-starting control unit. [FIG. 21] FIG. 21 is a flowchart showing an operation of an 10 ignition-stopping control unit. [FIG. 22] FIG. 22 is a flowchart showing an ignition prohibiting control process performed by an 'ignition prohibiting control unit. [FIG. 23] FIG. 23 is a graph illustrating the content of the ignition prohibiting control process performed by the ignition prohibiting control unit shown in Fig. 22. [FIG. 24] FIG. 24 is a flowchart showing another embodiment of the ignition prohibiting control process performed by the ignition prohibiting control unit. [FIG. 25] FIG. 25 is a graph showing the content of the ignition prohibiting control process performed by the ignition prohibiting control unit shown in FIG. 24. 11 {Mode for Carrying Out the Invention] Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 5 is a side view showing an entire configuration of a motorcycle on which an engine-stopping/starting control unit of the present invention is mounted. A body front portion 2 is joined to a body rear portion 3 via a low floor portion 4. The skeleton of a vehicular body is configured by a body frame including a down tube 6 and a main pipe 7. A fuel tank and a luggage box (both not shown) are supported by the main pipe 7, and a seat 8 is disposed over the fuel tank and the luggage box. The seat 8 serves as a lid of the luggage box provided under the seat 8. The luggage box is openable/closable by a hinge mechanism provided on a front portion FR of the luggage box. [0014] A steering head 5 is provided on an end portion, on 12 the body front portion 2 side, of the down tube 6. A front fork 12A is rotatably supported by the steering head 5. A handlebar 11A is mounted on an upwardly extending upper end of the front fork 12A, and a front wheel 13A is rotatably supported by lower ends of the front fork 12A. An upper portion of the handlebar 11A is covered with a handle cover 33 serving as an instrument panel. [0015] A link member (hanger) 37 is turnably supported by a mid point of the main pipe 7. A swing unit 17 is swingably connected to and supported by the main pipe 7 via the hanger 37. A single-cylinder/four-cycle engine 200' is mounted in a front portion of the swing unit 17. A belt-type continuously variable transmission 35 is provided in a portion, extending rearwardly from the engine 200', of the swing unit 17. A speed reduction mechanism 38 is provided on a rear portion of the belt-type continuously variable transmission 35 via a centrifugal clutch. A rear wheel 21 is rotatably supported by the speed reduction mechanism 38. A rear cushion 22 is interposed between an upper end of the speed reduction mechanism 38 and an upper bent portion of the main pipe 7. 13 [0016] An intake pipe 23 extending from a cylinder head 32 of the engine 200' is connected to the front portion of the swing unit 17. A carburetor 24 is connected to the intake pipe 23, and an air cleaner 25 is connected to the carburetor 24. A pivot 18 is provided on a lower portion of a swing unit case 31, and a main stand 26 is pivotably mounted to the main stand 26. The main stand 26 is raised at the time of parking of the vehicle (the raised state of the main stand 26 is shown by chain lines in FIG. 5). [0017] FIG. 1 is a sectional view, taken on line A-A of FIG. 5, showing a first embodiment of the swing unit 17, and FIG. 2 is a sectional view, taken on a plane perpendicular to a crankshaft of the engine, showing the swing unit 17. The swing unit 17 includes the engine 200' positioned on the front side of the vehicular body, a generator portion G connected to one end of a crankshaft 12, and a drive portion ATI and a driven portion AT2 of an automatic transmission connected to the other end of the crankshaft 12. [0018] The crankshaft 12 is rotatably supported by the swing unit case 31 via main bearings 10 and 11. A connecting rod 14 is connected to the crankshaft 12 via a crank pin 13. A generator unit 44 is provided on one end, projecting from a crank chamber 9, of the crankshaft 12. [0019] One sleeve 57a (on the crankshaft side) of a one way clutch 50 is fixed to an outer rotor 42 of the generator unit 44 by means of a screw 43. The other sleeve 55a (on the sprocket side) of the one-way clutch 50 is rotatably supported, together with a sprocket 58, by the crankshaft 12 at a position between the generator unit 44 and the main bearing 11. A chain 40 for transmitting a starting torque from a starter motor 49 shown in FIG. 2 is wound around the sprocket 58. [0020] A clutch portion 56a of the one-way clutch 50 prohibits idle rotation of the outer rotor 42 of the generator unit 44, that is, the crankshaft 12 in the reversal rotational direction relative to the sprocket 58, but permits idle rotation of the outer rotor 42 in the normal rotational direction. Accordingly, when the starter motor 49 is driven to drive the sprocket 58 in the normal rotational direction of the crankshaft 12 at the time of starting the engine, the crankshaft 12 is correspondingly driven in the normal rotational direction. [0021] On the contrary, after starting the engine, since the crankshaft 12 is idled relative to the sprocket 58 even when the starter motor 49 is stopped, a drive force of the crankshaft 12 is not transmitted to the starter motor 49. [0022] A sprocket 59 is fixed on the crankshaft 12 at a position between the sprocket 58 and the main bearing 11. A chain 60 for transmitting a power for driving a camshaft 69 from the crankshaft 12 is wound around the sprocket 59. In addition, the sprocket 59 is integrated with a gear 61 for transmitting a power to a pump (not shown) for circulating lubricating oil. [0023] A piston 63 disposed in a cylinder 62 is connected to a small-diameter end of the connecting rod 14. An ignition plug 65 is screwed in the cylinder head 32 in such a manner that an electrode portion of the ignition plug 65 faces to a combustion chamber formed between the head of a piston 63 and the cylinder head 32. The periphery of the cylinder 62 is surrounded by a water jacket 66. [0024] The camshaft 69 is rotatably supported by a portion, over the cylinder 62, in the cylinder head 32. A cam sprocket 72 is fixed to the camshaft 69. The above-described chain 60 is wound around the cam sprocket 72. The chain 60 acts to transmit the rotation of the sprocket 59, that is, the rotation of the crankshaft 12 to the camshaft 69. [0025] Rocker arms 73 are provided on an upper portion of the camshaft 69. When the camshaft 69 is rotated, the rocker arms 73 are rocked while following the cam shape of the camshaft 69. The cam shape of the camshaft 69 is determined in such a manner that intake/exhaust valves 95 and 96 are opened/closed in accordance with a specific stroke of the four-cycle engine. [0026] A pulley 83, around which a V-belt 82 is wound, is provided on an end portion, on the side opposed to the side provided with the generator unit 44, of the crankshaft 12. The pulley 83 is composed of a fixed pulley piece 83a fixed relative to the crankshaft 12 in both the rotational direction and the axial direction, and a movable pulley piece 83b slidable relative to the crankshaft 12 in the axial direction. A holder plate 84 17 is mounted to the back surface, being not in contact with the V-belt 82, of the movable pulley piece 83b. The motion of the holder plate 84 relative to the crankshaft 12 in both the rotational direction and the axial direction is restricted. That is to say, the holder plate 84 is rotated integrally with the crankshaft 12. A pocket for containing a roller 85 as a governor weight is formed in a space surrounded by the holder plate 84 and the movable pulley piece 83b. [0027] A fan 83c is integrally formed on the back surface, being not in contact with the V-belt 82, of the fixed pulley piece 83a. An air cleaner cover 70 including an air cleaner 71 for cleaning cooling wind and introducing it in an automatic transmission chamber is mounted to an opening portion, facing to the fan 83c, of the swing unit case 31. When the crankshaft 12 is normally rotated, the fan 83c sucks outside air in the automatic transmission chamber via the air cleaner 71. [0028] At the driven portion AT2 of the automatic transmission, a fixed pulley piece 132a of a pulley 132 is supported by a main shaft 125 of a clutch. A cup-shaped clutch plate 134 is fixed to an end portion of the main shaft 125 by means of a nut 133. A movable pulley piece 132b of the pulley 132 is provided on a sleeve 135 of the fixed pulley piece 132a in such a manner as to be slidable in the longitudinal direction of the main shaft 125. The movable pulley piece 132b is engaged with a disk 136 in such a manner as to be rotatable integrally therewith around the main shaft 125. A compression coil spring 137 is provided between the disk 136 and the movable pulley piece 132b, wherein the repulsive force of the compression coil spring 137 acts to extend the distance between the disk 136 and the movable pulley piece 132b. The main shaft 125, an idle shaft 142, and an output shaft 145 are meshed with each other, and a rim 21a of the rear wheel 21 is fixed to the output shaft 145. [0029] As described above, according to this embodiment, the starter motor 49 is connected to the crankshaft 12 via the chain 40 as endless connecting means and thereby the crankshaft 12 is driven via the chain 40 at the time of starting the engine. Accordingly, noise caused by rotation of the starter motor 49 at the time of starting the engine can be made smaller than that in the prior art configuration. [0030] When the generator unit 44 and the pulley 83 of the automatic transmission are provided on both sides of the crankshaft 12 with the crank chamber 9 put therebetween as in this embodiment, an axial region of the crank shaft 12 occupied by the pulley 83 of the automatic transmission becomes larger than an axial region of the crankshaft.12 occupied by the generator unit 44. As a result, the length of a portion of the crankshaft 12 on the pulley 83 side with respect to the crank chamber 9 becomes longer than the length of a portion of the crankshaft 12 on the generation unit 44 side with respect to the crank chamber 9. According to this embodiment, however, since the sprocket 58 and the one-way clutch 50 therefor are provided on the generation unit 44 side, the lengths of the portions of the crankshaft 12 on both the sides of the crank chamber 9 can be substantially equal to each other, with a result that the rotational balance of the crankshaft 12 can be stabilized. [0031] Further, according to this embodiment, since the chain 40 for connecting the crankshaft 12 to the starter motor 49 and the chain 60 for connecting the crankshaft 12 to the camshaft 69 are collectively provided on one side of the engine, it is possible to improve the maintenance performance for the chains 40 and 60. [0032] An automatic engine-stopping/starting control system to which the present invention is applied will be described below. The system includes an idling permitting mode (hereinafter, referred to as "engine-start & idle switch (SW) mode"), and an idling restricting (or prohibiting) mode (hereinafter, referred to as "engine-stopping & vehicle-starting mode"). [0033] In the "engine-start & idle switch (SW) mode" which permits idling, idling is temporarily permitted after a main power source is turned on and then the engine is initially started for performing warm-up operation at the time of starting the engine, and further, idling is permitted by the intention of the driver, that is, by turning on the idle switch (SW) even in the case other than the above-described idling after the initial starting of the engine. [0034] In the "engine-stopping & vehicle-starting mode" which restricts idling, when the vehicle is stopped, the engine is automatically stopped, and when an accelerator is operated in the engine-stopping state, the engine is automatically restarted to start the vehicle. [0035] FIG. 8 is a block diagram showing an entire configuration of an engine-starting/stopping control system. In the figure, parts corresponding to those described above are designated by the same reference numerals. [0036] An AC generator 172 is provided on the crankshaft 12 in such a manner as to be coaxial therewith. A power generated by the AC generator 172 is charged in a battery 168 via a regulator rectifier 167. The regulator rectifier 167 controls a voltage outputted from the AC generator 172 to a value between 12 V and 14.5 V. The battery 168 supplies, when a starter relay 162 is conducted, a drive current to the starter motor 49, and supplies a load current to various kinds of general electrical equipment 174, a main control unit 160, and the like via a main switch 173. [0037] A pulser 153, an idle switch 253, a seated state detecting switch 254, a vehicular speed sensor 255, a stand-by indicator 256, a throttle sensor 257, a starter switch 258, a stop switch 259, a battery indicator 276, and a water temperature sensor 155 are connected to the main control unit 160. The pulser 153 detects an ignition timing and an engine speed Ne. The idle switch 253 permits or restricts idling of the engine 200' in accordance with the intention of the driver. The seated state detecting switch 254 closes a contact and outputs a signal of the "H" level when the driver is seated. The vehicular speed sensor 255 detects the vehicular speed. The stand-by indicator 256 flashes in the "engine-stopping & vehicle-starting mode". The throttle sensor 257 (including a throttle switch 257a) detects a throttle opening degree 6 . The starter switch 258 drives the starter motor 49 to crank the engine 200'. The stop switch 259 outputs a signal of the "H" level in response to braking operation. The battery indicator 276 lights up when the voltage of the battery 168 is reduced to a predetermined value (for example, 10 V) or less to warn the driver of the shortage of the charged amount of power in the battery 168. The water temperature sensor 155 detects the temperature of cooling water for the engine. [0038] An ignitor (including an ignition coil) 161, a control terminal of the starter relay 162, a control terminal of a head lamp driver 163, and a control 23 terminal of a by-starter relay 164 are also connected to the main control unit 160. The ignitor 161 ignites the ignition plug 65 in synchronization with rotation of the crankshaft 12. The starter relay 162 supplies a power to the starter motor 49. The head lamp driver 163 supplies a power to the head lamp 169. The by- starter relay 164 supplies a power to a by-starter 165 mounted to a carburetor 166. The head lamp relay 163 includes switching elements such as FETs, and is controlled by a so-called chopping control method. In this chopping method, a voltage applied to the head lamp 169 is substantially controlled by interrupting the switching elements at a specific cycle and a specific duty ratio. [0039] FIGS. 9 to 12 are block diagrams (Parts. 1, 2, 3 and 4) each showing the function of a configuration of the main control unit 160. In these figures, the same reference numerals as those described in FIG. 8 designate the same or similar parts. [0040] FIGS. 13 and 14 show lists of control contents of a starter relay control unit 400, a by-starter control unit 900, a stand-by indicator control unit 600, a head lamp control unit 800, an engine-starting (in non-seated state 24 after vehicle-stopping) control unit 100, an ignition control unit 700, an ignition knock control unit 200, and a charging control unit 500. These control units constitute the main control unit 160. [0041] Referring to FIG. 9, when the state of the idling switch 253 and the state of the vehicle are under specific conditions, an operation switching unit 300 switches the operational mode of the main control unit 160 into either the "engine-start & idle SW mode" or "engine-stopping & vehicle-starting mode". [0042] A signal indicating the state of the idle switch 253 is inputted in an operational mode signal output unit 301 of the operation switching unit 300. The signal indicating the state of the idle switch 253 exhibits the "L" level if the idle switch 253 is in the OFF state (idling restricting state) , and exhibits the "H" level if the idle switch 253 is in the ON state (idling permitting idling state). The operational mode signal output unit 301 outputs an operational mode signal S301 for designating the operational mode of the main control unit 160 to either the "engine-start & idle SW mode" or "engine-stopping & vehicle-starting mode" in response to output signals from the idle switch 253, vehicular speed sensor 255 and water temperature sensor 155. [0043] FIG. 15 is a schematic diagram showing conditions for switching the operational modes by the operational mode signal output unit 301. If the main switch 173 is turned on to reset the main control unit 160 (a condition 1 is established), the level of the operational signal S301 is set to the "L" level for starting the "engine-start & idle SW mode". [0044] If, under the "engine-start & idle SW mode", the vehicular speed equal to or more than a predetermined speed (for example, 10 km/hr) is detected, the water temperature equal to or more than a specific temperature (for example, a temperature at which the warm-up operation is assumed to have been completed), and the idle switch 253 is turned off (a condition 2 is established), the level of the operational mode signal S301 is shifted from the "L" level to the "H" level for starting the "engine-stopping & vehicle-starting mode". [0045] If, under the "engine-stopping & vehicle-starting mode", the idle switch SW in the OFF state is turned into ON state (a condition 3 is established), the level of the operational mode signal S301 is shifted from the "H" level to the L" level, to return the operational mode from the "engine-stopping & vehicle-starting mode" into the "engine-start & idle SW mode". Even under each of the "engine-stopping & vehicle-starting mode" and the "engine-start & idle SW mode", if the main switch 173 is cut off (a condition 4 is established), the operational mode is turned off. [0046] Referring again to FIG 9 the starter relay control unit 400 starts the starter relay 162 under a specific condition in accordance with each of the operational modes. A detection signal from the pulser 153 is inputted in a cranking speed-or-less deciding unit 401 °yind an idling speed-or-less deciding unit 407 If the engine speed is equal to or less than a specific cranking speed (for example, 600 rpm), the cranking speed-or-less deciding unit 401 outputs a signal of the "H" level. If the engine speed is equal to or less than a specific idling speed (for example, 1200 rpm), the idling speed-or-less deciding unit 407^-outputs a signal of the "H' level. [0047] 27 An AND circuit 4 02 outputs a logic product of an output signal from the cranking speed-or-less deciding unit 401, a signal indicating the state of the stop switch 259, and a signal indicating the state of the starter switch 258. An AND circuit 404 outputs a logic product of an output signal from the idling speed-or-less deciding unit 407 a detection signal from the throttle switch 257a, and a signal indicating the state of a seated state detecting switch 254. [0048] An AND circuit 403 outputs a logic product of an output signal from the AND circuit 402 and a reversed signal of the operational mode signal S301. An AND circuit 405 outputs a logic product of an output signal from the AND circuit 404 and the operational mode signal S301. An OR circuit 406 outputs a logic sum of output signals from the AND circuits 403 and 405 as a starting signal Sin. If a pulse width of the starting signal Sin is shorter than a specific reference time, a starting signal extending unit 407 extends the pulse width of the starting signal Sin up to the reference time or more, and outputs the resultant signal to the starter relay 162. [0049] The starting signal extending unit 407 includes a multi-vibrator 407a for detecting the starting signal Sin and outputting one-shot of pulse signal, and an OR circuit 407b for outputting a logic sum of the starting signal Sin and an output signal from the multi-vibrator 407a as a starting signal Sout after extension. The width of a pulse to be outputted from the multi-vibrator 407a can be freely extended by changing a variable resistance value of the multi-vibrator 407a. [0050] FIG. 18 is a timing chart showing an operation of the starting signal extending unit 407. The variable resistance value of the multi-vibrator 407a is set to 0.6 sec although the width of the output pulse is a pulse width "ton" of the starting signal Sin. As a result, even if the starter switch 258 is kept in the ON state only in a period of time shorter than 0.6 sec, the width of the output pulse of the multi-vibrator 407a becomes 0.6 sec. [0051] Since the OR circuit 407b outputs the logic sum of the output pulse of the multi-vibrator 407a and the starting signal Sin, if the pulse width "ton" of the starting signal Sout is less than 0.6 sec, the output signal Sout of the starting signal extending unit 407 becomes 0.6 sec, and if the pulse width "ton" of the starting signal Sin is longer than 0.6 sec, the output signal Sout of the starting signal extending unit 407 becomes a signal of the pulse width "ton" longer than 0.6 sec. [0052] In the above-described embodiment, the starting signal is extended to 0.6 sec; however, the present invention is not limited thereto. The extended pulse width of the starting signal may be optimally set in accordance with the rotational speed of the starter motor and a reduction ratio. [0053] To be more specific, as shown in FIG. 19, when the engine is stopped, the piston is probably stopped at a point, immediately before the top dead center (TDC), in a compression stroke (assumed as a first compression stroke which is shown on the left side in the figure). If the starter motor 49 is driven from such a state at the time of the next starting of the engine, the engine is not ignited immediately before the TDC in the first compression stroke, and is exploded immediately before the TDC in the next compression stroke shown on the right side in the figure. Accordingly, the starter motor 49 is required to rotate the engine in such a manner that the piston reaches at least the TDC in the next compression stroke. [0054] However, if the starter motor 49 is stopped at a point of time when the piston has reached the vicinity of the TDC in the next compression stroke shown on the right side in the figure, there may occur a so-called back-kick that a load caused by explosion acts in the reversal rotational direction to reversely rotate the crankshaft 12. Accordingly, the extension time determined by the starting signal extending unit 4 07 is preferably set to a time required for the piston stopped immediately before the TDC in the first compression stroke to be driven to a position over both the TDC in the first compression stroke and the TDC in the next compression stroke. [0055] As described above, in this embodiment, the starting signal extending unit 407 is provided, wherein even if the starter switch 258 is kept in the ON state only in a period of time shorter than 0.6 sec, the starter motor 49 is driven at least for 0.6 sec. As a result, it is possible to prevent the back-kick at the time of starting the engine, and hence to reducing noise caused by starting the engine. 31 [0056] Further, according to this embodiment, since the starter motor can be driven for a time at least required for starting the engine only by opening an accelerator grip for a short time, the driver can start the engine easy via throttle operation with no attention given to an increase in engine speed, particularly, for a vehicle including an automatic centrifugal clutch. [0057] In accordance with this starter relay control, the AND circuit 403 becomes an enable state in the "engine-start & idle SW mode". Accordingly, if the starter switch 258 is turned on by the driver in a state that the engine speed is equal to or less than cranking speed and the stop switch 259 is in the ON state (during braking operation), that is, if the level of the output of the AND circuit 402 becomes the "H" level, the starter relay 162 is conducted to start the starter motor 49. [0058] In accordance with this starter relay control, the AND circuit 405 becomes an enable state in the "engine-stopping and vehicle-starting state". Accordingly, if the throttle is opened in a state that the engine speed is equal to or less than the idling speed and the seated 32 state detecting switch 254 is in the ON state (during a period that the driver is being seated), that is, if the level of the output of the AND circuit 404 becomes the "H" level, the starter relay 162 is conducted to start the starter motor 49. [0059] In the stand-by indicator control unit 600 shown in FIG. 10, a vehicular speed-zero deciding unit 601 receives a detection signal from the vehicular speed sensor 255 and outputs, if the vehicular speed is substantially zero, a signal of the "H" level. An Ne deciding unit 602 decides an engine speed on the basis of a detection signal from the pulser 153, and outputs, if the engine speed is equal to or less a predetermined value, a signal of the "H" level. An AND circuit 603 outputs a logic product of output signals from the deciding units 601 and 602. [0060] An AND circuit 604 outputs a logic product of an output signal from the AND circuit 603 and a reversed signal of an output signal from the seated state detecting switch 254. An AND circuit 605 outputs a logic product of an output signal from the AND circuit 603 and an output signal from the seated state detecting switch 254. A lighting/flashing control unit 606 outputs a lighting signal if an output signal from the AND circuit 604 exhibits the "H level and outputs a flashing signal if it exhibits the "L* level. An AND circuit 607 outputs a logic product of an output signal from the lighting/flashing control unit 606 and the operational mode signal S301. The stand-by indicator 256 lights in response to the lighting signal and flashes in response to the flashing signal. [0061] In accordance with this stand-by indicator control, as shown in FIG. 13, the stand-by indicator 256 lights up if the driver is not in the seated state when the vehicle is stopped in the "engine-stopping & vehicle-starting mode", and flashes if the driver is in the seated state when the vehicle is stopped in the "engine-stopping & vehicle-starting mode. As a result, if the stand-by indicator 256 flashes, the driver can recognize that he or her can immediately start the vehicle by opening an accelerator grip even if the engine is in the stopping state. [0062] The ignition control unit 700 shown in FIG. 10 starts, stops, or withholds (prohibits) an ignition 37 operation by the ignitor 161 under a specific condition in each of the operational modes. [0063] An ignition-starting control unit 701 turns on an ignition-starting signal S7 01 ("H" level) in response to a specific vehicle-starting operation, to permit the ignition operation by the ignitor 161. An ignition-stopping control unit 7 02 turns on an ignition-stopping signal S702 in response to a specific vehicle-stopping condition, to stop the ignition operation by the ignitor 161. An ignition prohibiting control unit 703 turns on an ignition prohibiting signal S703 only in a specific period containing an ignition timing at which back-kick probably occurs, to prohibit the ignition operation by the ignitor 161 irrespective of the state of the ignition-starting signal S7 01. The operations of the control units 701, 702, and 703 will be described below with reference to a flowchart. [0064] An AND circuit 704 outputs a logic product of the ignition-starting signal S701 and a reversed signal of the ignition-stopping signal S702. An AND circuit 705 outputs a logic product of an output signal from the AND circuit 704 and a reversed signal of the ignition prohibiting signal S703. An OR circuit 706 outputs a logic sum of an output signal from the AND circuit 705 and a reversed signal of the operational mode signal S301. [0065] As described above, according to this embodiment, in the "engine-start & idle SW mode", since the level of the output signal from the OR circuit 706 usually becomes the "H" level, the ignition operation is usually permitted. On the contrary, in the "engine-stopping & vehicle-starting mode", the ignition operation is permitted only when the ignition-starting signal S701 is in the ON state and the ignition prohibiting signal S703 is in the OFF state. [0066] FIG. 20 is a flowchart showing an ignition-starting control process executed by the ignition-starting control unit 701. The ignition-starting control process is executed while being repeated at a specific cycle. [0067] In step S201, it is decided on the basis of an output signal from the throttle switch 257a whether or not the throttle grip is opened. If the throttle grip is opened, the process goes on to step S203. In step S203, it is decided on the basis of an output signal from the seated state detecting switch 254 whether or not the driver is in the seated state. If the driver is in the seated state, the process goes on to step S205 in which the ignition-starting signal S701 is turned on ("H" level), to permit the ignition operation by the ignitor 161. [0068] Even when it is decided in step S201 that the throttle grip is not opened, if in step S202, it is decided on the basis of a detection signal from the vehicular speed sensor 255 that the vehicular speed is larger than zero, the process goes on to step S203. If it is decided in step S203 that the driver is in the seated state, the process goes on to step S205 in which the ignition-starting signal S701 is turned on, to permit the ignition operation by the ignitor 161. [0069] If the throttle grip is not opened and the vehicular speed is zero, the process goes on to step S204 in which the ignition-starting signal S701 is turned off ("L" level), to prohibit the ignition operation by the ignitor 161. [0070] As described above, according to this embodiment, if the throttle grip is opened or the vehicular speed is larger than zero when the driver is being seated, the ignition-starting signal S701 is turned on, to permit the ignition operation by the ignitor 161. [0071] FIG. 21 is a flowchart of an ignition-stopping control process executed by the ignition-stopping control unit 702. The ignition-stopping control process is executed while being repeated at a specific cycle. [0072] If in step S211, it is decided on the basis of an output signal from the throttle switch 257a that the throttle grip is closed, the process goes on to step S212. If in step S212, it is decided on the basis of a detection signal from the vehicular speed sensor 255 that the vehicular speed is zero, the process goes on to step S213. If in step S213, it is decided on the basis of an output signal from the seated state detecting switch 254 that the driver is in the seated state, the process goes on to step S214. In step S214, if a timer is not started, the timer is started. [0073] After that, if in step S215, the time out (set to 3 sec in this embodiment) of the timer is detected, the 38 process goes on to step S216 in which the ignition-stopping signal S702 is turned on ("H" level). As a result, since the AND circuit 704 becomes a disable state, the level of an output signal from the AND circuit 7 04 becomes the "L" level, to prohibit the ignition operation by the ignitor 161. [0074] In addition, if either of the answers to steps S211, S212 and S213 is negative, the process goes on to step S217 in which the ignition-stopping signal S702 is turned off ("L" level), and thereby the AND circuit 704 becomes an enable state to continue the ignition operation of the ignitor 161. [0075] In accordance with this ignition-stopping control, if the driver is in the seated state when the throttle is returned and thereby the vehicle is stopped, the ignition-stopping signal S702 is turned on to close the AND circuit 704, whereby the ignition operation of the ignitor 161 is stopped. [0076] FIG. 22 is a flowchart showing an ignition prohibiting control process by the ignition prohibiting control unit 703. In this embodiment, in the case of stopping the engine on the basis of establishment of the engine-stopping condition, that is, on the basis of turn-on of the ignition-stopping signal S702, the ignition operation of the ignitor 161 is prohibited in the engine-stopping process from the operational state to the stopping state, to thereby prevent occurrence of back-kick. [0077] FIG. 23 is a graph illustrating the content of the ignition prohibiting control, wherein the abscissa is a stroke of the four-cycle engine and the ordinate is an engine speed Ne. In the graph, character "compression" designates the top dead center in a compression stroke, and character "exhaust" designates the top dead center in an exhaust stroke. [0078] Referring to FIG. 23, when the engine-stopping condition is established at a time to and the ignition-stopping signal S702 is turned on, the operation of the ignitor 161 is stopped and thereby the engine speed is started to be reduced. At this time, in step S221 shown in FIG. 22, it is decided on the basis of detection of, for example, the rise of the ignition-stopping signal S7 02 that the engine-stopping condition is newly established, and the process goes on to step S222. [0079] After that, when the engine speed Ne becomes lower than 800 rpm at a time t2 as shown by a solid line A in FIG, 23, the engine speed thus reduced is detected in step S222, and the process goes on to step S223. In step S223, the ignition prohibiting signal S703 is turned on ("H" level). As a result, the AND circuit 705 becomes a disable state as shown in FIG. 10, and accordingly, in the "engine-stopping & vehicle-starting mode", when the engine speed Ne becomes lower than 800 rpm, the ignition operation by the ignitor 161 is not prohibited even if the ignition-starting signal S701 is turned on in response to the starting operation. [0080] In addition, according to this embodiment, if the starting operation is performed before the engine speed becomes lower than 800 rpm in the engine-stopping process, it is not required to prohibit the ignition operation of the ignitor 161 because the next ignition timing comes before the engine speed becomes lower than a specific engine speed at which back-kick probably occurs and the engine speed is turned to be increased. [0081] 41 In step S224, it is decided on the basis of an output signal from the pulser 153 whether or not the ignition timing comes. If an ignition timing P2 comes, the process goes on to step S225 in which an ignition prohibiting counter "n" is incremented. In addition, at this time, since the ignition prohibiting signal S703 is turned on, the ignition at the ignition timing P2 is withheld (prohibited). In step S226, it is decided whether or not the count value of the ignition prohibiting counter "n" reaches three times. If the count number is less than three times, the process is returned to step S224 in which the count of the ignition timing is continued. [0082] After that, the ignition at each of ignition timings P3 and P4 is similarly withheld, and each ignition timing is counted. If the count number of the ignition prohibiting counter "n" reaches three times, the process goes on step S227 in which the ignition prohibiting signal S703 is turned off ("L" level). As a result, at the next ignition timing P5, the ignition operation of the ignitor 161 is permitted, and accordingly, if the starter motor 49 is driven in a state in which the vehicle-starting operation has been detected and thereby the ignition-starting signal S701 has been turned on, the engine is ignited to be started. In step S228, the ignition prohibiting counter "n" is reset. [0083] As described above, according to this embodiment, in the case of stopping the engine on the basis of the establishment of the engine-stopping condition, if the engine speed is lower than a specific value, the ignition operation is withheld by a specific number. Accordingly, even if the engine-starting operation is performed before the engine is stopped and the piston of the engine reaches an ignition position immediately before the top dead center at a low speed, the engine is not ignited, with a result that back-kick does not occur. [0084] In addition, in the case of measuring the engine speed Ne on the basis of a detection signal from the pulser 153, the measured value contains an error of measurement due to a difference among the kinds of engines and a rotational deviation tending to largely appear, particularly, in an engine having a small number of cylinders. As a result, the measured engine speed is in a range having a lower limit shown by a broken line B and an upper limit shown by a broken line C in FIG. 23. [0085] According to this embodiment, however, the ignition operation is withheld by three times after the engine speed becomes lower than 800 rpm. Accordingly, if the engine speed shown by the broke line B becomes lower than 800 rpm at a time tl, the ignition operation can be withheld at the next three ignition timings PI, P2 and P3, while if the engine speed shown by the broken line C becomes lower than 800 rpm at a time t3, the ignition operation can be withheld at the next three ignition timings P3, P4, and P5. As a result, even if the measured value of the engine speed contains an error of measurement, the ignition operation can be usually prohibited at the ignition timing P3 at which back-kick probably occurs, so that it is possible to positively prevent occurrence of back-kick. [0086] As described above, according to the ignition control unit 700 of this embodiment, since the output signal from the OR circuit 7 06 is usually set to the "H" level in the "engine-start & idle SW mode" as shown in FIG. 14, the ignition operation can be usually permitted. [0087] On the contrary, in the "engine-stopping & vehicle- 44 starting mode", when the vehicle is stopped and the engine is automatically stopped, the ignition operation is permitted if the throttle is opened or the vehicular speed becomes larger than zero when the driver is being seated; while when the vehicle is stopped from the running state, if the seated state of the driver is detected, the ignition operation is prohibited and thereby the engine is automatically stopped, and if the seated state of the driver is not detected, the ignition operation is continuously permitted and thereby the engine is not automatically stopped. [0088] Accordingly, when the seated state of the driver cannot be detected due to a failure of the seated state detecting switch 254, the engine is not automatically stopped even if the vehicle is stopped from the running state, so that it is not required to start the engine at the time of starting the vehicle. As a result, even if there occurs a failure of the seated state detecting switch 254 in the system of permitting automatic starting of the engine under the condition that the driver is being seated, there does not occur any inconvenience of the running of the vehicle. [0089] According to this embodiment, even if the seated state of the driver is detected when the vehicle is stopped from the running state, the ignition operation is not immediately prohibited, that is, prohibited after an elapse of a specific time (set to 3 sec in this embodiment). Accordingly, when the vehicle is temporarily stopped at a crossing or when the vehicle takes a U-turn (in this case, the driver is in the seated state, the vehicular speed is substantially zero, and the throttle opening is nearly full closed), it is possible to continue the engine-starting state. [0090] According to this embodiment, since the ignition operation by the ignitor 161 is prohibited in the engine-stopping process from the operational state to the stopping state, even if the vehicle-starting condition is established before the engine is perfectly stopped and also the piston of the engine reaches an ignition position immediately before the top dead center at a low speed, the engine is not ignited to thereby prevent occurrence of back-kick. [0091] In this embodiment, when the engine speed becomes lower than 800 rpm in the engine-stopping process, the ignition operation is withheld by three times; however, the present invention is not limited thereto. For example, the ignition operation may be withheld for a specific time from a point of time when the engine speed becomes lower than 800 rpm. [0092] In this embodiment, the ignition operation is withheld by three times; however, if the engine speed can be accurately measured, the ignition operation may be withheld by two times or one time, or if the engine speed cannot be accurately measured, the ignition operation may be withheld by four or more times. [0093] FIG. 24 is a flowchart showing another embodiment of the ignition prohibiting control process by the ignition prohibiting control unit 703, and FIG. 25 is a graph illustrating the content of the ignition prohibiting control. [0094] According to this embodiment, at a time to shown in FIG. 25, the engine-stopping condition is established and thereby the ignition-stopping signal S702 from the ignition-stopping control unit 702 is turned on. At this time, in step S241 shown in FIG. 24, it is decided that the engine-stopping condition is newly established on the basis of detection of, for example, the rise of the ignition-stopping signal S702, and the process goes on to step S242. [0095] After that, when the engine speed Ne becomes lower than a reference engine speed Nrefl (for example, 800 rpm) at a time tl, the engine speed thus reduced is detected in step S242, and the process goes on to step 5243. In step S243, the ignition prohibiting signal S703 is turned on ("H" level). As a result, the AND circuit 705 shown in FIG. 10 becomes a disable state. Accordingly, in the "engine-stopping & vehicle-starting mode", when the engine speed Ne becomes lower than 800 rpm, even if the ignition-starting signal S701 is turned on in response to the engine-starting operation, the ignition operation by the ignitor 161 is not permitted. [0096] On the other hand, when the vehicle-starting condition is established at a time t2 after stopping the engine, the ignition-starting signal S701 from the ignition-starting control unit 701 is turned on and also the starter motor 49 is driven. At this time, in step 5244, it is decided that the vehicle-starting condition is newly established on the basis of detection of, for example, the rise of the ignition-starting signal S701, and the process goes on to step S245. [0097] After that, when the engine speed He becomes higher than a reference engine speed Nref2 (for example, 400 rpm), the engine speed Ne thus increased is detected in step S245, and the process goes on to step S246. In step S246, the ignition prohibiting signal S703 is turned off ("L" level) . As a result, the AND circuit 705 shown in FIG. 10 becomes an enable state, to permit the ignition operation by the ignitor 161. Accordingly, the ignition operation is executed at an ignition timing (time t4), to start the engine. [0098] According to this embodiment, since the reference engine speed Nrefl for prohibiting the ignition in the engine-stopping process from the operational state to the stopping state is higher than the reference engine speed Nref2 for prohibiting the ignition at the engine-starting process, it is possible to effectively prevent occurrence of back-kick while suppressing the withholding (prohibiting) number of ignition at minimum. [0099] Referring again to FIG. 10, the ignition knocking control unit 200 executes a control for preventing occurrence of knocking by retarding the ignition timing at the time of acceleration more than the ignition timing at the time of usual rotation in each of the operational modes. In particular, according to this embodiment, the retarded amount of the ignition timing at the time of vehicle-starting acceleration from the engine-stopping state is larger than the retarded amount of the ignition timing at the time of usual acceleration from the engine rotating state, whereby occurrence of knocking at the time of vehicle-starting acceleration, which is inherent to the vehicle on which the engine automatic stopping/starting control system is mounted, can be perfectly prevented. [0100] A standard ignition timing represented by a degree of advance angle (deg) from the top dead center (TDC) in a compression stroke is previously registered, as the function of the engine speed Ne and the throttle opening degree 6, in a standard ignition timing determining unit 207. FIG. 16 is a diagram showing a relationship between the engine speed Ne and the throttle opening degree 6 , and the standard ignition timing according to this embodiment. The standard ignition timing is taken as 15 (advance angle) in an engine speed range of less than 2500 rpm, and is gradually increased depending on the engine speed Ne in a range of engine speed of 2500 rpm or over. [0101] If the engine speed Ne is in a range of 700 rpm engine speed Ne is in a range of 700 rpm If a rate of change A 6 of the throttle opening degree 0 detected by the throttle sensor 257 exceeds a specific value, an acceleration deciding unit 205 decides that the accelerating operation has been performed and outputs an acceleration detection signal of the "H" level. A water temperature deciding unit 206 decides the temperature of engine cooling water on the basis of a detection signal from the waster temperature sensor 155, and outputs a signal of the "H" level if the water temperature exceeds a specific temperature (50°C in this embodiment). [0103] An AND circuit 202 outputs a logic product of the usual acceleration signal Saccl, an acceleration detecting signal, a water temperature detection signal, and a reversed signal of the operational mode signal S301. An AND circuit 2 03 outputs a logic product of the vehicle-starting acceleration signal Sacc2, an acceleration detection signal, a water temperature decision signal, and the operational mode signal S301. [0104] If the level of each of output signals from the AND circuits 202 and 203 is the "L" level, that is, if the vehicle is not in the acceleration state, an ignition timing (upon acceleration) correcting unit 204 supplies the standard ignition timing determined by the standard ignition timing determining unit 207 (see FIG. 16) to the ignitor 161. The ignitor 161 executes the ignition operation at the ignition timing supplied from the ignition timing (upon acceleration) correcting unit 204. [0105] If the level of an output signal from the AND circuit 202 becomes the "H" level, that is, if in the "engine-start & idle SW mode" shown in FIG. 14, the engine speed Me is in the range of 700 rpm If the level of an output signal from the AND circuit 203 becomes the "H" level, that is, if in the "engine-stopping & vehicle-starting mode" shown in FIG. 14, the engine speed Ne is in the range of 700 rpm value, the ignition timing is retarded up to 0* (advance angle) irrespective of the result determined by the standard ignition timing determining unit.207 as shown by a solid line B in FIG. 17. [0107] The ignition timing (upon acceleration) correcting unit 204 has a counter 204a. If the level of either of output signals from the AND circuits 202 and 203 becomes the "H" level, the above-described retarded ignition is immediately executed by a specific number of times (three times in this embodiment) by means of the ignition timing (upon acceleration) correcting unit 204, and then the retarded ignition is immediately returned to the usual ignition timing determined by the standard ignition timing determining unit 207. [0108] According to this ignition knocking control, it is possible to make the retarded amount at the time of vehicle-starting acceleration different from the retarded amount at the time of usual acceleration from an intermediate rotational region. To be more specific, by setting the retarded amount at the time of vehicle-starting acceleration larger than the retarded amount at the time of usual acceleration from the intermediate rotational region, it is possible to prevent occurrence of knocking not only at the time of the usual acceleration from the intermediate rotational region but also at the time of vehicle-starting acceleration. [0109] In the head lamp control unit 800 shown in FIG. 11, an Ne deciding unit 801 decides, on the basis of a detection signal from the pulser 153, whether or not the engine speed is equal to or more than a specific setting speed (less than the idling speed) . If the engine speed is equal to or more than the setting speed, the Ne deciding unit 801 outputs a signal of the "H" level. An AND circuit 802 outputs a logic product of an output signal from the Ne deciding unit 801 and a reversed signal of the operational mode signal S301. An AND circuit 803 outputs a logic product of an output signal from the Ne deciding unit 801 and the operational mode signal S301. [0110] If the level of an output signal from the AND circuit 802 is the "H* level, a lighting/dimming switching unit 804 outputs a signal of the "H" level. If the level of the output signal from the AND circuit 802 is the "L" level, the lighting/dimming switching unit 804 outputs a pulse signal of a duty ratio of 50%. If the level of an output signal from the AND circuit 803 is the "H" level, a lighting/multi-stage dimming switching unit 805 outputs a signal of the "H" level. If the level of the output signal from the AND circuit 803 is the L level, a timer 805a counts the continuation time of the outputted signal of the "L" level and the lighting/multi¬stage dimming switching unit 805 outputs a pulse signal of a duty ratio which is gradually reduced depending on the continuation time of the outputted signal of the "L" level. In this embodiment, the duty ratio is stepwise reduced from 95% to 50% with a stepwise period taken as 0.5 to 1 second. With such a stepwise dimming manner, since the quantity of light is instantly, linearly reduced, it is possible to achieve power-saving and to ensure a high commercial value. [0111] According to this head lamp control, as shown in FIG. 13, the head lamp is lighted or dimmed depending on the engine speed Ne in the "engine-start & idle SW mode", and is lighted and stepwise dimmed depending on the engine speed Ne in the "engine-stopping & vehicle-starting mode". Accordingly, it is possible to suppress the discharge of the battery at the time of vehicle stoppage while sufficiently keeping the visibility from a vehicle running in the opposed direction. As a result, the charged amount from the AC generator into a battery is reduced at the time of the subsequent vehicle-starting operation, to reduce an electronic load of the AC generator, thereby enhancing the acceleration performance at the time of starting vehicle. [0112] In the by-starter control unit 900 shown in FIG. 11, a detection signal from the water temperature sensor 155 is inputted in a water temperature deciding unit 901. If the water temperature becomes equal to or more than a first predetermined value (50°C in this embodiment), the water temperature deciding unit 901 outputs a signal of the "H" level to close the by-starter relay 164, and if the water temperature becomes equal to or than a second predetermined value (10°C in this embodiment), the water temperature deciding unit 901 outputs a signal of the "L" level to open the by-starter relay 164. [0113] According to this by-starter control, as the water temperature becomes higher, fuel becomes denser, and as the water temperature becomes lower, the fuel automatically becomes thinner. In this embodiment, since the opening/closing temperature of the by-starter relay 164 has hysteresis, it is possible to prevent an unnecessary opening/closing operation of the by-starter relay 164, which operation may be caused near a critical temperature. [0114] In the charging control unit 500 shown in FIG. 11, both a detection signal from the vehicular speed sensor 255 and a detection signal from the throttle sensor 257 are inputted in an acceleration operation detecting unit 502. As shown in FIG. 14, if the vehicular speed is larger than zero and the throttle is changed from the full-closed state to the full-opened state for 0.3 second or less, the acceleration detecting unit 502 decides that the acceleration operation is performed, and outputs an acceleration detecting pulse. [0115] A charging (upon acceleration) restricting unit 504 controls the regulator rectifier 167 in response to the acceleration detecting pulse signal to reduce a charging voltage of the battery 168 from a usual voltage (14.5 V) to 12.0 V. [0116] The charging (upon acceleration) restricting unit 504 starts a six-second timer 504a in response to the acceleration detecting pulse. If the timer 504a times out, the engine speed Ne becomes equal to or more than a setting speed, or the throttle opening degree is reduced, the charging restriction is released to return the charging voltage from 12.0 V to 14.5 V. 58 [0117] Detection signals from the vehicular speed sensor 255, the pulser 153, and the throttle sensor 257 are inputted in a vehicle-starting operation detecting unit 503. As shown in FIG. 14, if the vehicular speed is zero and the throttle is opened when the engine speed Ne is equal to or less the setting speed (2500 rpm in this embodiment), the vehicle-starting operation detecting unit 503 decides that the vehicle-starting operation is performed, and outputs a vehicle-starting operation detecting pulse. [0118] When detecting the vehicle-starting operation detecting pulse signal, a charging (upon vehicle-starting) restricting unit 505 controls the regulator rectifier 167 to reduce the charging voltage of the battery 168 from the usual voltage (14.5 V) to 12.0 V. [0119] The charging (upon vehicle-starting) restricting unit 505 starts a seven-second timer 505a in response to the vehicle-starting operation detecting pulse. If the timer 505a times out, the engine speed Ne becomes equal to or more than the setting speed, or the throttle opening degree is reduced, the charging restriction is released to return the charging voltage from 12.0 V to 14.5 V. [0120] According to this charging control, when the throttle is rapidly opened by the driver to effect rapid acceleration or when the vehicle is started from the stopping state, the charging voltage is suppressed at a low value to temporarily reduce the electric load of the AC generator 172. Accordingly, it is possible to reduce the mechanical load of the engine 200' applied from the AC generator 172 and hence to improve the accelerating performance. [0121] The engine-starting (in non-seated state after vehicle-stopping) control unit 100 shown in FIG. 12 exceptionally permits, the starting of the engine by the starter switch 258 which is basically prohibited, with a timing where the driver can experimentally start the engine by the starter switch. [0122] An AND circuit 102 outputs a logic product of the operational mode signal S301 and a reversed signal of an output signal from the seated state detecting switch 254. A non-seated state continuation deciding unit 101 has a timer 101a and detects, after automatic stopping of the engine, the "H" level of an output signal from the AND circuit 102 for a specific time or more. To be more specific, if in the "engine-stopping & vehicle-starting mode", the non-seated state of the driver is continued for a specific time or more after automatic stopping of the engine, the level of the output signal is set to the "H" level. As a result, the ignitor 161 is energized to become an ignition permissible state. [0123] An OR circuit 103 outputs a logic sum of output signals from the starter switch 258 and the throttle switch 257a. An AND circuit 104 generates a logic product of output signals from the non-seated state continuation deciding unit 101 and the OR circuit 103, and outputs the logic product to the starter relay 162. To be more specific, if the starter switch 258 is turned on or the throttle is opened after the non-seated state of the driver is continued for a specific time or more after automatic stopping of the engine in the "engine-stopping & vehicle-starting mode" (the level of an output signal from the non-seated state continuation deciding unit 101 becomes the "H" level), the starter relay 162 is energized to drive the starter motor 49. At this time, 61 since the ignitor 161 is energized by the non-seated state continuation deciding unit 101, the starting of the engine can be performed. [0124] According to this engine-starting control in the non-seated state after stopping the vehicle, even after the engine is stopped in response to the specific vehicle-stopping condition, the starting of the engine is exceptionally permitted by the starter switch 258 if it is detected that the non-seated state of the driver is continued for the specific time. Accordingly, if the driver leaves, after automatically stopping the engine at the time of stopping the engine, the vehicle without cutting-off the main power source, and after coming back to the vehicle, he or she forgets that the engine is under the automatic stopping control and operates the starter switch 258, the driver can still start the engine in the same manner as that in the usual state in which the engine is not under the automatic stopping control. [0125] In the above-described engine-starting control in the non-seated state after stopping the vehicle, the starting of the engine by the starter switch 258 is exceptionally permitted under the condition that the non- seated state of the driver is continued for the specific time or more after automatic stopping of the engine in the "engine-stopping & vehicle-starting mode"; however, as shown by a broken line in FIG. 12, the starting of the engine by the starter switch 258 may be permitted by controlling the operation switching unit 300 to switch the operational mode from the "engine-stopping & vehicle-starting mode" to the "engine-start & idle SW mode". Alternatively, as shown by the "condition 5" in FIG. 15, the starting of the engine by the starter switch 258 may be substantially permitted by cutting off the main switch 173. [0126] FIG. 3 is a sectional view showing a second embodiment of the swing unit 17. In the figure, parts corresponding to those described above are designated by the same reference numerals. [0127] In the above-described first embodiment, the sprocket 58 coupled to the starter motor 49 is connected to the outer rotor 42 of the generation unit 44 via the one-way clutch 50; however, in this embodiment, a sprocket 58 is connected to a crankshaft 12 via a one-way clutch 50 having the same function as that of the one-way clutch 50 in the previous embodiment at a position between a pulley 83 and a main bearing 10 on the side opposed to a generation unit 44 with respect to a crank chamber 9. [0128] The one-way clutch 50 includes one sleeve 57b fixed to the crankshaft 12, the other sleeve 55b for supporting the sprocket 58 rotatably relative to the crankshaft 12, and a clutch portion 56b for connecting the sleeves 55b and 57b to each other in such a manner as to prevent idling of the crankshaft 12 in the reversed direction relative to the sprocket 58 and permit idling of the crankshaft 12 in the normal direction relative to the sprocket 58. [0129] According to this embodiment, since the sprocket 58 for transmitting a drive force of the starter motor 49 to the crankshaft 12 is provided at a position offset to the side of the pulley 83 of the automatic transmission from the crank chamber 9, the length of a portion of the crankshaft 12 on the automatic transmission side with respect to the crank chamber 9 becomes longer than the length of a portion of the crankshaft 12 on the generation unit side with respect to the crank chamber 9. Accordingly, the center of the heavy engine can be located at the center of a tire, that is, the center of the vehicle, so that a torsional force or a moment is less applied to the swing unit 17, with a result that a weight distribution is improved and thereby the running stability is enhanced. [0130] Further, according to this embodiment, since the sprocket 58 coupled to the starter motor 49 is connected to the crankshaft 12 at a position apart from a tire 21 in the axial direction of the crankshaft 12, the diameter of the sprocket 58 can be enlarged, to obtain a large reduction ratio, thereby reducing the size and weight of the starter motor 49. {0131] FIG. 4 is a sectional view of a third embodiment of the swing unit 17. In the figure, parts corresponding to those described above are designated by the same reference numerals. [0132] In this embodiment, one sleeve 57c, on the crankshaft side, of a one-way clutch 50 is integrally formed on the back surface, being not in contact with a V-belt 82, of a fixed pulley piece 83a, and the other sleeve 55c is fixed to a flange portion 83d extending axially outwardly from the fixed pulley piece 83a, so that a sprocket 58 is connected to an end portion of a crankshaft 12 via both the one-way clutch 50 and the fixed pulley piece 83a. [0133] According to this embodiment, since the sprocket 58 and a chain 40 therefor are mounted to the outermost portion of the crankshaft 12, they can be easily mounted and dismounted. Accordingly, it is possible to facilitate the maintenance of the sprocket 58 and the chain 40 therefor, and to mount the sprocket 58 and the chain 40 therefor to an existing swing unit only by simple modification. [0134] Further, according to this embodiment, like the second embodiment, since the sprocket 58 is connected to the crankshaft 12 at a position apart from the time 21 in the axial direction of the crankshaft 12, the diameter of the sprocket 58 can be enlarged, to obtain a large reduction ratio, thereby reducing the size and weight of the starter motor 49. [0135] FIG. 6 is a sectional view of an essential portion of a fourth embodiment of the swing unit 17, and FIG. 7 is a sectional view, taken on a plane perpendicular to a crankshaft 12, showing the swing unit 17. In these figures, parts corresponding to those described above are designated by the same reference numerals. [0136] According to the first, second and third embodiments, in order to reduce noise occurring at the time of starting the engine, the sprocket 58 provided on the crankshaft 12 is connected to the starter motor 49 via the chain 40. On the contrary, according to this embodiment, a sprocket 58 is usually connected to a starter motor 49 via a gear train, and simultaneously the sprocket 58 is connected to a crankshaft 12 via a one-way clutch 50 as described above. Accordingly, the power transmission from the crankshaft 12 side to the starter motor 49 side is cut off without use of any ratchet. With this configuration, since the starter motor is connected to the crankshaft in one direction without use of any ratchet, it is possible to reduce noise at the time of starting the engine. [0137] Referring to FIGS. 6 and 7, gear teeth 221 are formed on the rotational shaft of the starter motor 49, 7 and the teeth of a large-diameter gear 222 connected to a drive shaft 234 are meshed with the gear teeth 221. A small-diameter gear 223 is coaxially formed on the drive shaft 234 at a position adjacent to the large-diameter gear 222, and the sprocket 58 connected to the crankshaft 12 is meshed with the small-diameter gear 223. [0138] To prevent an increase in noise due to sliding wear of the drive shaft 234 and looseness caused by such sliding wear, particularly, for an engine starter used at a high frequency, the drive shaft 234 is rotatably supported by a pair of oil impregnation bush type bearings 234a and 234b on both sides of the drive shaft 234 with the large-diameter gear 222 and the small-diameter gear 223 put therebetween. Further, according to this embodiment, in order to suppress noise generated from the above-described gear train, the gear teeth meshed with each other are subjected to shaving or grinding. [0139] By the way, in this embodiment, since the sprocket 58 provided on the crankshaft 12 is usually connected to the starter motor 49 via the fixed gear train without use of any ratchet, it is required to additionally provide a configuration for permitting the power transmission from the starter motor 49 side to the crankshaft 12 side but prohibiting the power transmission from the crankshaft 12 side to the starter motor 49 side. To meet such a requirement, in this embodiment, the sprocket 58 is connected to the crankshaft 12 via the one-way clutch 50 as described above. [0140] Accordingly, at the time of starting the engine, when the starter motor 49 is driven to rotate the sprocket 58 in the normal direction of the crankshaft 12, the crankshaft 12 is correspondingly driven in the normal direction. On the contrary, after starting the engine, even if the starter motor 49 is stopped, the crankshaft 12 is idled relative to the sprocket 58, so that the drive force of the crankshaft 12 is not transmitted to the starter motor 49. [0141] As described above, according to this embodiment, the starter motor 49 is connected to the crankshaft 12 without use of any ratchet, and consequently, since there does not occur any noise caused by operation of the ratchet, it is possible to reduce noise at the time of starting the engine. [0142] [Effect of the Invention] The present invention exhibits the following effects: [0143] (1) In the case of stopping the engine on the basis of establishment of an engine-stopping condition, if the engine speed becomes lower than a specific engine speed, the ignition operation is prohibited by a specific number, and accordingly, even if the vehicle-starting operation is performed before the engine is stopped and the piston of the engine reaches an ignition position immediately before the top dead center at a low speed, the engine is not ignited, to thereby prevent occurrence of back-kick. [0144] (2) Since the reference engine speed Nrefl for prohibiting ignition in the engine-stopping process from the operational state to the stopping state is higher than the reference engine speed Nref2 for prohibiting ignition in the engine-starting process, it is possible to effectively prevent occurrence of back-kick while suppressing the withholding (prohibiting) number of ignition at minimum. 70 WE CLAIM: 1. An engine starter for a vehicle, which includes a starter motor for cranking an engine in response to a specific engine-starting operation, and an ignitor for igniting said engine at a specific rotational angle in response to said engine-starting operation, said engine starter being characterized by including ignition prohibiting control unit for prohibiting an ignition operation of said ignitor in an engine-stopping process from an operational state to a stopping state; and wherein said ignition prohibiting control unit prohibits ignition operation of said ignitor if an engine speed is equal to or less than a first engine speed in an engine-stopping process from an operational state to a stopping state, and prohibits the ignition operation of said ignitor if the engine speed is equal to or less than a second engine speed in an engine-starting process from a stopping state, wherein said first engine speed is higher than said second speed. 2. An engine starter for a vehicle as claimed in claim 1, wherein said engine starter further includes ignition control unit for stopping the ignition operation of said ignitor in response to a specific vehicle-stopping condition during running of the vehicle, and restarting the ignition operation of said ignitor in response to a specific vehicle-starting operation after stopping the ignition operation of said ignitor. 3. An engine starter for a vehicle substantially as herein described with reference to the accompanying drawings. Dated this 6th day of August, 2001. (RITUSHKA NEGI) OF REMFRY &«AGAR ATTORNEY FOR THE APPLICANT[S] 72

Full Text

FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
& THE PATENTS RULES, 2003 COMPLETE SPECIFICATION
[See Section 10; rule 13]
"AN ENGINE STARTER FOR A VEHICLE"
HONDA MOTOR CO., LTD., a corporation of Japan, of 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan,
The following specification particularly describes the invention and the manner in which it is to be performed:

GRANTED
20-4-2006

The present invention relates to an engine starter for a vehicle.
The present invention relates to an engine starter for a vehicle, which is for starting the engine by making use of a starter motor, and particularly to an engine starter for a vehicle, which is suitable for a vehicle including an engine automatic stopping/starting system for automatically stopping the engine in response to a specific vehicle-stopping condition during running of the vehicle and restarting the engine in response to a specific vehicle-starting condition after stopping the engine. [0002] [Prior Art]
In the case of starting an engine, an ignitor starts its ignition operation simultaneously with an operation of starting a starter motor. Accordingly, in this case, if the ignition operation is performed in an initial state of drive of the engine, that is, at a point of time when an engine speed is very low, the piston of the engine is pushed down- with an exploded force caused by the ignition operation before it reaches the top dead center, with a result that a load is applied to the
2

starter motor and simultaneously noise occurs. Such a phenomenon is generally called "back-kick". [0003]

To reduce noise due to such back-kick occurring at the time of starting the engine, a technique for prohibiting an operation of an ignitor until an engine speed reaches a specific value has been proposed, for example, in Japanese Patent Laid-open No. Sho 60-187766 oryJLei 2-1473.
[Problem to be Solved by the Invention]
According to the above-described prior art, an engine speed is measured when a starting operation is detected, and if the engine speed is equal to or more than a specific value, the operation of the ignitor is permitted. In this prior art, since it is assumed that the engine is usually started from its stopping state, the engine speed is gradually increased along with cranking by a starter motor. Accordingly, if the measured engine speed is equal to or more than the specific value, the engine speed at the subsequent actual ignition timing is usually higher than the specific value, with a result that it is possible to effectively prevent occurrence of back-kick.
3

[0005]
On the contrary, if the engine-starting operation is performed in an engine-stopping process from the operational state to the stopping state, the ignition operation is permitted because the engine speed at the measurement timing is equal to or more than the specific value; however, since the engine speed may be often lower than the specific value at the subsequent actual ignition timing, there may occur back-kick.
[0006]
On the other hand, from the viewpoints of environment protection and energy-saving, vehicles including engine automatic stopping/starting systems have been developed and put on the market. The engine automatic stopping/starting system is operated to stop an ignition operation of an engine ignitor in response to a specific vehicle-stopping condition during running of a vehicle and to restart the ignition operation in response to a specific vehicle-starting operation after interruption of the ignition operation. In the vehicle including such an engine automatic stopping/starting system, since an engine-starting operation may be sometimes performed in an engine-stopping process from the operational state to the stopping state, there is a

possibility of occurrence of back-kick. [0007]
An object of the present invention is to solve the above-described problem of the prior art, and to provide an engine starter capable of preventing occurrence of back-kick at the time of starting an engine, thereby suppressing noise occurring at the time of starting the engine at a low value. [0008] [Means for Solving the Problem]
To achieve the above object, according to the present invention, there is provided ah engine starter for a vehicle, which includes a starter motor for cranking an engine in response to a specific engine-starting operation, and an ignitor for igniting the engine at a specific rotational angle in response to the engine-starting operation. The engine starter is characterized as follows: [0009]
(1) The engine starter includes ignition prohibiting means for prohibiting an ignition operation of the ignitor in an engine-stopping process from an operational state to a stopping state. [0010]

(2) The engine starter includes ignition prohibiting means for prohibiting an ignition operation of the ignitor if an engine speed is equal to or less than a first engine speed in an engine-stopping process from an operational state to a stopping state, and prohibiting the ignition operation of the ignitor if the engine speed is equal to or less than a second engine speed in an engine-starting process from a stopping state, wherein the first engine speed is higher than the second engine speed. [0011]
With the above-described feature (1), since the operation of the ignitor is prohibited in the engine-stopping process from the operational state to the stopping state, even if the engine-starting operation is performed in the engine-stopping process and the piston of the engine reaches an ignition position immediately before the top dead center at a low speed, the engine is not ignited, to thereby prevent occurrence of back-kick. [0012]
With the above-described feature (2), since the upper limit of the engine speed, at which the ignition operation of the ignitor is prohibited, in the engine-stopping process is set to be higher than that in the

engine-starting process, it is possible to positively prevent occurrence of back-kick not only in the engine-starting process but also in the engine-stopping process while suppressing the prohibiting number of the ignition operation at minimum.
The present invention relates to an engine starter for a vehicle, which includes a starter motor for cranking an engine in response to a specific engine-starting operation, and an ignitor for igniting said engine at a specific rotational angle in response to said engine-starting operation, said engine starter being characterized by
including ignition prohibiting means for prohibiting an ignition operation of said ignitor in an engine-stopping process from an operational state to a stopping state; and
wherein said ignition prohibiting means prohibits ignition operation of said ignitor if an engine speed is equal to or less than a first engine speed in an engine-stopping process from an operational state to a stopping state, and prohibits the ignition operation of said ignitor if the engine speed is equal to or less than a second engine speed in an engine-starting process form a stopping state,
wherein said first engine speed is higher than said second speed.

[Brief Description of the Drawings] [FIG. 1]
FIG. 1 is a sectional view of a first embodiment of a swing unit of a vehicle including an engine automatic stopping/starting system. [FIG. 2]
FIG. 2 is a sectional view, taken on a plane perpendicular to a crankshaft, showing the swing unit of the first embodiment. [FIG. 3]
FIG. 3 is a sectional view of a second embodiment of a swing unit of a vehicle including an engine automatic stopping/starting system. [FIG. 4]
FIG. 4 is a sectional view of a third embodiment of a swing unit of a vehicle including an engine automatic stopping/starting system. [FIG. 5]
FIG. 5 is a side view of a motorcycle on which an engine automatic stopping/starting system is mounted. [FIG. 6]
FIG. 6 is a sectional view of a fourth embodiment of a swing unit of a vehicle including an engine automatic stopping/starting system.
8

[FIG. 7]
FIG. 7 is a sectional view, taken on a plane perpendicular to a crankshaft, showing the swing unit of the fourth embodiment. [FIG. 8]
FIG. 8 is a block diagram showing an engine automatic stopping/starting system according to one embodiment of the present invention. [FIG. 9]
FIG. 9 is a block diagram showing the function of a main control unit (part 1). [FIG. 10]
FIG. 10 is a block diagram showing the function of the main control unit (part 2) . [FIG. 11]
FIG. 11 is a block diagram showing the function of the main control unit (part 3). [FIG. 12]
FIG. 12 is a block diagram showing the function of the main control unit (part 4). [FIG. 13]
FIG. 13 is a list of main operations of the main control unit (part 1). [FIG. 14]

FIG. 14 is a list of the main operations of the main control unit (part 2). [FIG. 15]
FIG. 15 is a diagram showing conditions for switching operational modes from each other. [FIG. 16]
Fig. 16 is a diagram showing a relationship between
an engine speed Ne and a throttle opening degree 6 , and a standard ignition timing. [FIG. 17]
Fig. 17 is a graph showing a relationship between an engine speed and an ignition timing. [FIG. 18]
FIG. 18 is a timing chart showing an operation of a starting signal extending unit shown in FIG. 9. [FIG. 19]
FIG. 19 is a diagram showing a method of determining an extension of a starting time by the starting signal extending unit shown in FIG. 9. [FIG. 20]
FIG. 20 is a flowchart showing an operation of an ignition-starting control unit. [FIG. 21]
FIG. 21 is a flowchart showing an operation of an
10

ignition-stopping control unit. [FIG. 22]
FIG. 22 is a flowchart showing an ignition prohibiting control process performed by an 'ignition prohibiting control unit. [FIG. 23]
FIG. 23 is a graph illustrating the content of the ignition prohibiting control process performed by the ignition prohibiting control unit shown in Fig. 22. [FIG. 24]
FIG. 24 is a flowchart showing another embodiment of the ignition prohibiting control process performed by the ignition prohibiting control unit. [FIG. 25]
FIG. 25 is a graph showing the content of the ignition prohibiting control process performed by the ignition prohibiting control unit shown in FIG. 24.
11

{Mode for Carrying Out the Invention]
Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 5 is a side view showing an entire configuration of a motorcycle on which an engine-stopping/starting control unit of the present invention is mounted. A body front portion 2 is joined to a body rear portion 3 via a low floor portion 4. The skeleton of a vehicular body is configured by a body frame including a down tube 6 and a main pipe 7. A fuel tank and a luggage box (both not shown) are supported by the main pipe 7, and a seat 8 is disposed over the fuel tank and the luggage box. The seat 8 serves as a lid of the luggage box provided under the seat 8. The luggage box is openable/closable by a hinge mechanism provided on a front portion FR of the luggage box. [0014]
A steering head 5 is provided on an end portion, on
12

the body front portion 2 side, of the down tube 6. A front fork 12A is rotatably supported by the steering head 5. A handlebar 11A is mounted on an upwardly extending upper end of the front fork 12A, and a front wheel 13A is rotatably supported by lower ends of the front fork 12A. An upper portion of the handlebar 11A is covered with a handle cover 33 serving as an instrument panel. [0015]
A link member (hanger) 37 is turnably supported by a mid point of the main pipe 7. A swing unit 17 is swingably connected to and supported by the main pipe 7 via the hanger 37. A single-cylinder/four-cycle engine 200' is mounted in a front portion of the swing unit 17. A belt-type continuously variable transmission 35 is provided in a portion, extending rearwardly from the engine 200', of the swing unit 17. A speed reduction mechanism 38 is provided on a rear portion of the belt-type continuously variable transmission 35 via a centrifugal clutch. A rear wheel 21 is rotatably supported by the speed reduction mechanism 38. A rear cushion 22 is interposed between an upper end of the speed reduction mechanism 38 and an upper bent portion of the main pipe 7.

13

[0016]
An intake pipe 23 extending from a cylinder head 32 of the engine 200' is connected to the front portion of the swing unit 17. A carburetor 24 is connected to the intake pipe 23, and an air cleaner 25 is connected to the carburetor 24. A pivot 18 is provided on a lower portion of a swing unit case 31, and a main stand 26 is pivotably mounted to the main stand 26. The main stand 26 is raised at the time of parking of the vehicle (the raised state of the main stand 26 is shown by chain lines in FIG. 5).
[0017]
FIG. 1 is a sectional view, taken on line A-A of FIG. 5, showing a first embodiment of the swing unit 17, and FIG. 2 is a sectional view, taken on a plane perpendicular to a crankshaft of the engine, showing the swing unit 17. The swing unit 17 includes the engine 200' positioned on the front side of the vehicular body, a generator portion G connected to one end of a crankshaft 12, and a drive portion ATI and a driven portion AT2 of an automatic transmission connected to the other end of the crankshaft 12.
[0018]
The crankshaft 12 is rotatably supported by the swing unit case 31 via main bearings 10 and 11. A

connecting rod 14 is connected to the crankshaft 12 via a crank pin 13. A generator unit 44 is provided on one end, projecting from a crank chamber 9, of the crankshaft 12. [0019]
One sleeve 57a (on the crankshaft side) of a one way clutch 50 is fixed to an outer rotor 42 of the generator unit 44 by means of a screw 43. The other sleeve 55a (on the sprocket side) of the one-way clutch 50 is rotatably supported, together with a sprocket 58, by the crankshaft 12 at a position between the generator unit 44 and the main bearing 11. A chain 40 for transmitting a starting torque from a starter motor 49 shown in FIG. 2 is wound around the sprocket 58. [0020]
A clutch portion 56a of the one-way clutch 50 prohibits idle rotation of the outer rotor 42 of the generator unit 44, that is, the crankshaft 12 in the reversal rotational direction relative to the sprocket 58, but permits idle rotation of the outer rotor 42 in the normal rotational direction. Accordingly, when the starter motor 49 is driven to drive the sprocket 58 in the normal rotational direction of the crankshaft 12 at the time of starting the engine, the crankshaft 12 is correspondingly driven in the normal rotational direction.

[0021]
On the contrary, after starting the engine, since the crankshaft 12 is idled relative to the sprocket 58 even when the starter motor 49 is stopped, a drive force of the crankshaft 12 is not transmitted to the starter motor 49.
[0022]
A sprocket 59 is fixed on the crankshaft 12 at a position between the sprocket 58 and the main bearing 11. A chain 60 for transmitting a power for driving a camshaft 69 from the crankshaft 12 is wound around the sprocket 59. In addition, the sprocket 59 is integrated with a gear 61 for transmitting a power to a pump (not shown) for circulating lubricating oil.
[0023]
A piston 63 disposed in a cylinder 62 is connected to a small-diameter end of the connecting rod 14. An ignition plug 65 is screwed in the cylinder head 32 in such a manner that an electrode portion of the ignition plug 65 faces to a combustion chamber formed between the head of a piston 63 and the cylinder head 32. The periphery of the cylinder 62 is surrounded by a water jacket 66.
[0024]

The camshaft 69 is rotatably supported by a portion, over the cylinder 62, in the cylinder head 32. A cam sprocket 72 is fixed to the camshaft 69. The above-described chain 60 is wound around the cam sprocket 72. The chain 60 acts to transmit the rotation of the sprocket 59, that is, the rotation of the crankshaft 12 to the camshaft 69. [0025]
Rocker arms 73 are provided on an upper portion of the camshaft 69. When the camshaft 69 is rotated, the rocker arms 73 are rocked while following the cam shape of the camshaft 69. The cam shape of the camshaft 69 is determined in such a manner that intake/exhaust valves 95 and 96 are opened/closed in accordance with a specific stroke of the four-cycle engine. [0026]
A pulley 83, around which a V-belt 82 is wound, is provided on an end portion, on the side opposed to the side provided with the generator unit 44, of the crankshaft 12. The pulley 83 is composed of a fixed pulley piece 83a fixed relative to the crankshaft 12 in both the rotational direction and the axial direction, and a movable pulley piece 83b slidable relative to the crankshaft 12 in the axial direction. A holder plate 84
17

is mounted to the back surface, being not in contact with the V-belt 82, of the movable pulley piece 83b. The motion of the holder plate 84 relative to the crankshaft 12 in both the rotational direction and the axial direction is restricted. That is to say, the holder plate 84 is rotated integrally with the crankshaft 12. A pocket for containing a roller 85 as a governor weight is formed in a space surrounded by the holder plate 84 and the movable pulley piece 83b. [0027]
A fan 83c is integrally formed on the back surface, being not in contact with the V-belt 82, of the fixed pulley piece 83a. An air cleaner cover 70 including an air cleaner 71 for cleaning cooling wind and introducing it in an automatic transmission chamber is mounted to an opening portion, facing to the fan 83c, of the swing unit case 31. When the crankshaft 12 is normally rotated, the fan 83c sucks outside air in the automatic transmission chamber via the air cleaner 71. [0028]
At the driven portion AT2 of the automatic transmission, a fixed pulley piece 132a of a pulley 132 is supported by a main shaft 125 of a clutch. A cup-shaped clutch plate 134 is fixed to an end portion of the

main shaft 125 by means of a nut 133. A movable pulley piece 132b of the pulley 132 is provided on a sleeve 135 of the fixed pulley piece 132a in such a manner as to be slidable in the longitudinal direction of the main shaft 125. The movable pulley piece 132b is engaged with a disk 136 in such a manner as to be rotatable integrally therewith around the main shaft 125. A compression coil spring 137 is provided between the disk 136 and the movable pulley piece 132b, wherein the repulsive force of the compression coil spring 137 acts to extend the distance between the disk 136 and the movable pulley piece 132b. The main shaft 125, an idle shaft 142, and an output shaft 145 are meshed with each other, and a rim 21a of the rear wheel 21 is fixed to the output shaft 145. [0029]
As described above, according to this embodiment, the starter motor 49 is connected to the crankshaft 12 via the chain 40 as endless connecting means and thereby the crankshaft 12 is driven via the chain 40 at the time of starting the engine. Accordingly, noise caused by rotation of the starter motor 49 at the time of starting the engine can be made smaller than that in the prior art configuration. [0030]

When the generator unit 44 and the pulley 83 of the automatic transmission are provided on both sides of the crankshaft 12 with the crank chamber 9 put therebetween as in this embodiment, an axial region of the crank shaft 12 occupied by the pulley 83 of the automatic transmission becomes larger than an axial region of the crankshaft.12 occupied by the generator unit 44. As a result, the length of a portion of the crankshaft 12 on the pulley 83 side with respect to the crank chamber 9 becomes longer than the length of a portion of the crankshaft 12 on the generation unit 44 side with respect to the crank chamber 9. According to this embodiment, however, since the sprocket 58 and the one-way clutch 50 therefor are provided on the generation unit 44 side, the lengths of the portions of the crankshaft 12 on both the sides of the crank chamber 9 can be substantially equal to each other, with a result that the rotational balance of the crankshaft 12 can be stabilized. [0031]
Further, according to this embodiment, since the chain 40 for connecting the crankshaft 12 to the starter motor 49 and the chain 60 for connecting the crankshaft 12 to the camshaft 69 are collectively provided on one side of the engine, it is possible to improve the

maintenance performance for the chains 40 and 60. [0032]
An automatic engine-stopping/starting control system to which the present invention is applied will be described below. The system includes an idling permitting mode (hereinafter, referred to as "engine-start & idle switch (SW) mode"), and an idling restricting (or prohibiting) mode (hereinafter, referred to as "engine-stopping & vehicle-starting mode"). [0033]
In the "engine-start & idle switch (SW) mode" which permits idling, idling is temporarily permitted after a main power source is turned on and then the engine is initially started for performing warm-up operation at the time of starting the engine, and further, idling is permitted by the intention of the driver, that is, by turning on the idle switch (SW) even in the case other than the above-described idling after the initial starting of the engine. [0034]
In the "engine-stopping & vehicle-starting mode" which restricts idling, when the vehicle is stopped, the engine is automatically stopped, and when an accelerator is operated in the engine-stopping state, the engine is

automatically restarted to start the vehicle. [0035]
FIG. 8 is a block diagram showing an entire configuration of an engine-starting/stopping control system. In the figure, parts corresponding to those described above are designated by the same reference numerals. [0036]
An AC generator 172 is provided on the crankshaft 12 in such a manner as to be coaxial therewith. A power generated by the AC generator 172 is charged in a battery 168 via a regulator rectifier 167. The regulator rectifier 167 controls a voltage outputted from the AC generator 172 to a value between 12 V and 14.5 V. The battery 168 supplies, when a starter relay 162 is conducted, a drive current to the starter motor 49, and

supplies a load current to various kinds of general electrical equipment 174, a main control unit 160, and the like via a main switch 173. [0037]
A pulser 153, an idle switch 253, a seated state detecting switch 254, a vehicular speed sensor 255, a stand-by indicator 256, a throttle sensor 257, a starter switch 258, a stop switch 259, a battery indicator 276,

and a water temperature sensor 155 are connected to the main control unit 160. The pulser 153 detects an ignition timing and an engine speed Ne. The idle switch 253 permits or restricts idling of the engine 200' in accordance with the intention of the driver. The seated state detecting switch 254 closes a contact and outputs a signal of the "H" level when the driver is seated. The vehicular speed sensor 255 detects the vehicular speed. The stand-by indicator 256 flashes in the "engine-stopping & vehicle-starting mode". The throttle sensor 257 (including a throttle switch 257a) detects a throttle opening degree 6 . The starter switch 258 drives the starter motor 49 to crank the engine 200'. The stop switch 259 outputs a signal of the "H" level in response to braking operation. The battery indicator 276 lights up when the voltage of the battery 168 is reduced to a predetermined value (for example, 10 V) or less to warn the driver of the shortage of the charged amount of power in the battery 168. The water temperature sensor 155 detects the temperature of cooling water for the engine. [0038]
An ignitor (including an ignition coil) 161, a control terminal of the starter relay 162, a control terminal of a head lamp driver 163, and a control
23

terminal of a by-starter relay 164 are also connected to the main control unit 160. The ignitor 161 ignites the ignition plug 65 in synchronization with rotation of the crankshaft 12. The starter relay 162 supplies a power to the starter motor 49. The head lamp driver 163 supplies a power to the head lamp 169. The by- starter relay 164 supplies a power to a by-starter 165 mounted to a carburetor 166. The head lamp relay 163 includes switching elements such as FETs, and is controlled by a so-called chopping control method. In this chopping method, a voltage applied to the head lamp 169 is substantially controlled by interrupting the switching elements at a specific cycle and a specific duty ratio. [0039]
FIGS. 9 to 12 are block diagrams (Parts. 1, 2, 3 and 4) each showing the function of a configuration of the main control unit 160. In these figures, the same reference numerals as those described in FIG. 8 designate the same or similar parts. [0040]
FIGS. 13 and 14 show lists of control contents of a starter relay control unit 400, a by-starter control unit 900, a stand-by indicator control unit 600, a head lamp control unit 800, an engine-starting (in non-seated state
24

after vehicle-stopping) control unit 100, an ignition control unit 700, an ignition knock control unit 200, and a charging control unit 500. These control units constitute the main control unit 160. [0041]
Referring to FIG. 9, when the state of the idling switch 253 and the state of the vehicle are under specific conditions, an operation switching unit 300 switches the operational mode of the main control unit 160 into either the "engine-start & idle SW mode" or "engine-stopping & vehicle-starting mode". [0042]
A signal indicating the state of the idle switch 253 is inputted in an operational mode signal output unit 301 of the operation switching unit 300. The signal indicating the state of the idle switch 253 exhibits the "L" level if the idle switch 253 is in the OFF state (idling restricting state) , and exhibits the "H" level if the idle switch 253 is in the ON state (idling permitting idling state). The operational mode signal output unit 301 outputs an operational mode signal S301 for designating the operational mode of the main control unit 160 to either the "engine-start & idle SW mode" or "engine-stopping & vehicle-starting mode" in response to

output signals from the idle switch 253, vehicular speed
sensor 255 and water temperature sensor 155.
[0043]
FIG. 15 is a schematic diagram showing conditions for switching the operational modes by the operational mode signal output unit 301. If the main switch 173 is turned on to reset the main control unit 160 (a condition 1 is established), the level of the operational signal S301 is set to the "L" level for starting the "engine-start & idle SW mode". [0044]
If, under the "engine-start & idle SW mode", the vehicular speed equal to or more than a predetermined speed (for example, 10 km/hr) is detected, the water temperature equal to or more than a specific temperature (for example, a temperature at which the warm-up operation is assumed to have been completed), and the idle switch 253 is turned off (a condition 2 is established), the level of the operational mode signal S301 is shifted from the "L" level to the "H" level for starting the "engine-stopping & vehicle-starting mode". [0045]
If, under the "engine-stopping & vehicle-starting mode", the idle switch SW in the OFF state is turned into

ON state (a condition 3 is established), the level of the operational mode signal S301 is shifted from the "H" level to the *L" level, to return the operational mode from the "engine-stopping & vehicle-starting mode" into the "engine-start & idle SW mode". Even under each of the "engine-stopping & vehicle-starting mode" and the "engine-start & idle SW mode", if the main switch 173 is cut off (a condition 4 is established), the operational mode is turned off. [0046]
Referring again to FIG 9 the starter relay control unit 400 starts the starter relay 162 under a specific condition in accordance with each of the operational modes. A detection signal from the pulser 153 is inputted in a cranking speed-or-less deciding unit 401 °yind an idling speed-or-less deciding unit 407 If the engine speed is equal to or less than a specific cranking speed (for example, 600 rpm), the cranking speed-or-less deciding unit 401 outputs a signal of the "H" level. If the engine speed is equal to or less than a specific idling speed (for example, 1200 rpm), the idling speed-or-less deciding unit 407^-outputs a signal of the "H' level. [0047]
27

An AND circuit 4 02 outputs a logic product of an output signal from the cranking speed-or-less deciding unit 401, a signal indicating the state of the stop switch 259, and a signal indicating the state of the starter switch 258. An AND circuit 404 outputs a logic product of an output signal from the idling speed-or-less deciding unit 407 a detection signal from the throttle switch 257a, and a signal indicating the state of a seated state detecting switch 254. [0048]
An AND circuit 403 outputs a logic product of an output signal from the AND circuit 402 and a reversed signal of the operational mode signal S301. An AND circuit 405 outputs a logic product of an output signal from the AND circuit 404 and the operational mode signal S301. An OR circuit 406 outputs a logic sum of output signals from the AND circuits 403 and 405 as a starting signal Sin. If a pulse width of the starting signal Sin is shorter than a specific reference time, a starting signal extending unit 407 extends the pulse width of the starting signal Sin up to the reference time or more, and outputs the resultant signal to the starter relay 162. [0049]
The starting signal extending unit 407 includes a

multi-vibrator 407a for detecting the starting signal Sin and outputting one-shot of pulse signal, and an OR circuit 407b for outputting a logic sum of the starting signal Sin and an output signal from the multi-vibrator 407a as a starting signal Sout after extension. The width of a pulse to be outputted from the multi-vibrator 407a can be freely extended by changing a variable resistance value of the multi-vibrator 407a. [0050]
FIG. 18 is a timing chart showing an operation of the starting signal extending unit 407. The variable resistance value of the multi-vibrator 407a is set to 0.6 sec although the width of the output pulse is a pulse width "ton" of the starting signal Sin. As a result, even if the starter switch 258 is kept in the ON state only in a period of time shorter than 0.6 sec, the width of the output pulse of the multi-vibrator 407a becomes 0.6 sec. [0051]
Since the OR circuit 407b outputs the logic sum of the output pulse of the multi-vibrator 407a and the starting signal Sin, if the pulse width "ton" of the starting signal Sout is less than 0.6 sec, the output signal Sout of the starting signal extending unit 407 becomes 0.6 sec, and if the pulse width "ton" of the

starting signal Sin is longer than 0.6 sec, the output signal Sout of the starting signal extending unit 407 becomes a signal of the pulse width "ton" longer than 0.6 sec. [0052]
In the above-described embodiment, the starting signal is extended to 0.6 sec; however, the present invention is not limited thereto. The extended pulse width of the starting signal may be optimally set in accordance with the rotational speed of the starter motor and a reduction ratio. [0053]
To be more specific, as shown in FIG. 19, when the engine is stopped, the piston is probably stopped at a point, immediately before the top dead center (TDC), in a compression stroke (assumed as a first compression stroke which is shown on the left side in the figure). If the starter motor 49 is driven from such a state at the time of the next starting of the engine, the engine is not ignited immediately before the TDC in the first compression stroke, and is exploded immediately before the TDC in the next compression stroke shown on the right side in the figure. Accordingly, the starter motor 49 is required to rotate the engine in such a manner that the

piston reaches at least the TDC in the next compression
stroke.
[0054]
However, if the starter motor 49 is stopped at a point of time when the piston has reached the vicinity of the TDC in the next compression stroke shown on the right side in the figure, there may occur a so-called back-kick that a load caused by explosion acts in the reversal rotational direction to reversely rotate the crankshaft 12. Accordingly, the extension time determined by the starting signal extending unit 4 07 is preferably set to a time required for the piston stopped immediately before the TDC in the first compression stroke to be driven to a position over both the TDC in the first compression stroke and the TDC in the next compression stroke. [0055]
As described above, in this embodiment, the starting signal extending unit 407 is provided, wherein even if the starter switch 258 is kept in the ON state only in a period of time shorter than 0.6 sec, the starter motor 49 is driven at least for 0.6 sec. As a result, it is possible to prevent the back-kick at the time of starting the engine, and hence to reducing noise caused by starting the engine.
31

[0056]
Further, according to this embodiment, since the starter motor can be driven for a time at least required for starting the engine only by opening an accelerator grip for a short time, the driver can start the engine easy via throttle operation with no attention given to an increase in engine speed, particularly, for a vehicle including an automatic centrifugal clutch.
[0057]
In accordance with this starter relay control, the AND circuit 403 becomes an enable state in the "engine-start & idle SW mode". Accordingly, if the starter switch 258 is turned on by the driver in a state that the engine speed is equal to or less than cranking speed and the stop switch 259 is in the ON state (during braking operation), that is, if the level of the output of the AND circuit 402 becomes the "H" level, the starter relay 162 is conducted to start the starter motor 49.
[0058]
In accordance with this starter relay control, the AND circuit 405 becomes an enable state in the "engine-stopping and vehicle-starting state". Accordingly, if the throttle is opened in a state that the engine speed is equal to or less than the idling speed and the seated
32

state detecting switch 254 is in the ON state (during a period that the driver is being seated), that is, if the level of the output of the AND circuit 404 becomes the "H" level, the starter relay 162 is conducted to start the starter motor 49. [0059]
In the stand-by indicator control unit 600 shown in FIG. 10, a vehicular speed-zero deciding unit 601 receives a detection signal from the vehicular speed sensor 255 and outputs, if the vehicular speed is substantially zero, a signal of the "H" level. An Ne deciding unit 602 decides an engine speed on the basis of a detection signal from the pulser 153, and outputs, if the engine speed is equal to or less a predetermined value, a signal of the "H" level. An AND circuit 603 outputs a logic product of output signals from the deciding units 601 and 602. [0060]
An AND circuit 604 outputs a logic product of an output signal from the AND circuit 603 and a reversed signal of an output signal from the seated state detecting switch 254. An AND circuit 605 outputs a logic product of an output signal from the AND circuit 603 and an output signal from the seated state detecting switch

254. A lighting/flashing control unit 606 outputs a lighting signal if an output signal from the AND circuit 604 exhibits the "H* level and outputs a flashing signal if it exhibits the "L* level. An AND circuit 607 outputs a logic product of an output signal from the lighting/flashing control unit 606 and the operational mode signal S301. The stand-by indicator 256 lights in response to the lighting signal and flashes in response to the flashing signal. [0061]
In accordance with this stand-by indicator control, as shown in FIG. 13, the stand-by indicator 256 lights up if the driver is not in the seated state when the vehicle is stopped in the "engine-stopping & vehicle-starting mode", and flashes if the driver is in the seated state when the vehicle is stopped in the "engine-stopping & vehicle-starting mode*. As a result, if the stand-by indicator 256 flashes, the driver can recognize that he or her can immediately start the vehicle by opening an accelerator grip even if the engine is in the stopping state. [0062]
The ignition control unit 700 shown in FIG. 10 starts, stops, or withholds (prohibits) an ignition
37

operation by the ignitor 161 under a specific condition
in each of the operational modes.
[0063]
An ignition-starting control unit 701 turns on an ignition-starting signal S7 01 ("H" level) in response to a specific vehicle-starting operation, to permit the ignition operation by the ignitor 161. An ignition-stopping control unit 7 02 turns on an ignition-stopping signal S702 in response to a specific vehicle-stopping condition, to stop the ignition operation by the ignitor 161. An ignition prohibiting control unit 703 turns on an ignition prohibiting signal S703 only in a specific period containing an ignition timing at which back-kick probably occurs, to prohibit the ignition operation by the ignitor 161 irrespective of the state of the ignition-starting signal S7 01. The operations of the control units 701, 702, and 703 will be described below with reference to a flowchart. [0064]
An AND circuit 704 outputs a logic product of the ignition-starting signal S701 and a reversed signal of the ignition-stopping signal S702. An AND circuit 705 outputs a logic product of an output signal from the AND circuit 704 and a reversed signal of the ignition

prohibiting signal S703. An OR circuit 706 outputs a logic sum of an output signal from the AND circuit 705 and a reversed signal of the operational mode signal S301. [0065]
As described above, according to this embodiment, in the "engine-start & idle SW mode", since the level of the output signal from the OR circuit 706 usually becomes the "H" level, the ignition operation is usually permitted. On the contrary, in the "engine-stopping & vehicle-starting mode", the ignition operation is permitted only when the ignition-starting signal S701 is in the ON state and the ignition prohibiting signal S703 is in the OFF state. [0066]
FIG. 20 is a flowchart showing an ignition-starting control process executed by the ignition-starting control unit 701. The ignition-starting control process is executed while being repeated at a specific cycle. [0067]
In step S201, it is decided on the basis of an output signal from the throttle switch 257a whether or not the throttle grip is opened. If the throttle grip is opened, the process goes on to step S203. In step S203, it is decided on the basis of an output signal from the

seated state detecting switch 254 whether or not the driver is in the seated state. If the driver is in the seated state, the process goes on to step S205 in which the ignition-starting signal S701 is turned on ("H" level), to permit the ignition operation by the ignitor 161. [0068]
Even when it is decided in step S201 that the throttle grip is not opened, if in step S202, it is decided on the basis of a detection signal from the vehicular speed sensor 255 that the vehicular speed is larger than zero, the process goes on to step S203. If it is decided in step S203 that the driver is in the seated state, the process goes on to step S205 in which the ignition-starting signal S701 is turned on, to permit the ignition operation by the ignitor 161. [0069]
If the throttle grip is not opened and the vehicular speed is zero, the process goes on to step S204 in which the ignition-starting signal S701 is turned off ("L" level), to prohibit the ignition operation by the ignitor 161. [0070]
As described above, according to this embodiment,

if the throttle grip is opened or the vehicular speed is larger than zero when the driver is being seated, the ignition-starting signal S701 is turned on, to permit the ignition operation by the ignitor 161. [0071]
FIG. 21 is a flowchart of an ignition-stopping control process executed by the ignition-stopping control unit 702. The ignition-stopping control process is executed while being repeated at a specific cycle. [0072]
If in step S211, it is decided on the basis of an output signal from the throttle switch 257a that the throttle grip is closed, the process goes on to step S212. If in step S212, it is decided on the basis of a detection signal from the vehicular speed sensor 255 that the vehicular speed is zero, the process goes on to step S213. If in step S213, it is decided on the basis of an output signal from the seated state detecting switch 254 that the driver is in the seated state, the process goes on to step S214. In step S214, if a timer is not started, the timer is started. [0073]
After that, if in step S215, the time out (set to 3 sec in this embodiment) of the timer is detected, the
38

process goes on to step S216 in which the ignition-stopping signal S702 is turned on ("H" level). As a result, since the AND circuit 704 becomes a disable state, the level of an output signal from the AND circuit 7 04 becomes the "L" level, to prohibit the ignition operation by the ignitor 161. [0074]
In addition, if either of the answers to steps S211, S212 and S213 is negative, the process goes on to step S217 in which the ignition-stopping signal S702 is turned off ("L" level), and thereby the AND circuit 704 becomes an enable state to continue the ignition operation of the ignitor 161. [0075]
In accordance with this ignition-stopping control, if the driver is in the seated state when the throttle is returned and thereby the vehicle is stopped, the ignition-stopping signal S702 is turned on to close the AND circuit 704, whereby the ignition operation of the ignitor 161 is stopped. [0076]
FIG. 22 is a flowchart showing an ignition prohibiting control process by the ignition prohibiting control unit 703. In this embodiment, in the case of

stopping the engine on the basis of establishment of the engine-stopping condition, that is, on the basis of turn-on of the ignition-stopping signal S702, the ignition operation of the ignitor 161 is prohibited in the engine-stopping process from the operational state to the stopping state, to thereby prevent occurrence of back-kick. [0077]
FIG. 23 is a graph illustrating the content of the ignition prohibiting control, wherein the abscissa is a stroke of the four-cycle engine and the ordinate is an engine speed Ne. In the graph, character "compression" designates the top dead center in a compression stroke, and character "exhaust" designates the top dead center in an exhaust stroke. [0078]
Referring to FIG. 23, when the engine-stopping condition is established at a time to and the ignition-stopping signal S702 is turned on, the operation of the ignitor 161 is stopped and thereby the engine speed is started to be reduced. At this time, in step S221 shown in FIG. 22, it is decided on the basis of detection of, for example, the rise of the ignition-stopping signal S7 02 that the engine-stopping condition is newly

established, and the process goes on to step S222.
[0079]
After that, when the engine speed Ne becomes lower than 800 rpm at a time t2 as shown by a solid line A in FIG, 23, the engine speed thus reduced is detected in step S222, and the process goes on to step S223. In step S223, the ignition prohibiting signal S703 is turned on
("H" level). As a result, the AND circuit 705 becomes a disable state as shown in FIG. 10, and accordingly, in the "engine-stopping & vehicle-starting mode", when the engine speed Ne becomes lower than 800 rpm, the ignition operation by the ignitor 161 is not prohibited even if the ignition-starting signal S701 is turned on in response to the starting operation.
[0080]
In addition, according to this embodiment, if the starting operation is performed before the engine speed becomes lower than 800 rpm in the engine-stopping process, it is not required to prohibit the ignition operation of the ignitor 161 because the next ignition timing comes before the engine speed becomes lower than a specific engine speed at which back-kick probably occurs and the engine speed is turned to be increased.
[0081]
41

In step S224, it is decided on the basis of an output signal from the pulser 153 whether or not the ignition timing comes. If an ignition timing P2 comes, the process goes on to step S225 in which an ignition prohibiting counter "n" is incremented. In addition, at this time, since the ignition prohibiting signal S703 is turned on, the ignition at the ignition timing P2 is withheld (prohibited). In step S226, it is decided whether or not the count value of the ignition prohibiting counter "n" reaches three times. If the count number is less than three times, the process is returned to step S224 in which the count of the ignition timing is continued. [0082]
After that, the ignition at each of ignition timings P3 and P4 is similarly withheld, and each ignition timing is counted. If the count number of the ignition prohibiting counter "n" reaches three times, the process goes on step S227 in which the ignition prohibiting signal S703 is turned off ("L" level). As a result, at the next ignition timing P5, the ignition operation of the ignitor 161 is permitted, and accordingly, if the starter motor 49 is driven in a state in which the vehicle-starting operation has been detected

and thereby the ignition-starting signal S701 has been turned on, the engine is ignited to be started. In step S228, the ignition prohibiting counter "n" is reset. [0083]
As described above, according to this embodiment, in the case of stopping the engine on the basis of the establishment of the engine-stopping condition, if the engine speed is lower than a specific value, the ignition operation is withheld by a specific number. Accordingly, even if the engine-starting operation is performed before the engine is stopped and the piston of the engine reaches an ignition position immediately before the top dead center at a low speed, the engine is not ignited, with a result that back-kick does not occur. [0084]
In addition, in the case of measuring the engine speed Ne on the basis of a detection signal from the pulser 153, the measured value contains an error of measurement due to a difference among the kinds of engines and a rotational deviation tending to largely appear, particularly, in an engine having a small number of cylinders. As a result, the measured engine speed is in a range having a lower limit shown by a broken line B and an upper limit shown by a broken line C in FIG. 23.

[0085]
According to this embodiment, however, the ignition operation is withheld by three times after the engine speed becomes lower than 800 rpm. Accordingly, if the engine speed shown by the broke line B becomes lower than 800 rpm at a time tl, the ignition operation can be withheld at the next three ignition timings PI, P2 and P3, while if the engine speed shown by the broken line C becomes lower than 800 rpm at a time t3, the ignition operation can be withheld at the next three ignition timings P3, P4, and P5. As a result, even if the measured value of the engine speed contains an error of measurement, the ignition operation can be usually prohibited at the ignition timing P3 at which back-kick probably occurs, so that it is possible to positively prevent occurrence of back-kick. [0086]
As described above, according to the ignition control unit 700 of this embodiment, since the output signal from the OR circuit 7 06 is usually set to the "H" level in the "engine-start & idle SW mode" as shown in FIG. 14, the ignition operation can be usually permitted. [0087]
On the contrary, in the "engine-stopping & vehicle-
44

starting mode", when the vehicle is stopped and the engine is automatically stopped, the ignition operation is permitted if the throttle is opened or the vehicular speed becomes larger than zero when the driver is being seated; while when the vehicle is stopped from the running state, if the seated state of the driver is detected, the ignition operation is prohibited and thereby the engine is automatically stopped, and if the seated state of the driver is not detected, the ignition operation is continuously permitted and thereby the engine is not automatically stopped. [0088]
Accordingly, when the seated state of the driver cannot be detected due to a failure of the seated state detecting switch 254, the engine is not automatically stopped even if the vehicle is stopped from the running state, so that it is not required to start the engine at the time of starting the vehicle. As a result, even if there occurs a failure of the seated state detecting switch 254 in the system of permitting automatic starting of the engine under the condition that the driver is being seated, there does not occur any inconvenience of the running of the vehicle. [0089]

According to this embodiment, even if the seated state of the driver is detected when the vehicle is stopped from the running state, the ignition operation is not immediately prohibited, that is, prohibited after an elapse of a specific time (set to 3 sec in this embodiment). Accordingly, when the vehicle is temporarily stopped at a crossing or when the vehicle takes a U-turn (in this case, the driver is in the seated state, the vehicular speed is substantially zero, and the throttle opening is nearly full closed), it is possible to continue the engine-starting state. [0090]
According to this embodiment, since the ignition operation by the ignitor 161 is prohibited in the engine-stopping process from the operational state to the stopping state, even if the vehicle-starting condition is established before the engine is perfectly stopped and also the piston of the engine reaches an ignition position immediately before the top dead center at a low speed, the engine is not ignited to thereby prevent occurrence of back-kick. [0091]
In this embodiment, when the engine speed becomes lower than 800 rpm in the engine-stopping process, the

ignition operation is withheld by three times; however, the present invention is not limited thereto. For example, the ignition operation may be withheld for a specific time from a point of time when the engine speed becomes lower than 800 rpm. [0092]
In this embodiment, the ignition operation is withheld by three times; however, if the engine speed can be accurately measured, the ignition operation may be withheld by two times or one time, or if the engine speed cannot be accurately measured, the ignition operation may be withheld by four or more times. [0093]
FIG. 24 is a flowchart showing another embodiment of the ignition prohibiting control process by the ignition prohibiting control unit 703, and FIG. 25 is a graph illustrating the content of the ignition prohibiting control. [0094]
According to this embodiment, at a time to shown in FIG. 25, the engine-stopping condition is established and thereby the ignition-stopping signal S702 from the ignition-stopping control unit 702 is turned on. At this time, in step S241 shown in FIG. 24, it is decided that

the engine-stopping condition is newly established on the basis of detection of, for example, the rise of the ignition-stopping signal S702, and the process goes on to step S242. [0095]
After that, when the engine speed Ne becomes lower than a reference engine speed Nrefl (for example, 800 rpm) at a time tl, the engine speed thus reduced is detected in step S242, and the process goes on to step
5243. In step S243, the ignition prohibiting signal S703
is turned on ("H" level). As a result, the AND circuit
705 shown in FIG. 10 becomes a disable state. Accordingly,
in the "engine-stopping & vehicle-starting mode", when
the engine speed Ne becomes lower than 800 rpm, even if the ignition-starting signal S701 is turned on in response to the engine-starting operation, the ignition operation by the ignitor 161 is not permitted. [0096]
On the other hand, when the vehicle-starting condition is established at a time t2 after stopping the engine, the ignition-starting signal S701 from the ignition-starting control unit 701 is turned on and also the starter motor 49 is driven. At this time, in step
5244, it is decided that the vehicle-starting condition

is newly established on the basis of detection of, for example, the rise of the ignition-starting signal S701, and the process goes on to step S245. [0097]
After that, when the engine speed He becomes higher than a reference engine speed Nref2 (for example, 400 rpm), the engine speed Ne thus increased is detected in step S245, and the process goes on to step S246. In step S246, the ignition prohibiting signal S703 is turned off ("L" level) . As a result, the AND circuit 705 shown in FIG. 10 becomes an enable state, to permit the ignition operation by the ignitor 161. Accordingly, the ignition operation is executed at an ignition timing (time t4), to start the engine. [0098]
According to this embodiment, since the reference engine speed Nrefl for prohibiting the ignition in the engine-stopping process from the operational state to the stopping state is higher than the reference engine speed Nref2 for prohibiting the ignition at the engine-starting process, it is possible to effectively prevent occurrence of back-kick while suppressing the withholding (prohibiting) number of ignition at minimum. [0099]

Referring again to FIG. 10, the ignition knocking control unit 200 executes a control for preventing occurrence of knocking by retarding the ignition timing at the time of acceleration more than the ignition timing at the time of usual rotation in each of the operational modes. In particular, according to this embodiment, the retarded amount of the ignition timing at the time of vehicle-starting acceleration from the engine-stopping state is larger than the retarded amount of the ignition timing at the time of usual acceleration from the engine rotating state, whereby occurrence of knocking at the time of vehicle-starting acceleration, which is inherent to the vehicle on which the engine automatic stopping/starting control system is mounted, can be perfectly prevented. [0100]
A standard ignition timing represented by a degree of advance angle (deg) from the top dead center (TDC) in a compression stroke is previously registered, as the function of the engine speed Ne and the throttle opening degree 6, in a standard ignition timing determining unit 207. FIG. 16 is a diagram showing a relationship between
the engine speed Ne and the throttle opening degree 6 , and the standard ignition timing according to this

embodiment. The standard ignition timing is taken as 15* (advance angle) in an engine speed range of less than 2500 rpm, and is gradually increased depending on the engine speed Ne in a range of engine speed of 2500 rpm or over. [0101]
If the engine speed Ne is in a range of 700 rpm engine speed Ne is in a range of 700 rpm If a rate of change A 6 of the throttle opening degree 0 detected by the throttle sensor 257 exceeds a specific value, an acceleration deciding unit 205 decides that the accelerating operation has been performed and outputs an acceleration detection signal of the "H" level. A water temperature deciding unit 206 decides the temperature of engine cooling water on the basis of a

detection signal from the waster temperature sensor 155, and outputs a signal of the "H" level if the water
temperature exceeds a specific temperature (50°C in this
embodiment).
[0103]
An AND circuit 202 outputs a logic product of the usual acceleration signal Saccl, an acceleration detecting signal, a water temperature detection signal, and a reversed signal of the operational mode signal S301. An AND circuit 2 03 outputs a logic product of the vehicle-starting acceleration signal Sacc2, an acceleration detection signal, a water temperature decision signal, and the operational mode signal S301. [0104]
If the level of each of output signals from the AND circuits 202 and 203 is the "L" level, that is, if the vehicle is not in the acceleration state, an ignition timing (upon acceleration) correcting unit 204 supplies the standard ignition timing determined by the standard ignition timing determining unit 207 (see FIG. 16) to the ignitor 161. The ignitor 161 executes the ignition operation at the ignition timing supplied from the ignition timing (upon acceleration) correcting unit 204. [0105]

If the level of an output signal from the AND circuit 202 becomes the "H" level, that is, if in the "engine-start & idle SW mode" shown in FIG. 14, the engine speed Me is in the range of 700 rpm If the level of an output signal from the AND circuit 203 becomes the "H" level, that is, if in the "engine-stopping & vehicle-starting mode" shown in FIG. 14, the engine speed Ne is in the range of 700 rpm value, the ignition timing is retarded up to 0* (advance angle) irrespective of the result determined by the standard ignition timing determining unit.207 as shown by a solid line B in FIG. 17. [0107]
The ignition timing (upon acceleration) correcting

unit 204 has a counter 204a. If the level of either of output signals from the AND circuits 202 and 203 becomes the "H" level, the above-described retarded ignition is immediately executed by a specific number of times (three times in this embodiment) by means of the ignition timing (upon acceleration) correcting unit 204, and then the retarded ignition is immediately returned to the usual ignition timing determined by the standard ignition timing determining unit 207. [0108]
According to this ignition knocking control, it is possible to make the retarded amount at the time of vehicle-starting acceleration different from the retarded amount at the time of usual acceleration from an intermediate rotational region. To be more specific, by setting the retarded amount at the time of vehicle-starting acceleration larger than the retarded amount at the time of usual acceleration from the intermediate rotational region, it is possible to prevent occurrence of knocking not only at the time of the usual acceleration from the intermediate rotational region but also at the time of vehicle-starting acceleration. [0109]
In the head lamp control unit 800 shown in FIG. 11,

an Ne deciding unit 801 decides, on the basis of a detection signal from the pulser 153, whether or not the engine speed is equal to or more than a specific setting speed (less than the idling speed) . If the engine speed is equal to or more than the setting speed, the Ne deciding unit 801 outputs a signal of the "H" level. An AND circuit 802 outputs a logic product of an output signal from the Ne deciding unit 801 and a reversed signal of the operational mode signal S301. An AND circuit 803 outputs a logic product of an output signal from the Ne deciding unit 801 and the operational mode signal S301. [0110]
If the level of an output signal from the AND circuit 802 is the "H* level, a lighting/dimming switching unit 804 outputs a signal of the "H" level. If the level of the output signal from the AND circuit 802 is the "L" level, the lighting/dimming switching unit 804 outputs a pulse signal of a duty ratio of 50%. If the level of an output signal from the AND circuit 803 is the "H" level, a lighting/multi-stage dimming switching unit 805 outputs a signal of the "H" level. If the level of the output signal from the AND circuit 803 is the *L* level, a timer 805a counts the continuation time of the

outputted signal of the "L" level and the lighting/multi¬stage dimming switching unit 805 outputs a pulse signal of a duty ratio which is gradually reduced depending on the continuation time of the outputted signal of the "L" level. In this embodiment, the duty ratio is stepwise reduced from 95% to 50% with a stepwise period taken as 0.5 to 1 second. With such a stepwise dimming manner, since the quantity of light is instantly, linearly reduced, it is possible to achieve power-saving and to ensure a high commercial value. [0111]
According to this head lamp control, as shown in FIG. 13, the head lamp is lighted or dimmed depending on the engine speed Ne in the "engine-start & idle SW mode", and is lighted and stepwise dimmed depending on the engine speed Ne in the "engine-stopping & vehicle-starting mode". Accordingly, it is possible to suppress the discharge of the battery at the time of vehicle stoppage while sufficiently keeping the visibility from a vehicle running in the opposed direction. As a result, the charged amount from the AC generator into a battery is reduced at the time of the subsequent vehicle-starting operation, to reduce an electronic load of the AC generator, thereby enhancing the acceleration performance

at the time of starting vehicle. [0112]
In the by-starter control unit 900 shown in FIG. 11, a detection signal from the water temperature sensor 155 is inputted in a water temperature deciding unit 901. If the water temperature becomes equal to or more than a first predetermined value (50°C in this embodiment), the water temperature deciding unit 901 outputs a signal of the "H" level to close the by-starter relay 164, and if the water temperature becomes equal to or than a second
predetermined value (10°C in this embodiment), the water temperature deciding unit 901 outputs a signal of the "L" level to open the by-starter relay 164. [0113]
According to this by-starter control, as the water temperature becomes higher, fuel becomes denser, and as the water temperature becomes lower, the fuel automatically becomes thinner. In this embodiment, since the opening/closing temperature of the by-starter relay 164 has hysteresis, it is possible to prevent an unnecessary opening/closing operation of the by-starter relay 164, which operation may be caused near a critical temperature. [0114]

In the charging control unit 500 shown in FIG. 11, both a detection signal from the vehicular speed sensor 255 and a detection signal from the throttle sensor 257 are inputted in an acceleration operation detecting unit 502. As shown in FIG. 14, if the vehicular speed is larger than zero and the throttle is changed from the full-closed state to the full-opened state for 0.3 second or less, the acceleration detecting unit 502 decides that the acceleration operation is performed, and outputs an acceleration detecting pulse. [0115]
A charging (upon acceleration) restricting unit 504 controls the regulator rectifier 167 in response to the acceleration detecting pulse signal to reduce a charging voltage of the battery 168 from a usual voltage (14.5 V) to 12.0 V. [0116]
The charging (upon acceleration) restricting unit 504 starts a six-second timer 504a in response to the acceleration detecting pulse. If the timer 504a times out, the engine speed Ne becomes equal to or more than a setting speed, or the throttle opening degree is reduced, the charging restriction is released to return the charging voltage from 12.0 V to 14.5 V.
58

[0117]
Detection signals from the vehicular speed sensor 255, the pulser 153, and the throttle sensor 257 are inputted in a vehicle-starting operation detecting unit 503. As shown in FIG. 14, if the vehicular speed is zero and the throttle is opened when the engine speed Ne is equal to or less the setting speed (2500 rpm in this embodiment), the vehicle-starting operation detecting unit 503 decides that the vehicle-starting operation is performed, and outputs a vehicle-starting operation detecting pulse.
[0118]
When detecting the vehicle-starting operation detecting pulse signal, a charging (upon vehicle-starting) restricting unit 505 controls the regulator rectifier 167 to reduce the charging voltage of the battery 168 from the usual voltage (14.5 V) to 12.0 V.
[0119]
The charging (upon vehicle-starting) restricting unit 505 starts a seven-second timer 505a in response to the vehicle-starting operation detecting pulse. If the timer 505a times out, the engine speed Ne becomes equal to or more than the setting speed, or the throttle opening degree is reduced, the charging restriction is

released to return the charging voltage from 12.0 V to
14.5 V.
[0120]
According to this charging control, when the throttle is rapidly opened by the driver to effect rapid acceleration or when the vehicle is started from the stopping state, the charging voltage is suppressed at a low value to temporarily reduce the electric load of the AC generator 172. Accordingly, it is possible to reduce the mechanical load of the engine 200' applied from the AC generator 172 and hence to improve the accelerating performance. [0121]
The engine-starting (in non-seated state after vehicle-stopping) control unit 100 shown in FIG. 12 exceptionally permits, the starting of the engine by the starter switch 258 which is basically prohibited, with a timing where the driver can experimentally start the engine by the starter switch. [0122]
An AND circuit 102 outputs a logic product of the operational mode signal S301 and a reversed signal of an output signal from the seated state detecting switch 254. A non-seated state continuation deciding unit 101 has a

timer 101a and detects, after automatic stopping of the engine, the "H" level of an output signal from the AND circuit 102 for a specific time or more. To be more specific, if in the "engine-stopping & vehicle-starting mode", the non-seated state of the driver is continued for a specific time or more after automatic stopping of the engine, the level of the output signal is set to the "H" level. As a result, the ignitor 161 is energized to become an ignition permissible state. [0123]
An OR circuit 103 outputs a logic sum of output signals from the starter switch 258 and the throttle switch 257a. An AND circuit 104 generates a logic product of output signals from the non-seated state continuation deciding unit 101 and the OR circuit 103, and outputs the logic product to the starter relay 162. To be more specific, if the starter switch 258 is turned on or the throttle is opened after the non-seated state of the driver is continued for a specific time or more after automatic stopping of the engine in the "engine-stopping & vehicle-starting mode" (the level of an output signal from the non-seated state continuation deciding unit 101 becomes the "H" level), the starter relay 162 is energized to drive the starter motor 49. At this time,
61

since the ignitor 161 is energized by the non-seated state continuation deciding unit 101, the starting of the engine can be performed. [0124]
According to this engine-starting control in the non-seated state after stopping the vehicle, even after the engine is stopped in response to the specific vehicle-stopping condition, the starting of the engine is exceptionally permitted by the starter switch 258 if it is detected that the non-seated state of the driver is continued for the specific time. Accordingly, if the driver leaves, after automatically stopping the engine at the time of stopping the engine, the vehicle without cutting-off the main power source, and after coming back to the vehicle, he or she forgets that the engine is under the automatic stopping control and operates the starter switch 258, the driver can still start the engine in the same manner as that in the usual state in which the engine is not under the automatic stopping control. [0125]
In the above-described engine-starting control in the non-seated state after stopping the vehicle, the starting of the engine by the starter switch 258 is exceptionally permitted under the condition that the non-

seated state of the driver is continued for the specific time or more after automatic stopping of the engine in the "engine-stopping & vehicle-starting mode"; however, as shown by a broken line in FIG. 12, the starting of the engine by the starter switch 258 may be permitted by controlling the operation switching unit 300 to switch the operational mode from the "engine-stopping & vehicle-starting mode" to the "engine-start & idle SW mode". Alternatively, as shown by the "condition 5" in FIG. 15, the starting of the engine by the starter switch 258 may be substantially permitted by cutting off the main switch 173. [0126]
FIG. 3 is a sectional view showing a second embodiment of the swing unit 17. In the figure, parts corresponding to those described above are designated by the same reference numerals. [0127]
In the above-described first embodiment, the sprocket 58 coupled to the starter motor 49 is connected to the outer rotor 42 of the generation unit 44 via the one-way clutch 50; however, in this embodiment, a sprocket 58 is connected to a crankshaft 12 via a one-way clutch 50 having the same function as that of the one-way

clutch 50 in the previous embodiment at a position between a pulley 83 and a main bearing 10 on the side opposed to a generation unit 44 with respect to a crank chamber 9. [0128]
The one-way clutch 50 includes one sleeve 57b fixed to the crankshaft 12, the other sleeve 55b for supporting the sprocket 58 rotatably relative to the crankshaft 12, and a clutch portion 56b for connecting the sleeves 55b and 57b to each other in such a manner as to prevent idling of the crankshaft 12 in the reversed direction relative to the sprocket 58 and permit idling of the crankshaft 12 in the normal direction relative to the sprocket 58. [0129]
According to this embodiment, since the sprocket 58 for transmitting a drive force of the starter motor 49 to the crankshaft 12 is provided at a position offset to the side of the pulley 83 of the automatic transmission from the crank chamber 9, the length of a portion of the crankshaft 12 on the automatic transmission side with respect to the crank chamber 9 becomes longer than the length of a portion of the crankshaft 12 on the generation unit side with respect to the crank chamber 9.

Accordingly, the center of the heavy engine can be located at the center of a tire, that is, the center of the vehicle, so that a torsional force or a moment is less applied to the swing unit 17, with a result that a weight distribution is improved and thereby the running stability is enhanced. [0130]
Further, according to this embodiment, since the sprocket 58 coupled to the starter motor 49 is connected to the crankshaft 12 at a position apart from a tire 21 in the axial direction of the crankshaft 12, the diameter of the sprocket 58 can be enlarged, to obtain a large reduction ratio, thereby reducing the size and weight of the starter motor 49. {0131]
FIG. 4 is a sectional view of a third embodiment of the swing unit 17. In the figure, parts corresponding to those described above are designated by the same reference numerals. [0132]
In this embodiment, one sleeve 57c, on the crankshaft side, of a one-way clutch 50 is integrally formed on the back surface, being not in contact with a V-belt 82, of a fixed pulley piece 83a, and the other

sleeve 55c is fixed to a flange portion 83d extending axially outwardly from the fixed pulley piece 83a, so that a sprocket 58 is connected to an end portion of a crankshaft 12 via both the one-way clutch 50 and the fixed pulley piece 83a. [0133]
According to this embodiment, since the sprocket 58 and a chain 40 therefor are mounted to the outermost portion of the crankshaft 12, they can be easily mounted and dismounted. Accordingly, it is possible to facilitate the maintenance of the sprocket 58 and the chain 40 therefor, and to mount the sprocket 58 and the chain 40 therefor to an existing swing unit only by simple modification. [0134]
Further, according to this embodiment, like the second embodiment, since the sprocket 58 is connected to the crankshaft 12 at a position apart from the time 21 in the axial direction of the crankshaft 12, the diameter of the sprocket 58 can be enlarged, to obtain a large reduction ratio, thereby reducing the size and weight of the starter motor 49. [0135]
FIG. 6 is a sectional view of an essential portion

of a fourth embodiment of the swing unit 17, and FIG. 7 is a sectional view, taken on a plane perpendicular to a crankshaft 12, showing the swing unit 17. In these figures, parts corresponding to those described above are designated by the same reference numerals. [0136]
According to the first, second and third embodiments, in order to reduce noise occurring at the time of starting the engine, the sprocket 58 provided on the crankshaft 12 is connected to the starter motor 49 via the chain 40. On the contrary, according to this embodiment, a sprocket 58 is usually connected to a starter motor 49 via a gear train, and simultaneously the sprocket 58 is connected to a crankshaft 12 via a one-way clutch 50 as described above. Accordingly, the power transmission from the crankshaft 12 side to the starter motor 49 side is cut off without use of any ratchet. With this configuration, since the starter motor is connected to the crankshaft in one direction without use of any ratchet, it is possible to reduce noise at the time of starting the engine. [0137]
Referring to FIGS. 6 and 7, gear teeth 221 are formed on the rotational shaft of the starter motor 49,
7

and the teeth of a large-diameter gear 222 connected to a drive shaft 234 are meshed with the gear teeth 221. A small-diameter gear 223 is coaxially formed on the drive shaft 234 at a position adjacent to the large-diameter gear 222, and the sprocket 58 connected to the crankshaft 12 is meshed with the small-diameter gear 223. [0138]
To prevent an increase in noise due to sliding wear of the drive shaft 234 and looseness caused by such sliding wear, particularly, for an engine starter used at a high frequency, the drive shaft 234 is rotatably supported by a pair of oil impregnation bush type bearings 234a and 234b on both sides of the drive shaft 234 with the large-diameter gear 222 and the small-diameter gear 223 put therebetween. Further, according to this embodiment, in order to suppress noise generated from the above-described gear train, the gear teeth meshed with each other are subjected to shaving or grinding. [0139]
By the way, in this embodiment, since the sprocket 58 provided on the crankshaft 12 is usually connected to the starter motor 49 via the fixed gear train without use of any ratchet, it is required to additionally provide a

configuration for permitting the power transmission from the starter motor 49 side to the crankshaft 12 side but prohibiting the power transmission from the crankshaft 12 side to the starter motor 49 side. To meet such a requirement, in this embodiment, the sprocket 58 is connected to the crankshaft 12 via the one-way clutch 50 as described above. [0140]
Accordingly, at the time of starting the engine, when the starter motor 49 is driven to rotate the sprocket 58 in the normal direction of the crankshaft 12, the crankshaft 12 is correspondingly driven in the normal direction. On the contrary, after starting the engine, even if the starter motor 49 is stopped, the crankshaft 12 is idled relative to the sprocket 58, so that the drive force of the crankshaft 12 is not transmitted to the starter motor 49. [0141]
As described above, according to this embodiment, the starter motor 49 is connected to the crankshaft 12 without use of any ratchet, and consequently, since there does not occur any noise caused by operation of the ratchet, it is possible to reduce noise at the time of starting the engine.

[0142] [Effect of the Invention]
The present invention exhibits the following effects: [0143]
(1) In the case of stopping the engine on the basis
of establishment of an engine-stopping condition, if the
engine speed becomes lower than a specific engine speed,
the ignition operation is prohibited by a specific number,
and accordingly, even if the vehicle-starting operation
is performed before the engine is stopped and the piston of the engine reaches an ignition position immediately before the top dead center at a low speed, the engine is not ignited, to thereby prevent occurrence of back-kick. [0144]
(2) Since the reference engine speed Nrefl for
prohibiting ignition in the engine-stopping process from
the operational state to the stopping state is higher
than the reference engine speed Nref2 for prohibiting
ignition in the engine-starting process, it is possible
to effectively prevent occurrence of back-kick while
suppressing the withholding (prohibiting) number of
ignition at minimum.
70

WE CLAIM:
1. An engine starter for a vehicle, which includes a starter motor for
cranking an engine in response to a specific engine-starting operation,
and an ignitor for igniting said engine at a specific rotational angle in
response to said engine-starting operation, said engine starter being
characterized by
including ignition prohibiting control unit for prohibiting an ignition operation of said ignitor in an engine-stopping process from an operational state to a stopping state; and
wherein said ignition prohibiting control unit prohibits ignition operation of said ignitor if an engine speed is equal to or less than a first engine speed in an engine-stopping process from an operational state to a stopping state, and prohibits the ignition operation of said ignitor if the engine speed is equal to or less than a second engine speed in an engine-starting process from a stopping state,
wherein said first engine speed is higher than said second speed.
2. An engine starter for a vehicle as claimed in claim 1, wherein said
engine starter further includes ignition control unit for stopping the
ignition operation of said ignitor in response to a specific vehicle-stopping
condition during running of the vehicle, and restarting
the ignition operation of said ignitor in response to a specific vehicle-starting operation after stopping the ignition operation of said ignitor.
3. An engine starter for a vehicle substantially as herein described with reference to the accompanying drawings.
Dated this 6th day of August, 2001.
(RITUSHKA NEGI)
OF REMFRY &«AGAR
ATTORNEY FOR THE APPLICANT[S]
72

Documents:

752-mum-2001-abstract (20-04-2006).pdf

752-mum-2001-abstract(20-04-2006).doc

752-mum-2001-cancelled pages (20-04-2006).pdf

752-mum-2001-claims (granted) (20-04-2006).pdf

752-mum-2001-claims(granted)-(20-04-2006).doc

752-mum-2001-correspondence (04-10-2006).pdf

752-mum-2001-correspondence (ipo) (27-09-2006).pdf

752-mum-2001-drawing (20-09-2001).pdf

752-mum-2001-form 1(06-08-2001).pdf

752-mum-2001-form 1(20-04-2006).pdf

752-mum-2001-form 18(16-06-2005).pdf

752-mum-2001-form 2(granted) (20-04-2006).pdf

752-mum-2001-form 2(granted)-(20-04-2006).doc

752-mum-2001-form 3(04-10-2006).pdf

752-mum-2001-form 3(06-08-2001).pdf

752-mum-2001-form 3(20-04-2006).pdf

752-mum-2001-form 3(25-05-2006).pdf

752-mum-2001-form 4(10-04-2006).pdf

752-mum-2001-form 5(20-04-2006).pdf

752-mum-2001-petition under rule-137(20-04-2006).pdf

752-mum-2001-petition under rule-138(20-04-2006).pdf

752-mum-2001-power of attorney (19-11-2001).pdf

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Patent Number

203904

Indian Patent Application Number

752/MUM/2001

PG Journal Number

42/2008

Publication Date

17-Oct-2008

Grant Date

09-Oct-2006

Date of Filing

06-Aug-2001

Name of Patentee

HONDA GIKEN KOGYO KABUSHIKI KAISHA

Applicant Address

BUSINESS AT 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO,

Inventors:

#	Inventor's Name	Inventor's Address
1	HITOSHI KUROSAKA	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA,
2	YUJI ONO	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA,

PCT International Classification Number

N/A

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA