Title of Invention	APPARATUS FOR CONTROLLING AIR INTAKE OF ENGINE IN SMALL VEHICLE
Abstract	APPARATUS FOR CONTROLLING AIR INTAKE OF ENGINE IN SMALL VEHICLE An apparatus for controlling air intake of an engine in a small vehicle, the apparatus having a throttle body (17) disposed between a luggage box (3) directly under a seat (2) and an engine (5) disposed under the luggage box (3), the throttle body (17) having an air intake path (17a) joined to an air intake port (7a) of the engine (5) and a throttle valve (21) for opening and closing the air intake path (17a), wherein sensors (64, 73, 76) for detecting operating conditions of the engine (5) and an electronic control unit (84) for controlling operation of a fuel injection valve (20) of the engine (5) according to output signals from the sensors (64, 73, 76) are attached on one of a right and left side of the throttle body (17), and a coupler (80) connected to the electronic control unit (84) and having a coupling mouth (80a) coupled with an external coupler (83) and opening to the other of the right and left sides of the throttle body (17) is disposed above the throttle body (17) characterized in that a valve stem (22) of the throttle valve (21) is disposed in a right to left direction orthogonal to the air intake path (17a), a throttle drum (23) is fixed to one end of the valve stem (22) on an opposite side from the electronic control unit (84), and a throttle cable (24) connected to the throttle drum (23) is disposed so as to pass below the coupling mouth (80a) of the coupler (80). 30 APR 2007

Title of Invention

APPARATUS FOR CONTROLLING AIR INTAKE OF ENGINE IN SMALL VEHICLE

Abstract

APPARATUS FOR CONTROLLING AIR INTAKE OF ENGINE IN SMALL VEHICLE An apparatus for controlling air intake of an engine in a small vehicle, the apparatus having a throttle body (17) disposed between a luggage box (3) directly under a seat (2) and an engine (5) disposed under the luggage box (3), the throttle body (17) having an air intake path (17a) joined to an air intake port (7a) of the engine (5) and a throttle valve (21) for opening and closing the air intake path (17a), wherein sensors (64, 73, 76) for detecting operating conditions of the engine (5) and an electronic control unit (84) for controlling operation of a fuel injection valve (20) of the engine (5) according to output signals from the sensors (64, 73, 76) are attached on one of a right and left side of the throttle body (17), and a coupler (80) connected to the electronic control unit (84) and having a coupling mouth (80a) coupled with an external coupler (83) and opening to the other of the right and left sides of the throttle body (17) is disposed above the throttle body (17) characterized in that a valve stem (22) of the throttle valve (21) is disposed in a right to left direction orthogonal to the air intake path (17a), a throttle drum (23) is fixed to one end of the valve stem (22) on an opposite side from the electronic control unit (84), and a throttle cable (24) connected to the throttle drum (23) is disposed so as to pass below the coupling mouth (80a) of the coupler (80). 30 APR 2007

Full Text	FORM 2 THE PATENTS ACT 1970 [39 OF 1970] COMPLETE SPECIFICATION [See Section 10] "APPARATUS FOR CONTROLLING AIR INTAKE OF ENGINE IN SMALL VEHICLE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan The following specification particularly describes the nature of the invention and the manner in which it is to be performed :- GRANTED -3 MAY 2002 The present invention relates to apparatus for controlling air intake of engine in small vehicle [Detailed Description of the Invention] [0001] [Technical Field to which the Invention Pertains] The present invention relates to an apparatus for controlling air intake of an engine in a small vehicle, in which apparatus a throttle body having an air intake path joined to an air intake port of the engine and a throttle valve for opening and closing the air intake path is disposed between a luggage box directly under a seat and the engine disposed under the luggage box. [0002] [Prior Art] Such an apparatus for controlling air intake of an engine in a small vehicle is already known, as disclosed in Japanese Patent Laid-Open No. 2000 138975, for example. [0003] Also, as disclosed in Japanese Patent Laid-Open No. Hei ll-294il6, for example, an apparatus for controlling fuel injection of an engine is already known in which a boost negative pressure sensor, an intake air temperature sensor, an electronic control unit for processing output signals from the boost negative pressure sensor and the intake air temperature sensor, and a coupler for input and output to the electronic control unit are provided in a concentrated manner over a throttle body, and operation of a fuel injection valve of the engine is controlled on the basis of the output signals from the boost negative pressure sensor, the intake air temperature sensor, and the like. [0004] [Problems to be Solved by the Invention] When the latter apparatus for controlling fuel injection is to be employed in the former apparatus for controlling air intake of an engine in a small vehicle, the electronic control unit, the coupler and the like will project high above the throttle body. The bottom portion of the luggage box situated above the electronic control unit, the coupler, and the like therefore needs to be moved upward in order to avoid interference with the electronic control unit, the coupler, and the like. This, however, reduces capacity of the luggage box, and hence is not desirable. [0005] The present invention has been made in view of the above, and it is accordingly an object of the present invention to provide an apparatus for controlling air intake of the engine in the small vehicle in which apparatus the sensors for controlling fuel injection, the electronic control unit, and the coupler are rationally-disposed around the throttle body so that the bottom portion of the luggage box can be held at as low a position as possible. [0006] [Means for Solving the Problems] In order to achieve the above object, according to a first feature of the present invention, in a small vehicle including a luggage box disposed under a seat and an engine disposed under the luggage box, and including a throttle body disposed between the luggage box and the engine, the throttle body having an air intake path joined to an air intake port of the engine and extending in a front to rear direction of the vehicle and a throttle valve for opening and closing the air intake path, sensors for detecting operating conditions of the engine and an electronic control unit for controlling operation of a fuel injection valve of the engine according to output signals from the sensors are attached on one of a right and a left side of the throttle body, and a coupler connected to the electronic control unit and having a coupling mouth coupled with an external coupler and opening to the other of the right and left sides of the throttle body is disposed above the throttle body. [0007] According to the first feature, the dispersed arrangement of the sensors and the electronic control unit and the coupler allows the sensors, the electronic control unit, and the coupler to be readily disposed even in a small space around the throttle body. In particular, the coupler can be flattened in a vertical direction, and therefore even when the coupler is disposed above the throttle body, there is practically no need for moving upward the bottom portion of the luggage box situated over the coupler, thus making it possible to increase the capacity of the luggage box. [0008] Moreover, since the coupling mouth of the coupler coupled with the external coupler opens to an opposite side from the electronic control unit, it is possible to readily connect the external coupler to the coupler without the electronic control unit and the engine being in the way, and to thus obtain great ease of assembly and maintenance. [0009] In addition, according to a second feature of the present invention, in addition to the first feature, a valve stem of the throttle valve is disposed in a right to left direction orthogonal to the air intake path, a throttle drum is fixed to one end of the valve stem on an opposite side from the electronic control unit, and a throttle cable connected to the throttle drum is disposed so as to pass below the coupling mouth of the coupler. [0010] According to the second feature, it is possible to avoid interference between the throttle cable and the wire harness of the external coupler coupled to the coupler, and to thereby increase the ease of assembly and maintenance. [0011] Moreover, according to a third feature of the present invention, in addition to the second feature, the throttle cable connected to the throttle drum is disposed so as to extend rearward for a distance, bend so as to form a U-shape, and then extend forward. [0012] According to the third feature, even when the throttle body is rocked together with the engine, mainly the U-shaped bending portion of the throttle cable bends without strain, whereby it is possible to prevent an excessive stress on the throttle cable and thus ensure the durability of the throttle cable. [0013] Furthermore, according to a fourth feature of the present invention, in addition to the second or third feature, the throttle drum is connected with a return spring that biases the throttle drum in a direction of closing the throttle valve and the single throttle cable that is pulled against the biasing force of the return spring to open the throttle valve, and the throttle cable passes a lower portion of the throttle drum and is then drawn out. [0014] According to the fourth feature, while the throttle drum and the coupling mouth of the coupler are disposed on the same side of the throttle body, a relatively large workspace where the throttle cable is not in the way can be obtained around the coupling mouth of the coupler, thus facilitating the connection of the external coupler to the coupling mouth. [0015] [Mode for Carrying our the Invention] A preferred embodiment of the present invention will hereinafter be described with reference to an example of the present invention shown in the accompanying drawings. [Brief Description of the Drawings] [Fig. 1] Fig. 1 is a side view of a motorcycle provided with an air intake control apparatus according to the present invention. [Fig. 2] Fig. 2 is an enlarged sectional view of a portion 2 in Fig. 1. [Fig. 3] Fig. 3 is a sectional view taken along a line 3-3 of Fig. 2. [Fig. 4] Fig. 4 is an exploded perspective view of the air intake control apparatus. [Fig. 5] Fig. 5 is a side view of the air intake control apparatus... [Fig. 6] Fig. 6 is a view taken in a direction of an arrow 6 of Fig. 5. [Fig. 7] Fig. 7 is a view taken in a direction of an arrow 7 of Fig. 5. [Fig. 8] Fig. 8 is a view taken in a direction of an arrow 8 of Fig. 7. [Fig. 9] Fig. 9 is a sectional view taken along a line 9-9 of Fig. 7. [Fig. 10] Fig. 10 is a sectional view taken along a line 10- 10 of Fig. 5. [Fig. 11] Fig. 11 is a sectional view taken along a line 11- 11 of Fig. 5. [Fig. 12] Fig. 12 is a sectional view taken along a line 12- 12 of Fig. 5. [Fig. 13] Fig. 13 is an enlarged view of a bypass valve in Fig. 12 and its vicinities. [Fig. 14] Fig. 14 is an enlarged sectional view taken along a line 14-14 of Fig. 5. [Fig. 15] Fig. 15 is an enlarged sectional view taken along a line 15-15 of Fig. 13. [Fig. 16] Fig. 16(A) is a side view taken from a measuring groove side of the bypass valve. Fig. 16(B) is a side view taken from a keyway side of the bypass valve. [Fig. 17] Fig. 17 is an enlarged sectional view of a portion 17 in Fig. 12. [0016] Fig. 1 is a side view of a motorcycle provided with an air intake control apparatus according to the present invention; Fig. 2 is an enlarged sectional view of a portion 2 in Fig. 1; Fig. 3 is a sectional view taken along a line 3-3 of Fig. 2; Fig. 4 is an exploded perspective view of the air intake control apparatus; Fig. 5 is a side view of the air intake control apparatus; Fig. 6 is a view taken in a direction of an arrow 6 of Fig. 5; Fig. 7 is a view taken in a direction of an arrow 7 of Fig. 5; Fig. 8 is a view taken in a direction of an arrow 8 of Fig. 7; Fig. 9 is a sectional view taken along a line 9-9 of Fig. 7; Fig. 10 is a sectional view taken along a line 10-10 of Fig. 5; Fig. 11 is a sectional view taken along a line 11-11 of Fig. 5; Fig. 12 is a sectional view taken along a line 12-12 of Fig. 5; Fig. 13 is an enlarged view of a bypass valve in Fig. 12 and its vicinities; Fig. 14 is a sectional view taken along a line 14-14 of Fig. 5; Fig. 15 is an enlarged sectional view taken along a line 15-15 of Fig. 13; Fig. 16(A) is a side view taken from a measuring groove side of the bypass valve; Fig. 16(B) is a side view taken from a keyway side of the bypass valve; and Fig. 17 is an enlarged sectional view of a portion 17 in Fig. 12. [0017] First, in Figs. 1 to 3, a motorcycle 1 is formed as a scooter type by disposing a power unit 4 directly under a luggage box 3 extending long in a front to rear direction and using a tandem type seat 2 also as a lid thereof. The power unit 4 is formed by an engine 5 having a cylinder block 6 greatly slanted forward, and a continuously variable transmission 8 having a transmission case 10 extending rearward joined integrally with one side of a crankcase 9 of the engine 5. A rear wheel 16 serving as a driving wheel is journaled in a rear end portion of the transmission case 10. [0018] In a body frame 11 of the motorcycle 1, upper brackets 12 and 12 are provided at a portion connecting a pair of right and left upper frames 11a and 11a supporting the luggage box 3 with rear end portions turned upward of a pair of right and left down tubes l1b and l1b extending from a head pipe, while a pair of right and left lower brackets 13 and 13 is formed on an upper surface of the crankcase 9 of the engine 5. The lower brackets 13 and 13 are rockably supported at a middle portion of a crank-shaped engine hanger 14 having both end portions rockably supported by the upper brackets 12 and 12. Thus, the power unit 4 is supported by the body frame 11 in a vertically rockable manner. A rear cushion unit 26 for cushioning the vertical rock is attached between rear frames 11 and 11 and the transmission case 10. [0019] A cylinder head 7 joined to a front end of the cylinder block 6 has an air intake port 7a formed with an upstream end opening to the rear of the vehicle body. A throttle body 17 that connects an air intake path 17a with the air intake port 7a is attached to the cylinder head 7 via a connecting tube 15. In this case, the throttle body 17 is disposed between the luggage box 3 and the engine 5 such that the air intake path 17a extends substantially horizontally (slightly slanting downward to the front in the example shown in the figures) in the front to rear direction. Thus, the throttle body 17 is of a horizontal type. The rear end of the throttle body 17 is connected with an air cleaner 19 via an air intake duct 18 passing over the engine hanger 14. [0020] A fuel injection valve 20 for injecting a fuel toward the downstream end of the air intake port 7a is attached to the cylinder head 7. [0021] Detailed description will now be made of the air intake control apparatus according to the present invention including the above-mentioned throttle body 17. [0022] As shown in Figs. 4 to 8, the air intake path 17a of the throttle body 17 has a throttle valve 21 of a butterfly type disposed to open and close the air intake path 17a of the throttle body 17, and a valve stem 22 supporting the throttle valve 21 horizontally traverses the air intake path 17a and is rotatably supported in both a right-side and a left-side wall of the throttle body 17. A throttle drum 23 is fixed to one end of the valve stem 22 that projects in a direction of one side of the throttle body 17. The throttle drum 23 is connected with a single throttle cable 24 and a return spring 25 that biases the throttle valve 21 in a closing direction. The throttle valve 21 is opened by pulling the throttle cable 24 by means of a throttle operating member not shown in the figures. [0023] The outer wall of the throttle body 17 from which the other end of the valve stem 22 projects is integrally formed with a connecting flange 27, which is parallel to the air intake path 17a and orthogonal to the valve stem 22. A control block 28 of a synthetic resin formed separately from the throttle body 17 is detachably connected to the connecting flange 27 with a plurality of bolts 29, 29, .... A bypass 30 that bypasses the throttle valve 21 and connects to the air intake path 17a is formed between the throttle body 17 and the control block 28. [0024] As clearly shown in Fig. 4, Fig. 9, and Fig. 13, the bypass 30 comprises: a bypass entrance 31i pierced in the throttle body 17 for communicating a side of the air intake path 17a upstream from the throttle valve 21 with a joint surface of the connecting flange 27; a bypass exit 31o pierced in the throttle body 17 for communicating a side of the air intake path 17a downstream from the throttle valve 21 with the joint surface of the connecting flange 27; a bypass upstream groove 32i formed in the joint surface of the connecting flange 27 and having one end connected to the bypass entrance 31i; a bypass downstream groove 32o formed in the joint surface of the connecting flange 27 and having one end connected to the bypass exit 31o; a valve hole entrance 33i formed in the control block 28 and joined to the other end of the bypass upstream groove 32i; a valve hole exit 33o formed in the control block 28 and joined to the other end of the bypass' downstream groove 32o; and a valve hole 34 in the shape of a bottomed cylinder formed in the control block 28 in parallel with the air intake path 17a for providing communication between the valve hole entrance 33i and the valve hole exit 33o. In this case, the valve hole 34 is disposed above the bypass entrance 31i and the bypass exit 31o, and the valve hole entrance 33i and the valve hole exit 33o open to a lower surface of the valve hole 34. [0025] In Fig. 12 and Fig. 13, a piston-shaped bypass valve 35 for controlling an amount of communication between the valve hole entrance 33i and the valve hole exit 33o is slidably fitted into the valve hole 34. The valve 35 is joined with a driving member 37 for driving the valve 35 in a direction of the axis thereof via an Oldham joint 50 such that the valve 35 and the driving member 37 can be displaced from each other in a diametrical direction, and the driving member 37 is joined with an output shaft 39a of a step motor 39 via a screw mechanism 40. Specifically, the output shaft 39a formed as a screw shaft is screwed into a threaded hole 41 of the driving member 37, whereby rotation of the output shaft 39a moves the driving member 37 in a direction of the axis thereof, and also moves the bypass valve 35 via the Oldham joint 50. [0026] The step motor 39 is inserted into an actuator housing 42 disposed on the same axis as that of the valve hole 34 and opening to one side of the control block 28, and is held by a plug 44 screwed into the opening of the actuator housing 42 via a seal member 43. [0027] As clearly shown in Figs. 16(A) and 16(B), the bypass valve 35 has a relatively deep cylindrical bottomed hollow portion 45 opening to the bottom portion of the valve hole 34, and a keyway 47 and a measuring groove 48 in the form of an indentation for providing communication between the interior and the exterior of the bottomed hollow portion 45. The keyway 47 is engaged with a key 49 erected from the bottom portion of the valve hole 34, thus acting as a stop for the bypass valve 35 while allowing the sliding of the bypass valve 35. The measuring groove 48 is disposed in correspondence with the valve hole exit 33o, and is formed by a wide portion 48a having a fixed groove width and extending in the direction of the axis of the bypass valve 35, and a tapered portion 48b joined to one end of the wide portion 48a and having a groove width that decreases with increasing distance from the wide portion 48a. [0028] As shown in Fig. 13 and Fig. 15, the Oldham joint 50 is formed by: a first square hole 51 disposed in the bypass valve 35 and adjoining the bottomed hollow portion 45; a joint member 53 fitted into the first square hole 51 so as to be slidable in a first lateral direction X; and a second square hole 52 disposed in the joint member 53 such that the driving member 37 is fitted into the second square hole 52 so as to be slidable in a second lateral direction Y perpendicular to the first lateral direction X. The driving member 37 is formed relatively long so as to penetrate the joint member 53, and is provided at one end with a large flange 37a in engagement with one end surface of the joint member 53 and the bypass valve 35. A small flange 37b situated in the bottomed hollow portion 45 is formed at the other end of the driving member 37. A retaining spring 54 for biasing the bypass valve 35 to the large flange 37a side is provided in a compressed state between the small flange 37b and the valve 35. Thus, the bypass valve 35 is resiliently sandwiched in the direction of the axis thereof between the large flange 37a and the retaining spring 54 on the driving member 37. In addition, both sides of the valve 35 in the direction of the axis thereof are communicated with each other via the first and second square holes 51 and 52 and a sliding clearance between the valve 35 and the valve hole 34. The joint member 53 is sandwiched in the direction of the axis thereof between a step portion 35a of the bypass valve 35 facing the first square hole 51 and the large flange 37a of the driving member 37. [0029] As is clear from Fig. 9, Fig. 13, and Fig. 14, the bypass valve 35 and the step motor 39 arranged on the same axis and in parallel with the air intake path 17a are disposed over the valve stem 22 horizontally arranged for the throttle valve 21. Also, the bypass valve 35 and the step motor 39 are arranged so as to face the upstream side and the downstream side, respectively, of the air intake path 17a, and correspondingly the bypass downstream groove 32o is formed so as to be longer than the bypass upstream groove 32i. [0030] Accordingly, the air intake control apparatus is miniaturized by arranging the valve hole 34 and hence the bypass valve 35 in parallel with the air intake path 17a. In addition, the step motor 39 and the bypass valve 35 can be disposed over the throttle valve stem 22 in a well-balanced manner, which also contributes to the miniaturization of the air intake control apparatus. [0031] In Fig. 12 and Fig. 13, the actuator housing 42 has a diameter greater than that of the valve hole 34 arranged in front of the actuator housing 42 on the same axis as that of the actuator housing 42, and has a ring-shaped step portion 55 formed at a boundary between the actuator housing 42 and the valve hole 34. A seal member 57 is sandwiched between the ring-shaped step portion 55 and the front end surface of the step motor 39 inserted in the actuator housing 42. Hence, the seal member 57 is held in place between the front end surface of the step motor 39 and the ring-shaped step portion 55 simultaneously with the insertion of the step motor 39 into the actuator housing 42, thus increasing the ease of assembly. [0032] The seal member 57 is formed by a ring-shaped reinforcing plate 58 made of a synthetic resin and an elastic covering 59 of rubber bonded by molding to the reinforcing plate 58 so as to cover the reinforcing plate 58. A pair of front and rear side lips 60 and 60 is formed in an outer circumference portion of the elastic covering 59, and an inner circumference lip 61 is formed on an inner circumference surface of the elastic covering 59. The side lips 60 and 60 are in close contact with the ring-shaped step portion 55 and the front end surface of the step motor 39, respectively, while the inner circumference lip 61 is in close contact with an outer circumference surface of a root portion of the output shaft 39a. The side lips 60 and 60 and the inner circumference lip 61 are retained in a proper seal position by the reinforcing plate 58, and are thus able to perform an excellent seal function at all times. [0033] A plurality of anchor holes 62 are pierced in the reinforcing plate 58, and are filled with the elastic covering 59 to enhance the bonding strength between the reinforcing plate 58 and the elastic covering 59. Furthermore, making the reinforcing plate 58 of a synthetic resin results in a reduction in weight of the seal member 57. [0034] In Fig. 5, Fig. 10, and Fig. 11, a throttle sensor 64 for detecting a degree of opening of the throttle valve 21 is attached to the control block 28. The throttle sensor 64 includes: a case 66 fitted into an attaching indentation portion 65 formed in an outer surface of the control block 28; a rotor 67 connected to an end portion of the valve stem 22 of the throttle valve 21 within the case 66; and a stator 68 fixed to the case 66 so as to detect a rotation angle of the rotor 67 as the degree of opening of the throttle valve 21. [0035] As shown in Fig. 5, Fig. 9, and Fig. 14, on one side of the attaching indentation portion 65 of the throttle sensor 64, the throttle body 17 and the control block 28 are provided with a first sensor inserting hole 71 that is orthogonal to the connecting flange 27 and opens to the upstream side of the air intake path 17a. An intake air temperature sensor 73 for detecting upstream temperature of the air intake path 17a is inserted into the first sensor inserting hole 71 from the control block 28 side. Also, a boost negative pressure detecting hole 74 opening to the downstream side of the air intake path 17a is formed in the throttle body 17, and a second sensor inserting hole 72 situated directly above the first sensor inserting hole 71 is formed in the control block 28. A communication path 75 for providing communication between the boost negative pressure detecting hole 74 and the second sensor inserting hole 72 is formed in the joint surface of the connecting flange 27 as a bending groove going around the throttle sensor 64 therebelow. A boost negative pressure sensor 76 for detecting negative pressure of the intake air on the downstream side of the air intake path 17a, that is, boost negative pressure of the engine 5 through the boost negative pressure detecting hole 74 is inserted into the second sensor inserting hole 72. Thus, the intake air temperature sensor 73 and the boost negative pressure sensor 76 are disposed at positions adjacent to each other. [0036] The bypass entrance 31i, or the upstream end of the bypass 30, is disposed at a position adjacent to the first sensor inserting hole 71 on a side of the air intake path 17a upstream from the inserting hole 71. Also, while the communication path 75 is disposed so as to go around the throttle sensor 64 therebelow, the bypass downstream groove 32o is disposed so as to go around the throttle sensor 64 thereover. [0037] In Figs. 4 to 8 and Fig. 14, a coupler 80 flattened in a vertical direction is provided over the control block 28. The coupler 80 includes: a coupler body 81 formed integrally with the control block 28; and a large number of connectors 82 embedded in the coupler body 81. The coupler body 81 extends beyond the connecting flange 27 to a position directly above the throttle body 17, and a coupling mouth 80a opens in a direction opposite from the control block 28. The coupling mouth 80a is coupled with an external coupler 83 connected with a wire harness 86 joined to a power supply and the like. [0038] The control block 28 provided with the coupler 80 is of a box shape in which an outer end surface on a side opposite from the connecting flange 27 is opened, and the outer end surface is provided with a board 84a of an electronic control unit 84. In this case, the board 84a is connected directly by soldering with connecting terminals 73a, 76a, and 64a of the intake air temperature sensor 73, the boost negative pressure sensor 76, and the throttle sensor 64 as well as inner ends of the connectors 82 of the coupler 80 (see Figs. 10 to 12). A reference numeral 85 denotes various semiconductor devices attached to the surface of the board 84a. [0039] Thus, even if a foreign substance such as a fuel oil drop enters the boost negative pressure detecting hole 74 from the air intake path 17a in the horizontal type throttle body 17 as a result of an intake air reversing phenomenon of the engine 5, the foreign substance cannot go up to the boost negative pressure sensor 76 because the communication path 75 provides a great level difference between the boost negative pressure detecting hole 74 and the boost negative pressure sensor 76 situated above the boost negative pressure detecting hole 74, and the communication path 75 forms a bent path having a high channel resistance. It is therefore possible to protect the boost negative pressure sensor 76 from a foreign substance and thereby ensure the function and durability of the boost negative pressure sensor 76. [0040] In addition, since the intake air temperature sensor 73 and the boost negative pressure sensor 76 are disposed on one side of the throttle sensor 64 in a concentrated manner, it is possible to connect the intake air temperature sensor 73 and the boost negative pressure sensor 76 to the electronic control unit 84 in a concentrated manner and thereby miniaturize the unit 84. [0041] Moreover, since the groove as the communication path 75 and the bypass upstream groove 32i and the bypass downstream groove 32o as a main portion of the bypass 30 are formed in the joint surface of the connecting flange 27 of the throttle body 17, it is possible to form the groove, the bypass upstream groove 32i, and the bypass downstream groove 32o simultaneously with the formation of the throttle body 17, thereby eliminating the need for special machining to form the groove, the bypass upstream groove 32i, and the bypass downstream groove 32o, and hence making it possible to enhance productivity. [0042] Furthermore, since the bypass entrance 31i is disposed at a position adjacent to the first sensor inserting hole 71 situated below the second sensor inserting hole 72, on a side of the air intake path 17a upstream from the inserting hole 71, it is possible to concentrate the first sensor inserting hole 71, the second sensor inserting hole 72, and the bypass entrance 31i without letting the first sensor inserting hole 71, the second sensor inserting hole 72, and the bypass entrance 31i interfere with each other, and to thereby contribute to miniaturization of the control block 28. [0043] Furthermore, since the bypass downstream groove 32o and the communication path 7 5 are disposed so as to surround the throttle sensor 64 from above and below the throttle sensor 64, it is possible to dispose the bypass downstream groove 32o and the communication path 75 around the throttle sensor 64 in a compact manner without letting the bypass downstream groove 32o and the communication path 75 interfere with each other, and to thereby contribute to further miniaturization of the control block 28. [0044] Returning to Fig. 4, a positioning projection 87 is formed at a pair of corner portions on one diagonal line of the outer end surface of the control block 28 provided with the coupler 80, and a threaded hole 88 is formed at corner portions on the other diagonal line. On the other hand, the board 84a is provided with a positioning hole 89 corresponding to the positioning projection 87 and a screw hole 90 corresponding to the threaded hole 88. The positioning hole 89 is engaged with the positioning projection 87, and a screw 91 inserted through the screw hole 90 is screwed into the threaded hole 88, whereby the board 84a is fixed at a predetermined position of the control block 28. [0045] As shown in Fig. 12 and Fig. 17, a connector piece 92 of a synthetic resin substantially in the form of a rectangular parallelepiped is positioned and fixed to the control block 28 between the step motor 39 and the board 84a. A plurality of lead frames 93, 93 ... are buried in the connector piece 92. A connecting terminal 93a formed at one end of each of the lead frames 93 is connected directly to the board 84a by soldering, and a connector hole 94 is formed at the other end of each of the lead frames 93. [0046] A plurality of connector pins 96, 96 ... project from a front end surface (front-side end surface as viewed in a direction of insertion of the step motor 39 into the actuator housing 42) of a terminal lead unit 95 provided on the outer surface of the step motor 39 in a projecting manner. The connector pins 96, 96 ... are inserted into the connector holes 94, 94 ... simultaneously with the insertion of the step motor 39 into the actuator housing 42. [0047] The electronic control unit 84 controls operation of not only the step motor 39 and the fuel injection valve 20 but also an ignition device (not shown) and the like on the basis of output signals from the throttle sensor 64, the boost negative pressure sensor 76, and the intake air temperature sensor 73 as well as an engine speed sensor, an engine temperature sensor, and the like not shown in the figures. The signals and power are supplied and received via the coupler 80 and the external coupler 83 connected to the coupler 80. [0048] As shown in Fig. 4 and Fig. 9, a seal groove 97 surrounding the periphery of the bypass upstream groove 32i, the bypass downstream groove 32o, the first sensor inserting hole 71, the boost negative pressure detecting hole 74, and the communication path 75 is formed in the joint surface of the connecting flange 27. A seal member 98 to be brought into close contact with the control block 28 is inserted in the seal groove 97 to thereby retain airtightness of the bypass upstream groove 32i, the bypass downstream groove 32o, and the like. [0049] As shown in Fig. 4, Fig. 11, and Fig. 12, a cap 101 made of an Al alloy plate for housing the electronic control unit 84 is socket-fitted onto a stepped fitting surface 100 formed on the periphery of the outer end portion of the control block 28 provided with the coupler 80. In this case, a latching projection 105 and a latching hole 106 formed on and in the fitting surfaces (see Fig. 4 and Fig. 11) are resiliently engaged with each other. The cap 101 is formed by the press forming of an Al alloy plate to provide a good appearance with no wrinkle. Thus, since the cap 101 provides a good appearance to the control block 28, the cap 101 is useful when the control block 28 is exposed to the outside as in the motorcycle 1. [0050] The control block 28 is provided with a potting opening 102 adjacent to an opened end surface of the cap 101, which opening communicates with the interior of the cap 101 and opens to an opposite side from the cap 101 (see Fig. 8 and Fig. 14) . With the cap 101 turned downward, a synthetic resin 103 is potted from the potting opening 102 into the cap 101 up to a socket-fitted portion of the cap 101, thereby covering the electronic control unit 84 and sealing the socket-fitted portion of the cap 101. [0051] The potting resin 103 protects the electronic control unit 84 from rain water, dust, and vibration, and, in particular, seals the portion of the cap 101 socket-fitted to the control block 28 to effectively provide water resistance and dust resistance. In addition, adhesive strength of the potting resin 103 can increase bonding strength of the cap 101 to the control block 28. [0052] Also, since with the electronic control unit 84 housed in the cap 101 and the cap 101 turned downward, the synthetic resin 103 is potted from the potting opening 102 situated at an upper position, it is possible to protect the electronic control unit 84 and bond the cap 101 effectively with a required minimum amount of the potting resin 103. Thus, it is possible to prevent the synthetic resin 103 from entering the bypass valve 35 and the step motor 39 situated above the cap 101. [0053] At the time of potting, it is possible to readily adjust the amount of potting while visually checking from the potting opening 102 a state of the potting of the synthetic resin into the cap 101. In addition, since the potting resin 103 embeds portions connected to the board 84a of the connecting terminals 64a, 73a, and 76a of the sensors 64, 73, and 76 and the connecting terminal 93a of the connector piece 92, the potting resin 103 can improve vibration resistance of the connecting terminals 64a, 73a, 76a, and 93a. [0054] Returning to Fig. 3 and Fig. 7, the control block 28 provided with the sensors 64, 73, and 76 and the electronic control unit 84 is disposed on one of a left and a right side of the throttle body 17, whereas the coupler 80 is disposed above the throttle body 17, that is, between the throttle body 17 and a bottom wall of the luggage box 3. Such a dispersed arrangement of the sensors 64, 73, and 76, the electronic control unit 84, and the coupler 80 allows the sensors 64, 73, and 76, the electronic control unit 84, and the coupler 80 to be readily disposed even in a small space around the throttle body 17 in the motorcycle 1. In particular, the coupler 80 can be flattened in a vertical direction, and therefore even when the coupler 80 is disposed above the throttle body 17, there is practically no need for moving upward the bottom portion of the luggage box 3 situated over the coupler 80, thus making it possible to increase capacity of the luggage box 3. [0055] Moreover, since the coupling mouth 80a of the coupler 80 to be coupled with the external coupler 83 opens on an opposite side from the electronic control unit 84, it is possible to readily connect the external coupler 83 to the coupler 80 without the electronic control unit 84 and the engine 5 being in the way, and to thus obtain great ease of assembly and maintenance. [0056] In addition, the throttle drum 23 is fixed to one end of the valve stem 22 extending in a right to left direction which end is on an opposite side from the electronic control unit 84, and the throttle cable 24 connected to the throttle drum 23 is disposed so as to pass below the coupling mouth 80a of the coupler 80 (see Fig. 8). This makes it possible to avoid interference between the throttle cable 24 and the wire harness 86 of the external coupler 83 coupled to the coupler 80, and to thereby increase the ease of assembly and maintenance. [0057] As shown in Fig. 2, Fig. 3, Fig. 7, and Fig. 8, the throttle cable 24 connected to the throttle drum 23 passes a lower portion of the throttle drum 23, extends rearward for a distance, bends so as to form a U-shape within the crank portion of the engine hanger 14, then extends forward along the down tube l1b on one side of the body frame 11, and is connected to a throttle operating member (not shown) provided to a steering handlebar 36 (Fig. 1). [0058] When the power unit 4 moves up and down in accordance with extension and contraction of the rear cushion unit 26 while the motorcycle 1 is moving, the throttle body 17 is also rocked together with the power unit 4. As the throttle body 17 is rocked, mainly the U-shaped bending portion of the throttle cable 24 bends without strain, whereby it is possible to prevent an excessive stress from occurring on the throttle cable 24 and thus ensure durability of the throttle cable 24. In addition, while the throttle drum 23 and the coupling mouth 80a of the coupler 80 are disposed on the same side of the throttle body 17, the single throttle cable 24 is disposed in a manner as described above. Hence, a relatively large workspace where the throttle cable 24 is not in the way can be obtained around the coupling mouth 80a of the coupler 80, thus facilitating the connection of the external coupler 83 to the coupling mouth 80a. [0059] Operation of the air intake control apparatus will be described in the following. [0060] When the throttle valve 21 is completely closed, the electronic control unit 84 determines an operating condition of the engine 5 at the times of a start of the engine, fast idling, normal idling, engine braking and the like on the basis of output signals from the throttle sensor 64, the intake air temperature sensor 73, the boost negative pressure sensor 76, and the like. In order to obtain a degree of opening of the bypass valve 35 corresponding to the operating condition, the electronic control unit 84 operates the step motor 39 to thereby rotate the output shaft 39a in a forward direction or a reverse direction. [0061] When the output shaft 39a is rotated in the forward direction or the reverse direction, the driving member 37 moves in the direction of the axis thereof to thereby slide the bypass valve 35 forward or rearward along the valve hole 34 via the joint member 53, so that an opening area of the measuring groove 48 in relation to the valve hole exit 33o, that is, the degree of opening of the bypass 30 is decreased or increased and thus the amount of intake air flow in the bypass 30 is controlled. In particular, by moving the tapered portion 48b of the measuring groove 48 in relation to the valve hole exit 33o, the amount of intake air flow can be finely controlled in a range of zero to a predetermined maximum value. As a result, the start of the engine, fast idling, and normal idling are automatically made properly. [0062] In this case, even when the axes of the bypass valve 35 and the output shaft 39a of the step motor 39 displace from each other due to a manufacturing error, the displacement is accommodated by the movement of the joint member 53 of the Oldham joint 50 along the first lateral direction X and the movement of the driving member 37 along the second lateral direction Y. Therefore, regardless of the displacement, smooth sliding of the bypass valve 35 can be ensured, and at the same time, vibration of the bypass valve 35 is controlled by the retaining spring 54. [0063] When the bypass valve 35 is completely closed, an intake negative pressure of the engine 5 acts on the side of the bypass valve 35 facing the valve hole exit 33o. In that case, the Oldham joint 50 allows translation of the bypass valve 35 in a direction of the action of the intake negative pressure. Hence, the bypass valve 35 is securely brought into close contact with the periphery of the valve hole exit 33o to thereby prevent or minimize a leak of bypass intake air from the valve hole exit 33o. Accordingly, the valve hole 34 and the bypass valve 35 do not require a particularly high dimensional accuracy, thus contributing to improvement of productivity. [0064] In addition, both end surfaces of the bypass valve 35 in the direction of the axis thereof are communicated with each other through the first and second square holes 51 and 52 of the Oldham joint 50 and the sliding clearance between the valve 35 and the valve hole 34. Hence, no matter what pressure is transmitted to the valve hole 34, no difference in pressure occurs between both the end surfaces of the bypass valve 35 in the direction of the axis thereof. It is therefore possible to operate the bypass valve 35 lightly even with a relatively low power of the step motor 39. This means a capability to realize a reduction in the power of the step motor 39 and hence a reduction in the size of the step motor 39 while enhancing response of the bypass valve 35. [0065] Moreover, the bypass valve 35 is biased by the retaining spring 54 in a direction of from the valve hole entrance 33i to the valve hole exit 33o, and the biasing force is received by the large flange 37a of the driving member 37 into which the output shaft 39a of the step motor 39 is screwed directly. Therefore, when the output shaft 39a is rotated in a direction of closing the bypass valve 35, in particular, the driving member 37 directly presses the bypass valve 35 in the closing direction by means of the large flange 37a. Thus, regardless of the presence of the retaining spring 54, closing speed of the bypass valve 35 can be increased. [0066] On the other hand, as the throttle valve 21 is gradually opened, an amount of intake air corresponding to the increase in the degree of opening is supplied through the air intake path 17a to the engine 5, thus controlling the output of the engine 5. [0067] In such an air intake control apparatus, the control block 28 provided with the coupler 80 is connected to the connecting flange 27 of the throttle body 17 as a unit separate from the connecting flange 27, and the control block 28 is provided with the bypass valve 35, the step motor 39, the intake air temperature sensor 73, the boost negative pressure sensor 76, the throttle sensor 64, and the electronic control unit 84. It is therefore possible to machine the throttle body 17 and manufacture the control system assembly including the control block 28 simultaneously. In particular, it is possible to conduct a function test on the step motor 39, the bypass valve 35, the sensors 64, 73, and 76, the electronic control unit 84, and the like by connecting the coupler 80 with a power supply and the like as required before connecting the control block 28 to the throttle body 17. Accordingly, only a product that has passed the test is attached to the throttle body 17, thereby eliminating useless assembly operation and hence making it possible to improve productivity. [0068] In addition, the electronic control unit 84 is installed on the outer end surface of the control block 28, and electrical connections are provided between the step motor 39, the sensors 64, 73, and 76, and the coupler 80 via the electronic control unit 84. It is therefore possible to simplify the connections between the step motor 39, the sensors 64, 73, and 76, and the coupler 80, and to thereby further enhance the ease of assembly. [0069] Moreover, the connector pins 96 projecting in the direction of inserting the step motor 39 into the actuator housing 42 are provided for the step motor 39, and the connector holes 94 in which the connector pins 96 are inserted are provided for the lead frames 93 joined to the coupler 80 on the control block 28 side. An electrical connection between the step motor 39 and the coupler 80 is therefore made simultaneously with the attachment of the step motor 39 to the control block 28. It is thus possible to eliminate the need for special operation for the electrical connection and to thereby further enhance the ease of assembly. [0070] Furthermore, the lead frames 93 having the connector holes 94 are embedded in the connector piece 92, which is a small part positioned and fixed to the control block 28 between the step motor 39 and the electronic control unit 84. The embedding of the lead frames 93 is therefore very easy and accurate as compared with the embedding of the lead frames 93 in the control block 28, which is a large part. By setting the connector piece 92 in the control block 28, the connector holes 94 of the lead frames 93 can be accurately disposed in position, whereby accurate engagement of the connector holes 94 with the connector pins 96 of the step motor 39 is ensured. [0071] Furthermore, the actuator housing 42 for inserting the step motor 39 is provided so as to open to a peripheral surface of the control block 28 different from the outer end surface of the control block 28 for installing the electronic control unit 84. It is therefore possible to miniaturize the control block 28. Also, the step motor 39 is detachable regardless of the installation of the electronic control unit 84. It is therefore possible to readily maintain the step motor 39 and the bypass valve 35. [0072] While the operation of the engine 5 is stopped, moisture in the air within the valve hole 34 can form condensation on the inner wall of the valve hole 34. The seal member 57 provided between the valve hole 34 and the actuator housing 42 prevents the condensed water drops from entering the step motor 39. It is therefore possible to protect the step motor 39 and enhance the durability of the step motor 39. [0073] In particular, the seal member 57 is sandwiched between the step motor 39 and the ring-shaped step portion 55 between the valve hole 34 and the actuator housing 42. The seal member 57 has, on its inner circumference surface, the inner circumference lip 61 in close contact with the outer circumference surface of the root portion of the output shaft 39a of the step motor 39. Therefore, the inner circumference lip 61 has a very low frictional resistance to the rotating surface of the output shaft 39a, thus eliminating its effect on the response of the bypass valve 35. In addition, even in the case of the bypass valve 35 that allows the tip of the output shaft 39a to be exposed to the inside of the valve hole 34, it is possible to provide a secure seal between the step motor 39 and the valve hole 34 with the single seal member 57. Thus, the seal member 57 can be applied regardless of the structure of the bypass valve 35, and therefore the seal member 57 has a wide range of applications. [0074] While the operation of the engine 5 is stopped, the bypass valve 35 normally closes the valve hole exit 33o completely. Therefore, even if a fuel gas produced on the downstream side of the air intake path 17a enters the downstream side of the bypass 30, the bypass valve 3 5 blocks the entry of the fuel gas into the valve hole 34. Thus, even if the sealing function of the seal member 57 should be degraded, the bypass valve 35 prevents the step motor 39 from being exposed to the fuel gas, and can thereby ensure the durability of the step motor 39. [0075] Furthermore, since length of the side of the bypass 30 downstream from the valve hole 34 is set sufficiently long, it is difficult for the fuel gas produced on the downstream side of the air intake path 17a to pass through the downstream portion of the sufficiently long bypass. It is therefore possible to prevent the entry of the fuel gas into the valve hole 34 and thereby further contribute to protection of the step motor 39. [0076] In addition, since the valve hole entrance 33i and the valve hole exit 33o situated above the bypass entrance 31i and the bypass exit 31o in the bypass 30 open to the lower side of the valve hole 34, it is difficult for a foreign substance such as dust to enter the valve hole 34 from the valve hole entrance 33i and the valve hole exit 33o. It is therefore possible to avoid a malfunction of the bypass valve 35 caused by the entry of a foreign substance. [0077] The present invention is not limited to the example described above, and is susceptible of various changes in design without departing from the spirit of the present invention. For example, the bypass upstream groove 32i, the bypass downstream groove 32o, and the communication path 75 may be formed on the joint surface side of the control block 28 joined to the connecting flange 27. [0078] [Effect of the Invention] As described above, according to a first feature of the present invention, in a small vehicle including a luggage box disposed under a seat and an engine disposed under the luggage box, and including a throttle body disposed between the luggage box and the engine, the throttle body having an air intake path joined to an air intake port of the engine and extending in a front to rear direction of the vehicle and a throttle valve for opening and closing the air intake path, sensors for detecting operating conditions of the engine and an electronic control unit for controlling operation of a fuel injection valve of the engine according to output signals from the sensors are attached on one of a right and a left side of the throttle body, and a coupler connected to the electronic control unit and having a coupling mouth coupled with an external coupler and opening to the other of the right and left sides of the throttle body is disposed above the throttle body. Therefore, the dispersed arrangement of the sensors and the electronic control unit and the coupler allows the sensors, the electronic control unit, and the coupler to be readily disposed even in a small space around the throttle body in the small vehicle. In particular, the coupler can be flattened in a vertical direction, and therefore even when the coupler is disposed above the throttle body, there is practically no need for moving upward the bottom portion of the luggage box situated over the coupler, thus making it possible to increase the capacity of the luggage box. [0079] Moreover, since the coupling mouth of the coupler coupled with the external coupler opens to an opposite side from the electronic control unit, it is possible to readily connect the external coupler to the coupler without the electronic control unit and the engine being in the way, and to thus obtain great ease of assembly and maintenance. [0080] In addition, according to a second feature of the present invention, in addition to the first feature, a valve stem of the throttle valve is disposed in a right to left direction orthogonal to the air intake path, a throttle drum is fixed to one end of the valve stem on an opposite side from the electronic control unit, and a throttle cable connected to the throttle drum is disposed so as to pass below the coupling mouth of the coupler. Therefore, it is possible to avoid interference between the throttle cable and the wire harness of the external coupler coupled to the coupler, and to thereby increase the ease of assembly and maintenance. [0081] Moreover, according to a third feature of the present invention, in addition to the second feature, the throttle cable connected to the throttle drum is disposed so as to extend rearward for a distance, bend so as to form a U-shape, and then extend forward. Therefore, even when the throttle body is rocked together with the engine, mainly the U-shaped bending portion of the throttle cable bends without strain, whereby it is possible to prevent an excessive stress on the throttle cable and thus ensure the durability of the throttle cable. [0082] Furthermore, according to a fourth feature of the present invention, in addition to the second or third feature, the throttle drum is connected with a return spring that biases the throttle drum in a direction of closing the throttle valve and the single throttle cable that is pulled against the biasing force of the return spring to open the throttle valve, and the throttle cable passes a lower portion of the throttle drum and is then drawn out. Therefore, while the throttle drum and the coupling mouth of the coupler are disposed on the same side of the throttle body, a relatively large workspace where the throttle cable is not in the way can be obtained around the coupling mouth of the coupler, thus facilitating the connection of the external coupler the coupling mouth. [Description of Reference Numerals] 2 . . . seat 3 . . . luggage box 5 . . . engine 7a...air intake port 17. . .throttle body 17a...air intake path 2 0...fuel injection valve 21... throttle valve 22...valve stem 23 ... throttle drum. 24 ... throttle cable 25...return spring 64...sensor (throttle sensor) 73...sensor (intake air temperature sensor) 76...sensor (boost negative pressure sensor) 80 . ..coupler 80a...coupling mouth 83 ... external coupler 84 ... electronic control unit 3. An apparatus for controlling air intake of an engine in a small vehicle as claimed in claim 1 or 2, wherein the throttle drum (23) is connected with a return spring (25) that biases the throttle drum (23) in a direction of closing the throttle valve (21) and the single throttle cable (24) that is pulled against the biasing force of the return spring (25) to open the throttle valve (21), and the throttle cable (24) passes a lower portion of the throttle drum (23) and is then drawn out. 4. An apparatus for controlling air intake of an engine in a small vehicle substantially as hereinbefore described with reference to the accompanying drawings. Dated this 03/05/2002 [RITUSHKA NEGI] OF REMFRY & SAGAR ATTORNEY OF THE APPLICANT We claim: 1. An apparatus for controlling air intake of an engine in a small vehicle, the apparatus having a throttle body (17) disposed between a luggage box (3) directly under a seat (2) and an engine (5) disposed under the luggage box (3), the throttle body (17) having an air intake path (17a) joined to an air intake port (7a) of the engine (5) and a throttle valve (21) for opening and closing the air intake path (17a), wherein sensors (64, 73, 76) for detecting operating conditions of the engine (5) and an electronic control unit (84) for controlling operation of a fuel injection valve (20) of the engine (5) according to output signals from the sensors (64, 73, 76) are attached on one of a right and left side of the throttle body (17), and a coupler (80) connected to the electronic control unit (84) and having a coupling mouth (80a) coupled with an external coupler (83) and opening to the other of the right and left sides of the throttle body (17) is disposed above the throttle body (17) characterized in that a valve stem (22) of the throttle valve (21) is disposed in a right to left direction orthogonal to the air intake path (17a), a throttle drum (23) is fixed to one end of the valve stem (22) on an opposite side from the electronic control unit (84), and a throttle cable (24) connected to the throttle drum (23) is disposed so as to pass below the coupling mouth (80a) of the coupler (80). 2. An apparatus for controlling air intake of an engine in a small vehicle as claimed in claim 1, wherein the throttle cable (24) connected to the throttle drum (23) is disposed so as to extend rearward for a distance, bend so as to form a U-shape, and then extend forward.

Full Text

FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
COMPLETE SPECIFICATION
[See Section 10]
"APPARATUS FOR CONTROLLING AIR INTAKE OF ENGINE IN SMALL VEHICLE"
HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan
The following specification particularly describes the nature of the invention and the manner in which it is to be performed :-

GRANTED

-3 MAY 2002

The present invention relates to apparatus for controlling air intake of engine in small vehicle
[Detailed Description of the Invention] [0001] [Technical Field to which the Invention Pertains]
The present invention relates to an apparatus for controlling air intake of an engine in a small vehicle, in which apparatus a throttle body having an air intake path joined to an air intake port of the engine and a throttle valve for opening and closing the air intake path is disposed between a luggage box directly under a seat and the engine disposed under the luggage box. [0002] [Prior Art]
Such an apparatus for controlling air intake of an engine in a small vehicle is already known, as disclosed in Japanese Patent Laid-Open No. 2000 138975, for example. [0003]
Also, as disclosed in Japanese Patent Laid-Open No. Hei ll-294il6, for example, an apparatus for controlling

fuel injection of an engine is already known in which a boost negative pressure sensor, an intake air temperature sensor, an electronic control unit for processing output signals from the boost negative pressure sensor and the intake air temperature sensor, and a coupler for input and output to the electronic control unit are provided in a concentrated manner over a throttle body, and operation of a fuel injection valve of the engine is controlled on the basis of the output signals from the boost negative pressure sensor, the intake air temperature sensor, and the like.
[0004]
[Problems to be Solved by the Invention]
When the latter apparatus for controlling fuel injection is to be employed in the former apparatus for controlling air intake of an engine in a small vehicle, the electronic control unit, the coupler and the like will project high above the throttle body. The bottom portion of the luggage box situated above the electronic control unit, the coupler, and the like therefore needs to be moved upward in order to avoid interference with the electronic control unit, the coupler, and the like. This, however, reduces capacity of the luggage box, and hence is not desirable.

[0005]
The present invention has been made in view of the above, and it is accordingly an object of the present invention to provide an apparatus for controlling air intake of the engine in the small vehicle in which apparatus the sensors for controlling fuel injection, the electronic control unit, and the coupler are rationally-disposed around the throttle body so that the bottom portion of the luggage box can be held at as low a position as possible.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to a first feature of the present invention, in a small vehicle including a luggage box disposed under a seat and an engine disposed under the luggage box, and including a throttle body disposed between the luggage box and the engine, the throttle body having an air intake path joined to an air intake port of the engine and extending in a front to rear direction of the vehicle and a throttle valve for opening and closing the air intake path, sensors for detecting operating conditions of the engine and an electronic control unit for controlling operation of a fuel injection valve of the engine

according to output signals from the sensors are attached on one of a right and a left side of the throttle body, and a coupler connected to the electronic control unit and having a coupling mouth coupled with an external coupler and opening to the other of the right and left sides of the throttle body is disposed above the throttle body. [0007]
According to the first feature, the dispersed arrangement of the sensors and the electronic control unit and the coupler allows the sensors, the electronic control unit, and the coupler to be readily disposed even in a small space around the throttle body. In particular, the coupler can be flattened in a vertical direction, and therefore even when the coupler is disposed above the throttle body, there is practically no need for moving upward the bottom portion of the luggage box situated over the coupler, thus making it possible to increase the capacity of the luggage box. [0008]
Moreover, since the coupling mouth of the coupler coupled with the external coupler opens to an opposite side from the electronic control unit, it is possible to readily connect the external coupler to the coupler

without the electronic control unit and the engine being in the way, and to thus obtain great ease of assembly and maintenance.
[0009]
In addition, according to a second feature of the present invention, in addition to the first feature, a valve stem of the throttle valve is disposed in a right to left direction orthogonal to the air intake path, a throttle drum is fixed to one end of the valve stem on an opposite side from the electronic control unit, and a throttle cable connected to the throttle drum is disposed so as to pass below the coupling mouth of the coupler.
[0010]
According to the second feature, it is possible to avoid interference between the throttle cable and the wire harness of the external coupler coupled to the coupler, and to thereby increase the ease of assembly and maintenance.
[0011]
Moreover, according to a third feature of the present invention, in addition to the second feature, the throttle cable connected to the throttle drum is disposed so as to extend rearward for a distance, bend so as to form a U-shape, and then extend forward.

[0012]
According to the third feature, even when the throttle body is rocked together with the engine, mainly the U-shaped bending portion of the throttle cable bends without strain, whereby it is possible to prevent an excessive stress on the throttle cable and thus ensure the durability of the throttle cable.
[0013]
Furthermore, according to a fourth feature of the present invention, in addition to the second or third feature, the throttle drum is connected with a return spring that biases the throttle drum in a direction of closing the throttle valve and the single throttle cable that is pulled against the biasing force of the return spring to open the throttle valve, and the throttle cable passes a lower portion of the throttle drum and is then drawn out.
[0014]
According to the fourth feature, while the throttle drum and the coupling mouth of the coupler are disposed on the same side of the throttle body, a relatively large workspace where the throttle cable is not in the way can be obtained around the coupling mouth of the coupler, thus facilitating the connection of the external coupler

to the coupling mouth. [0015] [Mode for Carrying our the Invention]
A preferred embodiment of the present invention will hereinafter be described with reference to an example of the present invention shown in the accompanying drawings. [Brief Description of the Drawings] [Fig. 1]
Fig. 1 is a side view of a motorcycle provided with an air intake control apparatus according to the present invention. [Fig. 2]
Fig. 2 is an enlarged sectional view of a portion 2 in Fig. 1. [Fig. 3]
Fig. 3 is a sectional view taken along a line 3-3 of Fig. 2. [Fig. 4]
Fig. 4 is an exploded perspective view of the air intake control apparatus. [Fig. 5]
Fig. 5 is a side view of the air intake control apparatus... [Fig. 6]
Fig. 6 is a view taken in a direction of an arrow 6 of Fig. 5.
[Fig. 7]

Fig. 7 is a view taken in a direction of an arrow 7 of Fig. 5. [Fig. 8]
Fig. 8 is a view taken in a direction of an arrow 8 of Fig. 7. [Fig. 9]
Fig. 9 is a sectional view taken along a line 9-9 of Fig. 7. [Fig. 10]
Fig. 10 is a sectional view taken along a line 10-
10 of Fig. 5.
[Fig. 11]
Fig. 11 is a sectional view taken along a line 11-
11 of Fig. 5.
[Fig. 12]
Fig. 12 is a sectional view taken along a line 12-
12 of Fig. 5.
[Fig. 13]
Fig. 13 is an enlarged view of a bypass valve in Fig. 12 and its vicinities. [Fig. 14]
Fig. 14 is an enlarged sectional view taken along a line 14-14 of Fig. 5. [Fig. 15]

Fig. 15 is an enlarged sectional view taken along a line 15-15 of Fig. 13. [Fig. 16]
Fig. 16(A) is a side view taken from a measuring groove side of the bypass valve.
Fig. 16(B) is a side view taken from a keyway side of the bypass valve. [Fig. 17]
Fig. 17 is an enlarged sectional view of a portion 17 in Fig. 12.
[0016]
Fig. 1 is a side view of a motorcycle provided with an air intake control apparatus according to the present invention; Fig. 2 is an enlarged sectional view of a portion 2 in Fig. 1; Fig. 3 is a sectional view taken along a line 3-3 of Fig. 2; Fig. 4 is an exploded perspective view of the air intake control apparatus; Fig.
5 is a side view of the air intake control apparatus; Fig.
6 is a view taken in a direction of an arrow 6 of Fig. 5; Fig. 7 is a view taken in a direction of an arrow 7 of Fig. 5; Fig. 8 is a view taken in a direction of an arrow 8 of Fig. 7; Fig. 9 is a sectional view taken along a line 9-9 of Fig. 7; Fig. 10 is a sectional view taken along a line 10-10 of Fig. 5; Fig. 11 is a sectional view taken along a line 11-11 of Fig. 5; Fig. 12 is a sectional view taken along a line 12-12 of Fig. 5; Fig.
13 is an enlarged view of a bypass valve in Fig. 12 and

its vicinities; Fig. 14 is a sectional view taken along a line 14-14 of Fig. 5; Fig. 15 is an enlarged sectional view taken along a line 15-15 of Fig. 13; Fig. 16(A) is a side view taken from a measuring groove side of the bypass valve; Fig. 16(B) is a side view taken from a keyway side of the bypass valve; and Fig. 17 is an enlarged sectional view of a portion 17 in Fig. 12. [0017]
First, in Figs. 1 to 3, a motorcycle 1 is formed as a scooter type by disposing a power unit 4 directly under a luggage box 3 extending long in a front to rear direction and using a tandem type seat 2 also as a lid thereof. The power unit 4 is formed by an engine 5 having a cylinder block 6 greatly slanted forward, and a continuously variable transmission 8 having a transmission case 10 extending rearward joined integrally with one side of a crankcase 9 of the engine 5. A rear wheel 16 serving as a driving wheel is journaled in a rear end portion of the transmission case 10. [0018]
In a body frame 11 of the motorcycle 1, upper brackets 12 and 12 are provided at a portion connecting a pair of right and left upper frames 11a and 11a supporting the luggage box 3 with rear end portions

turned upward of a pair of right and left down tubes l1b and l1b extending from a head pipe, while a pair of right and left lower brackets 13 and 13 is formed on an upper surface of the crankcase 9 of the engine 5. The lower brackets 13 and 13 are rockably supported at a middle portion of a crank-shaped engine hanger 14 having both end portions rockably supported by the upper brackets 12 and 12. Thus, the power unit 4 is supported by the body frame 11 in a vertically rockable manner. A rear cushion unit 26 for cushioning the vertical rock is attached between rear frames 11 and 11 and the transmission case 10.
[0019]
A cylinder head 7 joined to a front end of the cylinder block 6 has an air intake port 7a formed with an upstream end opening to the rear of the vehicle body. A throttle body 17 that connects an air intake path 17a with the air intake port 7a is attached to the cylinder head 7 via a connecting tube 15. In this case, the throttle body 17 is disposed between the luggage box 3 and the engine 5 such that the air intake path 17a extends substantially horizontally (slightly slanting downward to the front in the example shown in the figures) in the front to rear direction. Thus, the

throttle body 17 is of a horizontal type. The rear end of the throttle body 17 is connected with an air cleaner 19 via an air intake duct 18 passing over the engine hanger 14.
[0020]
A fuel injection valve 20 for injecting a fuel toward the downstream end of the air intake port 7a is attached to the cylinder head 7.
[0021]
Detailed description will now be made of the air intake control apparatus according to the present invention including the above-mentioned throttle body 17.
[0022]
As shown in Figs. 4 to 8, the air intake path 17a of the throttle body 17 has a throttle valve 21 of a butterfly type disposed to open and close the air intake path 17a of the throttle body 17, and a valve stem 22 supporting the throttle valve 21 horizontally traverses the air intake path 17a and is rotatably supported in both a right-side and a left-side wall of the throttle body 17. A throttle drum 23 is fixed to one end of the valve stem 22 that projects in a direction of one side of the throttle body 17. The throttle drum 23 is connected with a single throttle cable 24 and a return spring 25

that biases the throttle valve 21 in a closing direction. The throttle valve 21 is opened by pulling the throttle cable 24 by means of a throttle operating member not shown in the figures.
[0023]
The outer wall of the throttle body 17 from which the other end of the valve stem 22 projects is integrally formed with a connecting flange 27, which is parallel to the air intake path 17a and orthogonal to the valve stem 22. A control block 28 of a synthetic resin formed separately from the throttle body 17 is detachably connected to the connecting flange 27 with a plurality of bolts 29, 29, .... A bypass 30 that bypasses the throttle valve 21 and connects to the air intake path 17a is formed between the throttle body 17 and the control block 28.
[0024]
As clearly shown in Fig. 4, Fig. 9, and Fig. 13, the bypass 30 comprises: a bypass entrance 31i pierced in the throttle body 17 for communicating a side of the air intake path 17a upstream from the throttle valve 21 with a joint surface of the connecting flange 27; a bypass exit 31o pierced in the throttle body 17 for communicating a side of the air intake path 17a

downstream from the throttle valve 21 with the joint surface of the connecting flange 27; a bypass upstream groove 32i formed in the joint surface of the connecting flange 27 and having one end connected to the bypass entrance 31i; a bypass downstream groove 32o formed in the joint surface of the connecting flange 27 and having one end connected to the bypass exit 31o; a valve hole entrance 33i formed in the control block 28 and joined to the other end of the bypass upstream groove 32i; a valve hole exit 33o formed in the control block 28 and joined to the other end of the bypass' downstream groove 32o; and a valve hole 34 in the shape of a bottomed cylinder formed in the control block 28 in parallel with the air intake path 17a for providing communication between the valve hole entrance 33i and the valve hole exit 33o. In this case, the valve hole 34 is disposed above the bypass entrance 31i and the bypass exit 31o, and the valve hole entrance 33i and the valve hole exit 33o open to a lower surface of the valve hole 34. [0025]
In Fig. 12 and Fig. 13, a piston-shaped bypass valve 35 for controlling an amount of communication between the valve hole entrance 33i and the valve hole exit 33o is slidably fitted into the valve hole 34. The

valve 35 is joined with a driving member 37 for driving the valve 35 in a direction of the axis thereof via an Oldham joint 50 such that the valve 35 and the driving member 37 can be displaced from each other in a diametrical direction, and the driving member 37 is joined with an output shaft 39a of a step motor 39 via a screw mechanism 40. Specifically, the output shaft 39a formed as a screw shaft is screwed into a threaded hole 41 of the driving member 37, whereby rotation of the output shaft 39a moves the driving member 37 in a direction of the axis thereof, and also moves the bypass valve 35 via the Oldham joint 50.
[0026]
The step motor 39 is inserted into an actuator housing 42 disposed on the same axis as that of the valve hole 34 and opening to one side of the control block 28, and is held by a plug 44 screwed into the opening of the actuator housing 42 via a seal member 43.
[0027]
As clearly shown in Figs. 16(A) and 16(B), the bypass valve 35 has a relatively deep cylindrical bottomed hollow portion 45 opening to the bottom portion of the valve hole 34, and a keyway 47 and a measuring groove 48 in the form of an indentation for providing

communication between the interior and the exterior of the bottomed hollow portion 45. The keyway 47 is engaged with a key 49 erected from the bottom portion of the valve hole 34, thus acting as a stop for the bypass valve 35 while allowing the sliding of the bypass valve 35. The measuring groove 48 is disposed in correspondence with the valve hole exit 33o, and is formed by a wide portion 48a having a fixed groove width and extending in the direction of the axis of the bypass valve 35, and a tapered portion 48b joined to one end of the wide portion 48a and having a groove width that decreases with increasing distance from the wide portion 48a. [0028]
As shown in Fig. 13 and Fig. 15, the Oldham joint
50 is formed by: a first square hole 51 disposed in the bypass valve 35 and adjoining the bottomed hollow portion 45; a joint member 53 fitted into the first square hole
51 so as to be slidable in a first lateral direction X; and a second square hole 52 disposed in the joint member 53 such that the driving member 37 is fitted into the second square hole 52 so as to be slidable in a second lateral direction Y perpendicular to the first lateral direction X. The driving member 37 is formed relatively long so as to penetrate the joint member 53, and is

provided at one end with a large flange 37a in engagement with one end surface of the joint member 53 and the bypass valve 35. A small flange 37b situated in the bottomed hollow portion 45 is formed at the other end of the driving member 37. A retaining spring 54 for biasing the bypass valve 35 to the large flange 37a side is provided in a compressed state between the small flange 37b and the valve 35. Thus, the bypass valve 35 is resiliently sandwiched in the direction of the axis thereof between the large flange 37a and the retaining spring 54 on the driving member 37. In addition, both sides of the valve 35 in the direction of the axis thereof are communicated with each other via the first and second square holes 51 and 52 and a sliding clearance between the valve 35 and the valve hole 34. The joint member 53 is sandwiched in the direction of the axis thereof between a step portion 35a of the bypass valve 35 facing the first square hole 51 and the large flange 37a of the driving member 37. [0029]
As is clear from Fig. 9, Fig. 13, and Fig. 14, the bypass valve 35 and the step motor 39 arranged on the same axis and in parallel with the air intake path 17a are disposed over the valve stem 22 horizontally arranged

for the throttle valve 21. Also, the bypass valve 35 and the step motor 39 are arranged so as to face the upstream side and the downstream side, respectively, of the air intake path 17a, and correspondingly the bypass downstream groove 32o is formed so as to be longer than the bypass upstream groove 32i.
[0030]
Accordingly, the air intake control apparatus is miniaturized by arranging the valve hole 34 and hence the bypass valve 35 in parallel with the air intake path 17a. In addition, the step motor 39 and the bypass valve 35 can be disposed over the throttle valve stem 22 in a well-balanced manner, which also contributes to the miniaturization of the air intake control apparatus.
[0031]
In Fig. 12 and Fig. 13, the actuator housing 42 has a diameter greater than that of the valve hole 34 arranged in front of the actuator housing 42 on the same axis as that of the actuator housing 42, and has a ring-shaped step portion 55 formed at a boundary between the actuator housing 42 and the valve hole 34. A seal member 57 is sandwiched between the ring-shaped step portion 55 and the front end surface of the step motor 39 inserted in the actuator housing 42. Hence, the seal member 57 is

held in place between the front end surface of the step motor 39 and the ring-shaped step portion 55 simultaneously with the insertion of the step motor 39 into the actuator housing 42, thus increasing the ease of assembly. [0032]
The seal member 57 is formed by a ring-shaped reinforcing plate 58 made of a synthetic resin and an elastic covering 59 of rubber bonded by molding to the reinforcing plate 58 so as to cover the reinforcing plate
58. A pair of front and rear side lips 60 and 60 is formed in an outer circumference portion of the elastic covering 59, and an inner circumference lip 61 is formed on an inner circumference surface of the elastic covering
59. The side lips 60 and 60 are in close contact with the ring-shaped step portion 55 and the front end surface of the step motor 39, respectively, while the inner circumference lip 61 is in close contact with an outer circumference surface of a root portion of the output shaft 39a. The side lips 60 and 60 and the inner circumference lip 61 are retained in a proper seal position by the reinforcing plate 58, and are thus able
to perform an excellent seal function at all times. [0033]

A plurality of anchor holes 62 are pierced in the reinforcing plate 58, and are filled with the elastic covering 59 to enhance the bonding strength between the reinforcing plate 58 and the elastic covering 59. Furthermore, making the reinforcing plate 58 of a synthetic resin results in a reduction in weight of the seal member 57. [0034]
In Fig. 5, Fig. 10, and Fig. 11, a throttle sensor 64 for detecting a degree of opening of the throttle valve 21 is attached to the control block 28. The throttle sensor 64 includes: a case 66 fitted into an attaching indentation portion 65 formed in an outer surface of the control block 28; a rotor 67 connected to an end portion of the valve stem 22 of the throttle valve 21 within the case 66; and a stator 68 fixed to the case 66 so as to detect a rotation angle of the rotor 67 as the degree of opening of the throttle valve 21. [0035]
As shown in Fig. 5, Fig. 9, and Fig. 14, on one side of the attaching indentation portion 65 of the throttle sensor 64, the throttle body 17 and the control block 28 are provided with a first sensor inserting hole 71 that is orthogonal to the connecting flange 27 and

opens to the upstream side of the air intake path 17a. An intake air temperature sensor 73 for detecting upstream temperature of the air intake path 17a is inserted into the first sensor inserting hole 71 from the control block 28 side. Also, a boost negative pressure detecting hole 74 opening to the downstream side of the air intake path 17a is formed in the throttle body 17, and a second sensor inserting hole 72 situated directly above the first sensor inserting hole 71 is formed in the control block 28. A communication path 75 for providing communication between the boost negative pressure detecting hole 74 and the second sensor inserting hole 72 is formed in the joint surface of the connecting flange 27 as a bending groove going around the throttle sensor 64 therebelow. A boost negative pressure sensor 76 for detecting negative pressure of the intake air on the downstream side of the air intake path 17a, that is, boost negative pressure of the engine 5 through the boost negative pressure detecting hole 74 is inserted into the second sensor inserting hole 72. Thus, the intake air temperature sensor 73 and the boost negative pressure sensor 76 are disposed at positions adjacent to each other. [0036]

The bypass entrance 31i, or the upstream end of the bypass 30, is disposed at a position adjacent to the first sensor inserting hole 71 on a side of the air intake path 17a upstream from the inserting hole 71. Also, while the communication path 75 is disposed so as to go around the throttle sensor 64 therebelow, the bypass downstream groove 32o is disposed so as to go around the throttle sensor 64 thereover. [0037]
In Figs. 4 to 8 and Fig. 14, a coupler 80 flattened in a vertical direction is provided over the control block 28. The coupler 80 includes: a coupler body 81 formed integrally with the control block 28; and a large number of connectors 82 embedded in the coupler body 81. The coupler body 81 extends beyond the connecting flange 27 to a position directly above the throttle body 17, and a coupling mouth 80a opens in a direction opposite from the control block 28. The coupling mouth 80a is coupled with an external coupler 83 connected with a wire harness 86 joined to a power supply and the like. [0038]
The control block 28 provided with the coupler 80 is of a box shape in which an outer end surface on a side opposite from the connecting flange 27 is opened, and the

outer end surface is provided with a board 84a of an electronic control unit 84. In this case, the board 84a is connected directly by soldering with connecting terminals 73a, 76a, and 64a of the intake air temperature sensor 73, the boost negative pressure sensor 76, and the throttle sensor 64 as well as inner ends of the connectors 82 of the coupler 80 (see Figs. 10 to 12). A reference numeral 85 denotes various semiconductor devices attached to the surface of the board 84a. [0039]
Thus, even if a foreign substance such as a fuel oil drop enters the boost negative pressure detecting hole 74 from the air intake path 17a in the horizontal type throttle body 17 as a result of an intake air reversing phenomenon of the engine 5, the foreign substance cannot go up to the boost negative pressure sensor 76 because the communication path 75 provides a great level difference between the boost negative pressure detecting hole 74 and the boost negative pressure sensor 76 situated above the boost negative pressure detecting hole 74, and the communication path 75 forms a bent path having a high channel resistance. It is therefore possible to protect the boost negative pressure sensor 76 from a foreign substance and thereby ensure the

function and durability of the boost negative pressure sensor 76.
[0040]
In addition, since the intake air temperature sensor 73 and the boost negative pressure sensor 76 are disposed on one side of the throttle sensor 64 in a concentrated manner, it is possible to connect the intake air temperature sensor 73 and the boost negative pressure sensor 76 to the electronic control unit 84 in a concentrated manner and thereby miniaturize the unit 84.
[0041]
Moreover, since the groove as the communication path 75 and the bypass upstream groove 32i and the bypass downstream groove 32o as a main portion of the bypass 30 are formed in the joint surface of the connecting flange 27 of the throttle body 17, it is possible to form the groove, the bypass upstream groove 32i, and the bypass downstream groove 32o simultaneously with the formation of the throttle body 17, thereby eliminating the need for special machining to form the groove, the bypass upstream groove 32i, and the bypass downstream groove 32o, and hence making it possible to enhance productivity.
[0042]
Furthermore, since the bypass entrance 31i is

disposed at a position adjacent to the first sensor inserting hole 71 situated below the second sensor inserting hole 72, on a side of the air intake path 17a upstream from the inserting hole 71, it is possible to concentrate the first sensor inserting hole 71, the second sensor inserting hole 72, and the bypass entrance 31i without letting the first sensor inserting hole 71, the second sensor inserting hole 72, and the bypass entrance 31i interfere with each other, and to thereby contribute to miniaturization of the control block 28.
[0043]
Furthermore, since the bypass downstream groove 32o and the communication path 7 5 are disposed so as to surround the throttle sensor 64 from above and below the throttle sensor 64, it is possible to dispose the bypass downstream groove 32o and the communication path 75 around the throttle sensor 64 in a compact manner without letting the bypass downstream groove 32o and the communication path 75 interfere with each other, and to thereby contribute to further miniaturization of the control block 28.
[0044]
Returning to Fig. 4, a positioning projection 87 is formed at a pair of corner portions on one diagonal line

of the outer end surface of the control block 28 provided with the coupler 80, and a threaded hole 88 is formed at corner portions on the other diagonal line. On the other hand, the board 84a is provided with a positioning hole 89 corresponding to the positioning projection 87 and a screw hole 90 corresponding to the threaded hole 88. The positioning hole 89 is engaged with the positioning projection 87, and a screw 91 inserted through the screw hole 90 is screwed into the threaded hole 88, whereby the board 84a is fixed at a predetermined position of the control block 28. [0045]
As shown in Fig. 12 and Fig. 17, a connector piece 92 of a synthetic resin substantially in the form of a rectangular parallelepiped is positioned and fixed to the control block 28 between the step motor 39 and the board 84a. A plurality of lead frames 93, 93 ... are buried in the connector piece 92. A connecting terminal 93a formed at one end of each of the lead frames 93 is connected directly to the board 84a by soldering, and a connector hole 94 is formed at the other end of each of the lead frames 93. [0046]
A plurality of connector pins 96, 96 ... project

from a front end surface (front-side end surface as viewed in a direction of insertion of the step motor 39 into the actuator housing 42) of a terminal lead unit 95 provided on the outer surface of the step motor 39 in a projecting manner. The connector pins 96, 96 ... are inserted into the connector holes 94, 94 ... simultaneously with the insertion of the step motor 39 into the actuator housing 42.
[0047]
The electronic control unit 84 controls operation of not only the step motor 39 and the fuel injection valve 20 but also an ignition device (not shown) and the like on the basis of output signals from the throttle sensor 64, the boost negative pressure sensor 76, and the intake air temperature sensor 73 as well as an engine speed sensor, an engine temperature sensor, and the like not shown in the figures. The signals and power are supplied and received via the coupler 80 and the external coupler 83 connected to the coupler 80.
[0048]
As shown in Fig. 4 and Fig. 9, a seal groove 97 surrounding the periphery of the bypass upstream groove 32i, the bypass downstream groove 32o, the first sensor inserting hole 71, the boost negative pressure detecting

hole 74, and the communication path 75 is formed in the joint surface of the connecting flange 27. A seal member 98 to be brought into close contact with the control block 28 is inserted in the seal groove 97 to thereby retain airtightness of the bypass upstream groove 32i, the bypass downstream groove 32o, and the like.
[0049]
As shown in Fig. 4, Fig. 11, and Fig. 12, a cap 101 made of an Al alloy plate for housing the electronic control unit 84 is socket-fitted onto a stepped fitting surface 100 formed on the periphery of the outer end portion of the control block 28 provided with the coupler 80. In this case, a latching projection 105 and a latching hole 106 formed on and in the fitting surfaces (see Fig. 4 and Fig. 11) are resiliently engaged with each other. The cap 101 is formed by the press forming of an Al alloy plate to provide a good appearance with no wrinkle. Thus, since the cap 101 provides a good appearance to the control block 28, the cap 101 is useful when the control block 28 is exposed to the outside as in the motorcycle 1.
[0050]
The control block 28 is provided with a potting opening 102 adjacent to an opened end surface of the cap

101, which opening communicates with the interior of the cap 101 and opens to an opposite side from the cap 101 (see Fig. 8 and Fig. 14) . With the cap 101 turned downward, a synthetic resin 103 is potted from the potting opening 102 into the cap 101 up to a socket-fitted portion of the cap 101, thereby covering the electronic control unit 84 and sealing the socket-fitted portion of the cap 101. [0051]
The potting resin 103 protects the electronic control unit 84 from rain water, dust, and vibration, and, in particular, seals the portion of the cap 101 socket-fitted to the control block 28 to effectively provide water resistance and dust resistance. In addition, adhesive strength of the potting resin 103 can increase bonding strength of the cap 101 to the control block 28. [0052]
Also, since with the electronic control unit 84 housed in the cap 101 and the cap 101 turned downward, the synthetic resin 103 is potted from the potting opening 102 situated at an upper position, it is possible to protect the electronic control unit 84 and bond the cap 101 effectively with a required minimum amount of the potting resin 103. Thus, it is possible to prevent the

synthetic resin 103 from entering the bypass valve 35 and the step motor 39 situated above the cap 101.
[0053]
At the time of potting, it is possible to readily adjust the amount of potting while visually checking from the potting opening 102 a state of the potting of the synthetic resin into the cap 101. In addition, since the potting resin 103 embeds portions connected to the board 84a of the connecting terminals 64a, 73a, and 76a of the sensors 64, 73, and 76 and the connecting terminal 93a of the connector piece 92, the potting resin 103 can improve vibration resistance of the connecting terminals 64a, 73a, 76a, and 93a.
[0054]
Returning to Fig. 3 and Fig. 7, the control block 28 provided with the sensors 64, 73, and 76 and the electronic control unit 84 is disposed on one of a left and a right side of the throttle body 17, whereas the coupler 80 is disposed above the throttle body 17, that is, between the throttle body 17 and a bottom wall of the luggage box 3. Such a dispersed arrangement of the sensors 64, 73, and 76, the electronic control unit 84, and the coupler 80 allows the sensors 64, 73, and 76, the electronic control unit 84, and the coupler 80 to be

readily disposed even in a small space around the throttle body 17 in the motorcycle 1. In particular, the coupler 80 can be flattened in a vertical direction, and therefore even when the coupler 80 is disposed above the throttle body 17, there is practically no need for moving upward the bottom portion of the luggage box 3 situated over the coupler 80, thus making it possible to increase capacity of the luggage box 3.
[0055]
Moreover, since the coupling mouth 80a of the coupler 80 to be coupled with the external coupler 83 opens on an opposite side from the electronic control unit 84, it is possible to readily connect the external coupler 83 to the coupler 80 without the electronic control unit 84 and the engine 5 being in the way, and to thus obtain great ease of assembly and maintenance.
[0056]
In addition, the throttle drum 23 is fixed to one end of the valve stem 22 extending in a right to left direction which end is on an opposite side from the electronic control unit 84, and the throttle cable 24 connected to the throttle drum 23 is disposed so as to pass below the coupling mouth 80a of the coupler 80 (see Fig. 8). This makes it possible to avoid interference

between the throttle cable 24 and the wire harness 86 of the external coupler 83 coupled to the coupler 80, and to thereby increase the ease of assembly and maintenance.
[0057]
As shown in Fig. 2, Fig. 3, Fig. 7, and Fig. 8, the throttle cable 24 connected to the throttle drum 23 passes a lower portion of the throttle drum 23, extends rearward for a distance, bends so as to form a U-shape within the crank portion of the engine hanger 14, then extends forward along the down tube l1b on one side of the body frame 11, and is connected to a throttle operating member (not shown) provided to a steering handlebar 36 (Fig. 1).
[0058]
When the power unit 4 moves up and down in accordance with extension and contraction of the rear cushion unit 26 while the motorcycle 1 is moving, the throttle body 17 is also rocked together with the power unit 4. As the throttle body 17 is rocked, mainly the U-shaped bending portion of the throttle cable 24 bends without strain, whereby it is possible to prevent an excessive stress from occurring on the throttle cable 24 and thus ensure durability of the throttle cable 24. In addition, while the throttle drum 23 and the coupling

mouth 80a of the coupler 80 are disposed on the same side of the throttle body 17, the single throttle cable 24 is disposed in a manner as described above. Hence, a relatively large workspace where the throttle cable 24 is not in the way can be obtained around the coupling mouth 80a of the coupler 80, thus facilitating the connection of the external coupler 83 to the coupling mouth 80a.
[0059]
Operation of the air intake control apparatus will be described in the following.
[0060]
When the throttle valve 21 is completely closed, the electronic control unit 84 determines an operating condition of the engine 5 at the times of a start of the engine, fast idling, normal idling, engine braking and the like on the basis of output signals from the throttle sensor 64, the intake air temperature sensor 73, the boost negative pressure sensor 76, and the like. In order to obtain a degree of opening of the bypass valve 35 corresponding to the operating condition, the electronic control unit 84 operates the step motor 39 to thereby rotate the output shaft 39a in a forward direction or a reverse direction.
[0061]

When the output shaft 39a is rotated in the forward direction or the reverse direction, the driving member 37 moves in the direction of the axis thereof to thereby slide the bypass valve 35 forward or rearward along the valve hole 34 via the joint member 53, so that an opening area of the measuring groove 48 in relation to the valve hole exit 33o, that is, the degree of opening of the bypass 30 is decreased or increased and thus the amount of intake air flow in the bypass 30 is controlled. In particular, by moving the tapered portion 48b of the measuring groove 48 in relation to the valve hole exit 33o, the amount of intake air flow can be finely controlled in a range of zero to a predetermined maximum value. As a result, the start of the engine, fast idling, and normal idling are automatically made properly. [0062]
In this case, even when the axes of the bypass valve 35 and the output shaft 39a of the step motor 39 displace from each other due to a manufacturing error, the displacement is accommodated by the movement of the joint member 53 of the Oldham joint 50 along the first lateral direction X and the movement of the driving member 37 along the second lateral direction Y. Therefore, regardless of the displacement, smooth sliding of the

bypass valve 35 can be ensured, and at the same time, vibration of the bypass valve 35 is controlled by the retaining spring 54.
[0063]
When the bypass valve 35 is completely closed, an intake negative pressure of the engine 5 acts on the side of the bypass valve 35 facing the valve hole exit 33o. In that case, the Oldham joint 50 allows translation of the bypass valve 35 in a direction of the action of the intake negative pressure. Hence, the bypass valve 35 is securely brought into close contact with the periphery of the valve hole exit 33o to thereby prevent or minimize a leak of bypass intake air from the valve hole exit 33o. Accordingly, the valve hole 34 and the bypass valve 35 do not require a particularly high dimensional accuracy, thus contributing to improvement of productivity.
[0064]
In addition, both end surfaces of the bypass valve 35 in the direction of the axis thereof are communicated with each other through the first and second square holes 51 and 52 of the Oldham joint 50 and the sliding clearance between the valve 35 and the valve hole 34. Hence, no matter what pressure is transmitted to the valve hole 34, no difference in pressure occurs between

both the end surfaces of the bypass valve 35 in the direction of the axis thereof. It is therefore possible to operate the bypass valve 35 lightly even with a relatively low power of the step motor 39. This means a capability to realize a reduction in the power of the step motor 39 and hence a reduction in the size of the step motor 39 while enhancing response of the bypass valve 35.
[0065]
Moreover, the bypass valve 35 is biased by the retaining spring 54 in a direction of from the valve hole entrance 33i to the valve hole exit 33o, and the biasing force is received by the large flange 37a of the driving member 37 into which the output shaft 39a of the step motor 39 is screwed directly. Therefore, when the output shaft 39a is rotated in a direction of closing the bypass valve 35, in particular, the driving member 37 directly presses the bypass valve 35 in the closing direction by means of the large flange 37a. Thus, regardless of the presence of the retaining spring 54, closing speed of the bypass valve 35 can be increased.
[0066]
On the other hand, as the throttle valve 21 is gradually opened, an amount of intake air corresponding

to the increase in the degree of opening is supplied through the air intake path 17a to the engine 5, thus controlling the output of the engine 5. [0067]
In such an air intake control apparatus, the control block 28 provided with the coupler 80 is connected to the connecting flange 27 of the throttle body 17 as a unit separate from the connecting flange 27, and the control block 28 is provided with the bypass valve 35, the step motor 39, the intake air temperature sensor 73, the boost negative pressure sensor 76, the throttle sensor 64, and the electronic control unit 84. It is therefore possible to machine the throttle body 17 and manufacture the control system assembly including the control block 28 simultaneously. In particular, it is possible to conduct a function test on the step motor 39, the bypass valve 35, the sensors 64, 73, and 76, the electronic control unit 84, and the like by connecting the coupler 80 with a power supply and the like as required before connecting the control block 28 to the throttle body 17. Accordingly, only a product that has passed the test is attached to the throttle body 17, thereby eliminating useless assembly operation and hence making it possible to improve productivity.

[0068]
In addition, the electronic control unit 84 is installed on the outer end surface of the control block 28, and electrical connections are provided between the step motor 39, the sensors 64, 73, and 76, and the coupler 80 via the electronic control unit 84. It is therefore possible to simplify the connections between the step motor 39, the sensors 64, 73, and 76, and the coupler 80, and to thereby further enhance the ease of assembly.
[0069]
Moreover, the connector pins 96 projecting in the direction of inserting the step motor 39 into the actuator housing 42 are provided for the step motor 39, and the connector holes 94 in which the connector pins 96 are inserted are provided for the lead frames 93 joined to the coupler 80 on the control block 28 side. An electrical connection between the step motor 39 and the coupler 80 is therefore made simultaneously with the attachment of the step motor 39 to the control block 28. It is thus possible to eliminate the need for special operation for the electrical connection and to thereby further enhance the ease of assembly.
[0070]

Furthermore, the lead frames 93 having the connector holes 94 are embedded in the connector piece 92, which is a small part positioned and fixed to the control block 28 between the step motor 39 and the electronic control unit 84. The embedding of the lead frames 93 is therefore very easy and accurate as compared with the embedding of the lead frames 93 in the control block 28, which is a large part. By setting the connector piece 92 in the control block 28, the connector holes 94 of the lead frames 93 can be accurately disposed in position, whereby accurate engagement of the connector holes 94 with the connector pins 96 of the step motor 39 is ensured. [0071]
Furthermore, the actuator housing 42 for inserting the step motor 39 is provided so as to open to a peripheral surface of the control block 28 different from the outer end surface of the control block 28 for installing the electronic control unit 84. It is therefore possible to miniaturize the control block 28. Also, the step motor 39 is detachable regardless of the installation of the electronic control unit 84. It is therefore possible to readily maintain the step motor 39 and the bypass valve 35.

[0072]
While the operation of the engine 5 is stopped, moisture in the air within the valve hole 34 can form condensation on the inner wall of the valve hole 34. The seal member 57 provided between the valve hole 34 and the actuator housing 42 prevents the condensed water drops from entering the step motor 39. It is therefore possible to protect the step motor 39 and enhance the durability of the step motor 39.
[0073]
In particular, the seal member 57 is sandwiched between the step motor 39 and the ring-shaped step portion 55 between the valve hole 34 and the actuator housing 42. The seal member 57 has, on its inner circumference surface, the inner circumference lip 61 in close contact with the outer circumference surface of the root portion of the output shaft 39a of the step motor 39. Therefore, the inner circumference lip 61 has a very low frictional resistance to the rotating surface of the output shaft 39a, thus eliminating its effect on the response of the bypass valve 35. In addition, even in the case of the bypass valve 35 that allows the tip of the output shaft 39a to be exposed to the inside of the valve hole 34, it is possible to provide a secure seal between

the step motor 39 and the valve hole 34 with the single seal member 57. Thus, the seal member 57 can be applied regardless of the structure of the bypass valve 35, and therefore the seal member 57 has a wide range of applications.
[0074]
While the operation of the engine 5 is stopped, the bypass valve 35 normally closes the valve hole exit 33o completely. Therefore, even if a fuel gas produced on the downstream side of the air intake path 17a enters the downstream side of the bypass 30, the bypass valve 3 5 blocks the entry of the fuel gas into the valve hole 34. Thus, even if the sealing function of the seal member 57 should be degraded, the bypass valve 35 prevents the step motor 39 from being exposed to the fuel gas, and can thereby ensure the durability of the step motor 39.
[0075]
Furthermore, since length of the side of the bypass 30 downstream from the valve hole 34 is set sufficiently long, it is difficult for the fuel gas produced on the downstream side of the air intake path 17a to pass through the downstream portion of the sufficiently long bypass. It is therefore possible to prevent the entry of the fuel gas into the valve hole 34 and thereby further

contribute to protection of the step motor 39.
[0076]
In addition, since the valve hole entrance 33i and the valve hole exit 33o situated above the bypass entrance 31i and the bypass exit 31o in the bypass 30 open to the lower side of the valve hole 34, it is difficult for a foreign substance such as dust to enter the valve hole 34 from the valve hole entrance 33i and the valve hole exit 33o. It is therefore possible to avoid a malfunction of the bypass valve 35 caused by the entry of a foreign substance.
[0077]
The present invention is not limited to the example described above, and is susceptible of various changes in design without departing from the spirit of the present invention. For example, the bypass upstream groove 32i, the bypass downstream groove 32o, and the communication path 75 may be formed on the joint surface side of the control block 28 joined to the connecting flange 27.
[0078]
[Effect of the Invention]
As described above, according to a first feature of the present invention, in a small vehicle including a luggage box disposed under a seat and an engine disposed

under the luggage box, and including a throttle body disposed between the luggage box and the engine, the throttle body having an air intake path joined to an air intake port of the engine and extending in a front to rear direction of the vehicle and a throttle valve for opening and closing the air intake path, sensors for detecting operating conditions of the engine and an electronic control unit for controlling operation of a fuel injection valve of the engine according to output signals from the sensors are attached on one of a right and a left side of the throttle body, and a coupler connected to the electronic control unit and having a coupling mouth coupled with an external coupler and opening to the other of the right and left sides of the throttle body is disposed above the throttle body. Therefore, the dispersed arrangement of the sensors and the electronic control unit and the coupler allows the sensors, the electronic control unit, and the coupler to be readily disposed even in a small space around the throttle body in the small vehicle. In particular, the coupler can be flattened in a vertical direction, and therefore even when the coupler is disposed above the throttle body, there is practically no need for moving upward the bottom portion of the luggage box situated

over the coupler, thus making it possible to increase the capacity of the luggage box.
[0079]
Moreover, since the coupling mouth of the coupler coupled with the external coupler opens to an opposite side from the electronic control unit, it is possible to readily connect the external coupler to the coupler without the electronic control unit and the engine being in the way, and to thus obtain great ease of assembly and maintenance.
[0080]
In addition, according to a second feature of the present invention, in addition to the first feature, a valve stem of the throttle valve is disposed in a right to left direction orthogonal to the air intake path, a throttle drum is fixed to one end of the valve stem on an opposite side from the electronic control unit, and a throttle cable connected to the throttle drum is disposed so as to pass below the coupling mouth of the coupler. Therefore, it is possible to avoid interference between the throttle cable and the wire harness of the external coupler coupled to the coupler, and to thereby increase the ease of assembly and maintenance.
[0081]

Moreover, according to a third feature of the present invention, in addition to the second feature, the throttle cable connected to the throttle drum is disposed so as to extend rearward for a distance, bend so as to form a U-shape, and then extend forward. Therefore, even when the throttle body is rocked together with the engine, mainly the U-shaped bending portion of the throttle cable bends without strain, whereby it is possible to prevent an excessive stress on the throttle cable and thus ensure the durability of the throttle cable. [0082]
Furthermore, according to a fourth feature of the present invention, in addition to the second or third feature, the throttle drum is connected with a return spring that biases the throttle drum in a direction of closing the throttle valve and the single throttle cable that is pulled against the biasing force of the return spring to open the throttle valve, and the throttle cable passes a lower portion of the throttle drum and is then drawn out. Therefore, while the throttle drum and the coupling mouth of the coupler are disposed on the same side of the throttle body, a relatively large workspace where the throttle cable is not in the way can be obtained around the coupling mouth of the coupler, thus

facilitating the connection of the external coupler the coupling mouth.
[Description of Reference Numerals]
2 . . . seat
3 . . . luggage box 5 . . . engine
7a...air intake port 17. . .throttle body 17a...air intake path 2 0...fuel injection valve 21... throttle valve 22...valve stem
23 ... throttle drum.
24 ... throttle cable 25...return spring
64...sensor (throttle sensor)
73...sensor (intake air temperature sensor) 76...sensor (boost negative pressure sensor) 80 . ..coupler 80a...coupling mouth
83 ... external coupler
84 ... electronic control unit

3. An apparatus for controlling air intake of an engine in a small vehicle as claimed in claim 1 or 2, wherein the throttle drum (23) is connected with a return spring (25) that biases the throttle drum (23) in a direction of closing the throttle valve (21) and the single throttle cable (24) that is pulled against the biasing force of the return spring (25) to open the throttle valve (21), and the throttle cable (24) passes a lower portion of the throttle drum (23) and is then drawn out.
4. An apparatus for controlling air intake of an engine in a small vehicle substantially as hereinbefore described with reference to the accompanying drawings.
Dated this 03/05/2002
[RITUSHKA NEGI]
OF REMFRY & SAGAR
ATTORNEY OF THE APPLICANT

We claim:
1. An apparatus for controlling air intake of an engine in a small vehicle, the apparatus having a throttle body (17) disposed between a luggage box (3) directly under a seat (2) and an engine (5) disposed under the luggage box (3), the throttle body (17) having an air intake path (17a) joined to an air intake port (7a) of the engine (5) and a throttle valve (21) for opening and closing the air intake path (17a), wherein sensors (64, 73, 76) for detecting operating conditions of the engine (5) and an electronic control unit (84) for controlling operation of a fuel injection valve (20) of the engine (5) according to output signals from the sensors (64, 73, 76) are attached on one of a right and left side of the throttle body (17), and a coupler (80) connected to the electronic control unit (84) and having a coupling mouth (80a) coupled with an external coupler (83) and opening to the other of the right and left sides of the throttle body (17) is disposed above the throttle body (17) characterized in that a valve stem (22) of the throttle valve (21) is disposed in a right to left direction orthogonal to the air intake path (17a), a throttle drum (23) is fixed to one end of the valve stem (22) on an opposite side from the electronic control unit (84), and a throttle cable (24) connected to the throttle drum (23) is disposed so as to pass below the coupling mouth (80a) of the coupler (80).
2. An apparatus for controlling air intake of an engine in a small vehicle as claimed in claim 1, wherein the throttle cable (24) connected to the throttle drum (23) is disposed so as to extend rearward for a distance, bend so as to form a U-shape, and then extend forward.

Documents:

399-mum-2002-abstract(30-04-2007).doc

399-mum-2002-abstract(30-4-2007).pdf

399-mum-2002-cancelled page(3-5-2002).pdf

399-mum-2002-claims(granted)-(30-04-2007).doc

399-mum-2002-claims(granted)-(30-4-2007).pdf

399-mum-2002-correspondence(30-4-2007).pdf

399-mum-2002-correspondence(ipo)-(10-1-2008).pdf

399-mum-2002-drawings(30-4-2007).pdf

399-mum-2002-form 1(3-5-2002).pdf

399-mum-2002-form 1(30-4-2007).pdf

399-mum-2002-form 18(7-4-2006).pdf

399-mum-2002-form 2(granted)-(30-04-2007).doc

399-mum-2002-form 2(granted)-(30-4-2007).pdf

399-mum-2002-form 3(13-4-2004).pdf

399-mum-2002-form 3(3-5-2002).pdf

399-mum-2002-form 3(30-4-2007).pdf

399-mum-2002-form 3(5-8-2007).pdf

399-mum-2002-form 5(3-5-2002).pdf

399-mum-2002-petition under rule 137(30-4-2007).pdf

399-mum-2002-petition under rule 138(30-4-2007).pdf

399-mum-2002-power of authority(30-4-2007).pdf

399-mum-2002-power of authority(4-7-2002).pdf

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Patent Number

213725

Indian Patent Application Number

399/MUM/2002

PG Journal Number

42/2008

Publication Date

17-Oct-2008

Grant Date

10-Jan-2008

Date of Filing

03-May-2002

Name of Patentee

HONDA GIKEN KOGYO KABUSHIKI KAISHA

Applicant Address

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

Inventors:

#	Inventor's Name	Inventor's Address
1	KENICHI SUEDA	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA.
2	YUKIO HOSOYO	C/o Kabushiki Kaisha Honda Gijutsu Kenkyusho 4-1,Chuo 1-chome, Wako-shi, Saitama
3	SHUNJI AKAMATSU	C/o Kabushiki Kaisha Honda Gijutsu Kenkyusho 4-1,Chuo 1-chome, Wako-shi, Saitama
4	NOBUHIRO SHIMADA	C/o Kabushiki Kaisha Honda Gijutsu Kenkyusho 4-1,Chuo 1-chome, Wako-shi, Saitama

PCT International Classification Number

F02D35/00,F02M35/01

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2001-264528	2001-08-31	Japan