Title of Invention	"ENGINE-USE FUEL SUPPLY DEVICE"
Abstract	[Problem] To realize the miniaturization of a vehicle which includes a main fuel tank and a sub fuel tank. [Means for Resolution] In a vehicle which includes a sub fuel tank 84 which stores sub fuel 96 as starting fuel for enhancing the startability of a vehicle in addition to a main fuel tank 33 of a vehicle-use engine 12, the sub fuel tank 84 is arranged in the inside of the main fuel tank 33. Due to such a constitution, it is no more necessary to newly form a space in the inside of a vehicle body for arranging the sub fuel tank. To be more specific, out of left and right bulging portions of the saddle-type main fuel tank 33, the sub fuel tank 84 is arranged in one-side bulging portion which is not provided with a fuel cock.

Title of Invention

"ENGINE-USE FUEL SUPPLY DEVICE"

Abstract

[Problem] To realize the miniaturization of a vehicle which includes a main fuel tank and a sub fuel tank. [Means for Resolution] In a vehicle which includes a sub fuel tank 84 which stores sub fuel 96 as starting fuel for enhancing the startability of a vehicle in addition to a main fuel tank 33 of a vehicle-use engine 12, the sub fuel tank 84 is arranged in the inside of the main fuel tank 33. Due to such a constitution, it is no more necessary to newly form a space in the inside of a vehicle body for arranging the sub fuel tank. To be more specific, out of left and right bulging portions of the saddle-type main fuel tank 33, the sub fuel tank 84 is arranged in one-side bulging portion which is not provided with a fuel cock.

Full Text	[Designation of Document] Specification [Title of the Invention] ENGINE-USE FUEL SUPPLY DEVICE [Technical Field] [0001] The present invention relates to an improvement of an engine-use fuel supply device. [Background Art] [0002] Recently, as a vehicle-use fuel, fuel which contains alcohol as a main content has been used in place of gasoline which is fossil fuel. However, since a boiling point of alcohol is low compared to a boiling point of gasoline, alcohol exhibits poor startability when an engine is at a low temperature. To enhance this startability, gasoline or alcohol containing a large quantity of gasoline is used only at the time of starting, and a sub fuel tank for storing such starting fuel is mounted on a vehicle body separately from a main fuel tank. [0003] As a conventional engine-use fuel supply device including the above-mentioned sub fuel tank, there has been known a fuel supply device in which a main fuel tank is arranged on a front upper portion of a vehicle body frame and a sub fuel tank is arranged on a midst portion of the vehicle body frame (for example, see patent document 1). [Patent Document I] JP-A-57-164872 [0004] The patent document 1 is explained in conjunction with Fig. 1 hereinafter. A vehicle body frame A includes a head pipe 1 which is arranged on a front end of the vehicle body frame A, a main pipe 2 which extends in the oblique rearward and downward direction from the head pipe 1, a seat rail 4 which extends rearwardly from a midst portion of the main pipe 2, and a back stay 5 which connects a lower portion of the main pipe 2 and a midst portion of the seat rail 4 to each other. Amain fuel tank 9 is arranged astride a front portion of the head pipe 2, and a sub fuel tank 10 is arranged in a triangular space 8 defined by the main pipe 1, the seat rail 4 and the back stay 5. [Disclosure of the Invention] [Problems that the Invention is to Solve] [0005] In providing the sub fuel tank 10 in the space in addition to the main fuel tank 9, a small-sized vehicle such as a motorcycle cannot ensure a sufficient arrangement space for the sub fuel tank 10. Accordingly, when the sub fuel tank 10 is arranged in the space 8 without any modification, the vehicle becomes large-sized. Here arises a task that it is necessary to prevent such large-sizing of the vehicle. It is an object of the present invention to realize the miniaturization of a vehicle having a main fuel tank and a sub fuel tank. [Means for Solving the Problem] [0006] The invention according to claim I is characterized in that, in a vehicle which includes a sub fuel tank which stores starting fuel for enhancing the startability of the vehicle in addition to a main fuel tank of a vehicle-use engine, the sub fuel tank is arranged in the inside of the main fuel tank. [0007] To explain the manner of operation, by arranging the sub fuel tank in the inside of the existing main fuel tank, it is unnecessary to newly form a space in the inside of the vehicle body for arranging the sub fuel tank. Provided that fuels which cause no trouble even when the fuels are mixed into a fuel in the inside of the main tank and a fuel in the inside of the sub fuel tank are respectively stored in the tanks, it is unnecessary to adopt the structure which completely separates the main fuel tank and the sub fuel tank from each other and hence, the engine-use fuel supply device can be formed of the simple structure. [0008] The invention according to claim 2 is characterized in that a fuel supply port of the sub fuel tank is arranged inside a fuel supply port of the main fuel tank. To explain the manner of operation, by arranging the fuel supply port of the sub fuel tank inside the fuel supply port of the main fuel tank, a portion of tank which the fuel supply port of the sub fuel tank and the fuel supply port of the main fuel tank share in common can be simplified. Accordingly, the tank port structure can be simplified compared to the tank port structure in which a fuel supply port of a sub fuel tank and a fuel supply port of a main fuel tank are provided separately and independently. Further, the fuel supply port of the main fuel tank and the fuel supply port of the sub fuel tank are arranged close to each other and hence, a fuel filling operation can be performed efficiently when it is necessary to continuously fill main fuel and sub fuel. [0009] The invention according to claim 3 is characterized in that a small lid which closes the fuel supply port of the sub fuel tank is mounted on a back side of a lid of the fuel supply port of the main fuel tank. To explain the manner of operation, when the fuel supply port of the main fuel tank is closed by the lid, the fuel supply port of the sub fuel tank is simultaneously closed by the small lid. Further, even when the vehicle body is tilted, the small lid prevents the main fuel from being mixed with the sub fuel. [0010] The invention according to claim 4 is characterized in that, in a vehicle which includes a sub fuel tank which stores starting fuel for enhancing the startability of the vehicle in addition to a main fuel tank of a motorcycle-use engine, the sub fuel tank is arranged around a mono-backbone-type main frame on a front side of a vehicle in the vicinity of the main fuel tank. To explain the manner of operation, by arranging the sub fuel tank closer to the main fuel tank, the vehicle hardly becomes large-sized. [0011] The invention according to claim 5 is characterized in that a fuel pipe extends to an intake system below the sub fuel tank from the sub fuel tank and is connected to the intake system. To explain the manner of operation, it is possible to arrange the fuel pipe while preventing the bending of the fuel pipe between the sub fuel tank and the intake system more effectively. Further, it is possible to supply the fuel into the intake system by making use of the difference in height between the sub fuel tank and the intake system. [0012] The invention according to claim 6 is characterized in that a solenoid valve which controls a fuel flow time and a check valve which allows only the flow of fuel toward the intake system from a solenoid valve side are mounted on the fuel pipe extending from the sub fuel tank. [0013] To explain the manner of operation, by opening and closing the solenoid valve, a time which fuel requires to flow into the intake system through the check valve, that is, a fuel supply quantity is controlled. Due to the provision of the check valve, there exists no possibility that fuel flows back toward a sub fuel tank side from the intake system. [0014] The invention according to claim 7 is characterized in that a sub fuel supply pump is mounted on a midst portion of the fuel pipe, a discharge pressure of the sub fuel pump is set higher than a discharge pressure of a main fuel pump for the main fuel tank, and the sub fuel pump is connected to a fuel passage arranged upstream of a fuel injection valve for the main fuel tank by way of a one-way valve. [0015] To explain the manner of operation, by setting the discharge pressure of the sub fuel pump higher than the discharge pressure of the main fuel pump, the sub fuel in the inside of the sub fuel tank can be supplied to the upstream-side fuel passage through the fuel injection valve for the main fuel tank even during the operation of the main fuel pump. The one way valve is provided for preventing the main fuel discharged from the main fuel pump from flowing into the sub fuel tank when the sub fuel pump is not operated. [Advantage of the Invention] [0016] According to the invention described in claim 1, the sub fuel tank is arranged in the inside of the main fuel tank and hence, it is possible to effectively make use of the space in the inside of the main fuel tank. • Further, the structure of the main fuel tank and the sub fuel tank can be simplified thus preventing the large-sizing of the vehicle. For example, by arranging the sub fuel tank on a bottom portion of either one of left and right sides of the main fuel tank, it is possible to effectively make use of a dead space of the main fuel tank. [0017] According to the invention described in claim 2, the fuel supply port of the sub fuel tank is arranged inside the fuel supply port of the main fuel tank and hence, it is possible to realize the simplification of the fuel supply port structure . Further, the fuel supply port of the main fuel tank and the fuel supply port of the sub fuel tank can be arranged close to each other and hence, it is possible to efficiently perform the fuel filling operation. [0018] According to the invention described in claim 3, the small lid which closes the fuel supply port of the sub fuel tank is mounted on the backside of the lid of the fuel supply port of the main fuel tank and hence, these two fuel supply ports can be easily opened and closed. Further, even when an oil level is changed corresponding to the tilting of the vehicle body or the like, it is possible to prevent the fuel in the inside of the main fuel tank and the fuel in the inside of the sub fuel tank from being mixed with each other. [0019] According to the invention described in claim 4, the sub fuel tank is arranged around the mono-backbone-type main frame on the front side of the vehicle in the vicinity of the main fuel tank and hence, it is possible to arrange the sub fuel tank closer to the main fuel tank thus preventing the large-sizing of the vehicle. [0020] According to the invention described in claim 5, the fuel pipe extends to the intake system arranged below the sub fuel tank from the sub fuel tank and is connected to the intake system and hence, the fuel pipe from the sub fuel tank is hardly bent whereby the air leaking property can be enhanced. Further, the difference in fuel level can be utilized and hence, it is possible to easily supply the fuel to the intake system thus enhancing the startability of the engine. [0021] According to the invention described in claim 6, the solenoid valve which controls the fuel flow time and the check valve which allows only the flow of fuel toward the intake system side from the solenoid valve side are mounted on the ' fuel pipe extending from the sub fuel tank and hence, it is possible to easily control the supply quantity of the fuel which flows into the intake system using the solenoid valve . Further, it is possible to prevent a backflow of the fuel from the intake system to the sub fuel tank side using the check valve. [0022] According to the invention described in claim 7, the sub fuel pump is mounted on the midst portion of the fuel pipe, • the discharge pressure of the sub fuel pump is set higher than the discharge pressure of the main fuel pump for the main fuel tank, and the sub fuel pump is connected to the fuel passage arranged upstream of the fuel injection valve for the main fuel tank by way of the one-way valve. Accordingly, the main fuel tank side and the sub fuel tank side can use the fuel injection valve in common. Accordingly, the number of parts can be reduced thus realizing the reduction of cost. [Best Mode for Carrying Out the Invention] [0023] Best modes for carrying out the present invention are explained in conjunction with attached drawings. Here, the [Brief Description of the Drawings] [0082] [Fig. I] A side view of a vehicle which adopts an engine-use fuel supply device according to the present invention. [Fig. 2] A cross-sectional view showing a first embodiment of the fuel supply device according to the present invention. [Fig. 3] A transverse cross-sectional view (first embodiment) of a main fuel tank according to the present invention. [Fig. 4] An explanatory view (first embodiment) of a fuel supply port of the main fuel tank according to the present invention. [Fig. 5] A cross-sectional view showing a second embodiment of a fuel supply device according to the present invention. [Fig. 6] An explanatory view (second embodiment, third embodiment) showing a check valve according to the present invention. [Fig. 7] A cross-sectional view showing a fourth embodiment of a fuel supply device according to the present invention. [Fig. 8] A cross-sectional view showing a fifth embodiment of a fuel supply device according to the present invention. [Fig. 9] An explanatory view (a sixth embodiment, a seventh embodiment) showing an arrangement of a sub fuel tank according to the present invention. [Fig. 10] A cross-sectional view showing an eighth embodiment of a fuel supply device according to the present invention. [Fig. 11] A cross-sectional view showing a ninth embodiment of a fuel supply device according to the present invention. [Fig. 12] A cross-sectional view showing a tenth embodiment of a fuel supply device according to the present invention. [Fig. 13] A cross-sectional view showing an eleventh embodiment of a fuel supply device according to the present invention. [Fig. 14] A cross-sectional view showing a twelfth embodiment of a fuel supply device according to the present invention. drawings are viewed in the same direction as numerals. Fig. 1 is a side view of a vehicle which adopts an engine-use fuel supply device according to the present invention. The vehicle 10 is a motorcycle which is configured such that an engine 12 is arranged at a center portion of a vehicle body frame 11, a front fork 13 is steerablly supported on a front end of the vehicle body frame 11, and a rear fork 14 is supported on a rear lower portion of the vehicle body frame 11 in a vertically swingable manner. The vehicle 10 uses alcohol or mixed oil containing of gasoline and alcohol as a main fuel, and only when engine is started, for example, only when the atmospheric temperature is low and the startability of the engine is low, as a sub fuel, gasoline or mixed oil of gasoline and alcohol (a mixing ratio of gasoline set higher than a mixing ratio of main fuel) is used. [0024] The vehicle body frame 11 is constituted of a head pipe 21 which is arranged on a front end thereof, a main frame 22 which extends in the rearward direction from the head pipe 21, a center frame 23 which extends in the downward direction from a midst portion of the main frame 22, sub frames 24 which are respectively connected to a rear portion of the main frame 22 and a lower portion of the center frame 23, and a down frame 26 which extends in the oblique rearward and downward direction from the head pipe 21. The vehicle body frame 11 is a skeleton member formed by joining a plurality of parts which is formed by press forming. [0025] The head pipe 21 is a portion on which the front fork 13 is rotatably mounted, while the front fork 13 mounts a bar handle 31 on an upper portion thereof and a front wheel 32 on. a lower portion thereof. The main frame 22 which constitutes a portion of the vehicle body frame 11 mounts a main fuel tank 33 on a front portion thereof in a striding manner, and mounts a seat 34 on a rear portion thereof. A sub fuel tank described later in detail is formed in the inside of the main fuel tank 33. [0026] The center frame 23 which constitutes a portion of the vehicle body frame 11 is configured to support the engine 12 together with the down frame 26, and a pivot shaft 36 which is mounted on the center frame 23 constitutes a swing shaft of the rear fork 14. A rear wheel 35 is mounted on a rear end of the rear fork 14. A rear cushion unit 37 extends between the rear portion of the rear fork 14 and the rear portion of the main frame 22. The down frame 26 which constitutes a portion of the vehicle body frame 11 supports the engine 12 by way of a bracket 38. [0027] The engine 12 integrally mounts a transmission 41 on a rear portion thereof. A cylinder head 44 is mounted on a cylinder portion 43 which extends upwardly, an intake system 46 is connected to a rear portion of the cylinder head 44, and an exhaust system 47 is connected to a front portion of the cylinder head 44. [0028] The intake system 46 is constituted of an intake pipe 51 which has one end thereof connected to the cylinder head 44, a throttle body 52 which has one end thereof connected to another end of the intake pipe 51, and an air cleaner 54 which is connected to another end of the throttle body 52 by way of a connecting tube 53. [0029] The exhaust system 47 is constituted of an exhaust pipe 56 which has one end thereof connected to a front portion of the cylinder head 44 and extends from a front portion of the engine 12 in the downward and rearward direction, and a muffler 57 which is connected to another end of the exhaust pipe 56 and extends in the rearward direction. [0030] In the drawing, numeral 61 indicates a front cowl, numeral 62 indicates a head lamp, numeral 63 indicates a front fender, numeral 64 indicates a side cover which covers a side portion of the air cleaner 54, numeral 66 indicates a rear side cover, numeral 67 indicates a rear fender, numeral 68 indicates a tail lamp, numeral 71 indicates a main stand, numeral 72 indicates an output shaft of the transmission 41, numeral 73 indicates a drive sprocket which is mounted on the output shaft 72, numeral 74 indicates a driven sprocket which is integrally mounted on the rear Wheel 35, numeral 76 indicates a chain which is wound around the drive sprocket 73 and the driven sprocket 74, and numeral 77 indicates a chain cover. [0031] Fig. 2 is a cross-sectional view showing a first embodiment of the fuel supply device according to the present invention. The main fuel tank 33 is a saddle-type container and includes a fuel pump 82 mounted on a rear portion of a bottom portion 81 in a state that the fuel pump 82 extends upwardly. The main fuel tank 33 also incorporates a cylindrical sub fuel tank 84 which extends downwardly from a fuel supply port 83 therein and main fuel 86 is stored in the main fuel tank 33. Here, numeral 87 indicates a bottom portion which is arranged at a center of the main fuel tank 33 in the lateral direction. [0032] The main fuel pump 82 is connected to a fuel injection valve 91 which is mounted on the throttle body 52 by way of a fuel supply pipe 88. Here, numeral 92 indicates a throttle valve arranged in the inside of the throttle body 52. [0033] The sub fuel tank 84 is a container which arranges a fuel pump 94 on a bottom portion 93 thereof, and the sub fuel tank 84 stores sub fuel 96 therein. The fuel pump 94 is connected to a fuel injection valve 97 mounted on the throttle body 52 by way of a fuel supply pipe 98. [0034] Fig. 3 is a transverse cross-sectional view (first embodiment) of the main fuel tank according to the present invention. A left bulging portion 101 and a right bulging portion 102 which bulge downwardly are formed on both sides of the bottom portion 87 with respect to the center in the lateral direction of the main fuel tank 33. When a residual quantity of the main fuel 86 in the inside of the main fuel tank 33 becomes small, the left bulging portion 101 and the right bulging portion 102 can independently store the main fuel 86. Here, a fuel cock 104 is formed in a bottom of the left bulging portion 101 and hence, the main fuel 86 in the inside of the left bulging portion 101 can be used up. On the other hand, a small quantity of main fuel 86 which is stored at a bottom of the right bulging portion 102 can not be tapped and hence, the bottom portion forms a so-called "dead space". The present invention can effectively make use of the dead space by arranging the sub fuel tank 84 in the right bulging portion 102. [0035] Fig. 4 (a), (b) are explanatory views of the fuel supply port of the main fuel tank according to the present invention (first embodiment). Fig. 4 (a) shows the fuel supply port 83 of the main fuel tank 33 (see Fig. 2). A fuel supply port 106 of the sub fuel tank 84 (see Fig. 2) is arranged in the inside of the fuel supply port 83. The fuel supply port 83 includes a longitudinally-elongated oblong outer edge portion 111, and a fuel supply hole 112 for the main fuel tank 33 and a fuel supply hole 113 for the sub fuel tank 84 which are formed in an inner-side portion of the outer edge portion 111. Here, numeral 115 indicates a bottom wall arranged around the fuel supply hole 112, and numeral 116 indicates a bottom wall arranged around the fuel supply hole 113. The fuel supply port 106 of the sub fuel tank 84 is constituted of the fuel supply hole 113. In the drawing, symbol "REG" indicates regular gas, and symbol "ALC" indicates alcohol. As described above, by providing two fuel supply ports, the usability of the fuel tank can be enhanced. [0036] Fig. 4 (b) is a cross-sectional view taken along a line b-b in Fig. 4 (a) . In the drawings, a cap 118 is fitted on the fuel supply port 83. An upper end surface 112a of the fuel supply hole 112 is arranged at a position higher than the bottom wall 115, an upper end surface 113a of the fuel supply hole 113 is arranged at a position higher than the bottom wall 116, and the bottom wall 116 is 'arranged at a position higher than the bottom wall 115. By setting heights of the respective portions in such a manner, main fuel which overflows from the fuel supply holes 112, 113 can be discharged using a drain hose 121 mounted on the bottom wall 115. [0037] The cap 118 is constituted of an outer plate portion 124 and a rubber 126 which is mounted on an inner side of the outer plate portion 124 . The cap 118 also includes an annular portion 127 which is fitted in an inner surface Ilia of the outer edge portion 111 of the fuel supply port 83, a large lid portion 128 which closes the fuel supply hole 112, and a small lid portion 129 which closes the fuel supply hole 113. Here, numeral 113b indicates a drain hole which allows the sub fuel 96 to flow into the inside of the main fuel tank 33 when the sub fuel 96 in the inside of the sub fuel tank 84 overflows. [0038] Fig. 4 (c) is a transverse cross-sectional view of a main fuel tank 201 showing a modification of a sub fuel tank 202. As shown in Fig. 4(c), the sub fuel tank 202 is arranged in an upper portion of the inside of the saddle-type main fuel tank 201. The sub fuel tank 202 is formed with a large width in the vehicle width direction. Accordingly, even when the vehicle body is inclined leftwardly or rightwardly, the sub fuel 96 easily remains at left and right sides of the sub fuel tank 202. Here, numeral 205 indicates a cap which covers a fuel supply port. [0039] Fig. 4 (d) is a cross-sectional view of an essential part showing a fuel supply port 201a of the main fuel tank 201 as well as a fuel supply port 202a of the sub fuel tank 202. The fuel supply port 201a of the main fuel tank 201 is closed by a sub cap 206, while the fuel supply port 202a of the sub fuel tank 202 is closed by a sub cap 207. The sub caps 206, 207 are covered with the cap 205 from above. [0040] A gap 202c is formed between a tank body 202b which constitutes the sub fuel tank 202 and the fuel supply port 202a. The sub fuel 96 which overflows from the tank body 202b during the fuel filling operation to the sub fuel tank 202 flows into the inside of the main fuel tank 201 through the gap 202c. [0041] Fig. 5 is a cross-sectional view showing a second embodiment of the fuel supply device according to the present invention. In this fuel supply device, a fuel pump 82 of a main fuel tank 33 and a fuel injection valve 91 on a throttle-body-52 side are connected with each other using a fuel supply pipe 88, the inside of a sub fuel tank 84 and a throttle body 52 are connected with each other using a fuel supply pipe 131, a solenoid valve 132 which controls a flow time of a sub fuel 96, that is, a flow rate of the sub fuel 96 is mounted on a midst portion of the fuel supply pipe 131, and a check valve 133 is mounted on an end portion of the fuel supply pipe 131 on a throttle-body-52 side. [0042] The check valve 133 is configured such that when the solenoid valve 132 is opened with the supply of electricity, the check valve 133 allows only the flow of the sub fuel 96 toward the throttle body 52 from the sub fuel tank 84 by making use of the difference in height H between the sub fuel 96 stored in the inside of the sub fuel tank 84 and the check valve 133. The sub fuel 96 is supplied into the inside of the throttle body 52 through the check valve 133 at the time of starting the engine. [0043] Fig. 6 (a) to Fig. 6(d) are explanatory views showing the check valve according to the present invention. In Fig. 6 (a), the check valve 133 of a second embodiment is constituted of a valve casing 135 and a resin-made spherical valve body 136 which opens and closes a female tapered passage 135a formed in one end of the valve casing 135. The valve casing 135 forms a plurality of notched passages 135b in another end thereof. In the drawing, the check valve 133 is in a closed state. [0044] In Fig. 6 (b), when the solenoid valve 132 is opened and the sub fuel flows toward the throttle body 52 as indicated by an arrow, the valve body 136 of the check valve 133 is pushed away by the sub fuel and is brought into contact with another end side of the valve casing 135. The notched passages 135b are formed on another end of the valve casing 135 and hence, the sub fuel flows into the inside of the throttle body 52 through the notched passages 135b. [0045] Fig. 6(c) and Fig. 6(d) are explanatory views showing another embodiment (third embodiment) of the check valve. In Fig. 6(c), a check valve 141 is formed of a lead valve and includes a thin leaf spring 142 and a fixing member 143 which fixes an end portion of the thin leaf spring 142 to a throttle body 52. In the drawing, the check valve 141 is in a closed state. [0046] In Fig. 6 (d) , when the solenoid valve 132 is opened and the sub fuel flows toward the throttle body 52 as indicated by an arrow, the thin leaf spring 142 of the check valve 141 is pushed away by the sub fuel. Accordingly, the check valve 141 is opened so that the sub fuel flows into the inside of the throttle body 52. [0047] Fig. 7 is a cross-sectional view showing a fourth embodiment of a fuel supply device according to the present invention. In this fuel supply device, a fuel pump 82 of a main fuel tank 33 and a fuel, injection valve 91 on a side of a throttle body 52 are connected with each other using a fuel supply pipe 88, a fuel pump 94 of a sub fuel tank 84 and the fuel injection valve 91 are connected with each other using a fuel supply pipe 98, and a one-way valve 146 is arranged on a midst portion of the fuel supply pipe 98. The one-way valve 146 allows only the flow of sub fuel toward the fuel injection valve 91 from the fuel pump 94. [0048] Fig. 8 is a cross-sectional view showing a fifth embodiment of a fuel supply device according to the present invention. In this fuel supply device, a fuel pump 82 of a main fuel tank 33 and a fuel injection valve 91 on a throttle-body-52 side are connected with each other using a fuel supply pipe 88, a fuel pump 94 of a sub fuel tank 84 and a throttle body 52 are connected with each other using a fuel supply pipe 131, a solenoid valve 132 is arranged on a midst portion of the fuel supply pipe 131, and a throttling jet 148 is mounted on an end portion of the fuel supply pipe 131 on the throttle-body-52 side. [0049] The throttling jet 148 forms an orifice for restricting a flow rate of the sub fuel therein in a opened state/ and the throttling jet 148 is arranged more downstream of an intake system 4'6 'than the fuel injection valve 91. Due to such a constitution, by dropping sub fuel from the throttling jet 148 at the time of injecting main fuel 86 from the fuel injection valve 91, premixing of the main fuel 86 with air is accelerated by the main fuel 86 into which the sub fuel 96 is injected thus obtaining a stable combustion. [0050] Fig. 9 (a) to Fig. 9 (d) are explanatory views showing an arrangement of a sub fuel tank according to the present invention (sixth embodiment and seventh embodiment). Fig. 9 (a) is a plan view (sixth embodiment) . Out of a left bulging portion 151a and a right bulging portion 151b which constitute left and right front portions of a saddle-type main fuel tank 151, a partition wall 151c is provided to the left bulging portion 151a to form a sub fuel tank 152 (a cross-hatching portion). The sub fuel tank 152 is arranged close to a front portion of a vehicle body frame 11, to be more specific, a side of a front portion of a main frame 22. [0051] Fig. 9 (b) is a side view (sixth embodiment) of Fig. 9 (a) . An upper wall 151e is arranged at the same height as a front portion of a bottom portio.n 151d arranged at the center in the lateral direction of the main fuel tank 151, and the sub fuel tank 152 is formed below the upper wall 151e and in front of the partition wall 151c. Accordingly, it is possible to effectively make use of a dead space formed in the saddle-type main fuel tank 151. The sub fuel tank 152 is arranged to overlap a front portion of the vehicle body frame 11 as viewed in a side view. [0052] Fig. 9(c) is a plan view (seventh embodiment) . Out of a left bulging portion 155a and a right bulging portion 155b which constitute left and right front portions of a saddle-type main fuel tank 155, a recessed portion 155c which opens inwardly is formed in the left bulging portion 155a, and a sub fuel tank 156 (a cross-hatched portion) which is provided separately from the main fuel tank 155 is arranged in the recessed portion 155c. [0053] Due to such a constitution, by arranging the sub fuel tank 156 in the inside of the recessed portion 155c, the sub fuel tank 156 does not project to the outside from the main fuel tank 155 thus preventing the large-sizing of the vehicle. The sub fuel tank 156 is arranged close to the front portion of the vehicle body frame 11, to be more specific, a side of a front portion of the main frame 22. [0054] Fig. 9(d) is a side view (seventh embodiment) of the main fuel tank 155 and the sub fuel tank 156 shown in Fig. 9(c), wherein the sub fuel tank 156 is arranged below the bottom portion 155d which is positioned at a center in the lateral direction of the main fuel tank 155, for example. Accordingly, it is possible to effectively use a dead space of the saddle-type main fuel tank 155. [0055] The sub fuel tank 156 is arranged close to the front portion of the vehicle body frame 11, to be more specific, a side of a front portion of the main frame 22. The sub fuel tank 156 is arranged to overlap the front portion of the vehicle body frame 11 as viewed in a side view. [0056] Fig. 10 is a cross-sectional view of eighth embodiment of a fuel supply device according to the present invention. In this fuel supply device, a fuel pump 82 is mounted on a bottom portion 161a of a main fuel tank 161, a first filter 162 is arranged in the inside of the fuel pump 82, a second filter 164 is connected to the fuel pump 82 by way of a fuel supply pipe 163, a fuel injection valve 91 arranged on a throttle-body-52 side is connected to a check valve 166 mounted on the second filter 164 by way of a fuel supply pipe 167, and a fuel return pipe 169 extends to the inside of the main fuel tank 161 from a pressure regulator 168 mounted on the second filter 164. [0057] The check valve 166 allows only the flow of fuel toward the fuel injection valve 91 from the second filter 164. The pressure regulator 168 is provided for preventing the discharge pressure of the fuel pump 82 from becoming excessively high by allowing the main fuel 86 to flow into the inside of the main fuel tank 161 through the fuel return pipe 169 when there is no injection of fuel from the fuel injection valve 91. [0058] The first filter 162 has a coarser mesh than the second filter 164 and hence, clogging of the first filter 162 is hardly generated thus prolonging a filter exchange period and, at the same time, the discharge property of the fuel pump 82 can be maintained for a long period. Further, the second filter 164 is arranged outside separately from the fuel pump 82 and hence, the second filter 164 can be easily exchanged. [0059] Further, a sub fuel tank 171 is arranged below a fuel supply port 161b of the main fuel tank 161, a fuel supply pipe 172 extends downwardly from the sub fuel tank 171, and a distal end portion of the fuel supply pipe 172 is inserted into the inside of a float chamber 173 which is arranged below the throttle body 52. [0060] In the inside of the float chamber 173, a fuel suction pipe 176 which extends vertically, a throttling jet 178 which is connected to a distal end of the fuel suction pipe 176 by way of a solenoid valve 177, a float 181 which floats on the sub fuel 96, and a needle valve 183 which is mounted on the float 181 by way of a support member 182 are arranged. A distal end of the throttling jet 178 projects into the inside of the throttle body 52, and the needle valve 183 is arranged to move toward or retract from a distal end of the fuel supply pipe 172. [0061] When a quantity of the sub fuel 96 in the inside of the float chamber 173 is reduced to a predetermined quantity, the needle valve 183 retracts from the distal end of the fuel supply pipe 172 so that the sub fuel 96 flows into the inside of the float chamber 173 from the fuel supply pipe 172. When a predetermined quantity of sub fuel 96 is stored in the inside of the float chamber 173, the needle valve 183 is inserted into the distal end of the fuel supply pipe 172 so that the distal end of the fuel supply pipe 172 is closed by the needle valve 183 whereby the outflow of the sub fuel 96 from the fuel supply pipe 172 is stopped. [0062] When the solenoid valve 177 is opened with the supply of electricity, the sub fuel 96 is discharged into the inside of the throttle-body 52 through the fuel suction pipe 172, the solenoid valve 177 and the throttling jet 178. [0063] Fig. 11 is a cross-sectional view showing a ninth embodiment of a fuel supply device according to the present invention, wherein a fuel supply pipe 186 extends downwardly from a sub fuel tank 171 which is arranged in an upper portion of the inside of a main fuel tank 161, a distal end portion of the fuel supply pipe 186 is connected to a throttling jet 148 mounted on an intake pipe 51, and a one-way tickler 187 is mounted on a midst portion of the fuel supply pipe 186. [0064] The one-way tickler 187 allows only the flow of the sub fuel 96 toward a throttling-jet-148 side from the sub fuel tank 171 and, at the same time, forcibly injects the sub fuel from the throttling jet 148 by a manual operation or an automatic operation. [0065] Fig. 12 is a cross-sectional view showing a tenth embodiment of a fuel supply device according to the present invention. In this fuel supply device, a fuel supply pipe 191 extends to a position in the vicinity of a fuel pump 82 from a sub fuel tank 171 which is arranged in an upper portion in the inside of a main fuel tank 161, a distal end of the fuel supply pipe 191 is arranged around a fuel suction port of the fuel pump 82, and a one-way tickler 187 is mounted on a midst portion of the fuel supply pipe 191. [0066] By operating the one-way tickler 187 at the time of starting an engine, sub fuel 96 in the inside of the sub fuel tank 171 is sucked through the fuel suction port of the fuel pump 82 and the sub fuel 96 is injected from a fuel injection valve 91 through a second filter 164 and hence, the sub fuel 96 is burnt in a combustion chamber of an engine together with main fuel 86 thus enhancing the startability of the engine. [0067] Fig. 13 is a cross-sectional view showing an eleventh embodiment of a fuel supply device according to the present invention. In this fuel supply device, a bottom portion 191a of a sub fuel tank 191 which is mounted on a lower portion of a fuel supply port 190a of a main fuel tank 190 is arranged at a position higher than a lower end 190b of a fuel supply port 190a of the main fuel tank 190, a fuel supply pipe 193 extends to a position in the vicinity of a fuel pump 82 from the sub fuel tank 191, a distal end of the fuel supply pipe 193 is arranged around a fuel suction port of the fuel pump 82, and a fuel valve 194 is mounted on a midst portion of the fuel supply pipe 193. [0068] Even when the main fuel tank 190 is filled up with main fuel 86 up to the lower end 190b of the fuel supply port 190a, the difference in height H2 between the bottom portion 191a of the sub fuel tank 191 and the distal end 193a of the fuel supply pipe 193 is larger than the difference in height Hi between a liquid surface 86a of the main fuel 86 and the distal end 193a of the fuel supply pipe 193. Accordingly, when the fuel valve 194 is opened, it is always possible to discharge the sub fuel in the inside of the sub fuel tank 171 from the distal end 191a of the fuel supply pipe 191. Accordingly, the sub fuel 96 can be sucked through the fuel suction port of the fuel pump 82 together with the main fuel 86, and the sub fuel 96 and the main fuel 86 can be injected from the fuel injection valve 91 through a second filter 164. [0069] Fig. 14 is a cross-sectional view showing twelfth embodiment of a fuel supply device according to the present invention, wherein a fuel supply pipe 186 extends downwardly from a sub fuel tank 171 which is arranged on an upper portion in the inside of a main fuel tank 161, a distal end portion of the fuel supply pipe 186 is connected to a throttling jet 148 mounted on an intake pipe 51, and a solenoid valve 211 which controls a flowing time of a sub fuel 96, that is, a flow rate of the sub fuel 96 is arranged on a midst portion of the fuel supply pipe 186. [0070] An injection quantity of a main fuel 86 from the fuel inj ection valve 91 is controlled by an ECU (engine control unit) based on an engine rotational speed, a manifold air pressure, throttle opening, discharged oxygen density, an intake-air temperature, and an engine temperature. Further, in controlling a flow rate of fuel by the solenoid valve 211, an E density (ethanol density) is estimated and learnt by the ECU based on the discharged oxygen density, and the flow rate of fuel is controlled based on the E density, an intake-air temperature and an engine temperature. [0071] To be more specific, when an engine having a high density of ethanol (E100MAP state) is in a cold state and a temperature of the engine is low (equal to or less than 15C°) , regular gas (E22) is injected into the inside of an intake manifold (intake pipe 51) by a required quantity. [0072] As has been explained heretofore in conjunction with Fig. 2 and Fig. 3, the present invention is firstly characterized in that, in the vehicle 10 (see Fig. 1) which includes the sub fuel tank 84 which stores the sub fuel 96 as starting fuel for enhancing the startability of the vehicle 10 in addition to the main fuel tank 33 of the vehicle-use engine 12, the sub fuel tank 84 is arranged in the inside of the main fuel tank 33. [0073] Due to such a constitution, it is possible to effectively make use of the space in the inside of the main fuel tank 33, and the structure of the main fuel tank 33 and the sub fuel tank 84 can be simplified thus preventing the large-sizing of the vehicle 10. For example, by arranging the sub fuel tank 84 on the bottom portion (that is, right bulging portion 102) at either one of left and right sides of the main fuel tank 33, it is possible to effectively make use of the dead space of the main fuel tank 33. [0074] The present invention is secondly characterized in that, as shown in Fig. 2, Fig. 4(a) and Fig. 4(b), the fuel supply port 106 of the sub fuel tank 84 is arranged inside the fuel supply port 83 of the main fuel tank 33. Due to such a constitution, the structure of the fuel supply port 83 can be simplified. Further, the fuel supply port 83 of the main fuel tank 33 and the fuel supply port 106 of the sub fuel tank 84 can be arranged close to each other and hence, it is possible to efficiently perform the fuel filling operation. [0075] The present invention is thirdly characterized in that, the small lid portion 129 which closes the fuel supply port 106 of the sub fuel tank 84 is mounted on the backside of the cap 118 as a lid of the fuel supply port 83 of the main fuel tank 33. Due to such a constitution, these two fuel supply ports 82, 106 can be easily opened and closed and, further, even when an oil level is changed corresponding to the tilting of the vehicle body or the like, it is possible to prevent the main fuel 86 in the inside of the main fuel tank 33 and the sub fuel 96 in the inside of the sub fuel tank 84 from being mixed with each other. [0076] The present invention is fourthly characterized in that, as shown in Fig. 9 (a) to Fig. 9 (d) , in the vehicle 10 (see Fig. 1) which includes the sub fuel tank 152, 156 which stores the sub fuel 96 (see Fig. 2) for enhancing the startability of the vehicle in addition to the main fuel tank 151, 155 of the motorcycle-use engine 12 (see Fig. 1), the sub fuel tank 152, 156 is arranged around the mono-backbone-type main frame 22 on the front side of the vehicle in the vicinity of the main fuel tank 151, 155. Due to such a constitution, it is possible to arrange the sub fuel tank 152, 156 closer to the main fuel tank 151, 155 thus preventing the large-sizing of the vehicle 10. [0077] The present invention is fifthly characterized in that, as shown in Fig. 10, the fuel supply pipe 172 as the fuel pipe extends to the intake system 46 arranged below the sub fuel tank 171 from the sub fuel tank 171 and is connected to the intake system 46. Due to such a constitution, the fuel supply pipe 172 from the sub fuel tank 171 is hardly bent whereby the air leaking property can be enhanced. Further, the difference in height of the sub fuel 96 can be utilized and hence, it is possible to easily supply the sub fuel 96 to the intake system 46 thus enhancing the startability of the engine 12. [0078] The present invention is sixthly characterized in that, as shown in Fig. 5, the solenoid valve 132 which controls a fuel flow time of the sub fuel 96 and the check valve 133 which allows only the flow of the sub fuel 96 toward an intake-system-46 side from a solenoid-valve-132 side, to be more specific, toward the throttle-body-52 side from the solenoid-valve-132 side are mounted on the fuel supply pipe 131 as the fuel pipe extending from the sub fuel tank 84. [0079] Due to such a constitution, it is possible to easily control the supply quantity of the sub fuel which flows into the throttle body 52 using the solenoid valve 132. Further, it is possible to prevent a back-flow of the sub fuel from the throttle body 52 to the sub-fuel-tank-84 side using the check valve 133. [0080] The present invention is seventhly characterized in that, as shown in Fig. 7, the fuel pump 94 is mounted on the sub fuel tank 84, a discharge pressure of the fuel pump 94 is set higher than a discharge pressure of the fuel pump 82 for the main fuel tank 33 and, at the same time, the fuel supply pipe 98 is connected to the fuel injection valve 91 for the main fuel tank 33 by way of the one-way valve 146 from the fuel pump 94. Due to such a constitution, the main-fuel-tank-33 side and the sub-fuel-tank-84 side can use the fuel injection valve 91 in common. Accordingly, the number of parts can be reduced thus realizing the reduction of cost. [Industrial Applicability] [0081] An engine-use fuel supply device of the present invention is preferably applicable to a motorcycle. [Description of Reference Numerals and Signs] [0083] 10: vehicle 12: engine 33, 151, 155, 161: main fuel tank 82, 94: fuel pump 83: fuel supply port of main fuel tank 84, 152, 156, 171: sub fuel tank 96: starting fuel (sub fuel) 91: fuel injection valve 98, 131, 172: fuel pipe (fuel supply pipe) 106: fuel supply port of sub fuel tank 128: small lid (small lid portion) 132: solenoid valve 133: check valve 146: one-way valve [Designation of Document] Claims [Claim 1] An engine-use fuel supply device of a vehicle which includes a sub fuel tank which stores starting fuel for enhancing the startability of the vehicle in addition to a main fuel tank of a vehicle-use engine, wherein the sub fuel tank is arranged in the inside of the main fuel tank. [Claim 2] An engine-use fuel supply device according to claim 1, wherein a fuel supply port of the sub fuel tank is arranged inside a fuel supply port of the main fuel tank. [Claim 3] An engine-use fuel supply device according to claim 2, wherein a small lid which closes the fuel supply port of the sub fuel tank is mounted on a back side of a lid of the fuel supply port of the main fuel tank. [Claim 4] An engine-use fuel supply device of a vehicle which includes a sub fuel tank which stores starting fuel for enhancing the startability of the vehicle in addition to a main fuel tank of a motorcycle-use engine, wherein the sub fuel tank is arranged around amono-backbone-type main frame on a front side of a vehicle in the vicinity of the main fuel tank. [Claim 5] An engine-use fuel supply device according to claim 1 or claim 4, wherein a fuel pipe extends to an intake system below the sub fuel tank from the sub fuel tank and is connected to the intake system. [Claim 6] An engine-use fuel supply device according to claim 5, wherein a solenoid valve which controls a fuel flow time and a check valve which allows only the flow of fuel toward an intake system side from a solenoid valve side are mounted on the fuel pipe extending from the sub fuel tank. [Claim 7] An engine-use fuel supply device according to claim 5, wherein a sub fuel pump is mounted on a midst portion of the fuel pipe, a discharge pressure of the sub fuel pump is set higher than a discharge pressure of a main fuel pump for the main fuel tank, and the sub fuel pump is connected to a fuel passage arranged upstream of a fuel injection valve for the main fuel tank by way of a one-way valve. 8. An engine-use fuel supply device substantially as herein described with reference to the accompanying drawings.

Full Text

[Designation of Document] Specification
[Title of the Invention] ENGINE-USE FUEL SUPPLY DEVICE
[Technical Field]
[0001]
The present invention relates to an improvement of an
engine-use fuel supply device.
[Background Art]
[0002]
Recently, as a vehicle-use fuel, fuel which contains alcohol as a main content has been used in place of gasoline which is fossil fuel. However, since a boiling point of alcohol is low compared to a boiling point of gasoline, alcohol exhibits poor startability when an engine is at a low temperature. To enhance this startability, gasoline or alcohol containing a large quantity of gasoline is used only at the time of starting, and a sub fuel tank for storing such starting fuel is mounted on a vehicle body separately from a main fuel tank. [0003]
As a conventional engine-use fuel supply device including the above-mentioned sub fuel tank, there has been known a fuel supply device in which a main fuel tank is arranged on a front upper portion of a vehicle body frame and a sub fuel tank is arranged on a midst portion of the vehicle body frame (for example, see patent document 1).
[Patent Document I] JP-A-57-164872

[0004]
The patent document 1 is explained in conjunction with Fig. 1 hereinafter.
A vehicle body frame A includes a head pipe 1 which is arranged on a front end of the vehicle body frame A, a main pipe 2 which extends in the oblique rearward and downward direction from the head pipe 1, a seat rail 4 which extends rearwardly from a midst portion of the main pipe 2, and a back stay 5 which connects a lower portion of the main pipe 2 and a midst portion of the seat rail 4 to each other. Amain fuel tank 9 is arranged astride a front portion of the head pipe 2, and a sub fuel tank 10 is arranged in a triangular space 8 defined by the main pipe 1, the seat rail 4 and the back stay 5.
[Disclosure of the Invention] [Problems that the Invention is to Solve] [0005]
In providing the sub fuel tank 10 in the space in addition to the main fuel tank 9, a small-sized vehicle such as a motorcycle cannot ensure a sufficient arrangement space for the sub fuel tank 10. Accordingly, when the sub fuel tank 10 is arranged in the space 8 without any modification, the vehicle becomes large-sized. Here arises a task that it is necessary to prevent such large-sizing of the vehicle.
It is an object of the present invention to realize the

miniaturization of a vehicle having a main fuel tank and a sub
fuel tank.
[Means for Solving the Problem]
[0006]
The invention according to claim I is characterized in that, in a vehicle which includes a sub fuel tank which stores starting fuel for enhancing the startability of the vehicle in addition to a main fuel tank of a vehicle-use engine, the sub fuel tank is arranged in the inside of the main fuel tank. [0007]
To explain the manner of operation, by arranging the sub fuel tank in the inside of the existing main fuel tank, it is unnecessary to newly form a space in the inside of the vehicle body for arranging the sub fuel tank. Provided that fuels which cause no trouble even when the fuels are mixed into a fuel in the inside of the main tank and a fuel in the inside of the sub fuel tank are respectively stored in the tanks, it is unnecessary to adopt the structure which completely separates the main fuel tank and the sub fuel tank from each other and hence, the engine-use fuel supply device can be formed of the simple structure. [0008]
The invention according to claim 2 is characterized in that a fuel supply port of the sub fuel tank is arranged inside a fuel supply port of the main fuel tank.

To explain the manner of operation, by arranging the fuel supply port of the sub fuel tank inside the fuel supply port of the main fuel tank, a portion of tank which the fuel supply port of the sub fuel tank and the fuel supply port of the main fuel tank share in common can be simplified. Accordingly, the tank port structure can be simplified compared to the tank port structure in which a fuel supply port of a sub fuel tank and a fuel supply port of a main fuel tank are provided separately and independently.
Further, the fuel supply port of the main fuel tank and the fuel supply port of the sub fuel tank are arranged close to each other and hence, a fuel filling operation can be performed efficiently when it is necessary to continuously fill main fuel and sub fuel. [0009]
The invention according to claim 3 is characterized in that a small lid which closes the fuel supply port of the sub fuel tank is mounted on a back side of a lid of the fuel supply port of the main fuel tank.
To explain the manner of operation, when the fuel supply port of the main fuel tank is closed by the lid, the fuel supply port of the sub fuel tank is simultaneously closed by the small lid. Further, even when the vehicle body is tilted, the small lid prevents the main fuel from being mixed with the sub fuel. [0010]

The invention according to claim 4 is characterized in that, in a vehicle which includes a sub fuel tank which stores starting fuel for enhancing the startability of the vehicle in addition to a main fuel tank of a motorcycle-use engine, the sub fuel tank is arranged around a mono-backbone-type main frame on a front side of a vehicle in the vicinity of the main fuel tank.
To explain the manner of operation, by arranging the sub fuel tank closer to the main fuel tank, the vehicle hardly becomes large-sized. [0011]
The invention according to claim 5 is characterized in that a fuel pipe extends to an intake system below the sub fuel tank from the sub fuel tank and is connected to the intake system.
To explain the manner of operation, it is possible to arrange the fuel pipe while preventing the bending of the fuel pipe between the sub fuel tank and the intake system more effectively. Further, it is possible to supply the fuel into the intake system by making use of the difference in height between the sub fuel tank and the intake system. [0012]
The invention according to claim 6 is characterized in that a solenoid valve which controls a fuel flow time and a check valve which allows only the flow of fuel toward the intake

system from a solenoid valve side are mounted on the fuel pipe
extending from the sub fuel tank.
[0013]
To explain the manner of operation, by opening and closing the solenoid valve, a time which fuel requires to flow into the intake system through the check valve, that is, a fuel supply quantity is controlled. Due to the provision of the check valve, there exists no possibility that fuel flows back toward a sub fuel tank side from the intake system. [0014]
The invention according to claim 7 is characterized in that a sub fuel supply pump is mounted on a midst portion of the fuel pipe, a discharge pressure of the sub fuel pump is set higher than a discharge pressure of a main fuel pump for the main fuel tank, and the sub fuel pump is connected to a fuel passage arranged upstream of a fuel injection valve for the main fuel tank by way of a one-way valve. [0015]
To explain the manner of operation, by setting the discharge pressure of the sub fuel pump higher than the discharge pressure of the main fuel pump, the sub fuel in the inside of the sub fuel tank can be supplied to the upstream-side fuel passage through the fuel injection valve for the main fuel tank even during the operation of the main fuel pump. The one way valve is provided for preventing the main fuel discharged

from the main fuel pump from flowing into the sub fuel tank when the sub fuel pump is not operated. [Advantage of the Invention] [0016]
According to the invention described in claim 1, the sub fuel tank is arranged in the inside of the main fuel tank and hence, it is possible to effectively make use of the space in the inside of the main fuel tank. • Further, the structure of the main fuel tank and the sub fuel tank can be simplified thus preventing the large-sizing of the vehicle. For example, by arranging the sub fuel tank on a bottom portion of either one of left and right sides of the main fuel tank, it is possible to effectively make use of a dead space of the main fuel tank. [0017]
According to the invention described in claim 2, the fuel supply port of the sub fuel tank is arranged inside the fuel supply port of the main fuel tank and hence, it is possible to realize the simplification of the fuel supply port structure . Further, the fuel supply port of the main fuel tank and the fuel supply port of the sub fuel tank can be arranged close to each other and hence, it is possible to efficiently perform the fuel filling operation. [0018]
According to the invention described in claim 3, the small lid which closes the fuel supply port of the sub fuel

tank is mounted on the backside of the lid of the fuel supply port of the main fuel tank and hence, these two fuel supply ports can be easily opened and closed. Further, even when an oil level is changed corresponding to the tilting of the vehicle body or the like, it is possible to prevent the fuel in the inside of the main fuel tank and the fuel in the inside of the sub fuel tank from being mixed with each other. [0019]
According to the invention described in claim 4, the sub fuel tank is arranged around the mono-backbone-type main frame on the front side of the vehicle in the vicinity of the main fuel tank and hence, it is possible to arrange the sub fuel tank closer to the main fuel tank thus preventing the large-sizing of the vehicle. [0020]
According to the invention described in claim 5, the fuel pipe extends to the intake system arranged below the sub fuel tank from the sub fuel tank and is connected to the intake system and hence, the fuel pipe from the sub fuel tank is hardly bent whereby the air leaking property can be enhanced. Further, the difference in fuel level can be utilized and hence, it is possible to easily supply the fuel to the intake system thus enhancing the startability of the engine. [0021]
According to the invention described in claim 6, the

solenoid valve which controls the fuel flow time and the check valve which allows only the flow of fuel toward the intake system side from the solenoid valve side are mounted on the ' fuel pipe extending from the sub fuel tank and hence, it is possible to easily control the supply quantity of the fuel which flows into the intake system using the solenoid valve . Further, it is possible to prevent a backflow of the fuel from the intake system to the sub fuel tank side using the check valve. [0022]
According to the invention described in claim 7, the sub fuel pump is mounted on the midst portion of the fuel pipe, • the discharge pressure of the sub fuel pump is set higher than the discharge pressure of the main fuel pump for the main fuel tank, and the sub fuel pump is connected to the fuel passage arranged upstream of the fuel injection valve for the main fuel tank by way of the one-way valve. Accordingly, the main fuel tank side and the sub fuel tank side can use the fuel injection valve in common. Accordingly, the number of parts can be reduced thus realizing the reduction of cost. [Best Mode for Carrying Out the Invention] [0023]
Best modes for carrying out the present invention are explained in conjunction with attached drawings. Here, the
[Brief Description of the Drawings]
[0082]
[Fig. I]
A side view of a vehicle which adopts an engine-use fuel supply device according to the present invention. [Fig. 2]

A cross-sectional view showing a first embodiment of the fuel supply device according to the present invention. [Fig. 3]
A transverse cross-sectional view (first embodiment) of a main fuel tank according to the present invention. [Fig. 4]
An explanatory view (first embodiment) of a fuel supply port of the main fuel tank according to the present invention. [Fig. 5]
A cross-sectional view showing a second embodiment of a fuel supply device according to the present invention. [Fig. 6]
An explanatory view (second embodiment, third embodiment) showing a check valve according to the present invention. [Fig. 7]
A cross-sectional view showing a fourth embodiment of a fuel supply device according to the present invention. [Fig. 8]
A cross-sectional view showing a fifth embodiment of a fuel supply device according to the present invention. [Fig. 9]
An explanatory view (a sixth embodiment, a seventh embodiment) showing an arrangement of a sub fuel tank according to the present invention.

[Fig. 10]
A cross-sectional view showing an eighth embodiment of a fuel supply device according to the present invention. [Fig. 11]
A cross-sectional view showing a ninth embodiment of a fuel supply device according to the present invention. [Fig. 12]
A cross-sectional view showing a tenth embodiment of a fuel supply device according to the present invention. [Fig. 13]
A cross-sectional view showing an eleventh embodiment of a fuel supply device according to the present invention. [Fig. 14]
A cross-sectional view showing a twelfth embodiment of a fuel supply device according to the present invention.

drawings are viewed in the same direction as numerals.
Fig. 1 is a side view of a vehicle which adopts an
engine-use fuel supply device according to the present invention. The vehicle 10 is a motorcycle which is configured such that an engine 12 is arranged at a center portion of a vehicle body frame 11, a front fork 13 is steerablly supported on a front end of the vehicle body frame 11, and a rear fork 14 is supported on a rear lower portion of the vehicle body frame 11 in a vertically swingable manner. The vehicle 10 uses alcohol or mixed oil containing of gasoline and alcohol as a main fuel, and only when engine is started, for example, only when the atmospheric temperature is low and the startability of the engine is low, as a sub fuel, gasoline or mixed oil of gasoline and alcohol (a mixing ratio of gasoline set higher than a mixing ratio of main fuel) is used. [0024]
The vehicle body frame 11 is constituted of a head pipe 21 which is arranged on a front end thereof, a main frame 22 which extends in the rearward direction from the head pipe 21, a center frame 23 which extends in the downward direction from a midst portion of the main frame 22, sub frames 24 which are respectively connected to a rear portion of the main frame 22 and a lower portion of the center frame 23, and a down frame 26 which extends in the oblique rearward and downward direction from the head pipe 21. The vehicle body frame 11 is a skeleton member formed by joining a plurality of parts which is formed by press forming.

[0025]
The head pipe 21 is a portion on which the front fork 13 is rotatably mounted, while the front fork 13 mounts a bar handle 31 on an upper portion thereof and a front wheel 32 on. a lower portion thereof.
The main frame 22 which constitutes a portion of the vehicle body frame 11 mounts a main fuel tank 33 on a front portion thereof in a striding manner, and mounts a seat 34 on a rear portion thereof.
A sub fuel tank described later in detail is formed in the inside of the main fuel tank 33. [0026]
The center frame 23 which constitutes a portion of the vehicle body frame 11 is configured to support the engine 12 together with the down frame 26, and a pivot shaft 36 which is mounted on the center frame 23 constitutes a swing shaft of the rear fork 14. A rear wheel 35 is mounted on a rear end of the rear fork 14.
A rear cushion unit 37 extends between the rear portion of the rear fork 14 and the rear portion of the main frame 22. The down frame 26 which constitutes a portion of the vehicle body frame 11 supports the engine 12 by way of a bracket 38. [0027]
The engine 12 integrally mounts a transmission 41 on a

rear portion thereof. A cylinder head 44 is mounted on a cylinder portion 43 which extends upwardly, an intake system 46 is connected to a rear portion of the cylinder head 44, and an exhaust system 47 is connected to a front portion of the cylinder head 44. [0028]
The intake system 46 is constituted of an intake pipe 51 which has one end thereof connected to the cylinder head 44, a throttle body 52 which has one end thereof connected to another end of the intake pipe 51, and an air cleaner 54 which is connected to another end of the throttle body 52 by way of a connecting tube 53. [0029]
The exhaust system 47 is constituted of an exhaust pipe
56 which has one end thereof connected to a front portion of
the cylinder head 44 and extends from a front portion of the
engine 12 in the downward and rearward direction, and a muffler
57 which is connected to another end of the exhaust pipe 56
and extends in the rearward direction.
[0030]
In the drawing, numeral 61 indicates a front cowl, numeral 62 indicates a head lamp, numeral 63 indicates a front fender, numeral 64 indicates a side cover which covers a side portion of the air cleaner 54, numeral 66 indicates a rear side cover, numeral 67 indicates a rear fender, numeral 68 indicates

a tail lamp, numeral 71 indicates a main stand, numeral 72 indicates an output shaft of the transmission 41, numeral 73 indicates a drive sprocket which is mounted on the output shaft 72, numeral 74 indicates a driven sprocket which is integrally mounted on the rear Wheel 35, numeral 76 indicates a chain which is wound around the drive sprocket 73 and the driven sprocket 74, and numeral 77 indicates a chain cover. [0031]
Fig. 2 is a cross-sectional view showing a first embodiment of the fuel supply device according to the present invention. The main fuel tank 33 is a saddle-type container and includes a fuel pump 82 mounted on a rear portion of a bottom portion 81 in a state that the fuel pump 82 extends upwardly. The main fuel tank 33 also incorporates a cylindrical sub fuel tank 84 which extends downwardly from a fuel supply port 83 therein and main fuel 86 is stored in the main fuel tank 33. Here, numeral 87 indicates a bottom portion which is arranged at a center of the main fuel tank 33 in the lateral direction. [0032]
The main fuel pump 82 is connected to a fuel injection valve 91 which is mounted on the throttle body 52 by way of a fuel supply pipe 88. Here, numeral 92 indicates a throttle valve arranged in the inside of the throttle body 52. [0033]
The sub fuel tank 84 is a container which arranges a fuel

pump 94 on a bottom portion 93 thereof, and the sub fuel tank 84 stores sub fuel 96 therein. The fuel pump 94 is connected to a fuel injection valve 97 mounted on the throttle body 52 by way of a fuel supply pipe 98. [0034]
Fig. 3 is a transverse cross-sectional view (first embodiment) of the main fuel tank according to the present invention. A left bulging portion 101 and a right bulging portion 102 which bulge downwardly are formed on both sides of the bottom portion 87 with respect to the center in the lateral direction of the main fuel tank 33. When a residual quantity of the main fuel 86 in the inside of the main fuel tank 33 becomes small, the left bulging portion 101 and the right bulging portion 102 can independently store the main fuel 86. Here, a fuel cock 104 is formed in a bottom of the left bulging portion 101 and hence, the main fuel 86 in the inside of the left bulging portion 101 can be used up. On the other hand, a small quantity of main fuel 86 which is stored at a bottom of the right bulging portion 102 can not be tapped and hence, the bottom portion forms a so-called "dead space". The present invention can effectively make use of the dead space by arranging the sub fuel tank 84 in the right bulging portion 102. [0035]
Fig. 4 (a), (b) are explanatory views of the fuel supply

port of the main fuel tank according to the present invention (first embodiment).
Fig. 4 (a) shows the fuel supply port 83 of the main fuel tank 33 (see Fig. 2). A fuel supply port 106 of the sub fuel tank 84 (see Fig. 2) is arranged in the inside of the fuel supply port 83.
The fuel supply port 83 includes a longitudinally-elongated oblong outer edge portion 111, and a fuel supply hole 112 for the main fuel tank 33 and a fuel supply hole 113 for the sub fuel tank 84 which are formed in an inner-side portion of the outer edge portion 111. Here, numeral 115 indicates a bottom wall arranged around the fuel supply hole 112, and numeral 116 indicates a bottom wall arranged around the fuel supply hole 113.
The fuel supply port 106 of the sub fuel tank 84 is constituted of the fuel supply hole 113.
In the drawing, symbol "REG" indicates regular gas, and symbol "ALC" indicates alcohol.
As described above, by providing two fuel supply ports, the usability of the fuel tank can be enhanced. [0036]
Fig. 4 (b) is a cross-sectional view taken along a line b-b in Fig. 4 (a) . In the drawings, a cap 118 is fitted on the fuel supply port 83.
An upper end surface 112a of the fuel supply hole 112

is arranged at a position higher than the bottom wall 115, an upper end surface 113a of the fuel supply hole 113 is arranged at a position higher than the bottom wall 116, and the bottom wall 116 is 'arranged at a position higher than the bottom wall 115. By setting heights of the respective portions in such a manner, main fuel which overflows from the fuel supply holes 112, 113 can be discharged using a drain hose 121 mounted on the bottom wall 115. [0037]
The cap 118 is constituted of an outer plate portion 124 and a rubber 126 which is mounted on an inner side of the outer plate portion 124 . The cap 118 also includes an annular portion
127 which is fitted in an inner surface Ilia of the outer edge
portion 111 of the fuel supply port 83, a large lid portion
128 which closes the fuel supply hole 112, and a small lid
portion 129 which closes the fuel supply hole 113. Here,
numeral 113b indicates a drain hole which allows the sub fuel
96 to flow into the inside of the main fuel tank 33 when the
sub fuel 96 in the inside of the sub fuel tank 84 overflows.
[0038]
Fig. 4 (c) is a transverse cross-sectional view of a main fuel tank 201 showing a modification of a sub fuel tank 202. As shown in Fig. 4(c), the sub fuel tank 202 is arranged in an upper portion of the inside of the saddle-type main fuel tank 201.

The sub fuel tank 202 is formed with a large width in the vehicle width direction. Accordingly, even when the vehicle body is inclined leftwardly or rightwardly, the sub fuel 96 easily remains at left and right sides of the sub fuel tank 202. Here, numeral 205 indicates a cap which covers a fuel supply port. [0039]
Fig. 4 (d) is a cross-sectional view of an essential part showing a fuel supply port 201a of the main fuel tank 201 as well as a fuel supply port 202a of the sub fuel tank 202. The fuel supply port 201a of the main fuel tank 201 is closed by a sub cap 206, while the fuel supply port 202a of the sub fuel tank 202 is closed by a sub cap 207. The sub caps 206, 207 are covered with the cap 205 from above. [0040]
A gap 202c is formed between a tank body 202b which constitutes the sub fuel tank 202 and the fuel supply port 202a. The sub fuel 96 which overflows from the tank body 202b during the fuel filling operation to the sub fuel tank 202 flows into the inside of the main fuel tank 201 through the gap 202c. [0041]
Fig. 5 is a cross-sectional view showing a second embodiment of the fuel supply device according to the present invention. In this fuel supply device, a fuel pump 82 of a main fuel tank 33 and a fuel injection valve 91 on a

throttle-body-52 side are connected with each other using a fuel supply pipe 88, the inside of a sub fuel tank 84 and a throttle body 52 are connected with each other using a fuel supply pipe 131, a solenoid valve 132 which controls a flow time of a sub fuel 96, that is, a flow rate of the sub fuel 96 is mounted on a midst portion of the fuel supply pipe 131, and a check valve 133 is mounted on an end portion of the fuel supply pipe 131 on a throttle-body-52 side. [0042]
The check valve 133 is configured such that when the solenoid valve 132 is opened with the supply of electricity, the check valve 133 allows only the flow of the sub fuel 96 toward the throttle body 52 from the sub fuel tank 84 by making use of the difference in height H between the sub fuel 96 stored in the inside of the sub fuel tank 84 and the check valve 133. The sub fuel 96 is supplied into the inside of the throttle body 52 through the check valve 133 at the time of starting the engine. [0043]
Fig. 6 (a) to Fig. 6(d) are explanatory views showing the check valve according to the present invention.
In Fig. 6 (a), the check valve 133 of a second embodiment is constituted of a valve casing 135 and a resin-made spherical valve body 136 which opens and closes a female tapered passage 135a formed in one end of the valve casing 135.

The valve casing 135 forms a plurality of notched passages 135b in another end thereof. In the drawing, the check valve 133 is in a closed state. [0044]
In Fig. 6 (b), when the solenoid valve 132 is opened and the sub fuel flows toward the throttle body 52 as indicated by an arrow, the valve body 136 of the check valve 133 is pushed away by the sub fuel and is brought into contact with another end side of the valve casing 135. The notched passages 135b are formed on another end of the valve casing 135 and hence, the sub fuel flows into the inside of the throttle body 52 through the notched passages 135b. [0045]
Fig. 6(c) and Fig. 6(d) are explanatory views showing another embodiment (third embodiment) of the check valve. In Fig. 6(c), a check valve 141 is formed of a lead valve and includes a thin leaf spring 142 and a fixing member 143 which fixes an end portion of the thin leaf spring 142 to a throttle body 52. In the drawing, the check valve 141 is in a closed state. [0046]
In Fig. 6 (d) , when the solenoid valve 132 is opened and the sub fuel flows toward the throttle body 52 as indicated by an arrow, the thin leaf spring 142 of the check valve 141 is pushed away by the sub fuel. Accordingly, the check valve

141 is opened so that the sub fuel flows into the inside of
the throttle body 52.
[0047]
Fig. 7 is a cross-sectional view showing a fourth embodiment of a fuel supply device according to the present invention. In this fuel supply device, a fuel pump 82 of a main fuel tank 33 and a fuel, injection valve 91 on a side of a throttle body 52 are connected with each other using a fuel supply pipe 88, a fuel pump 94 of a sub fuel tank 84 and the fuel injection valve 91 are connected with each other using a fuel supply pipe 98, and a one-way valve 146 is arranged on a midst portion of the fuel supply pipe 98.
The one-way valve 146 allows only the flow of sub fuel toward the fuel injection valve 91 from the fuel pump 94. [0048]
Fig. 8 is a cross-sectional view showing a fifth embodiment of a fuel supply device according to the present invention. In this fuel supply device, a fuel pump 82 of a main fuel tank 33 and a fuel injection valve 91 on a throttle-body-52 side are connected with each other using a fuel supply pipe 88, a fuel pump 94 of a sub fuel tank 84 and a throttle body 52 are connected with each other using a fuel supply pipe 131, a solenoid valve 132 is arranged on a midst portion of the fuel supply pipe 131, and a throttling jet 148 is mounted on an end portion of the fuel supply pipe 131 on

the throttle-body-52 side. [0049]
The throttling jet 148 forms an orifice for restricting a flow rate of the sub fuel therein in a opened state/ and the throttling jet 148 is arranged more downstream of an intake system 4'6 'than the fuel injection valve 91. Due to such a constitution, by dropping sub fuel from the throttling jet 148 at the time of injecting main fuel 86 from the fuel injection valve 91, premixing of the main fuel 86 with air is accelerated by the main fuel 86 into which the sub fuel 96 is injected thus obtaining a stable combustion. [0050]
Fig. 9 (a) to Fig. 9 (d) are explanatory views showing an arrangement of a sub fuel tank according to the present invention (sixth embodiment and seventh embodiment).
Fig. 9 (a) is a plan view (sixth embodiment) . Out of a left bulging portion 151a and a right bulging portion 151b which constitute left and right front portions of a saddle-type main fuel tank 151, a partition wall 151c is provided to the left bulging portion 151a to form a sub fuel tank 152 (a cross-hatching portion).
The sub fuel tank 152 is arranged close to a front portion of a vehicle body frame 11, to be more specific, a side of a front portion of a main frame 22. [0051]

Fig. 9 (b) is a side view (sixth embodiment) of Fig. 9 (a) . An upper wall 151e is arranged at the same height as a front portion of a bottom portio.n 151d arranged at the center in the lateral direction of the main fuel tank 151, and the sub fuel tank 152 is formed below the upper wall 151e and in front of the partition wall 151c. Accordingly, it is possible to effectively make use of a dead space formed in the saddle-type main fuel tank 151.
The sub fuel tank 152 is arranged to overlap a front portion of the vehicle body frame 11 as viewed in a side view. [0052]
Fig. 9(c) is a plan view (seventh embodiment) . Out of a left bulging portion 155a and a right bulging portion 155b which constitute left and right front portions of a saddle-type main fuel tank 155, a recessed portion 155c which opens inwardly is formed in the left bulging portion 155a, and a sub fuel tank 156 (a cross-hatched portion) which is provided separately from the main fuel tank 155 is arranged in the recessed portion 155c. [0053]
Due to such a constitution, by arranging the sub fuel tank 156 in the inside of the recessed portion 155c, the sub fuel tank 156 does not project to the outside from the main fuel tank 155 thus preventing the large-sizing of the vehicle.
The sub fuel tank 156 is arranged close to the front portion of the vehicle body frame 11, to be more specific, a

side of a front portion of the main frame 22. [0054]
Fig. 9(d) is a side view (seventh embodiment) of the main fuel tank 155 and the sub fuel tank 156 shown in Fig. 9(c), wherein the sub fuel tank 156 is arranged below the bottom portion 155d which is positioned at a center in the lateral direction of the main fuel tank 155, for example. Accordingly, it is possible to effectively use a dead space of the saddle-type main fuel tank 155. [0055]
The sub fuel tank 156 is arranged close to the front portion of the vehicle body frame 11, to be more specific, a side of a front portion of the main frame 22.
The sub fuel tank 156 is arranged to overlap the front portion of the vehicle body frame 11 as viewed in a side view. [0056]
Fig. 10 is a cross-sectional view of eighth embodiment of a fuel supply device according to the present invention. In this fuel supply device, a fuel pump 82 is mounted on a bottom portion 161a of a main fuel tank 161, a first filter 162 is arranged in the inside of the fuel pump 82, a second filter 164 is connected to the fuel pump 82 by way of a fuel supply pipe 163, a fuel injection valve 91 arranged on a throttle-body-52 side is connected to a check valve 166 mounted on the second filter 164 by way of a fuel supply pipe 167, and

a fuel return pipe 169 extends to the inside of the main fuel tank 161 from a pressure regulator 168 mounted on the second filter 164. [0057]
The check valve 166 allows only the flow of fuel toward the fuel injection valve 91 from the second filter 164.
The pressure regulator 168 is provided for preventing the discharge pressure of the fuel pump 82 from becoming excessively high by allowing the main fuel 86 to flow into the inside of the main fuel tank 161 through the fuel return pipe 169 when there is no injection of fuel from the fuel injection valve 91. [0058]
The first filter 162 has a coarser mesh than the second filter 164 and hence, clogging of the first filter 162 is hardly generated thus prolonging a filter exchange period and, at the same time, the discharge property of the fuel pump 82 can be maintained for a long period. Further, the second filter 164 is arranged outside separately from the fuel pump 82 and hence, the second filter 164 can be easily exchanged. [0059]
Further, a sub fuel tank 171 is arranged below a fuel supply port 161b of the main fuel tank 161, a fuel supply pipe 172 extends downwardly from the sub fuel tank 171, and a distal end portion of the fuel supply pipe 172 is inserted into the

inside of a float chamber 173 which is arranged below the
throttle body 52.
[0060]
In the inside of the float chamber 173, a fuel suction pipe 176 which extends vertically, a throttling jet 178 which is connected to a distal end of the fuel suction pipe 176 by way of a solenoid valve 177, a float 181 which floats on the sub fuel 96, and a needle valve 183 which is mounted on the float 181 by way of a support member 182 are arranged. A distal end of the throttling jet 178 projects into the inside of the throttle body 52, and the needle valve 183 is arranged to move toward or retract from a distal end of the fuel supply pipe 172. [0061]
When a quantity of the sub fuel 96 in the inside of the float chamber 173 is reduced to a predetermined quantity, the needle valve 183 retracts from the distal end of the fuel supply pipe 172 so that the sub fuel 96 flows into the inside of the float chamber 173 from the fuel supply pipe 172. When a predetermined quantity of sub fuel 96 is stored in the inside of the float chamber 173, the needle valve 183 is inserted into the distal end of the fuel supply pipe 172 so that the distal end of the fuel supply pipe 172 is closed by the needle valve 183 whereby the outflow of the sub fuel 96 from the fuel supply pipe 172 is stopped.

[0062]
When the solenoid valve 177 is opened with the supply of electricity, the sub fuel 96 is discharged into the inside of the throttle-body 52 through the fuel suction pipe 172, the solenoid valve 177 and the throttling jet 178. [0063]
Fig. 11 is a cross-sectional view showing a ninth embodiment of a fuel supply device according to the present invention, wherein a fuel supply pipe 186 extends downwardly from a sub fuel tank 171 which is arranged in an upper portion of the inside of a main fuel tank 161, a distal end portion of the fuel supply pipe 186 is connected to a throttling jet 148 mounted on an intake pipe 51, and a one-way tickler 187 is mounted on a midst portion of the fuel supply pipe 186. [0064]
The one-way tickler 187 allows only the flow of the sub fuel 96 toward a throttling-jet-148 side from the sub fuel tank 171 and, at the same time, forcibly injects the sub fuel from the throttling jet 148 by a manual operation or an automatic operation. [0065]
Fig. 12 is a cross-sectional view showing a tenth embodiment of a fuel supply device according to the present invention. In this fuel supply device, a fuel supply pipe 191 extends to a position in the vicinity of a fuel pump 82 from

a sub fuel tank 171 which is arranged in an upper portion in the inside of a main fuel tank 161, a distal end of the fuel supply pipe 191 is arranged around a fuel suction port of the fuel pump 82, and a one-way tickler 187 is mounted on a midst portion of the fuel supply pipe 191. [0066]
By operating the one-way tickler 187 at the time of starting an engine, sub fuel 96 in the inside of the sub fuel tank 171 is sucked through the fuel suction port of the fuel pump 82 and the sub fuel 96 is injected from a fuel injection valve 91 through a second filter 164 and hence, the sub fuel 96 is burnt in a combustion chamber of an engine together with main fuel 86 thus enhancing the startability of the engine. [0067]
Fig. 13 is a cross-sectional view showing an eleventh embodiment of a fuel supply device according to the present invention. In this fuel supply device, a bottom portion 191a of a sub fuel tank 191 which is mounted on a lower portion of a fuel supply port 190a of a main fuel tank 190 is arranged at a position higher than a lower end 190b of a fuel supply port 190a of the main fuel tank 190, a fuel supply pipe 193 extends to a position in the vicinity of a fuel pump 82 from the sub fuel tank 191, a distal end of the fuel supply pipe 193 is arranged around a fuel suction port of the fuel pump 82, and a fuel valve 194 is mounted on a midst portion of the

fuel supply pipe 193. [0068]
Even when the main fuel tank 190 is filled up with main fuel 86 up to the lower end 190b of the fuel supply port 190a, the difference in height H2 between the bottom portion 191a of the sub fuel tank 191 and the distal end 193a of the fuel supply pipe 193 is larger than the difference in height Hi between a liquid surface 86a of the main fuel 86 and the distal end 193a of the fuel supply pipe 193. Accordingly, when the fuel valve 194 is opened, it is always possible to discharge the sub fuel in the inside of the sub fuel tank 171 from the distal end 191a of the fuel supply pipe 191. Accordingly, the sub fuel 96 can be sucked through the fuel suction port of the fuel pump 82 together with the main fuel 86, and the sub fuel 96 and the main fuel 86 can be injected from the fuel injection valve 91 through a second filter 164. [0069]
Fig. 14 is a cross-sectional view showing twelfth embodiment of a fuel supply device according to the present invention, wherein a fuel supply pipe 186 extends downwardly from a sub fuel tank 171 which is arranged on an upper portion in the inside of a main fuel tank 161, a distal end portion of the fuel supply pipe 186 is connected to a throttling jet 148 mounted on an intake pipe 51, and a solenoid valve 211 which controls a flowing time of a sub fuel 96, that is, a flow rate

of the sub fuel 96 is arranged on a midst portion of the fuel
supply pipe 186.
[0070]
An injection quantity of a main fuel 86 from the fuel inj ection valve 91 is controlled by an ECU (engine control unit) based on an engine rotational speed, a manifold air pressure, throttle opening, discharged oxygen density, an intake-air temperature, and an engine temperature.
Further, in controlling a flow rate of fuel by the solenoid valve 211, an E density (ethanol density) is estimated and learnt by the ECU based on the discharged oxygen density, and the flow rate of fuel is controlled based on the E density, an intake-air temperature and an engine temperature. [0071]
To be more specific, when an engine having a high density of ethanol (E100MAP state) is in a cold state and a temperature
of the engine is low (equal to or less than 15C°) , regular gas (E22) is injected into the inside of an intake manifold (intake pipe 51) by a required quantity. [0072]
As has been explained heretofore in conjunction with Fig. 2 and Fig. 3, the present invention is firstly characterized in that, in the vehicle 10 (see Fig. 1) which includes the sub fuel tank 84 which stores the sub fuel 96 as starting fuel for enhancing the startability of the vehicle 10 in addition to

the main fuel tank 33 of the vehicle-use engine 12, the sub fuel tank 84 is arranged in the inside of the main fuel tank 33. [0073]
Due to such a constitution, it is possible to effectively make use of the space in the inside of the main fuel tank 33, and the structure of the main fuel tank 33 and the sub fuel tank 84 can be simplified thus preventing the large-sizing of the vehicle 10. For example, by arranging the sub fuel tank 84 on the bottom portion (that is, right bulging portion 102) at either one of left and right sides of the main fuel tank 33, it is possible to effectively make use of the dead space of the main fuel tank 33. [0074]
The present invention is secondly characterized in that, as shown in Fig. 2, Fig. 4(a) and Fig. 4(b), the fuel supply port 106 of the sub fuel tank 84 is arranged inside the fuel supply port 83 of the main fuel tank 33.
Due to such a constitution, the structure of the fuel supply port 83 can be simplified. Further, the fuel supply port 83 of the main fuel tank 33 and the fuel supply port 106 of the sub fuel tank 84 can be arranged close to each other and hence, it is possible to efficiently perform the fuel filling operation. [0075]

The present invention is thirdly characterized in that, the small lid portion 129 which closes the fuel supply port 106 of the sub fuel tank 84 is mounted on the backside of the cap 118 as a lid of the fuel supply port 83 of the main fuel tank 33.
Due to such a constitution, these two fuel supply ports 82, 106 can be easily opened and closed and, further, even when an oil level is changed corresponding to the tilting of the vehicle body or the like, it is possible to prevent the main fuel 86 in the inside of the main fuel tank 33 and the sub fuel 96 in the inside of the sub fuel tank 84 from being mixed with each other. [0076]
The present invention is fourthly characterized in that, as shown in Fig. 9 (a) to Fig. 9 (d) , in the vehicle 10 (see Fig. 1) which includes the sub fuel tank 152, 156 which stores the sub fuel 96 (see Fig. 2) for enhancing the startability of the vehicle in addition to the main fuel tank 151, 155 of the motorcycle-use engine 12 (see Fig. 1), the sub fuel tank 152, 156 is arranged around the mono-backbone-type main frame 22 on the front side of the vehicle in the vicinity of the main fuel tank 151, 155.
Due to such a constitution, it is possible to arrange the sub fuel tank 152, 156 closer to the main fuel tank 151, 155 thus preventing the large-sizing of the vehicle 10.

[0077]
The present invention is fifthly characterized in that, as shown in Fig. 10, the fuel supply pipe 172 as the fuel pipe extends to the intake system 46 arranged below the sub fuel tank 171 from the sub fuel tank 171 and is connected to the intake system 46.
Due to such a constitution, the fuel supply pipe 172 from the sub fuel tank 171 is hardly bent whereby the air leaking property can be enhanced. Further, the difference in height of the sub fuel 96 can be utilized and hence, it is possible to easily supply the sub fuel 96 to the intake system 46 thus enhancing the startability of the engine 12. [0078]
The present invention is sixthly characterized in that, as shown in Fig. 5, the solenoid valve 132 which controls a fuel flow time of the sub fuel 96 and the check valve 133 which allows only the flow of the sub fuel 96 toward an intake-system-46 side from a solenoid-valve-132 side, to be more specific, toward the throttle-body-52 side from the solenoid-valve-132 side are mounted on the fuel supply pipe 131 as the fuel pipe extending from the sub fuel tank 84. [0079]
Due to such a constitution, it is possible to easily control the supply quantity of the sub fuel which flows into the throttle body 52 using the solenoid valve 132. Further,

it is possible to prevent a back-flow of the sub fuel from the throttle body 52 to the sub-fuel-tank-84 side using the check valve 133. [0080]
The present invention is seventhly characterized in that, as shown in Fig. 7, the fuel pump 94 is mounted on the sub fuel tank 84, a discharge pressure of the fuel pump 94 is set higher than a discharge pressure of the fuel pump 82 for the main fuel tank 33 and, at the same time, the fuel supply pipe 98 is connected to the fuel injection valve 91 for the main fuel tank 33 by way of the one-way valve 146 from the fuel pump 94.
Due to such a constitution, the main-fuel-tank-33 side and the sub-fuel-tank-84 side can use the fuel injection valve 91 in common. Accordingly, the number of parts can be reduced thus realizing the reduction of cost. [Industrial Applicability] [0081]
An engine-use fuel supply device of the present invention is preferably applicable to a motorcycle.

[Description of Reference Numerals and Signs]
[0083]
10: vehicle
12: engine
33, 151, 155, 161: main fuel tank
82, 94: fuel pump
83: fuel supply port of main fuel tank
84, 152, 156, 171: sub fuel tank
96: starting fuel (sub fuel)
91: fuel injection valve 98, 131, 172: fuel pipe (fuel supply pipe)
106: fuel supply port of sub fuel tank
128: small lid (small lid portion)
132: solenoid valve
133: check valve
146: one-way valve

[Designation of Document] Claims [Claim 1]
An engine-use fuel supply device of a vehicle which includes a sub fuel tank which stores starting fuel for enhancing the startability of the vehicle in addition to a main fuel tank of a vehicle-use engine, wherein
the sub fuel tank is arranged in the inside of the main fuel tank. [Claim 2]
An engine-use fuel supply device according to claim 1, wherein a fuel supply port of the sub fuel tank is arranged inside a fuel supply port of the main fuel tank. [Claim 3]
An engine-use fuel supply device according to claim 2, wherein a small lid which closes the fuel supply port of the sub fuel tank is mounted on a back side of a lid of the fuel supply port of the main fuel tank. [Claim 4]
An engine-use fuel supply device of a vehicle which includes a sub fuel tank which stores starting fuel for enhancing the startability of the vehicle in addition to a main fuel tank of a motorcycle-use engine, wherein
the sub fuel tank is arranged around amono-backbone-type main frame on a front side of a vehicle in the vicinity of the main fuel tank.

[Claim 5]
An engine-use fuel supply device according to claim 1 or claim 4, wherein a fuel pipe extends to an intake system below the sub fuel tank from the sub fuel tank and is connected to the intake system.
[Claim 6]
An engine-use fuel supply device according to claim 5, wherein a solenoid valve which controls a fuel flow time and a check valve which allows only the flow of fuel toward an intake system side from a solenoid valve side are mounted on the fuel pipe extending from the sub fuel tank. [Claim 7]
An engine-use fuel supply device according to claim 5, wherein a sub fuel pump is mounted on a midst portion of the fuel pipe, a discharge pressure of the sub fuel pump is set higher than a discharge pressure of a main fuel pump for the main fuel tank, and the sub fuel pump is connected to a fuel passage arranged upstream of a fuel injection valve for the main fuel tank by way of a one-way valve.
8. An engine-use fuel supply device substantially as herein described with reference to the accompanying drawings.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=f4koBvflc4ZYAZVleET03A==&loc=+mN2fYxnTC4l0fUd8W4CAA==

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Patent Number

279191

Indian Patent Application Number

182/DEL/2008

PG Journal Number

03/2017

Publication Date

20-Jan-2017

Grant Date

13-Jan-2017

Date of Filing

23-Jan-2008

Name of Patentee

HONDA MOTOR CO., LTD,

Applicant Address

1-1 MINAMI-AOYAMA 2-CHOME, MINATO-KU, TOKYO 107-8556, JAPAN.

Inventors:

#	Inventor's Name	Inventor's Address
1	MINORU UEDA	C/O HONDA R&D CO.LTD.,4-1, CHOU 1-CHOME, WAKO-SHI, SAITAMA 351-0193, JAPAN
2	TOSHIYUKI KUBOTA	C/O HONDA R&D CO.LTD.,4-1, CHOU 1-CHOME, WAKO-SHI, SAITAMA 351-0193, JAPAN.
3	SHIRO KOKUBO	C/O HONDA R&D CO.LTD.,4-1, CHOU 1-CHOME, WAKO-SHI, SAITAMA 351-0193, JAPAN

PCT International Classification Number

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2007-034149	2007-02-14	Japan