Title of Invention

"A FUEL APPARATUS"

Abstract

A fuel apparatus comprising: a pump injector (126, 238) comprising a fuel pump (14, 25) for fuel injection and injection nozzles (15, 26) integrally formed into one unit, the fuel feed piping (127, 235) for supplying fuel form the fuel tank (129, 215) to said pump injector (126, 238), a return piping (128, 236) for returning excessive fuel and vapor gas from said pump injector (126, 238) to said fuel tank (129, 215), and an auxiliary pump (134, 227) at the middle of said fuel feed piping (127, 235); said pump injectors (126, 238) comprises a sub tank (10, 20) for temporarily storing fuel from said fuel feed piping (127, 235), the sub tank (10,20) being provided with a fuel introduction port connected to said fuel feed piping (127, 235) and is used for introducing fuel from the fuel feed piping (127, 235) into the sub tanks (10, 20), an intake port for intaking fuel temporarily stored in the sub tanks (10, 20) into said fuel pump (14, 25), and a discharge port connected to said return piping (19, 24(128, 236)) through discharge pipes and located at the upper parts of the sub tank (10, 20) for discharging vapor gas inside sub tanks (10, 20); the fuel pump (11, 21) provided concentrically inside said sub tank (10) or at an outer portion of said sub tank (20) for pumping fuel from said sub tank (10, 20) through said intake port and supplying a constant volume of pressurized fuel to the injection nozzle (15, 26) as well as discharging excessive fuel from the return port to said return piping (19, 24 (128, 236)); and injection nozzle (15, 26) for injecting pressurized fuel from said fuel pumps (11, 21); characterized in that said auxiliary pump (134, 227) are disposed downwardly from said pump injector (126, 238); said fuel feed piping (127, 235) is made rise piping from said auxiliary pump (134, 227) up to said pump injector (126, 238).

Full Text

[Detailed Description of the Invention] [0001] [Technical Field of the Invention] The present invention relates to a fuel apparatus in a fuel injection system and a pump injector, and more specifically, to a fuel apparatus and a pump injector, in which the problem of arrangement space is eliminated and the degree freedom of the layout is increased by downsizing, and air bubbles including fuel being mixed in fuel, so-called vapor gas, are prevented from being retained in a fuel feed piping or in a return piping so that starting and operating capabilities can be improved. [0002] [Description of the Related Art] Fig. 11 shows a fuel apparatus in a fuel injection system according to the related art. Fuel stored in a fuel tank 1 is supplied to a fuel pump 4 through a fuel feed piping 2 and a fuel filter 3 provided at some midpoint of the fuel feed piping 2. Fuel pressurized by the fuel pump 4 is supplied to an injector 6 via the discharge pipe 5. Vapor gas existing in the fuel feed piping 2, the fuel filter 3, and fuel pump 4 is returned to the fuel tank 1 through an air vent duct 7,8, which correspond to return piping, by supplying fuel into the fuel tank 1 at the time of starting and when fuel is empty. Air is prevented from being mixed into fuel by a fuel trap chamber 9 provided at some midpoint of the air vent duct 8, so that fuel mixed with vapor gas therein is not supplied to the injector 6. Such fuel apparatus is disclosed in JP-UM-A-61-32567. [0003] [Problems that the Invention is to Solve] Since the fuel apparatus in the related art is constructed of a fuel pump and an injector separately, and a metallic discharge pipe being capable of distributing pressurized fuel connects therebetween, the number of components increases and thus the cost increases. In addition, the entire structure is upsized, and a space for arranging the fuel pump and the injector and a space for arranging a discharge pipe therebetween are required. Further, it is difficult to do the layout of the metallic discharge pipe and thus it is disadvantageous to be applied to compact vehicles such as motorcycles or autocycles that have only limited spaces. [0004] Under depressurization due to fuel suction from the fuel tank or high temperature, vapor gas gets mixed in fuel. A part of mixed vapor gas is discharged though the return piping, but vapor gas which is not discharged and thus remaining therein retains in the fuel feed piping or the return piping and impairs smooth fuel supply and actuation of the engine. In addition, when vapor gas is supplied to the fuel pump, the efficiency of the fuel pump is lowered and the accuracy of fuel measurement is lowered, which may result in that a constant quantity of fuel cannot be supplied to the injector. [0005] Accordingly, it is an object of the invention to eliminate the problem of arrangement space and to increase the degree of freedom of the layout by downsizing in the fuel injection type fuel apparatus, and further to prevent vapor gas mixed in fuel from being retained in the fuel feed piping or the return piping, so that vapor gas mixed into fuel can be separated and discharged smoothly. [0006] [Means for Solving the Problems] In order to solve the aforementioned problem, the first characteristic of the present invention is that a pomp injector for injecting fuel including a fuel pump and an injection nozzle integrally formed with each other, a fuel feed piping for supplying fuel from the fuel tank to the aforementioned pump injector, and a return piping for returning excessive fuel and vapor gas from the aforementioned pump injector to the aforementioned fuel tank are provided, and at least one of the aforementioned fuel feed piping and the aforementioned return piping is led from the aforementioned pump injector in the substantially horizontal direction. [0007] The second characteristic of the present invention is that the aforementioned pump injector is disposed in such a manner that the axis thereof is inclined from the vertical direction, and the aforementioned fuel feed piping is led from the lower side of the aforementioned pump injector. The third characteristic of the invention is that the aforementioned fuel feed piping is provided with an auxiliary pump. The fourth characteristic of the invention is that the aforementioned fuel feed piping is further provided with a filter. The fifth characteristic of the present invention is that the aforementioned pump injector is located at the position lower than the aforementioned fuel tank. [0008] The sixth characteristic of the present invention is that at least one of the aforementioned fuel feed piping and the aforementioned return piping has such an inner diameter not less than that enables vapor gas generated in the piping to move in the piping smoothly by its buoyancy. The seventh characteristic of the present invention is that the aforementioned fuel feed piping and the aforementioned return piping are formed of flexible pipe. The eighth characteristic of the present invention is that the aforementioned flexible pipe is a rubber pipe. [0009] The ninth characteristic of the present invention is that the opening end of the aforementioned return piping is exposed at the position higher than the fuel level in the fuel tank. The tenth characteristic of the present invention is that a filter for preventing foreign substances such as foreign particles from entering from the opening end of the aforementioned return piping is provided. The eleventh characteristic of the present invention is that a check valve is provided at the opening end of the aforementioned return piping. The twelfth characteristic of the present invention is that the fuel apparatus is applied on a motorcycle. The thirteenth characteristic of the present invention is that the aforementioned fuel feed piping and the aforementioned return piping are disposed along the under bone frame. [0010] The fourteenth characteristic of the present invention is a pump injector including a fuel pump and an injection nozzle formed integrally with each other comprising a sub tank having a fuel intake port, a supply port for supplying fuel therein to the fuel pump, and a discharge port provided at the upper portion for discharging vapor gas therein, a fuel pump provided concentrically in the sub tank for injecting fuel supplied from the aforementioned sub tank through the injector and discharging excessive fuel from return port, and an injection nozzle for injecting fuel pressurized by the aforementioned fuel pump. The fifteenth characteristic of the present invention is the pump injector having a fuel pump and an injection nozzle formed integrally with each other, wherein the fuel pump is provided outside the sub tank. The sixteenth characteristic of the present invention is that the discharge pipe connected to the discharge port of the aforementioned sub tank is oriented in the same direction as the flowing direction of excessive fuel returned from the return port of the aforementioned fuel pump. [0011] According to the first to sixteenth characteristics, the fuel apparatus can be downsized and the problem of arrangement space can be eliminated and thus the degree of freedom of the layout can be increased. According to the first to thirteenth characteristics, vapor gas mixed in fuel can be prevented from being retained in the fuel feed piping or the return piping, and vapor gas mixed in fuel can be separated and discharged smoothly. [0012] According to the second characteristic, the height difference between the fuel tank and the pump injector can be effectively utilized and vapor gas mixed in fuel can be prevented more effectively from being retained in the fuel feed piping or in the return piping. According to the third characteristic, lowering of sucking force in association with downsizing of the pump injector can be compensated, and fuel can be supplied to the pump injector which is located at the position higher than the fuel tank without any trouble. According to the fourth characteristic, the foreign substance generated from the auxiliary pump can be prevented from entering into the pump injector. [0013] According to the sixth characteristic, a surface tension can prevent vapor gas from being retained in the fuel feed piping or the return piping. According to the seventh characteristic, the layout of the piping can be done freely and easily. According to the eighth characteristic, a heat insulating property of rubber can reduce generation of vapor gas. According to the ninth through eleventh characteristics, foreign particles or dust can be prevented from entering from the opening end of the return piping. According to the twelfth and the thirteenth characteristics, the layout can easily be done in the limited space of the motorcycle. [0014] According to the fourteenth characteristic, since the concentric construction of the pump injector ensures stability of the action thereof when the vehicle or the like is inclined, and the configuration thereof has no orientation, the degree of freedom of the layout increases . According to the fifteenth characteristic, the volume of the sub tank may be increased, vapor gas can be separated and discharged smoothly, and fuel can be discharged stably. According to the sixteenth characteristic, vapor gas in the sub tank can be discharged smoothly along the flow of excessive fuel. [0015] [Mode for Carrying Out the Invention] Referring now to the drawings, an embodiment of the present invention will be described in detail. The present invention is premised on employing a pump injector including a fuel pump and an injection nozzle formed integrally with each other for downsizing the fuel apparatus in a fuel injection system, thereby achieving downsizing, eliminating the problem of arrangement space, and increasing the degree of freedom of the layout. [Brief Description of the Drawings] [Fig. 1] Fig. 1 is a schematic drawing showing a first embodiment of the present invention applied to a motorcycle. [Fig. 2] Fig. 2 is a schematic drawing showing a second embodiment of the present invention applied to a motorcycle. [Fig. 3] Fig. 3 is a schematic drawing showing the third embodiment of the present invention applied to a motorcycle. [Fig. 4] Fig. 4 is a schematic drawing showing a fourth embodiment of the present invention applied to a motorcycle as a scooter type vehicle. [Fig. 5] Fig. 5 is a schematic drawing showing an example of the opening end of the return piping in the present invention. [Fig. 6] Fig .6 is a schematic drawing showing another example of the opening end of the return piping in the present invention. [Fig. 7] Fig. 7 is a schematic drawing showing still another example of the opening end of the return piping in the present invention. [Fig. 8] Fig. 8 is a pattern diagram showing an example of the pump injector used in the present invention. [Fig. 9] Fig. 9 is a pattern diagram showing an example of the pump drive in the pump injector. [Fig. 10] Fig. 10 is a pattern diagram showing another example of the pump injector used in the present invention. [Fig. 11] Fig. 11 is a schematic drawing showing a fuel injection type fuel apparatus in the related art. [0016] Fig. 8 is a pattern diagram of an example of the pump injector employed in the present invention, in which a fuel pump including a solenoid plunger pump for example is disposed in the sub tank 10. Fuel is supplied from a fuel tank to the sub tank 10. The pump drive 11 is, as an example schematically shown in Fig. 9, constructed in such a manner that when a solenoid coil 16 is energized a plunger 18 provided with a spring 17 is moved up and down to suck fuel through intake port 12 provided with a check valve into the fuel pump portion 14, discharge excessive fuel from the return port 13, and inject fuel from the injection nozzle 15. [0017] The injection nozzle 15 is a poppet nozzle having an injection valve that is opened and closed in response to pressurization of fuel by the fuel pump. The pump drive 11 sucks fuel from the sub tank 10 into the fuel pump portion 14, returns excessive fuel into the fuel tank, and injects a constant quantity of fuel from the injection nozzle 15. It is also possible to construct the fuel pump of a Wesco pump that sucks and discharges by the use of rotation. [0018] Excessive fuel is returned from the return port 13 through the return piping 19 into the fuel tank. The discharge pipe connected to the discharge port located on the upper portion of the sub tank 10 is oriented to the same direction as the returning direction of the return piping 19 and communicates with the return piping 19. Vapor gas in the sub tank 10 is sucked by the flow of excessive fuel being returned to the fuel tank and is discharged to the fuel tank. [0019] Fig. 10 is a pattern diagram showing another example of the pump injector employed in the present invention, in which the fuel pump is combined as a separate structure to the outside of the sub tank 20 shown on the near side in the figure. This pump injector is identical in functions to the example shown in Fig. 8 in that it sucks fuel supplied from the fuel tank to the sub tank 20 into the fuel pump 25 through the intake port 22 by driving the pump drive 21, returns excessive fuel into the fuel tank through the return port 23 and the return piping 24, and injects a constant quantity of fuel from the injection nozzle 26. [0020] In this arrangement, the volume of the sub tank 20 can be increased, vapor gas can be separated and discharged smoothly, and fuel can be discharged stably. On the other hand, in the construction shown in Fig. 8, the degree of freedom of arrangement is high because the action of the pump injector is stable when it is inclined, and the configuration has no orientation. [0021] When the pump injector having a fuel pump and an injection nozzle formed integrally with each other is employed, a suction force is lowered in association with downsizing of the fuel pump, and low pressure fuel is distributed in the fuel feed piping from the fuel tank to the pump injector. Therefore, vapor gas generated in the fuel feed piping when fuel is sucked from the fuel tank or under high temperature may be retained in the fuel feed piping and may not be discharged. [0022] In addition, excessive fuel and vapor gas in the return piping may not be returned to the fuel tank smoothly. Especially, in the case of vehicles such as motorcycles, the fuel tank and the power unit are generally disposed at a significant distance, and thus the fuel feed piping or the return piping is relatively long, which may cause a serious problem. The present invention solves the aforementioned problem concerning vapor gas by adding ingenuity to the layout or the construction or the arrangement of the fuel feed piping and the return piping. [0023] Fig. 1 is a schematic drawing showing a first embodiment of the present invention applied to a motorcycle. A motorcycle 100 includes a under bone frame (main frame) 101 constructed of a frame extending from a head pipe downward toward the rear in the L-shape or U-shape, a head pipe 102, a front fork 103 mounted on the head pipe 102, a front wheel 104 mounted on the front fork 103, a pair of left and right side arms 105 connected to the under bone frame 101, a rear fork 106, a rear wheel 107 and a shock absorber 108 mounted on the rear fork 106, a seat 109, and a stand 110. A storage box (luggage box) 111 for storing a helmet or the like is provided under the seat 109. [0024] A power unit is suspended at the lower portion of the under bone frame 101 via brackets 112, 113, 114. The power unit and the brackets 112, 113, 114 are connected by a bolt. A driving force of the power unit drives the rear wheel 107 via a crankshaft 116 in the crankcase 115, a gear, not shown, a drive sprocket 117, and a chain in the chain case 118. The power unit is provided with a kick spindle 119 and a cell motor 120. The rear fork 106 is rotatably supported by a pivot 121 provided on the bracket 114. [0025] The power unit includes an air cleaner 122 and an air intake pipe 123 disposed at the front of the vehicle body, takes air therethrough, and exhausts through the muffler disposed at the rear portion of the vehicle body through an exhaust pipe 124. A throttle valve 125 and a pump injector 126 are provided at some midpoint of the air intake pipe 123. The pump injector 126 is connected to a fuel tank 129 disposed on the upper rear of the vehicle body by a fuel feed piping 127 and a return piping 128. The fuel feed piping 127 and the return piping 128 are disposed for example along the under bone frame 101. The fuel tank 129 is provided with a lid 13 0 as a fuel port from the outside and a strainer 131 as a filter on the fuel supply side. [0026] The pump injector 126 includes, as shown in Fig. 8 and Fig. 10, a fuel pump and an injection nozzle formed integrally with each other. The fuel feed piping 127 is introduced into the pump injector 126 in the substantially horizontal direction. As shown in the figure, the pump injector 126 is disposed in such a manner that the axis is inclined from the vertical direction with the fuel intake port placed on the lower side, and the fuel feed piping 127 is introduced in the substantially horizontal direction, fuel can be supplied to the pump injector 126 by effectively utilizing the height difference from the fuel tank 129. [0027] In vehicles such as motorcycles, the stand 110 is generally disposed on the left side with respect to the direction of travel, and thus it inclines toward the left when being parked. Therefore, it is also effective for fuel supply to the pump injector 126 at the time of restarting to dispose the pump injector 126 in such a manner that the axis is inclined from the vertical direction with the fuel intake port placed at the lower left portion and the fuel feed piping 127 is introduced in the substantially horizontal direction. When disposing the pump injector 126 in the inclined state, the orientation should be considered so that the direction of fuel injection faces to the air intake direction of the air intake pipe 123. [0028] In this arrangement, vapor gas mixed in fuel in the fuel feed piping 127 can be sucked by the pump injector 126 with less resistance, separated in the pump injector 126, and discharged to the fuel tank 129 with excessive fuel through the return piping 128. Vapor gas in the fuel feed piping 127 at the position near the fuel tank 129 returns to the fuel tank 129 by its own buoyancy based on the height difference. The length of the fuel feed piping 127 may be reduced by introducing it from the substantially horizontal direction into the pump injector 126. [0029] As is described thus far, the problem of a space for arranging the fuel apparatus is eliminated by using the pump injector 12 6 downsized by integration of the fuel pump and the injection nozzle, and vapor gas mixed in fuel is prevented from being retained in the fuel feed piping 12 7 by adding ingenuity to the arrangement so as to prevent the fuel feed piping 127 from extending upwardly at the position near the pump injector 126 and to utilize the height difference from the fuel pump effectively. [0030] Fig. 2 is a schematic diagram showing the second embodiment of the present invention applied to the motorcycle, and the reference numerals identical to the Fig. 1 represent the identical or equivalent parts. In this embodiment, introducing the fuel feed piping 127 from the substantially horizontal direction is not contemplated as in the first embodiment. Alternatively, a filter 133 and an auxiliary pump 134 are provided at some midpoints of the fuel feed piping 127. [0031] The auxiliary pump 134 is for compensating lowered suction force caused by usage of the pump injector 126, and thus may be a compact one. The filter 133 prevents foreign substances generated in the auxiliary pump 134 from entering into the pump injector 126. In the case where there is no possibility that the auxiliary pump 134 generates foreign substances, the filter 133 may be omitted. It is also possible to circulate fuel positively through the fuel feed piping 127 and the return piping 128 by means of the auxiliary pump 134 to discharge vapor gas. In the first embodiment, the auxiliary pump and the filter may be provided as in the second embodiment. [0032] Fig. 3 is a schematic drawing showing the third embodiment of the present invention applied to the motorcycle, in which the reference numerals identical to Fig. 1 represent the identical or equivalent parts. In this embodiment, introducing the fuel feed piping 127 from the substantial horizontal direction is not contemplated as in the first embodiment, and the auxiliary pump and the filter are not provided as in the second embodiment. Alternatively, the fuel feed piping 12 7 is adapted to have such an inner diameter not less than that enables vapor gas generated in the piping to move in the piping smoothly by its buoyancy. [0033] In general, the diameter of the air bubble of vapor gas is less than 5 mm [0034] Fig. 4 is a schematic drawing showing the fourth embodiment of the present invention applied to the motorcycle as a scooter type vehicle. A motorcycle 200 includes a vehicle body frame 201, a front fork 202 mounted on a head pipe 201a of the vehicle body frame 2 01, a front wheel 203 mounted on the front fork 202, a handle 204 connected to the front fork 202, a power unit 205 mounted at the rear portion of the vehicle body frame 201 so as to be swingable in the vertical direction, a rear wheel 2 06 mounted on the power unit 2 05, a rear cushion unit 207 suspending the rear end portion of the power unit 205, a storage box (luggage box) 208 mounted at the upper rear portion of the vehicle body frame 201, and a seat 209 mounted on the storage box 208 so as to be openable and closable. The storage box 208 can accommodate a helmet or the like. [0035] The vehicle body frame 2 01 includes a front fame 201F formed integrally with a head pipe 201a and the rear frame 201R connected with each other by a connecting portion 201X. The power unit 205 includes an engine 210 and a belt-type stepless speed changer 211 having a centrifugal clutch. The engine 210 is a water-cooled 4-cycle engine including a cylinder block 212 and a cylinder head 213 exposed into the head cover 214, that is, the cylinder portion is exposed between the storage box 208 and the fuel tank 215 and being inclined substantially horizontally. [0036] A fuel cap 215a having a key provide on the fuel tank 215 appears when the fuel supply lid 216 is opened toward the upper front, so that fuel can be supplied therethrough. The fuel tank 215 is provided with a fuel unit 217 for detecting the fuel level. [0037] The body cover 218 covering the vehicle body frame 2 01 includes a front cover 219, a leg shield 220, a step floor (low floor deck) 221, a pair of left and right floor side covers 222, an under cover 223, a lower seat cover 224, a rear cover 225, a pair of left and side covers 226. The fuel tank 215 and the auxiliary pump 227 are disposed under the step floor 221. [0038] The motorcycle 200 is provided with an air cleaner 228 mounted on the left side of the vehicle body, an engine cooling radiator 230 mounted on the right side of the crankshaft 210a of the engine 210, an engine exhaust pipe 231, an exhaust muffler 232 mounted on the right side of the vehicle body, a kick pedal 233 for starting the engine, a main stand 234, a fuel feed piping 235, a return piping 23 6, a filter 237 provided at some midpoint of the fuel feed piping 235 together with an auxiliary pump 227, and a pump injector 238. The pump injector 238 includes a fuel pump and a injection nozzle formed integrally with each other as shown in Fig. 8 and Fig. 10. [0039] In the motorcycle 200, the fuel tank 215 is located at the position higher than the pump injector 238. Lowering of a suction force due to utilization of the pump injector 238 and lowering of a suction force caused by a reverse height difference between the fuel tank 215 and the pump injector 236 are compensated by the auxiliary pump 227. In addition, the problem of a space for arranging the fuel apparatus is solved by using the pump injector 238 including the fuel pump and the injection nozzle formed integrally with each other. The exhaust effects of vapor gas can be further improved by adapting the furl feed piping 235 to have such an inner diameter not less than that enables vapor gas generated in the piping to move in the piping smoothly by its buoyancy, as in the case of the third embodiment. [0040] Though the fuel feed piping on the fuel feed side has been described thus far, it is also possible to add ingenuity to the return piping as described below. The present invention will further be effective by adding ingenuity to the fuel feed piping described in the first through third embodiments in addition to ingenuity added to the return piping described below. Ingenuity added to the return piping will be described below. [0041] As in Fig. 2, when the return piping 128 curves in the upwardly projecting shape in the vicinity of the exit of the pump injector 126, vapor gas may be retained in this portion. Retention of vapor gas in the portion of upwardly projecting curve of the return piping 128 may be reduced by employing the construction in which the return piping 128 is drawn from the pump injector 126 in the substantially horizontal direction as shown in Fig. 1, and the construction in which the return piping 128 is adapted to have such an inner diameter not less than that enables vapor gas generated in the piping to move in the piping smoothly by its buoyancy as shown in Fig. 3. [0042] It is also applicable to add ingenuity to the construction at the opening end of the return piping 128. Three examples of such ingenuity are shown in Fig. 5 thorough Fig. 7. Fig. 5 shows a state in which a convex chamber 31 divided off by a filter 30 is formed at the position higher than the fuel level in the fuel tank 129, for example, on the upper portion of the fuel tank 12 9, and the opening end of the return piping 128 is exposed thereto. [0043] In this arrangement, resistance generated when excessive fuel or vapor gas return through the return piping 128 is reduced. In addition, even when the fuel level is elevated to the position higher than the opening end of the return piping 128 when the vehicle is inclined for example, foreign substances such as foreign particles included in fuel do not enter into the pump injector 126 through the return piping 128. [0044] Fig. 6 shows a state in which the opening end of the return piping 128 is exposed to the position higher than the fuel level in the fuel tank 129 as Fig. 5, and the opening end of the return piping 128 is provided for example with a check valve having a steel ball 41 disposed in the chamber formed with a return hole 40, so that excessive fuel and vapor gas are returned thorough the return piping 128 and fuel in the fuel tank is prevented from entering into the return piping 128. Fig. 7 shows a construction in which when the vehicle is inclined to more than the prescribed extent, the steel ball 51 moves and the valve 50 is closed by a force of a spring 52, thereby closing the opening end of the return piping 128. Various other modifications, such as forming the opening end of the return piping 128 in the snorkel shape, may be employed. [0045] The fuel feed piping 127, 235 and the return piping 128, 236 are not for distributing high pressure fuel pressurized by the fuel pump, and thus no pressure resistance property is required. Therefore, a flexible pipe, for example, a rubber pipe can be employed, and the layout can be done freely and easily. In addition, in a vehicle such as a motorcycle, the vertical movement of the power unit generated during driving is absorbed by utilizing the flexible pipe. [0046] [Advantage of the Invention] As is clear from description above, according to the present invention, since the fuel pump and the injection nozzle for injecting fuel are integrated into a compact pump injector, and ingenuity is added in the fuel feed piping and the return piping with respect to the pump injector, downsizing of the apparatus is realized, the problem of arrangement space is solved, the degree of freedom of the layout is increased, and in addition, air bubbles mixed in fuel, that is, vapor gas is prevented from being retained in the fuel feed piping or in the return piping. [Reference Numerals] 10,20...sub tank, 11,21...pump drive, 14,25...fuel pump portion, 15,26...injection nozzle, 19,24,128,236...return piping, 30,133,237... filter, 10 0,200...motorcycle, 101...under bone frame, 122,228...air cleaner, 123...air intake pipe, 124,231...exhaust pipe, 125...throttle valve, 126,238...pump injector, 127,235... fuel feed piping, 129,215...fuel tank, 134,227...auxiliary pump We Claim: 1. A fuel apparatus comprising: a pump injector (126, 238) comprising a fuel pump (14, 25) for fuel injection and injection nozzles (15, 26) integrally formed into one unit, the fuel feed piping (127, 235) for supplying fuel form the fuel tank (129, 215) to said pump injector (126, 238), a return piping (128, 236) for returning excessive fuel and vapor gas from said pump injector (126, 238) to said fuel tank (129, 215), and an auxiliary pump (134, 227) at the middle of said fuel feed piping (127, 235); said pump injectors (126, 238) comprises a sub tank (10, 20) for temporarily storing fuel from said fuel feed piping (127, 235), the sub tank (10,20) being provided with a fuel introduction port connected to said fuel feed piping (127, 235) and is used for introducing fuel from the fuel feed piping (127, 235) into the sub tanks (10, 20), an intake port for intaking fuel temporarily stored in the sub tanks (10, 20) into said fuel pump (14, 25), and a discharge port connected to said return piping (19, 24(128, 236)) through discharge pipes and located at the upper parts of the sub tank (10, 20) for discharging vapor gas inside sub tanks (10, 20); the fuel pump (11,21) provided concentrically inside said sub tank (10) or at an outer portion of said sub tank (20) for pumping fuel from said sub tank (10, 20) through said intake port and supplying a constant volume of pressurized fuel to the injection nozzle (15, 26) as well as discharging excessive fuel from the return port to said return piping (19, 24 (128, 236)); and injection nozzle (15, 26) for injecting pressurized fuel from said fuel pumps (11, 21); characterized in that said auxiliary pump (134, 227) are disposed downwardly from said pump injector (126, 238); said fuel feed piping (127, 235) is made rise piping from said auxiliary pump (134, 227) up to said pump injector (126, 238). 2. A fuel apparatus as claimed in claim 1, comprising a filter (133, 237) provided in said fuel feed piping for the pump injector (126, 238) side with respect to the auxiliary pump. 3. A fuel apparatus as claimed in claim lor 2, wherein the said fuel feed piping (127, 235) are introduced in a substantial horizontal direction toward said pump injector (126, 238). 4. A fuel apparatus as claimed in claim 1 or 2, wherein the said pump injector (238) is located at a position higher than said fuel tank (215).

Documents:

1036-DEL-2002-Abstract-(16-06-2011).pdf

1036-del-2002-abstract.pdf

1036-DEL-2002-Claims-(16-06-2011).pdf

1036-del-2002-claims.pdf

1036-del-2002-Correspondence Others-(11-08-2014).pdf

1036-DEL-2002-Correspondence Others-(16-06-2011).pdf

1036-del-2002-Correspondence Others-(24-06-2014).pdf

1036-del-2002-Correspondence Others-(29-03-2012).pdf

1036-del-2002-correspondence-others.pdf

1036-del-2002-correspondence-po.pdf

1036-del-2002-description (complete).pdf

1036-del-2002-drawings.pdf

1036-DEL-2002-Form-1-(16-06-2011).pdf

1036-del-2002-form-1.pdf

1036-del-2002-form-18.pdf

1036-del-2002-form-2.pdf

1036-DEL-2002-Form-3-(16-06-2011).pdf

1036-del-2002-form-3.pdf

1036-DEL-2002-Form-5-(16-06-2011).pdf

1036-del-2002-form-5.pdf

1036-DEL-2002-GPA-(16-06-2011).pdf

1036-del-2002-Petition-137-(29-03-2012).pdf

1036-DEL-2012-Abstract-(11-04-2012).pdf

1036-DEL-2012-Claims-(11-04-2012).pdf

1036-DEL-2012-Correspondence Others-(11-04-2012).pdf

1036-DEL-2012-Form-1-(11-04-2012).pdf

1036-DEL-2012-Form-2-(11-04-2012).pdf

1036-DEL-2012-GPA-(11-04-2012).pdf

abstract.jpg

Petition (1036-DEL-2002).pdf