Fuel supply device for motorcycle and motorcycle

A fuel supply device for a motorcycle facilitates a narrower vehicle width to improve maneuverability. A fuel tank is disposed above a body frame, and a first fuel pump is fixed to a part of the fuel tank facing the body frame and positioned inside of the fuel tank via a mount seat. The first fuel pump is disposed such that at least a portion of the mount seat overlaps the vehicle body frame as viewed from above the motorcycle.

RELATED APPLICATIONS

This application claims the benefit of priority under 35 USC 119 of Japanese patent application no. 2005-305637, filed on Oct. 20, 2005, and Japanese patent application no. 2006-086251, filed on Mar. 27, 2006, which applications are hereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a fuel supply device that supplies fuel to an engine of a motorcycle.

2. Description of Related Art

A fuel supply device for a motorcycle is disclosed in JP-A-2002-293281. This fuel supply device has a suction section of a fuel pump disposed out of a fuel tank, and has an expelling section communicating with the lowest portion of the fuel tank from an external location and disposed out of the fuel tank. An outer conduit connects the suction section and the expelling section to each other. The fuel tank straddles over a right and left pair of frame structural members (upper pipes) forming a front half portion of a vehicle body frame. The fuel pump is attached to a bottom surface of the fuel tank so that the fuel pump is positioned between the right and left frame structural members as viewed in a fore to aft direction of the vehicle, and a lower portion of the fuel pump protrudes downward beyond the bottom surface. The protruding portion has the suction section. Thereby, an ineffective residual amount of fuel in the fuel tank is reduced, external appearance and arrangement around the fuel tank is improved, and a capacity of the fuel tank is expanded.

In a conventional fuel supply device as described above, because the suction section is disposed outside of and protrudes from the fuel tank, it is difficult to narrow a width of the vehicle in the fuel tank portion.

On the other hand, in a vehicle on which a rider frequently rides under a standing condition always a narrower width of the vehicle around the fuel tank narrower is always needed to improve maneuverability.

SUMMARY OF THE INVENTION

Therefore, the present invention provides a fuel supply device for a motorcycle that makes a vehicle width narrower to improve maneuverability.

A fuel supply device for a according to the invention comprises a body frame extending in a fore to aft direction of a motorcycle, a fuel tank disposed above the body frame, and a first fuel pump attached to a bottom portion of the fuel tank via a mount seat. At least a portion of the mount seat overlaps the body frame as viewed in a width direction of the motorcycle.

In one embodiment, the body frame includes a right frame and a left frame in the width direction of the motorcycle, and the first fuel pump is positioned between the right frame and the left frame in the width direction.

In another embodiment, the fuel tank includes a right side tank section positioned on an outer lateral side of the right frame, a left side tank section positioned on an outer lateral side of the left frame, and a connecting section for connecting the right side tank section and the left side tank section such that the connecting section straddles the right frame and the left frame.

In another embodiment, the first fuel pump is disposed within the fuel tank to incline rearward and downward of the motorcycle.

In another embodiment, a pump support member for supporting the first fuel pump is disposed between the first fuel pump and the mount seat.

In another embodiment, a partition plate is provided for partitioning the bottom portion of the fuel tank into a side of the mount seat and another side of a first liquid accumulating section in which a suction port of the first fuel pump is positioned.

In another embodiment, a bottom surface of the first liquid accumulating section is positioned lower than a bottom surface of the mount seat.

In another embodiment, the pump support member includes the partition plate partitioning the bottom portion of the fuel tank.

In another embodiment, a second liquid accumulating section is formed on the side of the mount seat of the bottom portion of the fuel tank, a bottom surface of the second liquid accumulating section is positioned lower than a bottom of the first liquid accumulating section, and the bottom of the second liquid accumulating section has a second fuel pump that suctions fuel accumulating in the second liquid accumulating section and expels the fuel to the first liquid accumulating section.

In another embodiment, a filter is connected to the suction port of the first fuel pump, and the suction port of the first fuel pump and the filter are disposed.

In another embodiment, the second fuel pump is a jet pump suctioning the fuel accumulating in the second liquid accumulating section using a negative pressure generated by a flow of surplus fuel returning from an injector of the first fuel pump.

In another embodiment, the second liquid accumulating section is formed in a front portion of the fuel tank.

In another embodiment, a rider's seat covers a top surface of the fuel tank as viewed from a lateral side of the motorcycle.

In another embodiment, the fuel tank has a fuel supply port for supplying fuel to an engine, and the fuel supply port is positioned at a bottom portion and a peripheral end portion of the fuel tank.

In another embodiment, the fuel supply port is positioned between a right end and a left end of the body frame.

In another embodiment, the first fuel pump is generally positioned at a center of the fuel tank in the width direction, the fuel supply port is positioned on one side in the width direction relative to a position where the first fuel pump is disposed, and the filter is positioned on the other side in the width direction relative to the position where the first fuel pump is disposed.

In another embodiment, an accumulating chamber disposed in the first liquid accumulating section and having the suction port of the first fuel pump is provided, and a supply port connecting the first liquid accumulating section and an inside of the accumulating chamber to each other is formed at a top surface of the accumulating chamber.

In another embodiment, the accumulating chamber is positioned at a bottom end which is the lowest portion of the first liquid accumulating section.

In another embodiment, a filter is connected to the suction port of the first fuel pump, and the filter is positioned in the inside of the accumulating chamber.

In another embodiment, the accumulating chamber includes an enclosing section for enclosing the filter, and a separating wall is spaced a predetermined distance apart from the enclosing section to cover the enclosing section, and the separating wall has the supply port.

In another embodiment, the supply port is positioned at a center portion of the top surface.

In another embodiment, the accumulating section has an auxiliary expelling port for expelling surplus fuel returning from an injector of the first fuel pump.

In another embodiment, a second liquid accumulating section is formed on the side of the mount seat of the bottom portion of the fuel tank, a bottom surface of the second liquid accumulating section is positioned lower than a bottom surface of the first liquid accumulating section, and the bottom of the second liquid accumulating section has a second fuel pump that suctions fuel accumulating in the second liquid accumulating section and expels the fuel to the accumulating chamber.

is the invention also provides a motorcycle with a body frame extending in a fore to aft direction, a fuel tank disposed above the body frame, and a first fuel pump attached to a bottom portion of the fuel tank via a mount seat. At least a portion of the mount seat overlaps the body frame in a width direction of the motorcycle.

According to the present invention, the fuel pump is disposed in such a manner that at least a portion of the mount seat overlaps the vehicle body frame as viewed from above the vehicle; thereby, the vehicle width is narrower and maneuverability is improved.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention is now described with reference toFIGS. 1-6.FIG. 1is a side elevational view of a fuel supply device which is under a mounted condition to the vehicle.FIG. 2is a top plan view of the fuel supply device which is under the mounted condition to the vehicle.FIG. 3is a side elevational view of the fuel supply device.FIG. 4is a cross sectional view taken along line A-A ofFIG. 3.FIG. 5is a cross sectional view taken along line B-B ofFIG. 2.FIG. 6is a top plan view of a pump support member viewed in the direction of arrow C ofFIG. 3.

As shown inFIG. 1, a fuel supply device1is embodied in a vehicle70such as a motocross-bike. Fuel supply device1is mainly formed with a fuel tank10accumulating liquid fuel and a first fuel pump20suctioning the fuel in fuel tank10to supply the fuel to an engine71while pressurizing it.

A vehicle body frame80of vehicle70to which fuel supply device1is attached has a semi-double cradle configuration. As shown inFIGS. 1 and 2, a head pipe81is positioned at a front end of frame80. An upper frame82is provided to a top end portion of head pipe81, while an under frame83is provided to a bottom end of head pipe81.

Upper frame82is formed with a pipe member. Upper frame82generally has a shape of the letter Y in which a right frame82R and a left frame82L are bifurcated in a width direction of vehicle70from an upper base frame82afixed to head pipe81, and is formed to extend rearward and downward of vehicle70from head pipe81. Right frame82R and left frame82L are coupled with under frame83at respective bottom end portions thereof. A seat rail84having a ladder shape and forming vehicle body frame80extends rearward of vehicle70from right frame82R and left frame82L, and a rider's seat72is fixed thereto.

Fuel tank10has a saddle shape and is disposed above vehicle body frame80. A front portion of fuel tank10is divided into a right front tank section11R and a left front tank section11L to straddle upper base frame82aand communicate with each other through a connecting section11apositioned at a top portion of fuel tank10. A rear portion of fuel tank10communicates with the front portion of fuel tank10and is disposed above right frame82R and left frame82L. The front portion of fuel tank10expands downward and is formed narrower from a front to a rear end portion as viewed from above and from a lateral side of vehicle70. Fuel tank10is fixed to upper base frame82ausing a front fixing section12positioned at a front end portion, and is fixed to seat rail84using a rear fixing section (not shown) positioned at a rear end portion.

A fuel supply port13for supplying fuel from tank10to engine71is positioned inside of vehicle body frame80in a width direction of vehicle70and is positioned at a bottom and peripheral end portion of tank10. Fuel supply port13is disposed on a left side of fuel tank10, where a side stand for supporting vehicle70when vehicle70is parked is disposed. An out-of-tank connecting section (not shown) of fuel supply port13and an injector73are connected to each other through a high pressure hose to supply fuel from tank10to engine71.

A front end portion of rider's seat72overlaps and covers a top surface of fuel tank10.

First fuel pump20is generally cylindrically shaped. A main suction port21is positioned on a tip end side of first fuel pump20, while a main expelling port22is positioned on a base end side thereof. The base end side is fixed to the interior of fuel tank10via a mount seat30. Mount seat30has a plurality of cap nuts31positioned in a circular seat surface on the interior side of fuel tank10and is fixed to fuel tank10by bolts32.

First fuel pump20is formed such that a fuel route does not pierce mount seat30and only a wire harness for controlling first fuel pump20pierces mount seat30so that a portion protruding from mount seat30external to fuel tank10is small. Further, a mount recess14recessed to the interior side of fuel tank10is formed at a portion of fuel tank10to which mount seat30is attached to prevent the portion to which mount seat30is attached from protruding to the side of vehicle body frame80when first fuel pump20is mounted. Mount seat30is positioned such that a portion thereof overlaps with right frame82R and left frame82L as viewed from above the vehicle and such that first fuel pump20is positioned between the right frame and the left frame.

First fuel pump20is disposed within the fuel tank in such a manner that the tip end side protrudes rearward of the vehicle generally parallel. A pump support member40is disposed between mount seat30, which forms a bottom surface of fuel tank10, and first fuel pump20. Pump support member40is formed with a mount section41and a support partitioning wall section42as a partitioning plate. Pump support member40is interposed between first fuel pump20and mount seat30by putting mount section41onto cap nuts31in order not to come out. Support partitioning wall section42extends to side walls of fuel tank10to partition the bottom portion of fuel tank10into a forward portion and a rear portion. Thereby, a first liquid accumulating section15is formed such that a bottom surface15athereof is positioned at a rear part of the bottom portion of fuel tank10and at a location lower than a bottom surface30aof mount seat30. Main suction port21has a filter23positioned to suction fuel from first liquid accumulating section15. Main expelling port22is connected to a tank-in connecting section13aof fuel supply port13through a tank-in high pressure hose61.

In fuel supply device1, a jet pump50is disposed which acts as a second fuel pump using an ejector effect by fuel which first fuel pump20suctions. That is, a negative pressure is generated around a flow of the fuel accelerated by first fuel pump20. Using the generated negative pressure, jet pump50suctions the fuel through auxiliary suction ports51, which are suction ports of jet pump50, and expels the fuel to first liquid accumulating section15in which an auxiliary expelling port52, which is an expelling port of jet pump50, is disposed. Additionally, auxiliary suction ports51are positioned on the side of mount seat30of the bottom portion of fuel tank10as second liquid accumulating sections. Auxiliary suction ports51are placed in a bottom surface16aof a lowest portion16which is formed by being expanded in respective bottom end portions of right front tank section11R and left front tank section11L.

Regarding fuel supply routes, first, when first fuel pump20operates, main suction port21suctions fuel accumulating in first liquid accumulating section15and pressurizes the fuel to supply the fuel to injector73through tank-in high pressure hose61, fuel supply port13and a high pressure hose62.

First fuel pump20always operates to expel an amount of fuel corresponding to the maximum fuel consumption amount of engine71. Because this is a surplus fuel supply amount under normal vehicle running conditions, a pressure regulator (not shown) makes the surplus fuel return to first liquid accumulating section15through a surplus fuel route. At this moment, the surplus fuel is supplied to jet pump50to suction the fuel in first liquid accumulating section15from lowest portion16of fuel tank10, which is the second liquid accumulating section, by the negative pressure generated around the surplus fuel when the surplus fuel flows through the conduit.

Additionally, when fuel is supplied to engine71by first fuel pump20, care must be taken to prevent cavitations from occurring in a suction head for first fuel pump20because such cavitations affect the fuel injection amounts of injector73. On the other hand, when fuel is suctioned from the lowest portion of fuel tank10to first liquid accumulating section15, jet pump50sufficiently functions because the cavitations, if any, do not affect the fuel injection amounts of injector73.

Because first fuel pump20is disposed within fuel tank10in such a manner that at least the portion of mount seat30overlaps vehicle body frame80, a size in the width direction of the vehicle can be smaller.

Because first fuel pump20is between right frame82R and left frame82L, first fuel pump20is protected by right frame82R and left frame82L even if vehicle70falls to the ground.

Because first fuel pump20is disposed within fuel tank10to protrude rearward of the vehicle, a size of the fuel tank in a vertical direction can be small. Thereby, a rider can easily transfer his or her weight to the upper portion of fuel tank10while riding, and maneuverability is thus improved. Also, because the suction head for first fuel pump20is small, first fuel pump20is compact while cavitations are prevented from occurring.

Because the first fuel pump20is supported by the pump support member40, a shock transferred to the first fuel pump20when the vehicle70surmounts a bump can be reduced. Thereby, the mount seat30of the first fuel pump20can be smaller and the size in the width direction of the vehicle can be smaller.

Support partitioning wall section42partitions the bottom portion of fuel tank10to form bottom surface15aof first liquid accumulating section15which is lower than bottom surface30aof mount seat30, and main suction port21is disposed in first liquid accumulating section15. Therefore, even though a surface of the fuel waves within fuel tank10while the vehicle runs and is not stable, first fuel pump20steadily suctions the fuel.

Jet pump50using the ejector effect by fuel which first fuel pump20suctions is provided, auxiliary suction ports51are positioned in the lowest portion of fuel tank10, and auxiliary expelling port52is positioned in first liquid accumulating section15. If first fuel pump20directly suctions fuel, cavitations can occur and make steady suction difficult. Therefore, jet pump50temporarily suctions fuel accumulating at lowest portion16of fuel tank10to first liquid accumulating section15and then first fuel pump20suctions the fuel from first liquid accumulating section15. Because the bottom configuration of fuel tank10is a configuration suitable for maneuvering, maneuverability of vehicle70is improved.

Because the front portion of fuel tank10is swelled out downward, the height of the tank can be lowered, while the capacity of the tank is sufficiently ensured. Therefore, the rider can easily transfer his or her weight onto the upper portion of the fuel tank while riding, and maneuverability is improved.

Because rider's seat72is overlaps with the top surface of fuel tank10, the rider can easily transfer his or her weight onto the upper portion of fuel tank10while riding, and the maneuverability is improved.

Fuel supply port13is positioned at the bottom and peripheral end portion of fuel tank10and is also positioned inside of vehicle body frame80as viewed from above vehicle70. Thus, workability for attaching and detaching fuel tank10to and from vehicle70is improved, and vehicle body frame80protects fuel supply port13when vehicle70falls to the ground.

Additionally, the portion to which mount seat30of fuel tank10is attached does not protrude to the side of vehicle body frame80; thereby, the area where mount seat30overlaps with vehicle body frame80is increased.

Also, the fuel supply port has no means for opening and closing the flow path because fuel is prevented from flowing out under the condition that first fuel pump20is stopped. However, by providing a fuel cock to open and close the flow path, a fuel leak when fuel tank10is attached or detached can be further prevented.

Next, an alternative embodiment of the invention is described with reference toFIGS. 7-9.FIG. 7is a top plan view of a fuel supply device which is under a mounted condition to the vehicle.FIG. 8is a side elevational view of the fuel supply device.FIG. 9is a cross sectional view taken along line D-D ofFIG. 7.

A point of difference relative to the first embodiment resides in the structure of a part of main suction port21of first fuel pump20. Although filter23is connected to main suction port21in the first embodiment, an accumulating chamber90is formed at main suction port21in this alternative embodiment. Because structures of the remaining parts are the same as those in the first embodiment, duplicate descriptions are omitted and the same structural portions in the drawings are assigned with the same reference numerals or symbols.

Accumulating chamber90is placed at lowest bottom surface15bin first liquid accumulating section15. Accumulating chamber90is formed by separating walls91to ensure an internal capacity, as a preset internal capacity, with which engine71can continue operating for at least several seconds even though only the fuel in accumulating chamber90is used. Also, in accumulating chamber90, an enclosing section93spaced apart from separating walls91is formed. Enclosing section93is filled with a filter23.

Supply openings92connecting first liquid accumulating section15and the interior to each other are disposed in a center area of a top surface of accumulating chamber90. Main suction port21of first fuel pump20is connected to a lateral side surface of accumulating chamber90on a side of the center of the vehicle.

An auxiliary expelling port52ais connected to a rear surface of accumulating chamber90. Surplus fuel returning from the injector of first fuel pump20is expelled from auxiliary expelling port52ainto accumulating chamber90, and fuel in the lowest portion suctioned by jet pump50is expelled from auxiliary expelling port52ainto accumulating chamber90.

When the quantity of fuel expelled to accumulating chamber90is greater than the quantity of fuel suctioned through main suction port21, the fuel is expelled from supply openings92of the top surface to first accumulating section15. When the quantity of fuel expelled from auxiliary expelling port52ais less than the quantity of fuel suctioned through main suction port21, the fuel is supplied from liquid accumulating section15to accumulating chamber90through supply openings92.

In a structure where fuel is sprayed into intake air using an injector, there is no chamber like a float chamber and thus a shortage of fuel in fuel tank10results. If the position of the vehicle changes in a running state, a position of a liquid surface in fuel tank10varies to cause a condition under which fuel cannot be suctioned through main suction port21. Under such condition, no fuel is supplied and engine71stops.

However, in the alternative discussed above, in which accumulating chamber90is provided and fuel is suctioned from accumulating chamber90, engine71continues operating without being affected by the position of the vehicle.

Also, because supply openings92are disposed in the center area of the top surface of accumulating chamber90, the interior of accumulating chamber90is always filled with fuel without being affected by the position of the vehicle.

Because returning fuel is directly supplied to accumulating chamber90, the interior of accumulating chamber90is always filled with fuel without being affected by the position of the vehicle.

Because jet pump50is disposed to suction fuel accumulating in lowest portion16and to expel the fuel into accumulating chamber90, the fuel directly supplied to accumulating chamber90increases. The influence of the position of the vehicle thus becomes smaller.

Additionally, fuel tank10is formed so that accumulating chamber90is fitted into a part of lowest bottom surface15bof first liquid accumulating section15. Therefore, all fuel in first liquid accumulating section15is supplied to accumulating chamber90through supply openings92.

The particular embodiments of the invention described in this document should be considered illustrative, rather than restrictive. Modification to the described embodiments may be made without departing from the spirit of the invention as defined by the following claims.