JPH11141438A - Fuel injection device for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel injection device for motorcycles, which can improve the heat restarting performance and the fuel control accuracy of a fuel injection valve. SOLUTION: A fuel injection device is provided with a fuel distributing pipe C to which a fuel injection valve J is attached, an enclosed fuel chamber A in which a fuel pump P is contained, a pressure adjusting valve B, and the fuel chamber A and pressure adjusting valve B are integrally arranged above the fuel distributing pipe C, and the discharge passage 11 of the fuel pump P is communicated to the fuel distributing passage 50 of the fuel distributing pipe C through a fuel discharge passage 25, and a first passage 35, which ranges to the fuel distributing passage 50 of the pressure adjusting valve B, and a fuel return passage 26 are communicated to the inside of the fuel chamber A. This fuel injection device is arranged below a fuel tank T, and the fuel chamber A and the fuel tank T are communicated to each other through a vapor bleeding passage 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device for a motorcycle, which supplies fuel via a fuel injection valve to an engine mounted on the motorcycle.

[0002]

2. Description of the Related Art A conventional fuel injection device for a motorcycle is disclosed in Japanese Patent Application Laid-Open No. 3-117680. according to this,
A fuel pump and a fuel injection valve are integrally disposed below the intake pipe, and an intake hole of the fuel pump is connected to a fuel tank via a fuel inflow passage. On the other hand, a first discharge hole opened in the casing of the fuel pump is connected to a fuel injection valve via a fuel discharge passage. Thus, when the rotor of the fuel pump rotates during operation of the engine, the fuel in the fuel tank is sucked into the fuel pump via the fuel inflow passage and the suction hole, and is pressurized. The pressurized fuel in the casing is sent to the fuel injection valve through the first discharge hole and the fuel discharge path,
The fuel controlled by the fuel injection valve is injected and supplied into the intake pipe.

[0003]

The conventional fuel injection device has the following disadvantages. (1) It is not possible to obtain good engine startability at a high engine ambient temperature. This is because the fuel tank and the fuel injection valve are connected to the fuel inflow passage, the suction hole and pump section of the fuel pump, the casing,
This is because the first discharge port is directly connected via the fuel discharge path and does not have a vapor removing function. That is, at the time of a hot restart in which the engine ambient temperature is greatly increased (a state in which the engine is operated and stopped for a certain period of time and then the engine is started again), the fuel inflow passage, the fuel pump, and the fuel discharge passage are at high temperatures. Is heated. According to the above description, the fuel in the fuel inflow passage, the pump portion of the fuel pump, and the inside of the casing is warmed, and vapor is generated. This vapor causes a fuel lock phenomenon in the fuel inflow passage, the pump portion, the inside of the casing, and the like. This is because fuel cannot be supplied to the fuel injection valve in response to the starting operation. (2) During operation of the engine, accurate fuel cannot be metered from the fuel injection valve. Further, stable supply of fuel cannot be performed. This is because, similarly to the above, the vapor generated in the fuel inflow passage, the fuel pump, etc. is discharged into the intake pipe through the fuel injection valve, and corresponds to the vapor contained in the fuel, and This is because the amount of injected fuel tends to decrease. (3) When used in a fuel injection device of a type in which fuel injection valves are provided in a plurality of intake pipes connected to a multi-cylinder engine and fuel is injected from each fuel injection valve into the corresponding intake pipe, It becomes difficult to design a fuel discharge passage connecting the casing and each fuel injection valve. this is,
A plurality of fuel discharge passages corresponding to the number of fuel injection valves need to be provided extending from the casing of the fuel pump. The length of the casing in the longitudinal direction is determined by the fuel pump, and does not always match the connection pitch of the plurality of intake pipes. by.

[0004]

A fuel injection device according to the present invention has been made in view of the above-mentioned problems, and has an object to improve the startability of an engine in a state where the engine ambient temperature is high and to improve the fuel control accuracy of a fuel injection valve. A main object of the present invention is to provide a fuel injection device for a motorcycle that can be used.

[0005]

In order to achieve the above object, a fuel injection device for a motorcycle according to the present invention supplies fuel pressurized by a fuel pump to a suction pipe connected to an engine via a fuel injection valve. In a fuel injection device for a motorcycle, a fuel distribution pipe is formed inside and a fuel distribution pipe in which a fuel injection valve is mounted, and a fuel distribution pipe is disposed below the fuel tank in the direction of gravity and the gravity of the fuel distribution pipe is reduced. A fuel chamber integrally formed at an upper position in the direction, a fuel pump disposed in the fuel chamber, and pressurizing and discharging fuel in the fuel chamber, and regulating a fuel pressure in the fuel distribution pipe to a constant pressure. A pressure regulating valve integrally mounted on a fuel distribution pipe or a fuel chamber, a fuel inflow passage for supplying fuel in the fuel tank to the fuel chamber, and a fuel communicating between the pressure regulating valve and the fuel chamber. A return passage, a fuel discharge passage for communicating the discharge passage and the fuel distribution path of the fuel pump, a first feature in that a vapor vent passage communicating with said fuel chamber and the fuel tank.

[0006] In addition to the first feature, the present invention provides a fuel tank, wherein when the fuel tank is set up on a side stand attached to a motorcycle body, a fuel liquid level formed in the fuel tank is lowered in a gravity direction. The second feature is that they are arranged at the positions.

[0007] In addition to the first feature, the present invention is characterized in that a downstream of the fuel inflow passage is opened at a position below the fuel chamber in the direction of gravity.

According to a fourth feature of the present invention, in addition to the first feature, a first strainer is disposed upstream of the fuel inflow passage, and the first strainer is disposed in a fuel tank. And

According to a fifth aspect of the present invention, in addition to the third feature, a suction hole of the fuel pump is opened at a position below a fuel inflow passage opening in the fuel chamber in a direction of gravity. Features.

Further, in addition to the first feature, the present invention further comprises a vapor discharge hole extending from a pump chamber of the fuel pump.
A sixth feature is that the fuel chamber is opened at an upper position in the direction of gravity.

In a seventh aspect of the present invention, in addition to the first aspect, an effective flow path cross-sectional area in the fuel chamber is set to a range allowing a maximum discharge amount of the fuel pump.

In addition, in addition to the first feature, the present invention further comprises the step of: setting an opening position of the fuel return passage into the fuel chamber, in the direction of gravity, an opening of a fuel pump suction hole in the fuel chamber, and a vapor removal passage. An eighth feature is that the opening is provided between the first and second openings.

According to the present invention, in addition to the first feature, the fuel chamber has a circular cross section in a radial direction with respect to a longitudinal axis in a gravity direction, and the fuel return passage extends in a tangential direction of the fuel chamber. The ninth feature is that the opening is provided.

Further, in the present invention, in addition to the ninth feature, a tenth feature is that a throttle portion is provided on an inner wall of the fuel chamber to partially reduce a flow passage area in the fuel chamber.

Further, in the present invention, in addition to the first feature, a first strainer is provided in the fuel discharge passage.
This is the feature of 1.

Further, according to the present invention, in addition to the first feature, the vapor removal passage has an upstream end opening at a position above the fuel chamber in the direction of gravity, and a downstream end having a fuel level in the fuel tank. A twelfth feature is that it is opened upward.

Further, the present invention provides, in addition to the twelfth feature,
The first is that the vapor removal passage is formed substantially linearly.
3.

Further, in the present invention, in addition to the first feature, a fourteenth feature is that a passage sectional area of the vapor removal passage is larger than a passage sectional area of the fuel return passage.

Still further, according to the present invention, in addition to the first feature, the fuel distribution passage of the fuel distribution pipe includes a protruding concave portion protruding upward in the direction of gravity when the fuel distribution pipe is mounted on the engine. The fifteenth feature is that the opening of (1) is opened in the projecting recess.

[0020]

According to the first feature, the fuel in the fuel tank is
It is supplied to the fuel chamber through the fuel inflow channel by gravity,
Fuel is stored in the fuel chamber. The fuel in the fuel chamber is pressurized by the fuel pump, and the pressurized fuel is supplied into the fuel distribution passage via the fuel discharge passage. The fuel pressure in the fuel distribution passage is controlled to a constant pressure by the pressure regulating valve, and at this time, the return fuel of the pressure regulating valve is returned to the fuel chamber via the fuel return passage. On the other hand, the vapor present in the fuel chamber is returned to the fuel tank via the vapor removal passage. Thus, the fuel injection valve injects and supplies the fuel in a constant pressure state into the intake pipe connected to the engine.

According to the second feature, in the inclined state in which the side stand of the motorcycle is set up, the fuel chamber is disposed at a position below the fuel level in the fuel tank in the direction of gravity, so that sufficient fuel can be supplied to the fuel chamber. Can be stored. Thus,
When the side stand is removed and the fuel pump is driven in accordance with the operation of the engine, fuel can be immediately supplied from the fuel pump to the fuel distribution pipe, and the fuel is supplied from the fuel injection valve into the intake pipe without delay. it can.

According to the third feature, a sufficient head difference between the fuel tank and the fuel inflow passage can be obtained, and the fuel in the fuel tank can be immediately and smoothly supplied to the fuel chamber. Further, the vapor contained in the fuel flowing into the fuel chamber through the fuel inflow passage is separated from the fuel in the fuel chamber, and the vapor is directed upward of the fuel chamber, so that the separation of the fuel and the vapor in the fuel chamber is ensured. It is performed.

According to the fourth feature, foreign matter contained in the fuel flowing from the fuel tank into the fuel chamber via the fuel inflow passage is removed by the first strainer. Can be inhaled. Further, by disposing the first strainer in the fuel tank, a change in the outer shape of the fuel tank can be suppressed as much as possible.

According to the fifth feature, the vapor contained in the fuel flowing into the fuel tank from the opening of the fuel inflow passage is:
It immediately moves upward from the opening in the fuel chamber. Since the suction hole of the fuel pump is opened at a position lower than the opening of the fuel inflow passage, the vapor contained in the fuel flowing into the fuel chamber through the fuel inflow passage is not sucked into the fuel pump.

According to the sixth feature, the vapor generated in the pump chamber of the fuel pump is discharged above the fuel chamber through the vapor discharge hole. Therefore, the vapor generated in the pump chamber is not sucked into the fuel pump again through the suction hole of the fuel pump.

According to the seventh feature, when the fuel pump sucks the fuel in the fuel chamber, the fuel in the fuel chamber can be supplied to the fuel pump without shortage even at the maximum discharge amount of the fuel pump.

According to the eighth feature, the vapor contained in the return fuel flowing in the fuel return passage is discharged into the fuel tank from the vapor removal passage immediately after flowing into the fuel chamber.

According to the ninth feature, the vapor contained in the return fuel flowing in the fuel return passage makes a one-way swirling flow in the fuel chamber. Thus, the vapors gather together as the swirl progresses to become large vapors, are quickly converged to a position above the fuel chamber, and are discharged into the fuel tank from the vapor removal passage.

According to the tenth feature, the return fuel swirling in the fuel chamber has a large swirling flow velocity in the upstream area of the throttle formed in the fuel chamber, so that the vapor gathers and becomes large, thereby increasing the buoyancy. The provided vapor is quickly converged to a position above the fuel chamber and discharged into the fuel tank from the vapor removal passage.

According to the eleventh feature, foreign matter contained in the fuel flowing in the fuel discharge passage is removed by the second strainer, so that clean fuel is supplied to the fuel injection valve and the pressure control valve. . Thus, the closing properties of the fuel injection valve and the pressure control valve, particularly the valve portion, can be remarkably improved.

According to the twelfth feature, all the vapors remaining in the fuel chamber are gathered at a position above the fuel chamber, and this vapor can be effectively discharged to the upper portion of the fuel tank which is substantially at atmospheric pressure.

According to the thirteenth feature, the vapor gathering at the upper part of the fuel chamber is effectively discharged into the fuel tank.

According to the fourteenth feature, the return fuel flows smoothly from the fuel return passage to the fuel chamber, and the vapor contained in the return fuel is discharged well into the fuel chamber.

According to a fifteenth feature, the vapor in the fuel distribution passage collects in the protruding concave portion, and the vapor is discharged into the fuel chamber through the fuel return passage of the pressure regulating valve.

[0035]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fuel injection device for a motorcycle according to an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a single fuel chamber including a fuel pump. FIG. 2 is a longitudinal sectional view of the pressure regulating valve. FIG. 3 is a longitudinal sectional view including a fuel system diagram of the fuel injection device. The fuel injection device includes a fuel chamber A including a fuel pump P.
, A pressure regulating valve B, and a fuel distribution pipe C including a fuel injection valve J. Referring to FIG. 1, the fuel pump P includes a pump unit D and a driving unit E, and is disclosed in, for example, Japanese Patent Application Laid-Open No. 62-214294. Pump part D
The pump chamber 3 is formed on a contact surface between the pump cover 1 and the pump housing 2, and an impeller 4 having a plurality of blade grooves formed on an outer peripheral surface is rotatably arranged in the pump chamber 3. In the pump chamber 3, a suction hole 5 formed in the pump housing 2 is opened, and a discharge hole (not shown) formed in the pump cover 1 is opened. The drive unit E is a known DC motor, and the rotation of the output shaft 7 extending from the DC motor is connected to the impeller 4 via a D-cut groove.

The pump section D and the drive section E are integrally mounted in the cylindrical housing 8. That is, the pump portion D is disposed inside the lower end of the cylindrical housing 8,
The drive unit E is disposed at the intermediate portion, and the housing cover 9 is disposed inside the upper end. In this state, the output shaft 7B above the drive unit E is supported by the bearing 10A of the housing cover 9, and the lower output shaft 7A Is the bearing 10B of the pump cover 1
Further, the lower end of the cylindrical housing 8 is caulked to the outer peripheral surface of the pump housing 2, and the upper end of the cylindrical housing 8 is caulked to the outer peripheral surface of the housing cover 9. The fuel pump P is formed as described above. The suction hole 5 opening to the pump chamber 3 opens below the pump housing 2 and the discharge hole (not shown) formed in the pump cover 1 opening to the pump chamber 3. ) Passes between the outer periphery of the drive section E and the inner periphery of the cylindrical housing 8 and is connected to a discharge path 11 opened above the housing cover 9.

A is a fuel chamber which houses the fuel pump P therein, and is composed of the following. The fuel chamber A includes a lower fuel body 21 having a bottomed tubular shape with an upper opening and an upper fuel body 22 having a bottomed tubular shape with a lower opening. The openings of both fuel bodies 21 and 22 are in contact with each other. The sealed fuel chamber A is formed by joining the surfaces 21A and 22A in contact with each other.

The fuel pump P is connected to both fuel main bodies 2.
1 and 22 are fixedly disposed in the fuel chamber A when joining them, and a concave portion 2A provided in the pump housing 2 of the fuel pump P projects from a bottom portion of the lower fuel main body 21 with a guide projection 21B. Is positioned and supported by the fuel pump P
The discharge passage 11 protruding upward from the housing cover 9 is positioned and supported by a guide hole 22 </ b> B of the upper fuel main body 22.

At a position below the fuel chamber A (specifically, below the lower fuel main body 21), a downstream 23A of the fuel inflow passage 23 opens. Also, at a position above the fuel chamber A,
(Specifically, above the upper fuel body 22) The upstream 24A of the vapor removal passage 24 is opened. Also, the upper fuel body 22
The fuel discharge passage 25 is formed in connection with the guide hole 22B of the fuel pump P. The fuel discharge passage 25 is connected to the discharge passage 11 of the fuel pump P. Further, an upstream 26A of the fuel return passage 26 is opened at a position above the fuel chamber A (specifically, above the upper fuel main body 22).

That is, at the position below the fuel chamber A, the downstream 23A of the fuel inflow passage 23 and the suction hole 5 of the fuel pump P are opened. In addition, at an upper position of the fuel chamber A, an upstream 24A of the vapor removal passage 24 and an upstream 26A of the fuel return passage 26 are opened.

Next, the pressure regulating valve B will be described with reference to FIG. Reference numeral 30 denotes a lower body having a bottomed cylindrical shape that opens upward, and 31 denotes an upper body that has a bottomed cylindrical shape that opens downward, and a partition such as a diaphragm is provided between the openings of the two bodies. The body 32 is arranged and the two bodies 30, 31 are joined. In this example, the outer periphery of the upper main body 31 was caulked inward toward the lower main body 30. According to the above, the partition 32
The fuel chamber 33 is formed by the lower surface of the lower body 30 and the recess of the lower body 30, and the pressure chamber 34 is formed separately by the upper surface of the partition 32 and the recess of the upper body 31. A first passage 35 is opened at the bottom of the fuel chamber 33, and a second passage 37 is opened at the center of the fuel chamber 33 via a valve seat 38. The first passage 35 opens at the lower bottom surface of the flange 30 </ b> A of the lower body 30. Further, a valve body 39 is integrally disposed in the partition 32 facing the fuel chamber 33, and the valve body 39 opens and closes a valve seat 38. Further, a spring 40 whose one end is locked to the partition 32 is contracted in the pressure chamber 34, and the spring 40 urges the partition 32 toward the fuel chamber 33. In other words, the valve body 39 urges the valve seat 38 toward the closing side. An opening 34A is formed in the pressure chamber 34, and the opening 34A is connected to, for example, an intake pipe (not shown) connected to the engine or the atmosphere.

Next, the fuel injection device will be described with reference to FIG. A fuel tank T stores fuel therein, and a fuel distribution pipe C is disposed below the fuel tank T in the direction of gravity. In the fuel distribution pipe C, a fuel distribution passage 50 hermetically sealed therein is formed in a horizontal direction, and a fuel injection valve J is mounted on the fuel distribution pipe C. The fuel injection valve J is provided corresponding to the number of intake pipes connected to the engine. The fuel injection valve J is connected to the upstream of the fuel distribution passage 50 and opened, and the downstream thereof is opened to the inside of the intake pipe. In the present embodiment, three fuel injection valves J are prepared, but the number is appropriately set.

A fuel chamber A having a fuel pump P
Is disposed above the fuel distribution pipe C in the direction of gravity. Specifically, the lower surface 21C of the mounting flange 21B provided below the lower fuel body 21 of the fuel chamber A is
, And screwed and fixed with screws 51 in this state. According to the above description, the fuel distribution pipe C is disposed at the lowest position in the gravity direction, the fuel chamber A is disposed above the fuel distribution pipe C, and the fuel tank T is disposed at the most upper position in the gravity direction.

A pressure control valve B is further disposed on the upper surface Ca of the fuel distribution pipe C. Specifically, the flange 30A of the lower main body 30 is arranged on the upper surface Ca, and in this state, it is fixed by screwing with screws 52. The pressure control valve B may be mounted outside the fuel chamber A.

The first passage 35 of the pressure control valve B is
Fuel distribution path 5 through passage Cb drilled in fuel distribution pipe C
It is communicated within 0.

Each passage forming the fuel injection device is connected as follows. Fuel inflow passage 23 provided in fuel chamber A
Is connected to the bottom of the fuel tank T, and the upstream 23B of the fuel inflow passage 23 is connected to the bottom of the fuel tank T. Then, a first strainer 53 is disposed in the fuel inflow passage 23. Here, the first strainer 53 according to this embodiment is used.
Were placed in the fuel tank T.

The downstream 24B of the vapor removal passage 24 opening into the fuel chamber A is opened above the fuel level in the fuel tank T. That is, the upstream 2 of the vapor removal passage 24
4A opens at an upper position in the direction of gravity of the fuel chamber A,
The downstream 24B opens above the fuel level of the fuel tank T.

The fuel discharge passage 25 is connected to a fuel distribution passage 50.

Then, a second strainer 54 is arranged in the fuel discharge passage 25.

The second passage 37 of the pressure control valve B is connected to the fuel chamber A via the fuel return passage 26.

In this embodiment, the first strainer 53
And a vapor pipe 24 </ b> C that forms a downstream of the vapor removal passage 24 is formed integrally with the flat plate member 56, and the flat plate member 56 is brought into contact with a lower opening of the fuel tank T to close the first strainer. 53 was placed in the fuel tank T, and the vapor pipe 24C was opened and placed on the fuel level of the fuel tank T.

A fuel chamber A provided with a fuel pump P and a pressure control valve B are integrally mounted on a fuel distribution pipe 50 provided with a fuel injection valve J. In this state, the second strainer The fuel discharge passage 25 having the fuel supply passage 54 is connected to the fuel distribution passage 50, and the fuel return passage 26 connects the fuel chamber A to the second passage 37 of the pressure control valve B. According to the above, all of the components constituting the main part of the fuel injection device are assembled in a sub-assembly state in advance.

The motorcycle is shown in FIG. 4, in which a fuel tank T is disposed at an upper position in the direction of gravity, and a plurality of intake pipes K connected to each cylinder of the engine H are disposed below the fuel tank T. An air cleaner L is disposed upstream. R is a throttle valve for controlling the amount of air flowing through the intake pipe K, and is controlled to be opened and closed by the driver.

The fuel injection device in the sub-assembly state is inserted and fixedly disposed in a space between the fuel tank T and the intake pipe K. At this time, the fuel injection valve mounted on the fuel distribution pipe C The front end opening of J is arranged to open toward each intake pipe K. In this state, the vapor removal passage 24 is connected to a vapor pipe 24 </ b> C protruding from the bottom of the fuel tank T, and is connected to the upstream 23 of the fuel inflow passage 23.
B is a first strainer 53 disposed in the fuel tank T.
Connected to.

The mounting of the fuel injection device on the motorcycle is completed as described above, and this state is shown in FIG.

Next, the operation will be described. The fuel stored in the fuel tank T passes through the fuel inflow passage 23,
It is supplied into the fuel chamber A by the head difference,
At this time, the upper portion of the fuel chamber is opened above the fuel level in the fuel tank T through the vapor removal passage 24 and is maintained at the atmospheric pressure, so that the fuel is automatically supplied and stored in the fuel chamber A. .

On the other hand, when the operation of the engine is started, the driving section E of the fuel pump P rotates and the impeller 4 of the pump section D rotates in the pump chamber 3. According to the above, fuel chamber A
The fuel inside the pump housing 3 is sucked into the pump chamber 3 through the suction hole 5 of the pump housing 2, and the fuel pressurized in the pump chamber 3 is supplied to the discharge passage of the pump cover 1 (not shown) and the drive unit E.
The fuel is supplied to the fuel discharge passage 25 through the discharge passage 11 through the space between the outer periphery of the cylinder housing 8 and the inner periphery of the cylindrical housing 8, and the fuel flowing through the fuel discharge passage 25 is supplied to the fuel through the second strainer 54. The fuel is supplied into the fuel distribution passage 50 of the distribution pipe C.
Then, the fuel in the fuel distribution passage 50 is introduced into the fuel chamber 33 of the pressure regulating valve B via the passage Cb and the first passage 35.

When the pressure of the fuel supplied into the fuel chamber 33 rises above the set constant pressure, the partition 3
2 moves toward the upper pressure chamber 34 side in FIG. 3 against the spring force of the spring 40, whereby the valve body 39 opens the valve seat 38, and a part of the fuel in the fuel chamber 33 is transferred to the second passage. 3
7. The fuel is returned into the fuel chamber A via the fuel return passage 26. Therefore, the fuel pressure in the fuel chamber 33 of the pressure control valve B is regulated to a constant pressure, whereby the pressure in the fuel distribution passage 50 is also controlled to a constant pressure.

On the other hand, the fuel injection valve J includes E, C,
The valve opening time is controlled by the output signal from U, and the fuel in the fuel distribution passage 50 is injected and supplied into the intake pipe K via the fuel injection valve J according to the output signal.
Thus, the operation of the engine is performed. When the fuel in the fuel chamber A is reduced by being sucked out by the fuel pump P,
Since the fuel in the fuel tank T is immediately and continuously supplied to the fuel chamber A via the fuel inflow passage 23, the fuel can be continuously supplied from the fuel injection valve J into the intake pipe K. .

According to the fuel injection device of the present invention, the vapor generated in the device is discharged as follows. First, the vapor contained in the fuel flowing from the fuel inflow passage 23 into the fuel chamber A will be considered. In such a vapor, the fuel in the fuel tank T foams due to the vibration of the fuel tank T, and the foam is wound into the fuel inflow path 23 via the first strainer 53 and flows. Alternatively, the fuel inflow passage 23 itself is heated by the engine ambient temperature. And so on. When the fuel containing the vapor flows into the fuel chamber A through the fuel inflow passage 23, the vapor moves upward in the fuel chamber A by the buoyancy of the vapor and gathers. The fuel is discharged into the fuel tank T through a vapor removal passage 24 opening at the top of the fuel tank. Therefore, the vapor supplied from the fuel inflow passage 23 into the fuel chamber A is
Separated and discharged in the fuel chamber A.

Further, the fuel chamber A itself is also heated by the increase in the engine ambient temperature, and vapor is generated in the fuel in the fuel chamber A. However, the vapor moves upward in the fuel chamber A in the same manner as described above, and is discharged into the fuel tank through the vapor removal passage 24. According to the above, all the vapor flowing into the fuel chamber A or the vapor generated in the fuel chamber A is discharged out of the fuel chamber A.

On the other hand, when the fuel pump P is driven, the temperature of the rotor around which the armature coil is wound rises. And that the impeller 4 rotates at a high speed in the pump chamber 3. Vapor is generated from the above, and pressurized fuel including the vapor is supplied to the fuel distribution passage 50 and the fuel chamber 33 of the pressure control valve B via the fuel discharge passage 25. Further, the fuel discharge passage 25 itself is also heated by the rise of the engine ambient temperature, and the vapor generated in the fuel discharge passage is also supplied into the fuel chamber 33. Here, in the fuel chamber 33 of the pressure control valve B, a second passage 37 connected to the fuel return passage 26 maintained at a substantially atmospheric pressure state and a fuel distribution passage 50 of the fuel distribution pipe C connected to maintain a pressurized state. The first passage 35 is opened. According to the above, the vapor contained in the fuel flowing into the fuel distribution passage 50 and the fuel chamber 33 is discharged together with the return fuel into the second passage 37 in a state of a large pressure difference with the fuel pressure in the fuel chamber 33, The fuel containing the vapor is discharged into the fuel chamber A through the fuel return passage 26. The vapor discharged into the fuel chamber A is supplied to the vapor removal passage 2 in the same manner as described above.
The fuel is discharged into the fuel tank T via the fuel tank 4. Here, considering the fuel including the vapor discharged into the fuel chamber A, the fuel including the vapor is returned to the fuel chamber A instead of the fuel tank T. A, only the vapor component separated in A returns to the fuel tank, and the fuel from which the vapor component has been
The vapor components in the mixture do not mix with unseparated fresh fuel. Therefore, there is an effect of preventing fuel deterioration in the fuel tank T. When the fuel containing the vapor is returned to the fuel chamber A, the vapor and the fuel are separated. Fuel chamber A
Since a fuel pump for sucking / discharging fuel is disposed in the inside, the fuel returned to the fuel chamber A can be positively used first. Therefore, it is possible to use the fuel from which the vapor component is separated, sequentially. In the fuel chamber A, the uppermost surface is set lower than the lowermost surface in the fuel tank T, and the fuel chamber A is provided with a vapor removal passage 24 communicating with the atmospheric pressure. The fuel chamber A will be filled with fuel, and the fuel chamber A will be free of oxygen. Since the fuel containing the vapor returns to the fuel chamber A without oxygen, there is an effect of suppressing the oxidation of the fuel. In particular, the fuel is easily oxidized in a high temperature state. For example, the fuel chamber A is in a high temperature state due to the heat radiated by the engine.
Since there is no oxygen for the above reason, oxidation of the fuel is suppressed even at a high temperature.

The pump chamber 3 has a vapor discharge hole 60.
Is provided. The upstream side of the vapor discharge hole 60 is bored in the pump housing 2 and opens to the inside of the pump chamber 3, and the downstream side thereof opens to an upper position in the fuel chamber A by a pipe. In this embodiment, the pipe has a U-shape, and a tip 60A of a bent portion on one side is connected to the pump housing 2.
, And the tip of the bent portion 60 </ b> B on the other side is supported by the upper fuel main body 22. And the tip 60B of the bending part on the other side
A hole 60C opening above the fuel chamber A is formed in the vicinity. According to the above description, when a vapor is generated in the pump chamber 3 by driving the fuel pump P, the vapor enters the vapor discharge hole 60 and the vapor discharge hole 6.
The fuel is discharged above the fuel chamber A through the opening 60C.
Then, the vapor discharged into the fuel chamber A is discharged into the fuel tank T via the vapor removal passage 24.
Thus, the vapor generated in the pump chamber 3 is not mixed into the fuel discharged from the fuel pump P toward the fuel discharge passage 25. Also, the vapor discharge hole 6
0 is housed and arranged in the fuel chamber A, so that the external shape of the fuel chamber A is not complicated, and even if the fuel leaks from the vapor discharge hole 60, the fuel does not leak to the outside. .

As described above, according to the fuel injection device for a motorcycle according to the present invention, the vapor generated in the fuel inflow passage 23, the fuel chamber A, the fuel pump P, and the fuel discharge passage 25 all gather above the fuel chamber A. The vapor is discharged onto the fuel level of the fuel tank T via the vapor passage 24. Therefore, at the time of a hot restart of the engine in which the engine ambient temperature has risen significantly, the locking phenomenon of the fuel in the fuel piping system is completely suppressed, and the fuel can be supplied to the fuel injection valve without delay, and the hot The startability was greatly improved.

Further, as described above, according to the fact that the vapor in the fuel piping system can be discharged into the fuel tank, the fuel injected from the fuel injection valve toward the intake pipe contains no vapor. According to this, the amount of fuel injected from the fuel injection valve is accurately measured and supplied in accordance with the valve opening time of the fuel injection valve, so that accurate fuel measurement accuracy can be guaranteed.

Furthermore, according to the above, it is possible to continuously supply only the measured fuel that does not include the vapor, and it is possible to supply fuel stably without intermittent fuel supply. This greatly improved the operability of the engine.

According to the present invention, the fuel distribution pipe C is provided with the fuel chamber A having the fuel pump P and the pressure control valve B. And connecting the fuel chamber A and the fuel distribution path 50 by the fuel discharge path 25. The pressure regulating valve B and the fuel chamber A are connected by the fuel return passage 26.
Thereby, most of the configuration of the fuel injection device can be brought into a subassembly state. According to the above, the fuel injection device can be implemented in an environment with a high degree of freedom in assemblability, so that the assembling workability can be greatly improved. Is arranged and fixed in a mounting space formed between the fuel tank T and the intake pipe K. And connecting the fuel tank T and the fuel chamber A via the fuel inflow passage 23. The fuel chamber A and the fuel tank T are connected to the vapor removal passage 24.
Please contact at. In this case, the work of mounting the fuel injection device on the motorcycle and the ease of maintenance can be greatly improved.

Further, since the fuel chamber A of the fuel injection device can be disposed directly below the fuel tank T in the direction of gravity, the lengths of the fuel inflow passage 23 and the vapor removal passage 24 can be shortened. The fuel chamber A and the pressure regulating valve B attached to the fuel distribution pipe C,
5. The length of the fuel return passage 26 can be reduced.
Thus, the fuel passages can be extremely simple and compact, and the appearance thereof is not impaired.

Further, since the fuel pump P is housed in the fuel chamber A, it is difficult for the fuel pump P to be directly heated by the ambient temperature. It is effective in suppressing occurrence. Further, since the fuel pump P is protected by the fuel chamber A, when a small stone or the like scatters and collides during traveling of the motorcycle, the cylindrical housing 8 of the fuel pump P is not deformed, and the pump performance is not affected. It does not have any adverse effects. Exposing the fuel chamber A directly to the outside is preferable in terms of the design of the motorcycle because the external shape of the fuel chamber A can be freely selected. The fuel chamber A only needs to have a function of storing fuel, and does not impose any restriction on the appearance.

When the engine is stopped, the motorcycle is left standing with the side stand upright, and in such a state, the motorcycle main body is held inclined to the side in the running direction. Here, in the fuel injection device of the present invention,
In such an inclined holding state, the fuel chamber A is arranged as follows. That is, the fuel chamber A is arranged at a position below the fuel level formed in the fuel tank T in the direction of gravity in a state where the motorcycle on which the stand stands is held in an inclined state. According to the above, even when the engine is stopped, the fuel chamber A
The fuel in the fuel tank T is constantly supplied through the fuel inflow passage 23 so that the fuel chamber A can be filled with the fuel. Therefore, when operating the engine, even if you remove the side stand and start the engine immediately,
Fuel can be supplied to the engine without delay, and a good engine can be operated.

Further, according to the fact that the fuel inflow passage 23 opens the downstream 23A of the fuel inflow passage 23 which opens into the fuel chamber A at a position below the fuel chamber A in the direction of gravity, the vapor inflow into the fuel chamber A The upward moving distance can be increased, whereby small vapors gather and grow into large vapors, so that the vapor collection speed above the fuel chamber A can be increased, and the separation of fuel and vapor can be achieved. The action can be performed more effectively. Further, the space between the fuel tank T and the intake pipe K (particularly the distance in the direction of gravity) is limited, and the fuel chamber A is disposed below a position relatively close to the fuel tank T. Here, as described above, the fuel inflow path 23
Is opened at a position below the fuel chamber A, the liquid level head between the fuel tank A and the fuel chamber A can be set to be the largest in a limited space. Inflow can be improved.

Further, since the first strainer 53 accommodated in the fuel tank T is disposed upstream of the fuel inflow passage 23, foreign substances contained in the fuel supplied to the fuel chamber A are removed. Thus, clean fuel is supplied into the fuel chamber A. Therefore, the wear of the rotating part of the fuel pump P can be suppressed, and in particular, the durability of the fuel pump P can be improved. Further, since the first strainer 53 is accommodated and arranged in the fuel tank T, the shape of the fuel tank T can be optimized without the first strainer 53 protruding outside the fuel tank T, and the merchantability can be improved. And the degree of freedom of arrangement of the first strainer 53 can be increased. That is, the first strainer 53 does not have to be arranged in a limited space.

Further, a fuel inflow passage 23 which opens a suction hole 5 provided in the pump housing 2 of the fuel pump P into the fuel chamber A is provided.
Of the fuel flowing from the fuel inflow passage 23 into the fuel chamber A through the suction hole 5 into the fuel pump P. Can be deterred.

Further, in particular, the inner peripheral wall of the fuel chamber A and the fuel pump P
The effective flow path cross-sectional area S of the fuel chamber A formed by the gap between the outer periphery of the cylindrical housing 8 and the outer periphery of the
In the entire discharge range, a sufficient amount of fuel can be supplied to the suction hole 5 without any shortage, and there is no shortage of fuel discharged from the fuel pump P in any operating state.

The opening 26A of the fuel return passage 26 into the fuel chamber A is provided between the opening of the suction hole 5 of the fuel pump P and the opening 24A of the vapor removal passage 24 in the direction of gravity of the fuel chamber A. According to the opening, the vapor contained in the fuel flowing into the fuel chamber A from the fuel return passage 26 is not sucked into the fuel pump P from the suction hole 5 again in the fuel chamber A. Fuel return passage 26
Is discharged into the fuel tank T via the opening 24A of the vapor removal passage 24.

Referring to FIG. 5, which is a cross sectional view taken along the line NN of FIG. 1, the fuel chamber A is orthogonal to the longitudinal axis XX (shown in FIG. 1) in the direction of gravity. The radial cross section is circular, and the opening 26A of the fuel return passage 26 is opened in the tangential direction of the fuel chamber A. According to this, the discharge performance of the vapor flowing into the fuel chamber A from the fuel return passage 26 can be improved. That is, the fuel flowing from the fuel return passage 26 into the fuel chamber A forms a swirling flow along the inner peripheral wall of the fuel chamber A. According to the swirling flow, the vapor difference between the vapor and the fuel is caused by the mass difference between the vapor and the fuel. Is reliably separated in the swirling flow, in which fine vapors are aggregated and grow into relatively large vapors. The vapor has a larger buoyancy than the vapor in a fine state, and the vapor is effectively discharged into the fuel tank T through the vapor removal passage 24 by moving toward the upper part of the fuel chamber A by the buoyancy. You. Further, since the vapor is present in the swirling flow, the movement of the fuel pump A to a position below the fuel chamber A is suppressed, and the fuel pump P is provided through the suction hole 5 of the fuel pump P located below the fuel chamber A. It is difficult to be inhaled again. Further, by the fuel suction of the fuel pump P,
When a space is formed in the upper portion of the fuel chamber A, the fuel flowing into the fuel chamber A from the fuel return passage 26 flows along the inner peripheral wall of the fuel chamber A, and the fuel existing in the fuel chamber A Can be suppressed, and generation of vapor accompanying fuel undulation can be suppressed.

Further, as shown in FIG. 5, a throttle portion 2 for partially reducing the flow passage area in the fuel chamber A is provided on the inner peripheral wall of the fuel chamber A.
According to the protrusion 2A protruding inward, the vapor contained in the fuel flowing into the fuel chamber A from the fuel return passage 26 collides with the throttle portion 22A. The velocity energy has a large decrease, moves upward due to the buoyancy owned by itself, and is discharged from the vapor removal passage 24. This throttle unit 2
Collision of the vapor in the fuel with 2A is effective in the case where the buoyancy of the vapor is large because the particle diameter of the vapor is relatively large. That is, the swirling flow hinders the upward movement of the vapor due to its inherent buoyancy.

Further, the second strainer 5 is provided in the fuel discharge passage 25.
4 shows that the fuel chamber 33 of the pressure regulating valve B
Foreign matter contained in the fuel flowing into the inside is removed by the second strainer 54, so that clean fuel is supplied into the fuel distribution path 50 and the fuel chamber 33. Foreign matter is included in the fuel in the fuel discharge passage 25 due to foreign matter remaining in the fuel pump P, foreign matter remaining in the fuel discharge passage 25, and the like. When clean fuel is supplied into the fuel chamber 33 of the pressure regulating valve B, foreign matter does not bite between the valve body 39 and the valve seat 38, and the closing property of the valve body 39 is improved. And the durability of the valve body 39 and the valve seat 38 can be improved. Furthermore, since even cleaner fuel can be supplied to the fuel injection valve J, it is possible to achieve improved closeability of the fuel injection valve J and stable supply of fuel.

Further, according to the fact that the upstream 24A of the vapor removal passage 24 is opened in the direction of gravity above the fuel chamber A and the downstream 24B is opened above the fuel level of the fuel tank T, The vapor remaining in A can be immediately discharged into the fuel tank T without any resistance.

Further, since the vapor removal passage 24 is formed in a substantially linear shape, resistance to the flow of the vapor passing through the vapor removal passage 24 is not given, and the dischargeability of the vapor can be improved. In the present embodiment, the vapor removal passage 24 is formed as a straight line from the lower side to the upper side in the direction of gravity. However, even if there are some curved portions in the passage, the above-described effect is achieved. The curved portion in the case is, for example, a J-shaped or U-shaped curved portion, that is, a portion in which a curved portion directed from above to below is not formed in the middle of the passage going from below to above in the direction of gravity. Say.).

Further, according to the passage cross-sectional area of the vapor removal passage 24 being larger than the passage cross-sectional area of the fuel return passage 26, the fuel flow from the fuel return passage 26 into the fuel chamber A is Since the vapor or fuel in A does not become a resistance, a good pressure regulation can be performed without any hindrance to the pressure regulation operation in the pressure regulating valve B. In other words, the fuel chamber A of the fuel return passage 26
No pressure acts on the opening 26A.

Further, the fuel distribution passage 50 of the fuel distribution pipe C
According to the provision of the projecting recess 50B projecting upward in the weight direction when mounted on the engine E, the vapor present in the fuel distribution passage 50 is gathered in the projecting recess 50B. Then, the first passage 3 connected to the pressure regulating valve B
5 is opened in the protruding concave portion 50B, so that the dischargeability of the vapor in the fuel distribution passage 50 can be further improved. The vapor flowing from the fuel distribution passage 50 into the fuel chamber 33 of the pressure regulating valve B via the first passage 35 is discharged into the fuel chamber A via the fuel return passage 26 as described above. In the present embodiment, the projecting recess 50B is configured such that the upper position of the fuel distribution passage 50 is continuously inclined to the upper right, but the recess 50B may be formed to partially project upward.

The fuel pump P and the pressure regulating valve B are not limited to those in this embodiment. In particular, the second strainer 54 can be attached to the fuel chamber A and the fuel distribution pipe 54. According to this, the second strainer 54
It is not necessary to prepare a member that specifically supports.

[0084]

As described above, the fuel injection system for a motorcycle according to the present invention has the following effects. According to the first feature, the vapor generated in the fuel injection device gathers above the fuel chamber, and the vapor is discharged into the fuel tank through the vapor removal passage. According to the above, the hot restartability of the engine can be greatly improved. Further, since the fuel injected into the intake pipe from the fuel injection valve does not include vapor, the accuracy of measurement and stability of the fuel injection valve can be improved, and the operability of the engine can be greatly improved. Also, by mounting a fuel chamber and a pressure control valve on the fuel distribution pipe and connecting the fuel discharge path and the fuel return path to each other, most of the configuration of the fuel injection device can be assembled in a sub-assembly state. . According to the above, the assembly workability of the fuel injection device itself can be improved. It is possible to improve the assemblability for mounting on a motorcycle and the maintainability. In addition, since the fuel chamber is disposed directly below the fuel tank and the fuel distribution pipe is equipped with the fuel chamber and the pressure regulating valve, the fuel inflow passage, the vapor removal passage, the fuel discharge passage, and the fuel return passage are removed. The length of each passage can be made as short as possible, so that the fuel injection device can be simply and compactly assembled without deteriorating its appearance. This external shape is important as a fuel injection device mounted on a motorcycle. The arrangement of the fuel pump in the fuel chamber is preferable from the viewpoint of suppressing the temperature rise of the fuel pump, protecting the fuel pump from obstacles, and further improving the appearance.

According to the second feature, in the inclined holding state in which the side stand of the motorcycle is set up, the fuel chamber is filled with fuel and held. Therefore, when the engine is started with the side stand removed, the fuel can be supplied immediately and the engine can be started satisfactorily.

According to the third feature, the downstream of the fuel inflow passage is opened at a position below the fuel chamber in the direction of gravity, so that the vapor separating operation in the fuel chamber is effectively performed, and the fuel chamber and the fuel tank are separated. The liquid level head can be made large in a limited space, and the inflow of fuel into the fuel chamber can be enhanced.

According to the fourth feature, since the first strainer accommodated in the fuel tank is disposed upstream of the fuel inflow passage, clean fuel can be supplied to the fuel pump, and the durability of the fuel pump can be improved. Since this can be achieved and the first strainer does not protrude out of the fuel tank, the degree of freedom of arrangement of the first strainer is increased and the appearance of the fuel tank is not impaired.

According to the fifth feature, since the suction hole of the fuel pump is opened at a position lower than the opening of the fuel inflow passage into the fuel chamber, the fuel pump is prevented from sucking the vapor in the fuel chamber. You.

According to the sixth feature, since the pump chamber and the upper part of the fuel chamber are connected by the vapor discharge hole, the vapor generated in the pump chamber is formed by the vapor discharge hole, the fuel chamber,
It is reliably discharged through the vapor removal passage. Thus,
Vapor in the pump chamber is not mixed and supplied from the fuel pump toward the fuel discharge path. Further, since the vapor discharge hole is built in the fuel chamber, even if the vapor discharge hole leaks, it does not leak out of the fuel chamber.
Further, the vapor discharge hole does not impair the appearance.

According to the seventh feature, since the effective flow passage area in the fuel chamber is set to a range allowing the maximum discharge amount of the fuel pump, a good pump discharge flow rate can be obtained in the entire discharge range of the fuel pump. .

According to the eighth feature, since the opening of the fuel return passage is opened between the opening of the suction hole of the fuel pump and the opening of the vapor removal passage, the return fuel returning from the fuel return passage to the fuel chamber is opened. Is not sucked into the fuel pump again.

According to the ninth feature, since the cross section of the fuel chamber is circular and the fuel return passage is opened along the tangential direction of the fuel chamber, the return fuel flowing from the fuel return passage into the fuel chamber is swirled. This makes it possible to enhance the dischargeability of the vapor contained in the return fuel, and suppresses the suction of the vapor into the fuel pump.

According to the tenth feature, a throttle portion is provided on the inner wall of the fuel chamber. According to this, especially when the particle diameter of the vapor is relatively large, the discharge performance of the vapor can be enhanced. .

According to the eleventh feature, the fuel discharge path is connected to the fuel distribution pipe, and the second strainer is disposed in the fuel discharge path. According to this, it is possible to improve the closeability of the pressure regulating valve and the fuel injection valve, and particularly to improve the durability of the on-off valve portion.

According to the twelfth feature, the upstream of the vapor removal passage opens above the fuel chamber, and the downstream opens above the liquid level of the fuel tank. According to this, the vapor discharge performance from the fuel chamber to the fuel tank can be improved.

According to the thirteenth feature, the vapor removal passage is made substantially linear, so that the vapor discharge performance from the fuel chamber to the fuel tank can be further improved.

According to the fourteenth feature, since the passage cross-sectional area of the vapor removal passage is larger than the passage cross-sectional area of the fuel return passage, the return fuel can be smoothly discharged from the fuel return passage into the fuel chamber without any resistance. And does not hinder the pressure regulating action of the pressure regulating valve.

According to the fifteenth feature, the projecting recess projecting upward is provided in the fuel distribution pipe, and the pressure regulating valve is opened to the projecting recess, so that the dischargeability of the vapor in the fuel distribution pipe can be further improved. Thus, vapor is not mixed into the fuel injected from the fuel injection valve.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a fuel chamber constituting a fuel injection device according to the present invention.

FIG. 2 is a longitudinal sectional view showing one embodiment of a pressure regulating valve constituting the fuel injection device according to the present invention.

FIG. 3 is a longitudinal sectional view showing one embodiment of the fuel injection device according to the present invention.

FIG. 4 is a simplified side view showing a state where the fuel injection device according to the present invention is mounted on a motorcycle.

FIG. 5 is a transverse sectional view taken along line NN of FIG. 1;

[Explanation of symbols]

 Reference Signs List A fuel chamber P fuel pump B pressure regulating valve C fuel distribution pipe T fuel tank H engine K intake pipe 23 fuel inflow path 24 vapor removal path 25 fuel discharge path 26 fuel return path 53 first strainer 54 second strainer

Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02M 55/00 F02M 55/00 A 55/02 340 55/02 340B 340E 350 350U

Claims (15)

[Claims] 1. A motorcycle fuel injection device in which fuel pressurized by a fuel pump is supplied through a fuel injection valve into an intake pipe connected to an engine, wherein a fuel distribution passage is formed therein and the fuel injection valve is formed. The fuel distribution pipe mounted with, a fuel chamber disposed at a lower position in the direction of gravity of the fuel tank and integrally formed at an upper position in the direction of gravity of the fuel distribution pipe, disposed in the fuel chamber, A fuel pump for increasing the pressure of the fuel in the fuel chamber and discharging the fuel; a pressure regulating valve integrated with the fuel distribution pipe or the fuel chamber while regulating the fuel pressure in the fuel distribution pipe to a constant pressure; A fuel inflow passage for supplying the fuel into the fuel chamber, a fuel return passage connecting the pressure regulating valve to the fuel chamber, and a fuel discharge passage communicating the discharge passage of the fuel pump and the fuel distribution passage. A fuel injection device for a motorcycle, comprising: an outgoing passage; and a vapor removal passage connecting the fuel chamber and the fuel tank. 2. A fuel tank according to claim 1, wherein the fuel chamber is disposed below a fuel level formed in the fuel tank in a direction of gravity when a side stand attached to the motorcycle body is set up. The fuel injection device for a motorcycle according to the above. 3. The fuel injection device for a motorcycle according to claim 1, wherein a downstream side of the fuel inflow passage is opened at a position below the fuel chamber in the direction of gravity. 4. The fuel injection device for a motorcycle according to claim 1, wherein a first strainer is disposed upstream of the fuel inflow passage, and the first strainer is disposed in a fuel tank. 5. The fuel injection device for a motorcycle according to claim 3, wherein a suction hole of the fuel pump is opened at a position lower in a gravitational direction than an opening of a fuel inflow passage opening into the fuel chamber. 6. The fuel injection device for a motorcycle according to claim 1, wherein a vapor discharge hole extending from a pump chamber of the fuel pump is opened at a position above the fuel chamber in the direction of gravity. 7. The fuel injection device for a motorcycle according to claim 1, wherein an effective flow path cross-sectional area in the fuel chamber is set within a range allowing a maximum discharge amount of the fuel pump. 8. An opening position of the fuel return passage into the fuel chamber in a gravity direction between an opening of a suction hole of the fuel pump and an opening of a vapor removal passage in the fuel chamber. The fuel injection device for a motorcycle according to claim 1, wherein 9. The fuel chamber according to claim 1, wherein the fuel chamber has a circular cross section in a radial direction with respect to a longitudinal axis in a gravity direction, and the fuel return passage is opened in a tangential direction of the fuel chamber. Fuel injection device for motorcycles. 10. The fuel injection device for a motorcycle according to claim 9, wherein a throttle portion for partially reducing a flow passage area in the fuel chamber is provided on an inner wall of the fuel chamber. 11. The fuel injection device for a motorcycle according to claim 1, wherein a second strainer is disposed in the fuel discharge path. 12. The fuel cell system according to claim 1, wherein an upstream end of the vapor removal passage is opened at a position above the fuel chamber in the direction of gravity, and a downstream end of the passage is opened at a fuel level in the fuel tank. The fuel injection device for a motorcycle according to any one of the preceding claims. 13. The fuel injection device for a motorcycle according to claim 12, wherein the vapor removal passage is formed substantially linearly. 14. The fuel injection device for a motorcycle according to claim 1, wherein a passage cross-sectional area of the vapor removal passage is larger than a passage cross-sectional area of the fuel return passage. 15. The fuel distribution path of the fuel distribution pipe includes a protruding recess that protrudes upward in the direction of gravity when mounted on an engine, and an opening of the pressure regulating valve is opened in the protruding recess. The fuel injection device for a motorcycle according to claim 1, wherein