JP2863950B2 - Motorcycle fuel pump - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel pump for a mechanical motorcycle that supplies fuel to an engine.

[Conventional technology]

2. Description of the Related Art Conventionally, there is a vehicle engine such as a motorcycle engine that injects a mixture of air and fuel into a combustion chamber in order to obtain clean exhaust gas and improve fuel efficiency. In this type of fuel injection engine, a cylinder is provided with a combustion chamber fuel injection device, and air and fuel are pressure-fed to the combustion chamber fuel injection device by an air pump and a fuel pump, respectively. When the fuel injection engine is applied to a motorcycle, the air pump and the fuel pump are mechanically driven by the engine because the power supply capacity of the motorcycle is small.

As a conventional mechanical fuel pump, for example,
There is one disclosed in Japanese Patent No. 45650. The fuel pump has a structure in which a pump body constituting a gear pump is fixed to a side cover on an engine side, and is driven by a crankshaft. The pump drive shaft of this fuel pump is parallel to the crankshaft, and is connected to the crankshaft via a spur gear. Since the pump drive shaft is parallel to the crankshaft, the pump main body disposed on the same axis as the pump drive shaft is mounted on the side of the side cover in a state of protruding laterally.

[Problems to be solved by the invention]

However, when the pump main body is attached to the side portion of the side cover in this manner, there is a problem that the fuel pump increases the engine width. In addition, since the fuel suction pipe and the fuel discharge pipe connected to the fuel pump pass through the side of the engine, the piping path becomes complicated.

[Means for solving the problem]

The fuel pump for a motorcycle according to the present invention is configured such that the drive shaft of the fuel pump is vertically oriented so as to be rotatably supported on the crankcase perpendicularly to the crankshaft, and that the fuel pump body is mounted on the crankcase. And a drive gear provided on the drive shaft is meshed with a gear driven by a crankshaft.

[Action]

The fuel pump is mounted on the upper side of the crankcase and does not protrude to the side of the engine.

〔Example〕

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 is a side view of an air / fuel injection engine using a motorcycle fuel pump according to the present invention, and FIG.
3 is a longitudinal sectional view of the motorcycle fuel pump according to the present invention, FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is a sectional view in FIG. It is a VV line sectional view. In these figures, reference numeral 1 denotes an air / fuel injection engine, and the engine 1 is a two-stroke engine for a motorcycle. Reference numeral 2 denotes a crankcase of the engine 1, reference numeral 3 denotes a cylinder block, and reference numeral 4 denotes a cylinder head. The cylinder head 4 is provided with an ignition plug 5 and a combustion chamber fuel injection device 7 for mixing and injecting air and fuel into the combustion chamber 6. Further, a combustion chamber fuel injector 8 is attached to the combustion chamber fuel injection device 7 at a predetermined angle to the front side of the engine with respect to the device body.

Reference numeral 9 denotes a crankshaft rotatably provided in the crankcase 2, and reference numeral 10 denotes a piston connected to the crankshaft 9 via a connecting rod 11. Reference numeral 12 denotes a reed valve mounted on an intake passage of the crankcase 2, reference numeral 13 denotes an intake pipe connected to the intake passage, and an intake pipe fuel injector 14 for injecting fuel into the intake passage. Is installed. The upstream end of the intake pipe 13 is communicated with an air cleaner (not shown) through a throttle valve (not shown). By opening and closing the throttle valve, the flow rate of air guided to the intake passage is controlled. It is configured to be.

Reference numeral 15 denotes a main shaft of the engine 1. The main shaft 15 is connected to the crankshaft 9 via a reduction gear 16 and a multi-plate clutch 17.
It is connected to. The reduction gear 16 is rotatably supported by the main shaft 15 and meshes with a small-diameter gear 9 a provided at the shaft end of the crankshaft 9. The drive side of the multi-plate clutch 17 is connected to the reduction gear 16, and the driven side is connected to the main shaft 15. That is, when the multi-plate clutch 17 is in the engaged state, the rotation of the crankshaft 9 is controlled by the small-diameter gear 9a and the reduction gear 1a.
6, and is transmitted to the main shaft 15 via the multi-plate clutch 17. Reference numeral 18 denotes an output shaft connected to the main shaft 15 via a transmission 19. The output shaft 18 is provided with a drive sprocket (not shown) for driving rear wheels.

Reference numeral 21 denotes a pump main shaft for driving a fuel pump, which will be described later. The pump main shaft 21 is parallel to the crankshaft 9, and has a bearing 23, a crankcase cover 22 that covers the crankcase 2 and a right side portion of the crankcase 2. It is rotatably supported via 24. In addition, this pump main shaft 21
The large diameter portion 21a and the small diameter portion 21b are formed, and the bearing 23 is fitted to the large diameter portion 21a, and the bearing 24 is fitted to the small diameter portion 21b. Further, a drive gear 25 that meshes with the reduction gear 16 and a worm 26 for driving a fuel pump, which will be described later, are key-connected to the small diameter portion 21b.

Reference numeral 31 denotes a fuel pump for pumping fuel to the combustion chamber fuel injector 8 and the intake pipe fuel injection injector 14 of the combustion chamber fuel injection device 7 via a fuel hose 32. The fuel pump 31 is mounted on the upper right side of the crankcase 2 and substantially above the main shaft 15, and is fixed to the crankcase cover 22. Reference numeral 33 denotes a refueling hose connecting the fuel inlet of the fuel pump 31 and a fuel tank (not shown). This fuel pump 31
Is a rotary pump including an eccentric piston 35 rotating in a cylinder 34 and a plurality of centrifugal rollers 36 rotating together with the eccentric piston 35, and a pump unit including the cylinder 34, the eccentric piston 35, etc. Two housings 37 and 38 are formed so as to be overlapped vertically. Reference numeral 39 denotes a partition member interposed between the upper and lower cylinders 34 to define a space between the two cylinders.The partition member 39 has an oil supply hose connection portion 39a, and is opened on both upper and lower surfaces of the partition member 39. A fuel supply passage 39b for supplying fuel to both cylinders 34 is provided, and fuel is supplied from the partition member 39 to each cylinder. The fuel discharged from the lower cylinder 34 passes through a lower cylinder discharge passage 39c formed in the partition member 39, and the fuel discharged from the upper cylinder 34 is formed in the upper housing 37. It is configured to be guided to the outside of the pump through the formed upper cylinder discharge passage 37a.

In the present embodiment, five centrifugal rollers 36 are mounted on one eccentric piston 35 at equal intervals in the circumferential direction of the eccentric piston 35. Further, as shown in FIGS. 4 and 5, the mounting position of the centrifugal roller 36 is set so that those mounted on the upper and lower eccentric pistons 35 are not at the same position in the vertical direction. . In this embodiment, the lower centrifugal roller 36 is positioned between the upper five centrifugal rollers 36. When the upper and lower centrifugal rollers 36 are displaced from each other by a half pitch in this manner, the number of pulsations in the discharged fuel generated when the upper and lower eccentric pistons 35 make one rotation at the same time can be made the same as the total number of the centrifugal rollers 36.

Reference numeral 40 denotes a drive shaft for driving the eccentric piston 35. The drive shaft 40 is orthogonal to the crankshaft 9 by directing the drive shaft 40 in a substantially vertical direction. The main shaft 21 is connected to the pump main shaft 21 through the above. The connection shaft 41 is disposed on the same axis as the drive shaft 40, and a worm gear 41 provided at the lower end thereof.
a meshes with the worm 26 of the pump main shaft 21. Therefore, the power of the crankshaft 9 transmitted to the pump main shaft 21 via the reduction gear 16 and the drive gear 25 is transmitted from the pump main shaft 21 to the drive shaft 40 via the worm 26, the worm gear 41a and the connection shaft 41. Will be conveyed. Also, the connecting shaft
The connection structure between the drive shaft 40 and the drive shaft 40 is formed at the upper end of the connection shaft 41 so that the drive shaft 40 can be connected to the connection shaft 41 after the connection shaft 41 is supported by the crankcase 2. The structure is such that the lower end of the drive shaft 40 is fitted in the fitting groove. That is, in order to incorporate the fuel pump 31 into the engine 1, first, the crankcase cover 22 is attached with the crankshaft 2 supporting the connecting shaft 41. And
The pump body including the cylinder 34, the housings 37, 38 and the like is placed on the crankcase cover 22 while the drive shaft 40 is connected to the connection shaft 41. In this state, the lower housing 38 is fixed to the crankcase cover 22 with bolts or the like to complete the assembly. Reference numeral denotes an accumulator that keeps the pressure of the fuel discharged from the fuel pump 31 at a predetermined value. This accumulator
Reference numeral 42 is attached to a side portion of the pump body, and supplies fuel from the lower cylinder discharge passage 39c of the partition member 39 and the upper cylinder discharge passage 37a of the upper housing 37 to the fuel hose 32 through the pressure regulating portion 42a. It is configured to supply to. An electromagnetic valve 44 for switching the fuel supply destination to the pressure regulating section 42a and the fuel circulation pipe 43 is provided at a portion of the accumulator 42 through which the fuel from the upper cylinder discharge passage 37a passes. ing. The solenoid valve 44 is connected to a control unit 45. The control unit 45 supplies fuel to the pressure regulating section 42a when the engine speed is in a low speed range, and supplies fuel to the fuel circulation pipe 4 when the engine speed is in a high speed range.
It is configured to lead to 3. The fuel circulation pipe 43
Is connected to a fuel tank or a fuel inlet of the fuel pump 31, and the fuel supplied to the fuel circulation pipe 43 is returned to the fuel pump 31 again. The solenoid valve 44
When the engine speed is low, such as at the time of starting, the fuel is supplied from the upper and lower cylinders 34 to the fuel hose 32.
When the engine speed is in the high-speed range, it is supplied only from the lower cylinder 34. That is, when the engine is running at a low speed (when the fuel pump 31 is running at a low speed), the number of pulsations in the discharged fuel is greater than when the engine is at a high speed. Therefore, even when the time interval of the pulsation of the discharged fuel is relatively long, such as when the fuel pump 31 is rotating at a low speed, the fuel can be supplied in a state where the pressure fluctuation is small.

An air pump 51 supplies air to the combustion chamber fuel injection device 7 through an air hose 52. The air pump 51 is provided on the crankcase 2 at a position adjacent to the fuel pump 31. And this air pump 51
The drive shaft is connected to a pump main shaft 21 for driving a fuel pump, and is configured to be driven by the crankshaft 9 together with the fuel pump 31. 53 is the air pump 51
2 shows an intake hose for communicating an air inlet (not shown) with an air cleaner (not shown).

The fuel pump 31 according to the present invention configured as described above includes:
The drive shaft 40 is driven by the engine 1 because the drive shaft 40 is connected to the crankshaft 9 via the connection shaft 41 and the pump main shaft 21. The drive shaft 40 and the connection shaft 41 are vertically oriented so as to be perpendicular to the pump main shaft 21 and the crankshaft 9, and the pump body is disposed on the crankcase 2. It will not protrude further.

Therefore, it is possible to prevent the engine width from being expanded by the fuel pump 31.

Further, as shown in the present embodiment, when the worm 26 and the worm gear 41a are used to connect the connection shaft 41 of the fuel pump 31 to the pump main shaft 21 in a state of being orthogonal, a large reduction ratio can be adopted. Compared to a case where the same reduction ratio is obtained by using a bevel gear or the like, the distance between the two shafts can be set shorter, and the size of the engine can be easily reduced.

Furthermore, when the fuel pump 31 is a rotary pump including the eccentric piston 35 and the centrifugal roller 36 as shown in the present embodiment, the fuel pump 31 can obtain a discharge pressure sufficient to inject fuel into the combustion chamber, as compared with a gear pump or the like. The pump body can be small. In the case of a rotary pump having an eccentric piston and a centrifugal roller, pressure fluctuation due to pulsation of discharged fuel is more likely to occur at a low rotation speed than in a gear pump. However, as shown in this embodiment, an electromagnetic path for switching the flow path is provided to the accumulator 42. Provide valve 44,
By supplying fuel from the upper and lower cylinders 34 when the engine speed is in the low speed range, such a problem can be solved. That is, in the fuel pump 31 shown in the present embodiment, the pressure fluctuation due to the pulsation can be suppressed even at the time of low rotation, so that the pressure of the fuel supplied to the engine 1 is widened from the idling state to the overspeed state. It can be constant, and the fuel injection can be performed with an accurate amount.

〔The invention's effect〕

As described above, the fuel pump for a motorcycle according to the present invention is configured such that the drive shaft of the fuel pump is vertically oriented so that the fuel pump is rotatably supported by the crankcase so as to be orthogonal to the crankshaft. Since the main body is installed on the crankcase and the drive gear provided on the drive shaft is meshed with the gear driven by the crankshaft, the fuel pump does not protrude to the side of the engine. Therefore, it is possible to prevent the engine width from being expanded by the fuel pump, so that the size of the engine can be reduced. In addition, the fuel hose connected to the fuel pump is connected to the fuel tank and the fuel injection device through the crankcase without extending to the side of the crankcase. It becomes easy to handle the hose.

[Brief description of the drawings]

FIG. 1 is a side view of an air / fuel injection type engine using a motorcycle fuel pump according to the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. FIG. 4 is a longitudinal sectional view of the fuel pump for a motorcycle, and FIG.
FIG. 5 is a sectional view taken along the line IV-IV in FIG. 3, and FIG. 5 is a sectional view taken along the line VV in FIG. 1 ... Air / fuel injection engine, 2 ... Crankcase, 9 ... Crankshaft, 9a ... Small diameter gear, 16 ... Reduced gear, 21 ... Pump main shaft, 22 ... Crankcase cover,
25 ... drive gear, 26 ... worm, 31 ... fuel pump,
34 ... cylinder, 35 ... eccentric piston, 36 ... centrifugal roller, 37, 38 ... housing, 40 ... drive shaft, 41 ... connecting shaft, 41a ... worm gear.

Claims (1)

(57) [Claims] 1. A mechanical motorcycle fuel pump for supplying fuel to an engine, wherein a drive shaft of the fuel pump is
By directing in the vertical direction, the fuel pump body is rotatably supported on the crankcase in a direction perpendicular to the crankshaft, and the fuel pump body is installed on the crankcase. A fuel pump for a motorcycle, wherein the fuel pump is engaged with a gear driven by the motor.