JP2000064924A - Fuel supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel supply device for an internal combustion engine, which can improve the operational performance of the piston of a priming pump by reducing the operating physical force of the priming pump at the time of deflating operation in a fuel piping system. SOLUTION: One of the teeth 18 of the inner rotor 14 of a feed pump 4 supplying fuel in the inside of a fuel tank 2 to an injection pump 3 is formed into a broken tooth 19 so as to form a communicating passage (gap between teeth) 23 that a channel cross sectional area is wider than the normal gap between the teeth of the inner rotor 14 and an outer rotor 15, thereby the inlet port and exhausting port of the feed pump 4 are communicated with each other under a condition that having the wide channel cross sectional area. Thereby, when the piston 32 of a priming pump 5 arranged in the middle of a fuel suction passage 33 is manually operated, operational resistance at the time of deflating operation in a fuel piping system can be reduced and operational efficiency of deflating operation in the fuel piping system can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manually operated type used for bleeding air from a feed pump, an injection pump and a fuel pipe in the middle of a fuel suction pipe of a feed pump for supplying fuel from a fuel tank to an injection pump. The present invention relates to a fuel supply device provided with a priming pump.

[0002]

2. Description of the Related Art As a conventional technique, there is a fuel supply apparatus 100 for an internal combustion engine as shown in FIG. Generally, when assembling a vehicle, the priming pump 101 is connected to the fuel tank 1.
Intake passage 10 connecting the fuel pump 02 and the feed pump 103
4 and feed pump 103 and injection pump 1
By performing a priming operation (air bleeding operation) for bleeding air from the fuel pipe 05 and the fuel pipe 106, the fuel pipe system is filled with fuel.

The priming pump 101 is composed of a cylinder 112 forming a pump chamber 111 communicating with the fuel suction passage 104, and a plunger 113 for manually expanding and contracting the pump chamber 111. Here, 107 is a common rail, 108 is an injector, and 114 and 115 are check valves.

[0004]

However, in the conventional fuel supply apparatus 100 for an internal combustion engine, the area of the fuel passage in the feed pump 103 is very small as compared with other parts, so that the priming is performed when performing the air bleeding operation. Pump 1
When the fuel discharged from 01 flows, the resistance becomes large. As a result, the operability of the priming pump 101 is deteriorated due to an increase in the operating force of the priming pump 101 during the air bleeding operation.

In the technique described in Japanese Utility Model Publication No. Sho 62-15486, the work resistance when screwing and fixing the plunger of the priming pump into the cylinder after the completion of the air bleeding operation is reduced. There is no effect of improving the work resistance.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel supply device capable of improving the operability of a priming pump by reducing the operation force of the priming pump during an air bleeding operation.

[0007]

According to the first aspect of the present invention, a communication passage having a flow path cross-sectional area larger than an inter-tooth gap in a meshing portion between a first gear and a second gear of a feed pump. Is provided, the suction port and the discharge port of the feed pump communicate with each other in a state where the flow path cross-sectional area is wide. This allows the fuel to pass through the communication passage at the time of manual operation of the priming pump, thereby reducing the work resistance during the air bleeding operation, thereby reducing the operating force of the priming pump. As a result, the operability of the priming pump during the air bleeding operation can be improved, so that the work efficiency of the air bleeding operation in the fuel piping system can be improved.

According to the invention described in claims 2 to 4, when the feed pump is an internal gear pump, some teeth of the external gear are made shorter than other teeth, and By providing a communication path between the teeth of the gear and the internal gear, and using a communication hole that communicates both side surfaces of some of the teeth of the external gear as the communication path, the inlet and outlet of the feed pump can be discharged. The outlet and the outlet can be communicated in a state where the flow path cross-sectional area is wide. Thereby, work resistance at the time of air bleeding work can be reduced.

According to the fifth aspect of the present invention, the position of the keyway used for fixing the first gear at the predetermined position of the camshaft and the position of the communication path are made to coincide with each other,
It is possible to easily perform the air bleeding operation at a position where the flow path cross-sectional area is wide and the working resistance is reduced.

According to the sixth aspect of the present invention, when the feed pump is an external gear pump, some teeth of the drive gear and some teeth of the driven gear are shorter than other teeth.
By providing a communication path between the teeth of the driving gear and the driven gear, the suction port and the discharge port of the feed pump can be communicated in a state where the flow path cross-sectional area is wide. Thereby, work resistance at the time of air bleeding work can be reduced.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Structure of Embodiment] An embodiment of the present invention will be described based on an embodiment with reference to the drawings. here,
FIG. 1 is a view showing a fuel pipe system of a fuel supply device for an internal combustion engine, FIG. 2 is a view showing an entire structure of a feed pump, and FIG. 3 is a view showing a main structure of the feed pump.

The fuel supply device 1 for an internal combustion engine according to the present embodiment
A feed pump 4 for supplying the fuel in the fuel tank 2 to the injection pump 3; a priming pump 5 for bleeding air from the fuel piping system when an initial injection pump is attached, such as when assembling an automobile; and a fuel tank via the feed pump 4 And a fuel pipe 6 connecting the fuel injection pump 2 and the injection pump 3.

The fuel tank 2 is mounted, for example, below a rear seat of the automobile. The injection pump 3 pressurizes the sucked fuel to a common rail 7 at a high pressure. The common rail 7 is a type of surge tank that stores high-pressure fuel of a relatively high pressure. Are linked.

The injection pump 3 has a camshaft (drive shaft of the feed pump 4) 10 driven by a gear or a belt on a crankshaft (not shown) of the internal combustion engine. The camshaft 10 operates the plunger (not shown) of the injection pump 3 and the feed pump 4 while being driven by the internal combustion engine.

The feed pump 4 includes a trochoid pump body (hereinafter abbreviated as a pump body) 11 and the pump body 1.
And a housing 13 having an annular portion 12 that rotatably supports the trochoid pump 1. The pump body 11 pumps the fuel in the fuel tank 2 and discharges it to the injection pump 3 by changing the inter-tooth volume between the inner rotor 14 and the outer rotor 15 formed by the trochoid curve.

The inner rotor 14 is a first gear of the present invention,
It is equivalent to an external gear, and is fixed by fitting a key 17 into a key groove 16 on the outer periphery of the tip of the camshaft 10 protruding from the injection pump 3. A plurality of (in this example, six) teeth 18 are provided on the outer circumference of the inner rotor 14.
Is provided, for example, with a width of 22 mm, and one of them is
Each tooth is a missing tooth 19. The missing tooth 19 is a tooth located on the outer peripheral side of the key 17 and is shorter than the other teeth 18 by, for example, 1 mm to 3 mm.

The outer rotor 15 is a second gear of the present invention,
A plurality of (six in this example) teeth 20 which correspond to the internal gear and can mesh with the plurality of teeth 18 and the missing teeth 19 of the inner rotor 14 are provided with a width of, for example, 22 mm. The interdental gap between the teeth 20 and the teeth 18 is, for example, 50 μm to 100 μm.

Further, between the tooth 20 and the missing tooth 19, during the air bleeding operation (priming operation), the pump body 11
Suction port formed in (corresponding to the suction port of the present invention)
A communication path 23 is formed to connect the discharge port 21 and a discharge port (corresponding to a discharge port of the present invention) 22. The communication passage 23
Is an interdental gap (gap) formed between the tooth 20 and the missing tooth 19. A fuel inlet 24 communicating with the suction port 21 and a fuel outlet 2 communicating with the discharge port 22 are provided on the front wall surface of the housing 13 of the feed pump 4.
5 are formed.

The priming pump 5 has a cylindrical cylinder 31 forming a pump chamber 30 communicating with the fuel pipe 6 between the fuel tank 2 and the feed pump 4, and is slidably assembled in the cylinder 31. And a piston (plunger) 32 for expanding and contracting the pump chamber 30. When the priming pump 5 is not used, the cylinder 31 is screwed into the housing 13 with the pump chamber 30 contracted by the piston 32.

The fuel passage formed in the fuel pipe 6 and the housing 13 is provided in the fuel suction passage 3 of the feed pump 4.
3 and a fuel discharge passage 34 of the feed pump 4. The fuel suction passage 33 is a fuel passage for guiding the fuel in the fuel tank 2 through the suction port 21 into the pump main body 11 of the feed pump 4.
36 are installed.

A fuel passage 29 communicating with the pump chamber 30 of the priming pump 5 is formed in the housing 13 so as to branch off from the fuel suction passage 33. The fuel discharge passage 34 is a fuel passage for guiding the high-pressure fuel discharged from the discharge port 22 of the pump body 11 to the injection pump 3.

The check valves 35 and 36 are connected to the seat 3
7, 38, ball valves (valve elements) 39, 40 for closing the fuel suction passage 33 when seated on the seats 37, 38, and a spring 4 having a spring load of, for example, 200 g to 300 g.
1, 42 and the like. Accordingly, when the pressure on the fuel tank 2 side becomes higher than the pressure on the feed pump 4 by a set value or more, the check valves 35 and 36 are displaced to the ball valves 39 and 40 toward the feed pump 4 and open.

Next, the operation of the fuel supply device 1 for an internal combustion engine according to this embodiment will be briefly described with reference to FIGS.

A) At the time of air bleeding operation of the fuel piping system When sucking fuel from the fuel tank 2 side by the priming pump 5, first, the operator pulls up the piston 32, so that the downstream side of the pressure on the upstream side of the check valve 35. Pressure drops (becomes negative pressure). As a result, the ball valve 3
9 is displaced rightward in the figure, and the check valve 35 is opened.

As a result, the fuel in the fuel tank 2 flows through the fuel suction passage 33 and the fuel
Is pumped up into the pump chamber 30. At this time, since the pressure on the upstream side of the check valve 36 is lower than the pressure on the downstream side, the check valve 36 is kept closed.

Next, when the priming pump 5 discharges fuel to the injection pump 3 side, the operator
By depressing 2, the pressure on the downstream side of the check valve 36 is lower than the pressure on the upstream side (negative pressure). As a result, the ball valve 40 is displaced rightward in the figure by overcoming the urging force of the spring 42, and the check valve 3
6 opens.

Therefore, the fuel in the pump chamber 30 of the priming pump 5 is supplied to the fuel passage 37, the fuel suction passage 33,
The fuel is supplied into the injection pump 3 through the suction port 21, the communication passage 23, the discharge port 22, and the fuel discharge passage 34.
Thereby, the air in the fuel piping system from the fuel tank 2 to the injection pump 3 is vented.

B) During normal operation The inner rotor 14 of the feed pump 4 is rotated by the camshaft 10 which is driven to rotate by the internal combustion engine.
The discharge side of the pump body 11 becomes positive pressure, and the pump body 11
Is negative pressure. Therefore, the pressure on the upstream side of the pump body 11 (the internal pressure of the fuel suction passage 33) decreases, and the pressure on the downstream side of the pump body 11 (the fuel discharge passage 34).
Internal pressure). As a result, the check valves 35 and 36 are opened.

For this reason, the fuel in the fuel tank 2 is supplied to the injection pump 3 through the fuel suction passage 33, the suction port 21, the communication passage 23, the discharge port 22, and the fuel discharge passage 34. The high-pressure fuel pressurized by is sent to the common rail 7. Then, the high-pressure fuel stored in the common rail 7 is sent to each injector 9, and the high-pressure fuel is injected into each cylinder of the internal combustion engine.

[Effects of the Embodiment] As described above, in the fuel supply device 1 for an internal combustion engine of the present embodiment, the fuel discharged from the pump chamber 30 of the priming pump 5 during the air bleeding operation has a cross-sectional area of the flow passage. The teeth 18 of the inner rotor 14 and the outer rotor 1 of the pump body 11 are very small as compared with other parts.
5 flows through the communication passage 23 having a larger flow passage cross-sectional area than the interdental gap with the fifth tooth 20.

As a result, the working resistance during the air bleeding operation is reduced.
2 can reduce the operating force. Therefore, the operability of the piston 32 of the priming pump 5 at the time of the air bleeding operation can be improved, so that the work efficiency of the air bleeding operation in the fuel piping system constituted by the injection pump 3, the feed pump 4, and the fuel piping 6 is improved. can do.

In the normal air bleeding operation, the initial injection pump is often attached (or when there is no gas), so that the crank angle of the internal combustion engine and the angle of the camshaft 10 of the injection pump 3 are made equal to a predetermined angle. The position of the missing teeth 19 of the inner rotor 14 is matched to a predetermined angle. In particular,
Since the position of the key groove 16 of the camshaft 10 corresponds to a predetermined crank angle of the internal combustion engine, the position of the key groove 16 of the camshaft 10 and the position of the missing tooth 19 of the inner rotor 14 are determined in this embodiment. If the rotational position of the inner rotor 14 is determined by, for example, matching the positions in the radial direction as described above, the position of the cross-sectional area of the flow path can be easily increased, that is, the chipped teeth 19 can be easily obtained.
The air bleeding operation can be performed without any work resistance at the position.

Here, the provision of the missing teeth 19 on the inner rotor 14 facilitates the priming operation. However, the missing teeth 19 slightly reduces the feedability of the feed pump 4 during normal operation. If viscosity is not considered, if one of the six teeth 18 is made to be a missing tooth 19, the pumping capacity will be reduced by 1/6, but since the fuel is viscous, 1 mm However, in the case of the feed pump 4 having one missing tooth 19 which is shaved more than the other teeth 18, the pumping capacity is actually reduced by 10% or less.

[Modification] In this embodiment, a trochoid pump is used as the pump body 11 of the feed pump 4, but an internal gear pump or an external gear pump may be used as the pump body of the feed pump 4.

When the internal gear pump is used as the pump body of the feed pump 4 as the communication passage, some teeth of the external gear are shorter than other teeth (the missing teeth 19). Is provided), a communication path 23 is provided between the teeth of the external gear and the internal gear, or both sides of some teeth of the external gear or both sides of some teeth of the internal gear are communicated. A communication hole may be provided, and the communication hole may be used as a communication passage.

When an external gear pump is used as the pump main body of the feed pump 4, some teeth of the drive gear are made shorter than other teeth (notch teeth are provided), and a part of the driven gear is formed. May be made shorter (provided with missing teeth) than normal teeth, and a communication path may be provided between the teeth of the driving gear and the driven gear. When the number of teeth of the driving gear and the number of teeth of the driven gear are the same, if the position of one of the driving gear and the driven gear is adjusted to the key groove of the camshaft 10, the communication path can be easily positioned.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a fuel pipe system of a fuel supply device for an internal combustion engine (Example).

FIG. 2 is a cross-sectional view showing an entire structure of a feed pump (Example).

FIG. 3 is a sectional view showing a main structure of a feed pump (Example).

FIG. 4 is a configuration diagram showing a fuel piping system of a fuel supply device for an internal combustion engine (prior art).

[Explanation of symbols]

 Reference Signs List 1 fuel supply device for internal combustion engine 2 fuel tank 3 injection pump 4 feed pump 5 priming pump 6 fuel pipe 9 injector 10 camshaft 14 inner rotor (first gear, external gear) 15 outer rotor (second gear, internal gear) 18 Tooth 19 Missing tooth 20 Teeth 21 Suction port (suction port) 22 Discharge port (discharge port) 23 Communication path 33 Fuel suction path 34 Fuel discharge path

Claims (6)

[Claims] A feed pump for sucking fuel in a fuel tank from a suction port, pressurizing the fuel inside the fuel tank, and discharging the fuel from a discharge port to an injection pump by changing a tooth space between the first gear and the second gear; A fuel pipe for communicating the fuel tank with the injection pump via the feed pump; and a priming pump provided in the middle of the fuel pipe for removing air from the feed pump, the injection pump, and the fuel pipe. The feed pump further includes a communication passage that, at a meshing portion between the first gear and the second gear, has a flow path cross-sectional area larger than a gap between teeth and communicates the suction port and the discharge port. A fuel supply device comprising: 2. The fuel supply device according to claim 1, wherein the feed pump is an internal gear pump having an external gear that forms the first gear and an internal gear that forms the second gear. A fuel supply device, characterized in that: 3. The fuel supply device according to claim 1, wherein the communication path is configured such that some teeth of the external gear are shorter than other teeth, and the external gear and the external gear are connected to each other. A fuel supply device provided between teeth with an internal gear. 4. The fuel supply device according to claim 1, wherein the communication passage is a communication hole that communicates both side surfaces of some teeth of the external gear. Feeding device. 5. The fuel supply device according to claim 1, wherein the injection pump is driven to rotate by an internal combustion engine to rotate a first gear of the feed pump. A fuel supply device, wherein a position of a key groove used when fixing the first gear at a predetermined position of the camshaft and a position of the communication path are matched to perform an air bleeding operation. . 6. The fuel supply device according to claim 1, wherein the feed pump is an external gear pump having a drive gear forming the first gear and a driven gear forming the second gear. Is provided between the drive gear and the driven gear, with some of the teeth of the drive gear and some of the teeth of the driven gear shorter than the other teeth. apparatus.