JPS6246699B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for supplying fuel to a vehicle engine, and more particularly to an apparatus including an electric fuel pump for pressurizing and supplying fuel in a fuel tank.

A typical fuel supply system installed in a fuel injection engine uses a fuel pump to pressurize and supply fuel in a fuel tank, and a pressure regulator to regulate the pressure of the fuel to a constant level. The surplus fuel at that time is returned to the fuel tank, and the above-mentioned constant pressure regulated fuel is injected from the injector to the engine.
The basic structure is to supply

However, in such a fuel supply device, vapor may be generated in the fuel supply piping when replenishing the fuel tank after it is once empty or when the engine is operated under severe conditions. Then, due to the decrease in fuel pressure due to the generation of vapor, it becomes impossible to supply an appropriate amount of fuel to the engine, which may cause the engine to be unable to start or cause an engine stall due to vapor lock.

In this way, when vapor is generated in the piping and the fuel pressure decreases, in the device with the basic configuration described above, the pressure regulator closes, which causes the high pressure side (discharge side) piping of the fuel pump to close. It becomes closed. Therefore, in order to return to a normal fuel supply state, it is necessary to open the pressure regulator to expel the vapor, but even with a fuel pump that sucks air (vapor), the pressure regulator cannot be opened. In practice, it is difficult to increase the discharge pressure until the rotor opens.

Conventionally, positive displacement pumps such as vane or roller pumps, which are self-priming and have the ability to pressurize air in addition to fuel, have been used as fuel pumps, and these pumps are constantly operated by motors. Therefore, the above-mentioned vapor generation is dealt with.

However, in this case, first, the positive displacement pump, which requires such various capabilities, requires a high degree of machining precision, resulting in an increase in price. Moreover, since it is constantly operated as mentioned above, it is required to have sufficient durability, and the actual situation is that the cost is inevitably increased in order to take countermeasures for this. Second
Even with the use of the above-mentioned positive displacement pump, there is a problem in that it is actually difficult to reliably discharge vapor as long as the conventional piping configuration is used.
Therefore, once vapor is generated, a situation often arises in which the fuel must be allowed to cool down until the vapor no longer occurs.

The present invention has been made in view of the above points, and a first object thereof is to provide a fuel pump that is advantageous in terms of processing accuracy and durability and is capable of efficient pumping action. In addition, a second object of the present invention is to provide a fuel supply system capable of reliably discharging vapor in combination with the fuel pump described above.

Hereinafter, the present invention will be explained according to embodiments shown in the drawings.

FIG. 1 is a system diagram of an embodiment of the present invention.
In the figure, double lines indicate the fuel system, single lines indicate the electrical signal system, and broken lines indicate mechanical connections.

According to this embodiment, as shown in this figure, a fuel pump 3 is connected to a fuel tank 1 through a low pressure side pipe 2.
is connected to the fuel pump 3, and an injector 5, which serves as a means for supplying fuel to an engine (not shown), is connected to the fuel pump 3 via a high-pressure side pipe 4. High pressure side piping 4
A pressure regulator 6 is provided branching off from this, and the regulator 6 is connected to the fuel tank 1 by a return pipe 7. With this basic configuration, fuel stored in the fuel tank 1 is sucked in by the fuel pump 3 via the low pressure side pipe 2, and is pressurized and supplied to the high pressure side pipe 4. The pressurized and supplied fuel is regulated to a constant pressure by a pressure regulator 6, and excess fuel at that time is returned to the fuel tank 1 via a return pipe 7. Then, the pressure-regulated fuel is transferred from the injector 5 to the engine intake pipe (not shown) when the valve is opened.
is injected and supplied to

Fuel pump 3 for pressurizing and supplying the above fuel
are main pump 31, sub pump 32, clutch 33
and a motor 34. Main pump 31
For example, a regeneration pump without self-priming is used as the pump, and this pump is connected to the motor 34 and is connected to the motor 34.
4, it is made to operate at all times. On the other hand, as the sub-pump 32, for example, a flexible vane pump having self-priming property is used. This sub pump 32 serves to supplement the self-priming ability of the main pump 31, and is connected to the main pump 31 via a clutch 33.
The main pump 31 is connected to the main pump 31 and operated together with the main pump 31 only when self-priming is required. When only the main pump 31 is in operation, fuel is sucked into the main pump 31 via the check valve 35, and is pressurized and supplied to the high pressure side pipe 4 through the motor 34. When both the main and sub pumps 31, 32 are in operation, fuel is also sucked in, pressurized and supplied by the sub pump 32.

The clutch 33 operates when the fuel pump 3 requires self-priming, that is, when the pump 3 is started and when vapor is generated in the pipes 2 and 4.
Both the main and sub pumps 31, 32 are operatively connected. For this reason, a clutch 33 that responds to the fuel pressure is used, and the fuel discharge pressure (pressure in the high pressure side pipe 4) is controlled by the clutch 33.
guided by. When the pump is started, the fuel pressure decreases when vapor is generated, so the clutch 33 operates due to this decrease in fuel pressure, and both pumps 31,
Connect 32.

Even if an electromagnetic clutch is used as the clutch and is activated when vapor is generated by a signal from a control means described later, the clutch 33 described above may be operated.
It is possible to obtain the same operation as .

A release means 8 is connected to the high pressure side piping 4. This opening means 8 is for opening the high-pressure side pipe 4 to the fuel tank 1 or the low-pressure side pipe 2 (ie, the low-pressure side), and here it is constituted by a solenoid and is provided in the pressure regulator 6. The opening means 8 made of a solenoid forcibly opens the pressure regulator 6 when activated, connects the high pressure side pipe 7 with the fuel tank 1 via the return pipe 7, and opens it to the low pressure side. .

As an opening means, it is also possible to connect a special pipe communicating with the low pressure side to the high pressure side pipe 4 and install a solenoid valve here, but compared to this case, according to the above configuration, a special pipe that communicates with the low pressure side Advantages such as no need for piping can be obtained.

The opening means 8 is configured to be operated by the control means 9 to open the pressure regulator 6 when vapor is generated in the pipes 2 and 4. The control means 9 here include the motor 34 of the fuel pump 3.
The generation of vapor is detected from the current change, and the solenoid 8 is energized. When the pump 3 is sucking vapor, the pump is in an idling state, and the DC component of the motor current is lower and the AC component is larger than when the pump is sucking fuel normally. FIG. 2 shows this state, where part a shows the motor current when vapor is sucked in, and part b shows the motor current when it is normal. Therefore, the control means 9
determines the occurrence of vapor from such changes in motor current.

According to the fuel supply device configured as described above, during normal times when no vapor is generated, fuel is pressurized and supplied by the main pump 31 and the pressure regulator 6
performs a regular fuel pressure regulating action to maintain the fuel at a constant pressure, and fuel is injected from the injector 5 in the same manner as in a general fuel supply system.

However, when the pump 3 is started or when the fuel discharge pressure decreases due to the generation of vapor, the clutch 33 also operates the auxiliary pump 32. When vapor occurs, a mixture of vapor and fuel is supplied to the pump, so the main pump 31, which does not have self-priming
However, by operating the auxiliary pump 32, which has self-priming properties, reliable pumping action can be continued.

If a large amount of vapor is generated and the idle state continues even with the operation of the sub pump 32, the control means 9 operates the opening means 8 due to a decrease in the DC component of the motor current or an increase in the AC component. Ru. As a result, the high pressure side piping 4 is forcibly opened to the low pressure side. Therefore, the load on the discharge side of the pump 3 is reduced, and vapor is easily expelled from the high pressure side piping 4 to the tank 1. As a result, the normal state is restored and normal fuel injection from the injector 5 continues.

3 to 6 show an example of a specific configuration of the fuel pump 3. As shown in FIG.

As shown in these figures, the fuel pump 3 has a cylindrical outer case 36 and an end plate 37 fixed to the right end thereof. A fuel inlet 361 is formed at the left end of the outer case 36, a fuel outlet 371 is formed at the end plate 37, and a discharge valve 38 for maintaining residual pressure, which is a check valve, is arranged. The inlet 361 is connected to the low pressure side piping 2 in FIG. 1, and the outlet 371 is connected to the high pressure side piping 4. Main pump 31, sub pump 32,
The clutch 33 and motor 34 are arranged inside the outer case 36 and end plate 37.

An inner case 39 is fixed to the inner periphery of the outer case 36, and a magnet 341 serving as a field of the motor 34 is fixed to the inner periphery. motor 34
The armature 342 is disposed inside the magnet 341, and is configured to rotate in the clockwise rotation direction when viewed from the right side in FIG. 3 due to the current supply path including the brush 343. A motor shaft 344 integrated with the armature 342 has a protruding portion from the left end of the armature 342 formed into a cylindrical shape in relation to a clutch 33 to be described later.

The regeneration pump 31 serving as the main pump has an impeller 31 keyed to the left end of the motor shaft 344.
1, and an inlet housing 312 and an outlet housing 313 surrounding the impeller 311 from both sides. The impeller 311 has a plurality of grooves 311a on both sides of the outer periphery. This grooved outer periphery is connected to the annular grooves 312a, 31 of both housings 312, 313 provided correspondingly.
It rotates within the flow path consisting of 3a. As a result, the regeneration pump 31 sucks fuel from the suction port 314 provided in the inlet housing 312, pressurizes it by swirling flow, and then releases the fuel from the discharge port 315 of the outlet housing 313 to the inner case 39.
is discharged into the inner space of the The fuel is supplied from the outlet 371 to the high pressure side pipe 4 (FIG. 1) by opening the discharge valve 38.

The outlet housing 313 rotatably supports a motor shaft 344 with a bearing 316.

Flexible vane pump 32 serving as a sub pump
has a shaft 321, a rotor 322 keyed to the shaft 321, a casing 323 whose circumferential surface 323a is eccentric to the shaft 321, and a side cover 324 disposed at the left end of the casing 323. The right end of the casing 323 is the inlet housing 312 of the regeneration pump 31.
The inlet housing 312 also serves as a casing on the outlet side of the flexible vane pump 32.

The shaft 321 is the inlet housing 312
and a side cover 324, and are rotatably supported by bearings 325 and 326, respectively.
The rotor 322 connected to the shaft 321 is made of an elastic body such as rubber, and has a plurality of (six) vanes 3 inscribed in the inner peripheral surface 323a of the casing 323.
22a. Due to the rotation of the rotor 322 eccentric to the casing inner circumferential surface 323a, each vane 32
2a rotates while being elastically deformed while its tip is in contact with the inner circumferential surface 323a. As a result, fuel is sucked in through the arc-shaped suction port 327, pressurized, and then discharged from the arc-shaped discharge port 328. Inlet 327 is inlet 3
61 and is provided on the side cover 324. The discharge port 328 is connected to the inlet housing 312.
The regeneration pump 31 is connected to the suction port 314 of the regeneration pump 31 .

The casing 323, side cover 324 and inlet housing 312 have an inlet 36.
1 and the suction port 314 of the regeneration pump 31 is provided, and a check valve 35 biased by a spring 352 is disposed in this passage. Passage 351 forms a fuel passage to regeneration pump 31. Check valve 35 only allows fuel to flow from inlet 361 to suction port 314.

The inlet housing 312, outlet housing 313, casing 323, and side cover 324 are fixed to the inner case 39 by four bolts 391, and are mutually coupled and disposed inside the outer case 36.

In the clutch 33, the clutch member 331 is fitted inside the motor shaft 344, which is formed into a cylindrical shape as described above. This clutch member 3
31 is connected to the shaft 321 of the flexible vane pump 32 by splines 331a, 321a, so that it is slidable in the axial direction with respect to the shaft 321 and rotated together in the rotational direction. The left inner circumference of the motor shaft 344 and the left outer circumference of the clutch portion 331 are provided with tapered surfaces 344b and 331b that match each other. The clutch member 331 is biased by a spring 332 in a direction in which the tapered surface 331b is pressed against the tapered surface 344b. When both tapered surfaces 331b and 344b are pressed by the spring 332 in this manner, the rotational force from the motor shaft 344 is transmitted to the clutch member 331 by the frictional force of both tapered surfaces, and the clutch member 331 transfers this to the shaft. 321 to operate the flexible vane pump 32.

A clutch member 33 is attached to the motor shaft 344.
A plurality of holes 344a are provided to communicate the chamber on the right end surface of the inner case 39 with the inside of the inner case 39. Therefore, the fuel pressure (discharge pressure) inside the inner case 39 acts on the right end surface of the clutch member 331, and the clutch member 331 is pressed leftward against the spring 332. At normal fuel pressure of the pump, the tapered surface 331b of the clutch member 331 is maintained at a position away from the tapered surface 344b of the motor shaft 344, and the clutch 33 assumes a disengaged state. Then, only when the fuel pressure decreases, the clutch member 331 connects with the motor shaft 344 to cause the motor 34 to operate the flexible vane pump 32.

With the above configuration, the fuel pump 3 pressurizes and supplies fuel by operating only the regeneration pump 31, which is the main pump, during normal times when no vapor is generated, and when the pump is started or when vapor is generated. When self-priming is required, fuel is pressurized and supplied by the operation of the clutch 33 due to a drop in fuel pressure, and the operation of the flexible vane pump 32, which serves as a sub pump in addition to the main pump. It is clear that efficient pumping action can be obtained by properly using such pumps in relation to the performance required of the pump, and fuel can always be properly pressurized and supplied.

Since the main pump 31 does not need to have self-priming properties, high accuracy is not required for its processing, and it is easy to provide sufficient durability, which can greatly improve There is no increase in costs. Although the auxiliary pump 32 requires self-priming, it is advantageous in terms of durability because it only operates on special occasions, and no special measures are required to improve durability.

As a result, the fuel pump 3 has excellent practical advantages in that it is easy to manufacture, has excellent durability, and can achieve efficient pumping action.

FIG. 7 shows a concrete structure of the pressure regulator 6 equipped with the above-mentioned opening means 8.

In this case, a first case 61 and a second case 62 are connected by seaming with the outer edge of a diaphragm 63 sandwiched therebetween, and the first case 61 and the diaphragm 63 form a fuel chamber. 64 is
Further, a pressure chamber 65 is formed by the second case 62 and the diaphragm 63. A valve holding member 66 is held in the center of the diaphragm 63, and a valve body 67 located on the fuel chamber 64 side is held in this in a known manner. Diaphragm 68 and second case 62
A spring 68 is provided between the diaphragm 68 and the diaphragm 68 to urge the diaphragm 68 toward the fuel chamber.

The first case 61 is provided with a fuel inlet 611 on the side and a fuel outlet 612 on the bottom.
The inlet 611 is connected to the high pressure side pipe 4 (Fig. 1), and the outlet 611 is connected to the high pressure side piping 4 (Fig. 1).
12 is connected to the return pipe 7 (FIG. 1).
The outlet 612 has a pipe 6 located inside the fuel chamber 64.
9 is connected, and its upper end is disposed opposite to the valve body 67. The second case 62 has a pressure intake pipe 621
is provided, and is connected to an intake pipe of an engine (not shown).

Fuel from the high pressure side pipe 4 is supplied to the fuel chamber 64 from the inlet 611, and the pressure acts on the diaphragm 63. Intake negative pressure of the engine is introduced into the pressure chamber 65, and this also acts on the diaphragm 63.
The diaphragm 63 is displaced by the balance between the fuel pressure, the intake negative pressure, and the opposing force of the spring 68, and the valve body 67 follows this and opens and closes the pipe 69, while also reducing the area of the passage leading to the pipe 69. change. The fuel pressure is thereby kept constant (e.g. 2.55 kg/cm ² ) with respect to the intake negative pressure.
The excess fuel is forced out through the outlet 612 through the pipe 69.

A solenoid 8 serving as an opening means is fixed to the second case 62 inside the pressure chamber 65. and,
When energized, the protrusion 661 of the valve holding member 66 is sucked. The solenoid 8 allows the member 66 to move freely when it is not energized, and when it is energized it attracts it and forcibly lifts the valve body 67. This opens the pipe 69, opens the high pressure side piping to the low pressure side, and enables the fuel pump 3 to expel vapor.

As the opening means, in addition to a solenoid, it is also possible to use a combination of a motor and a gear to lift the member 66.

FIG. 8 shows an example of the circuit configuration of the control means 9. This circuit 9 detects the occurrence of vapor from the energizing current (Fig. 2) of the fuel pump motor 34 driven by the current from the battery 10, and energizes the solenoid 8 provided in the pressure regulator. control.

The circuit 9 includes a constant voltage circuit 91 and an amplifier 92 that amplifies the motor current. A DC component is extracted from the amplified motor current by a resistor 93 and a capacitor 94, and a first comparator 96 compares this with a set value set by a variable resistor 95. on the other hand,
Capacitors 97, 98, diodes 99, 100
The alternating current component of the motor current is taken out by the resistor 101 and compared with the set value set by the variable resistor 102 by the second comparator 103.

The outputs of both comparators 96 and 103 are connected to the NOR circuit 10.
4. Transistor 106 via NOT circuit 105
added to. The transistor 106 is turned on and energizes the solenoid 8 when either the DC component of the motor current is smaller than the set value or the AC component of the motor current is larger than the set value.

In this way, the control means 9 detects the occurrence of vapor from the motor current value, and when vapor occurs, the opening means (solenoid) 8 is energized to open the high pressure side piping 4 to the low pressure side.

Note that the generation of vapor can be detected not only by the motor current value as described above but also by a sensor that detects air bubbles.

As explained above, the present invention has a main pump that is always operated as a fuel pump, and a sub-pump that is operated via a clutch when vapor is generated and is capable of pumping even when vapor is generated. Features. According to this, the pump is easy to manufacture, has sufficient durability, and can pressurize and supply fuel with efficient pump action.

In addition to the first feature, the second feature of the present invention is that the high-pressure side piping is opened to the low-pressure side when vapor is generated. According to this, the vapor can be discharged easily and reliably, and even if vapor occurs, the normal fuel supply state can be immediately restored.
Unable to start the engine and vapor lock can be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the device of the present invention;
Figure 2 is a diagram showing changes in the current flowing to the motor.
Figure 3 is a cross-sectional front view of the fuel pump, Figures 4 and 5.
6 and 6 are a sectional view, a sectional view and a sectional view, respectively, of FIG. 3, FIG. 7 is a partially sectional front view of the pressure regulator with release means, and FIG. 8 is a circuit of the control means. It is a diagram. 1...Fuel tank, 2...Low pressure side piping, 3...
Fuel pump, 31... Main pump, 32... Sub pump, 33... Clutch, 34... Motor, 4...
High pressure side piping, 5... Injector serving as fuel supply means, 6... Pressure regulator, 8... Opening means, 9... Control means.

Claims (1)

[Claims] 1. A fuel supply means for supplying fuel to an engine, a fuel tank for storing fuel, a pump for pressurizing and supplying the fuel in the fuel tank to the fuel supply means, A fuel pump including a main pump, a sub pump arranged in series with the main pump, a clutch selectively connecting both the main and sub pumps, and a motor connected to the main pump; and a fuel pump, and a high-pressure side pipe that connects the fuel pump and the fuel supply means, and when vapor is generated in the low-pressure side pipe or the high-pressure side pipe, the clutch of the fuel pump is 1. A fuel supply device for an engine, characterized in that the main pump and the sub pump are connected when the main pump and the sub pump are operated. 2. A fuel supply means for supplying fuel to the engine, a fuel tank for storing fuel, a pump for pressurizing and supplying the fuel in this fuel tank to the fuel supply means, which includes a main pump and a fuel tank for storing fuel; A fuel pump including a sub-pump arranged in series with the pump and having a self-priming property, a clutch for selectively connecting both the main and sub-pumps, and a motor connected to the main pump; and the fuel tank. a low-pressure side pipe that connects the fuel pump and the fuel pump; a high-pressure side pipe that connects the fuel pump and the fuel supply means; and a pressure regulator that is installed in the high-pressure side pipe and regulates the fuel pressure in the pipe to a constant level. an opening means connected to the high-pressure side piping to selectively open the same to the fuel tank or the low-pressure side piping, and detecting the occurrence of vapor in the low-pressure side piping or the high-pressure side piping, control means for operating the opening means to open the high pressure side piping to the low pressure side; when the opening means is operated, the clutch of the fuel pump is operated to connect the main pump and the sub pump. A fuel supply device for an engine, which is characterized by: