JPS6239265B2 - - 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. and,
Due to the drop in fuel pressure due to vapor generation, it becomes impossible to supply the appropriate amount of fuel to the engine.
There is a risk that the engine will not be able to start or the engine will 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 if the fuel pump is sucking air (vapor), the pressure regulator will open. It is actually difficult to increase the discharge pressure until the valve opens.

In view of the above-mentioned points, an object of the present invention is to provide a fuel supply device that can reliably and easily discharge vapor when it occurs and return to a normal fuel supply state. In particular, the present invention provides a simple arrangement for this purpose.

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

FIG. 1 is a system diagram of the apparatus of the present invention, in which double lines indicate a fuel system and single lines indicate an electrical signal system.

According to the present invention, as shown in this figure, a fuel pump 3 is connected to a fuel tank 1 through a low-pressure side pipe 2, and an engine (not shown) is connected to the fuel pump 3 through a high-pressure side pipe 4. ) is connected to an injector 5 which serves as a fuel supply means. A pressure regulator 6 is connected to the high pressure side pipe 4, and the regulator 6 is connected to the fuel tank 1 via a return pipe 7. As the fuel pump 3, one having a fuel pressurizing ability and driven by a motor is used. This fuel pump 3 has gas (air)
Pressurizing ability is not particularly required.

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 the pressure regulator 6, and the excess fuel at that time is transferred to the fuel tank 1 through the return pipe 7.
be returned to. The regulated fuel is then injected and supplied from the injector 5 to an intake pipe (not shown) of the engine when the valve is opened.

The pressure regulator 6 connected to the high pressure side pipe 4 is provided with an opening means 8. 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 (i.e., the low-pressure side), and here it is composed of a solenoid, which forcibly closes the pressure regulator 6 when energized. The high pressure side piping 7 is opened to the low pressure side via the return piping 7.

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.

Here, the control means 9 detects the occurrence of vapor from a change in the current of the motor 34 of the fuel pump 3, and energizes the solenoid 8. 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 a change in the 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 fuel pump 3, 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 fuel pump 3 becomes idle due to the generation of vapor, the control means 9 operates the opening means 8 due to a decrease in the DC component or an increase in the AC component of the motor current.

As a result, the pressure regulator 6 opens, and 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.

FIG. 3 shows a concrete construction of the pressure regulator 6 equipped with the above-mentioned opening means 8. As shown in FIG.

In this case, a first case 61 and a second case 62 are joined together by seaming with the outer edge of a diaphragm 63 sandwiched therebetween, and the first case 61 and the diaphragm 63 are connected to each other by the amount of fuel. 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 63 and second case 62
A spring 68 is provided between the diaphragm 63 and the diaphragm 63 to urge the diaphragm 63 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 discharged from 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.

In addition to the solenoid, a mechanism for lifting the member 66 using a combination of a motor and a gear can also be used as the opening mechanism.

When the opening means 8 is provided in the pressure regulator 6 as described above, the return pipe 7 of the pressure regulator 6 can also be used as a pipe for opening the high pressure side pipe 4 to the low pressure side. As a result, there is no need to provide special piping, which helps simplify the configuration.

FIG. 8 shows an example of the circuit configuration of the control means 9. This circuit 9 is connected to the energizing current (second
(Figure), the generation of vapor is detected and the energization of the solenoid 8 provided in the pressure regulator is controlled.

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 one of the following conditions is satisfied: the DC component of the motor current is smaller than the set value, but 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 occurrence 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 is characterized in that when vapor occurs, the pressure regulator is forcibly opened to open the high pressure side piping to the low pressure side. According to this, vapor can be discharged reliably and easily by using the pressure regulator's own piping, and even if vapor occurs, the normal fuel supply state can be immediately restored. It becomes possible. Therefore, inability 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;
Fig. 2 is a diagram showing changes in the motor current of the fuel pump, Fig. 3 is a partial cross-sectional front view of the pressure regulator which forms the main part of the present invention, and Fig. 4 is a circuit diagram of the control means. . 1...Fuel tank, 2...Low pressure side piping, 3...
Fuel pump, 4... High pressure side piping, 5... 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 fuel pump that pressurizes and supplies the fuel in the fuel tank to the fuel supply means, the fuel tank and A low-pressure side pipe that connects the fuel pump, a high-pressure side pipe that connects the fuel pump and the fuel supply means, and a pressure leg that is connected to the high-pressure side pipe and regulates the fuel pressure in the high-pressure side pipe to a constant level. a regulator, an opening means provided in the pressure regulator for forcibly opening the pressure regulator, and a means for detecting the occurrence of vapor in the low-pressure side piping or high-pressure side piping, and control means for operating the opening means to open the pressure regulator when vapor occurs; A fuel supply device for an engine, characterized in that it is opened to the fuel tank or low pressure side piping.