JPH0569989B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injection device suitably used to supply fuel in a fuel tank to, for example, an automobile engine. The present invention relates to a fuel injection device equipped with a fuel tank consisting of:

[Conventional technology]

In general, fuel tanks for automobiles are divided into a main tank and a sub-tank due to constraints on the vehicle body structure and requests for increased tank capacity.

FIG. 5 shows a prior art fuel injection device equipped with this type of fuel tank.

In the figure, reference numeral 1 denotes a fuel tank containing fuel A. The fuel tank 1 is formed into a saddle shape consisting of a main tank part 2 and a sub-tank part 3, and a bottom part 1A straddles the rear axle housing 4. A main tank part 2 and a sub-tank part 3 are arranged so as to be located on the left and right sides. And fuel tank 1
A fuel filler port 5 and a fuel pump insertion port 6 are formed on the upper side.

Reference numeral 7 denotes a fuel pump that is located in the fuel tank 1 on the side of the main tank section 2 and pumps fuel A to a fuel injection valve 13, which will be described later.The fuel pump 7 has a pump section and a motor section inside its casing. A filter 7C connected to the suction port 7B of the pump main body 7A, and a discharge port 7D provided in the pump main body 7A and equipped with a check valve for maintaining residual pressure inside, It is supported via a bracket 8 by a lid 9 provided on the fuel pump insertion port 6.

10, one end side is the discharge port 7D of the fuel pump 7.
A pressure regulator 12 is connected to the other end of the supply pipe 10, and a fuel filter 11 is interposed in the middle of the supply pipe. 13,1
3,... are fuel injection valves (not shown) provided in a number corresponding to the number of cylinders of the engine, and the fuel injection valves 1
3, 13, . . . are connected between the fuel filter 11 and the pressure regulator 12 of the supply pipe 10. A control pressure introduction pipe 15 is connected to the pressure regulator 12, which introduces, as a control pressure, a difference in the magnitude of negative pressure generated within the intake manifold 14 by opening and closing a throttle valve (not shown). And the pressure regulator 12
By introducing control pressure into the fuel tank 1 through the introduction pipe 15, the return flow rate returned to the fuel tank 1 via the return pipe 16, which will be described later, is controlled based on the fuel pressure (fuel pressure) supplied from the fuel pump 7. , the fuel pressure supplied to each fuel injection valve 13 is controlled to a predetermined set pressure.

16 is a return pipe for returning surplus oil of fuel A supplied from the fuel pump 7 to the fuel tank 1 side, one end side of the return pipe 16 is connected to the pressure regulator 12, and the other end side is connected to the fuel tank 1 side.
It extends toward the main tank section 2 inside.

Reference numeral 17 is located on the main tank section 2 side and provided on the tip side of the return pipe 16 in order to suck the fuel A stored in the sub tank section 3 of the fuel tank 1 and flow it into the main tank section 2 side. The fuel suction pump serves as an ejector, and the base end side of a suction pipe 18 is connected to the fuel suction pump 17, and the suction port (filter) on the distal end side 18A of the suction pipe 18 is arranged at the inner bottom of the sub-tank part 3. ing. The fuel suction pump 17 is operated when the fuel A that is recirculated from the pressure regulator 12 via the return pipe 16 passes through the fuel suction pump 17 and flows out into the main tank section 2. The fuel A in the sub-tank section 3 is suctioned through the suction pipe 18 by the negative pressure generated in the sub-tank section 3.

The conventional technology is configured as described above, and its operation will be explained next.

The fuel pump 7 is driven, and the fuel A in the fuel tank 1 is supplied to the fuel injection valves 13 and 1 via the supply pipe 10.
3. Supply to... At this time, pressure regulator 1
2 introduces negative pressure from the intake manifold 14 as a control pressure, and controls the fuel pressure supplied from the fuel pump 7 to control the fuel injection valves 13 and 1.
The pressure of fuel A supplied to 3, . . . is controlled to a predetermined set pressure.

Thus, the fuel injection valve 1 is injected by the fuel pump 7.
A part of the fuel A supplied to the fuel injection valves 13, 13, . brought back inside.

In addition, the fuel suction pump 17 provided at the tip side of the return pipe 16 generates negative pressure inside the fuel suction pump 17 when excess oil from the return pipe 16 passes through the pump 17 as a return flow. The fuel A in the sub-tank section 3 is suctioned by negative pressure through the suction pipe 18, and is sequentially sent to the main tank section 2 side together with excess oil.

[The problem that the idea aims to solve]

By the way, when the fuel liquid level in the fuel tank 1 is located above the square portion 1A, it is not necessary to operate the fuel suction pump 17. Furthermore, when the fuel A in the sub-tank section 3 is almost empty, air enters through the suction pipe 18 and gas is mixed into the liquid in the fuel suction pump 17, resulting in a It is better not to operate the fuel suction pump 17 because this will cause an abnormal noise. Furthermore, when starting or restarting the engine with the temperature of the fuel A being high, so-called hot restart, vapor may be generated in the return pipe 16. It is better not to operate the fuel suction pump 17 because it generates noise.

However, in the above-mentioned conventional technology, the surplus oil that is returned to the main tank section 2 via the return pipe 16 is always returned to the fuel suction pump 17 regardless of the fuel level in the sub-tank section 3, the fuel temperature, etc. Since the pump 17 is operated by being sent to the fuel suction pump 17, it is always operating in each of the above states, and there is a problem that abnormal noise is generated within the fuel suction pump 17.

The present invention was developed in view of the problems of the prior art described above, and is capable of selectively stopping the operation of the fuel suction pump when abnormal noise is likely to occur, thereby reliably preventing the occurrence of abnormal noise. It is an object of the present invention to provide a fuel injection device as described above.

[Means to solve the problem]

In order to solve the above-mentioned problems, a fuel injection device according to the present invention includes a fuel tank in which a main tank and a sub-tank are formed in a saddle shape with a bottom side interposed therebetween, and a fuel injection device provided on the main tank side of the fuel tank. a fuel pump, a supply pipe that supplies the fuel discharged from the fuel pump to the injection valve, a pressure regulator installed in the middle of the supply pipe to adjust the internal fuel pressure, and surplus oil from the pressure regulator. a return pipe for returning the fuel to the main tank side of the fuel tank; and a return pipe provided at the tip side of the return pipe, and using the return flow of the surplus oil to draw the fuel in the sub-tank to the main tank side via a suction pipe. It is equipped with a fuel suction pump.

The feature of the configuration adopted by the present invention is that the return piping is interposed in the middle, and one switch position connects the inflow side to the fuel suction pump side, and the other switch position connects the inflow side directly to the main tank. a solenoid valve having a switching position; a liquid level sensor provided in the sub-tank to detect the height of the liquid level in the sub-tank; and a fuel temperature sensor to detect the temperature of the fuel stored in the fuel tank. According to the signals from the liquid level sensor and the fuel temperature sensor, it is determined that the liquid level in the sub-tank is between the upper limit setting position corresponding to the bottom part and the lower limit setting position corresponding to the almost empty state, and the fuel temperature is When the temperature is below a predetermined temperature, the solenoid valve is set to one switching position, and even if the liquid level in the sub-tank is between the upper limit setting position and the lower limit setting position, when the fuel temperature is above the predetermined temperature, it remains constant after engine startup. and a solenoid valve control device that sets the solenoid valve to the other switching position for a certain amount of time.

[Effect]

With the above configuration, the solenoid valve control device controls the solenoid valve based on the detection signals from the liquid level sensor and the fuel temperature sensor, and in the following conditions, connects the return piping directly to the main tank side or Connect to the suction pump side.

When the fuel level in the fuel tank is higher than the upper limit setting position and the fuel is not separated into the main tank and sub tank, there is no need to operate the fuel suction pump, and the liquid level sensor detects this. Based on the signal, the solenoid valve control device switches the solenoid valve to allow excess oil from the return pipe to flow directly into the main tank.

Additionally, when the fuel in the sub-tank drops to the lower limit setting position and is almost empty, the fuel suction pump sucks air from the sub-tank side, causing abnormal noise, which is detected by the liquid level sensor. Then, based on the detection signal, the solenoid valve control device switches the solenoid valve to allow the return oil from the return pipe to flow directly into the main tank.

Furthermore, the liquid level is lower than the upper limit setting position and the fuel is separated into the main tank and sub tank.
When there is more fuel remaining in the sub-tank than the lower limit setting position and the temperature of the fuel is high at engine start or at the time of start, so-called hot restart, vapor is generated in the return pipe and the fuel suction pump The liquid level sensor and fuel temperature sensor detect these noises, and based on these detection signals, the solenoid valve control device switches the solenoid valve and closes the return piping for a certain period of time after the engine is started or restarted. Excess oil from the tank will be drained directly into the main tank.

As a result, the operation of the fuel suction pump is stopped according to each of the above states, and the generation of abnormal noise can be reliably prevented.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 4. In this embodiment, the same components as those of the prior art described above are given the same reference numerals, and the explanation thereof will be omitted.

In the figure, 21 indicates a solenoid valve located in the fuel tank 1 and provided in the middle of the return pipe 16,
The electromagnetic valve 21 is constituted by, for example, a three-port, two-position electromagnetic switching valve. Here, the solenoid valve 21 has its inflow port 21A communicating with the return pipe 16, and the outflow port 21A at one switching position.
1B is connected to the fuel suction pump 17 side, and the outflow port 21C at the other switching position is connected to a bypass pipe 22 extending below the main tank section 2. Then, by setting the solenoid valve 21 to one switching position by a solenoid valve control device 25 to be described later, the inflow port 21A is switched to the one outflow port 2.
1B and the other switching position, the inflow port 21A is controlled to communicate with the other outflow port 21C.

Reference numeral 23 indicates a liquid level sensor as a liquid level detector located on the side of the sub-tank portion 3 of the fuel tank 1. The sensor 23 is constituted by a float-type fuel gauge or the like, and is a float floating on the liquid surface of the fuel A. 23A
The displacement of the arm 23B is extracted as a rotation angle (swing angle), and a detection signal H representing the liquid level as the remaining amount of fuel on the sub-tank portion 3 side is outputted to the electromagnetic valve control device 25.

Reference numeral 24 denotes a fuel temperature sensor that is installed, for example, in the middle of the supply pipe 10 and detects the temperature of the fuel A stored in the fuel tank 1. 10
The temperature of the fuel A sent to the pressure regulator 12 side via the pressure regulator 12 is detected.

Further, 25 indicates a solenoid valve control device, to which a liquid level sensor 23, a fuel temperature sensor 24 and an engine switch 26 are connected to the input side, and a solenoid valve 21 to the output side. There is.

The solenoid valve control device 25 is composed of a microcomputer, etc., and has an input/output control circuit, for example.
For example, a processing circuit consisting of a CPU, MPU, etc.
It is configured to include a storage circuit consisting of ROM, RAM, etc. The storage circuit stores a storage area 27 shown in FIG. 3, a control program shown in FIG. 4, a soft timer (not shown) for counting time, and the like. The memory area 27 of the memory circuit stores a memory for an upper limit setting position α set at the height of the square portion 1A of the fuel tank 1, which is the upper limit setting position for performing the liquid level position determination processing operation. Area 27 ₁ and memory for the lower limit setting position β, which is set at a position higher than the bottom of the sub-tank part 3 by 18A on the tip side of the suction pipe 18, which is the lower limit setting position for performing the liquid level position determination processing operation. area 27 ₂ and a set temperature t ₀ that is preset to a predetermined temperature (50°C) for performing the fuel temperature determination processing operation.
and a storage area ₂₇₄ for a set time _S0 , which is preset to a predetermined time (3 minutes) for performing _a time determination processing operation.

The fuel injection system according to this embodiment has the above-mentioned configuration, and the processing operation of the electromagnetic valve control device 25 will be explained next with reference to the program shown in FIG. 4.

First, the process is started by turning on the engine switch 26, and at step 1, the soft timer of the solenoid valve control device 25 starts counting time, and at the same time, at step 2, the detection signal H from the liquid level sensor 23 is read. Proceeding to step 3, it is determined whether the value of the detection signal H is higher than the liquid level α, which is the upper limit setting position. Now, when the determination in step 3 is "NO", it means that the liquid level H in the fuel tank 1 has fallen below the cross section 1A and the fuel A has been separated into the main tank section 2 and the sub tank section 3. Then, proceeding to step 4, it is determined whether the value of the detection signal H is below the liquid level β. Then, if the determination in step 4 is "NO", sub tank 1
This indicates that the liquid level H of fuel A in B is lower than α and higher than β, and the process moves to step 5, where the detection signal t from the fuel temperature sensor 24 is read. Then, the process moves to step 6 and the value of the detection signal t becomes the set temperature t ₀
(50° C.) or higher, and when the determination is “NO”, the process moves to step 7 and the solenoid valve 21 is switched to the fuel suction pump 17 side. As a result, excess oil from the return pipe 16 is distributed to the fuel suction pump 17 via the solenoid valve 21, and the sub-tank section 3
The fuel A inside is sucked into the main tank section 2 side through the suction pipe 18.

On the other hand, if the determination in step 3 is "YES", the liquid level of fuel A in the fuel tank 1 is
This indicates that there is no need to operate the fuel suction pump 17, and the process moves to step 8, where the solenoid valve 21 is switched to the bypass pipe 22 side. As a result, excess oil from the return pipe 16 is distributed to the bypass pipe 22 via the solenoid valve 21, and the operation of the fuel suction pump 17 is stopped.

Also, if the determination in step 4 is "YES", the remaining amount of fuel A in the sub-tank section 3 is low;
This indicates a state in which when the fuel suction pump 17 is operated, there is a possibility that air will be sucked in as well and abnormal noise will be generated, so the process moves to step 8 and the solenoid valve 21 is switched to the bypass pipe 22 side. As a result, excess oil from the return pipe 16 is passed through the solenoid valve 21 to the bypass pipe 22, and the operation of the fuel suction pump 17 is stopped.

Furthermore, if it is determined as "YES" in step 6, this indicates that the temperature of fuel A has exceeded 50°C and there is a risk that a large amount of vapor will be generated in the return pipe 16, so proceed to step 9. It is determined whether the elapsed time S of the soft timer that started counting in step 1 has passed the set time S ₀ (3 minutes), and if it is determined to be ``YES'', the process moves to step 7 and performs the control described above. Fuel suction pump 17
Activate. If the determination in step 9 is "NO", the process moves to step 8 and the above-described control is performed to stop the fuel suction pump 17.

The above control is repeated from the time the engine is started to the time the engine is stopped.

Thus, in this embodiment, there is no need to operate the fuel suction pump 17 and a state where abnormal noise is likely to occur in the fuel suction pump 17, that is,
When the liquid level of the fuel A in the fuel tank 1 is located above the square part 1A, when the fuel A in the sub-tank part 3 is almost empty, or when the temperature of the fuel A is high. When starting or restarting the engine in this state, each sensor 23,
24 and the engine switch 26, the solenoid valve control device 25 controls the solenoid valve 21 to activate or deactivate the fuel suction pump 17 as appropriate, thereby reliably preventing the fuel suction pump 17 from generating abnormal noise. You will be able to do this.

In addition, the operating time of the fuel suction pump 17 can be significantly shortened compared to conventional technology, and the load on the fuel pump 7 is increased by draining excess oil from the return pipe 16 via the bypass pipe 22. This can prevent power consumption from increasing, and the life of the fuel pump 7 can be improved.

Although the fuel temperature sensor 24 is provided in the middle of the supply pipe 10 in this embodiment, the fuel temperature sensor 24 is not limited thereto, and may be provided inside the fuel tank 1, the fuel pump 7, etc.

In addition, although the bypass piping 22 is connected to the outflow port 21C of the solenoid valve 21, the bypass piping 22 may be provided as necessary, and the outflow may be caused to flow directly into the fuel tank 1 from the outflow port 21C. .

Furthermore, the electromagnetic valve control device 25 may not have a software configuration using a microcomputer or the like, but may have a hardware configuration using a relay circuit or the like.

〔Effect of the invention〕

As detailed above, according to the present invention, a solenoid valve installed in the middle of the return pipe, a liquid level sensor provided in the sub-tank, and a fuel temperature sensor that detects the fuel temperature in the fuel tank, Equipped with a solenoid valve control device that controls a solenoid valve using signals from a liquid level sensor and a fuel temperature sensor, when the fuel suction pump does not need to be operated and when abnormal noise is likely to occur in the fuel suction pump, The solenoid valve control device controls the solenoid valves based on the signals from each sensor to stop the fuel suction pump.
It is possible to reliably prevent the occurrence of abnormal noise in the fuel suction pump, and since the load acting on the fuel pump is reduced, the life of the fuel pump can be extended.

[Brief explanation of the drawing]

1 to 4 show embodiments of the present invention,
Figure 1 is an overall configuration diagram of the fuel injection system, Figure 2 is a block diagram showing the circuit configuration of the solenoid valve, sensor, solenoid valve control device, etc. in Figure 1, and Figure 3 is a diagram of the storage area in the memory circuit. FIG. 4 is a flowchart showing the control processing operation of the electromagnetic valve control device, and FIG. 5 is an overall configuration diagram of a conventional fuel injection device. 1...Fuel tank, 2...Main tank section, 3
...Sub tank section, 7...Fuel pump, 10...
Supply piping, 12... Pressure regulator, 13...
Fuel injection valve, 16... Return piping, 17... Fuel suction pump, 21... Solenoid valve, 22... Bypass piping, 23... Liquid level sensor, 24... Fuel temperature sensor, 25... Solenoid valve control device .

Claims (1)

[Claims] 1. A fuel tank in which a main tank and a sub-tank are formed in a saddle shape with a bottom side interposed therebetween, a fuel pump provided on the main tank side of the fuel tank, and a fuel pump that injects the fuel discharged from the fuel pump. A supply pipe that supplies the valve, a pressure regulator that is interposed in the middle of the supply pipe to adjust internal fuel pressure, and a return pipe that returns excess oil from the pressure regulator to the main tank side of the fuel tank. In the fuel injection device, the fuel injection device includes a fuel suction pump that is provided at the tip side of the return piping and sucks the fuel in the sub-tank into the main tank side through the suction pipe by using the return flow of the surplus oil. a solenoid valve interposed in the middle of the sub-tank and having one switching position for communicating the inflow side with the fuel suction pump side and the other switching position for communicating the inflow side directly with the main tank; a liquid level sensor that detects the height of the liquid level in the sub-tank; a fuel temperature sensor that detects the temperature of the fuel stored in the fuel tank;
Based on the signals from the liquid level sensor and fuel temperature sensor,
When the liquid level in the sub-tank is between the upper limit setting position corresponding to the water-shaped portion and the lower limit setting position corresponding to the almost empty state, and the fuel temperature is below a predetermined temperature, the solenoid valve is set to one switching position. , a solenoid valve that sets the solenoid valve to the other switching position for a certain period of time after starting the engine when the fuel temperature is above a predetermined temperature even if the liquid level in the sub-tank is between an upper limit setting position and a lower limit setting position; A fuel injection device comprising: a control device;