JPH02163454A - fuel injector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] 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:

[Prior Art] In general, fuel tanks for automobiles are divided into a main tank and a sub-tank due to restrictions on the structure of the vehicle body 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 that accommodates fuel A. The fuel tank 1 is formed into a branch shape consisting of a main tank part 2 and a sub-tank part 3, and the opening part IA at the bottom 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,
A fuel filler port 5 and a fuel pump insertion port 6 are formed on the upper side of the fuel tank 1.

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 a suction lower B of the pump main body 7A, and a discharge lower D provided in the pump main body 7A and equipped with a check valve for maintaining residual pressure inside, It is supported by a lid 9 provided in the fuel pump insertion port 6 via a bracket 8.

lO is a supply pipe whose one end side is connected to the discharge lower D of the fuel pump 7, and a fuel filter 11 is interposed in the middle,
A pressure regulator 12 is connected to the other end of the supply pipe 10. 13゜13, . . . are fuel injection valves provided in a number corresponding to the number of cylinders of the engine (not shown);
The fuel injection valve 13.13. ... 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. The control pressure introduction pipe 15 introduces, as a control pressure, a difference in the magnitude of negative pressure generated in the intique manifold 14 by opening and closing of a throttle valve (not shown). Then, by introducing control pressure into the pressure regulator 12 via the introduction pipe 15, the fuel pressure (fuel pressure) supplied from the fuel pump 7 is returned to the fuel tank I via the return pipe 16, which will be described later. The return flow rate is controlled to control the fuel pressure supplied to each fuel injection valve 13 to a predetermined set pressure.

Reference numeral 16 denotes 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.

17 is for sucking the fuel A stored in the sub tank part 3 of the fuel tank 1 and causing it to flow into the main tank part 2 side.
The return pipe 16 is located on the main tank portion 2 side.
A fuel suction pump serving as an ejector is provided at the distal end of the fuel suction pump 17.The proximal end of the 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 connected to the sub-tank section. 3 located on the inner bottom. The fuel suction pump 17 is operated when the fuel A returned 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 to supply fuel A in the fuel tank 1 to the fuel injection valves 13, 13, . . . via the supply pipe 10. At this time, the pressure regulator 12 introduces the negative pressure from the intake manifold 14 as a control pressure, and controls the fuel pressure supplied from the fuel pump 7, thereby controlling the fuel supplied to the fuel injection valves 13, 13, . The pressure at A is controlled to a predetermined set pressure.

Thus, by the fuel pump 7, the fuel injector 13.13
．． A part of the fuel A supplied to the fuel injection valve 13
,13. ..., and the remaining surplus oil is returned from the pressure regulator 12 to the fuel tank 1 via the return pipe 16.

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 sucked through the suction pipe 18 by negative pressure, and is sequentially fed into the main tank section 2 side together with excess oil.

[The problem that the idea aims to solve]

By the way, when the fuel level in the fuel tank 1 is located above the mouth portion IA, 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 "sewage" occurs due to gas mixing with the liquid in the fuel suction pump 17. 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, at the time of a 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 the pump 17, it is always operating in each of the above states.
There is a problem in 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, the feature of the configuration adopted by the present invention is that the return piping is interposed in the middle of the return piping, and one switching position connects the inflow side to the fuel suction pump side, and the other switch position connects the inflow side to the main fuel suction pump side. a solenoid valve having the other switching position that communicates directly with the tank side; a liquid level sensor provided in the sub-tank to detect the height of the liquid level in the sub-tank; and a temperature of the fuel stored in the fuel tank. A fuel temperature sensor detects the temperature, and signals from the liquid level sensor and the fuel temperature sensor set the solenoid valve to one switching position when the sub tank is in a low liquid level state and the fuel temperature is below a predetermined temperature. The present invention further includes a solenoid valve control device which sets the solenoid valve to the other switching position for a certain period of time after engine startup when the fuel temperature is higher than a predetermined temperature even when the fuel level is low.

[Operation J] 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 connects the return pipe directly to the main tank side in the following conditions. , or connect it to the fuel suction pump side.

When the fuel level in the fuel tank is high and the fuel is not separated into the main tank and sub tank, there is no need to operate the fuel suction pump (the liquid level sensor detects this,
Based on the detection signal, the solenoid valve control device switches the solenoid valve to directly drain excess oil from the return piping into the main tank.

Also, when the fuel in the sub-tank 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.
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.

In addition, when the liquid level is low (the fuel is separated into the main tank and the sub-tank, but there is still fuel left in the sub-tank, and the temperature of the fuel is high at the time of starting or re-starting the engine, so-called hot re-start). At the start,
Vapor is generated in the return piping, which tends to cause abnormal noise in the fuel suction pump, so the liquid level sensor and fuel temperature sensor detect this, and the solenoid valve control device switches the solenoid valve based on these detection signals. Excess oil from the return piping is directly discharged to the main tank side for a certain period of time after the engine starts or after the engine starts.

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.

[Embodiment J] Hereinafter, an embodiment of the present invention will be described based on 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, reference numeral 21 indicates a solenoid valve located in the fuel tank 1 and provided in the middle of the return pipe 16, and the solenoid valve 21 is constituted by, for example, a 3-bottom, 2-position solenoid switching valve. . Here, the solenoid valve 21 is connected to its inflow boat 2.
LA is communicated with the return pipe 16, the outflow boat 21B at one switching position is communicated with the fuel suction pump 17 side, and the outflow boat 21G at the other switching position is extended to below the main tank section 2. 22. Then, by setting the solenoid valve 21 to one switching position by a solenoid valve control device 25 to be described later, the inflow boat 21A is communicated with one outflow boat 21B, and by setting the solenoid valve 21 to the other switching position, the inflow boat 21A is connected to the other outflow boat 21B. It is controlled to communicate with the boat 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, etc. The electromagnetic valve control device 2 extracts the displacement as the rotation angle (swing angle) of the arm 23B and generates a detection signal H representing the liquid level as the remaining amount of fuel on the sub-tank portion 3 side.
It is designed to output to 5.

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. Pressure regulator 1 through 10
The temperature of fuel A sent to the second side is detected.

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

The solenoid valve control device 25 is composed of a micro-combiner, etc., and includes an input/output control circuit, a processing circuit such as a CPU or MPU, and a storage circuit such as a ROM or RAM. There is. The memory circuit includes a storage area 27 shown in FIG. 3, a control program shown in FIG. 4, and a soft timer (not shown) for counting time.
etc. are stored. The memory area 27 of the memory circuit stores a memory for an upper limit setting position α set at the height of the mouth IA of the fuel tank l, which is the upper limit setting position for performing the liquid level position determination processing operation. Area 27. A storage area 27□ for the lower limit setting position β is set at a position higher than the bottom of the sub-tank section 3 by 18A on the tip side of the suction tube 18, which is the lower limit setting position for performing the liquid level position determination processing operation. and a storage area 27 for a set temperature to, which is set in advance 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 in step 1, the soft timer of the solenoid valve control device 25 starts counting time, and in 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. If rNOJ is determined in step 3, this indicates that the liquid level H in the fuel tank 1 has fallen below the mouth part IA and the fuel A has been separated into the main tank part 2 and the sub-tank part 3. Then, it is determined whether the value of the detection signal H is equal to or lower than the liquid level β. If the determination in step 4 is "NO", this indicates that the liquid level H of fuel A in the sub-tank IB is lower than α (more than β), and the process proceeds to step 5. Read the detection signal t.Then, proceed to step 6 and the value of the detection signal t will be the set temperature tO (50°C).
It is determined whether or not the above is true, 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.
Fuel A in the sub-tank section 3 is sucked into the main tank section 2 side via the suction pipe 18.

On the other hand, if rYESJ is determined in step 3, this indicates that the liquid level of fuel A in the fuel tank l is higher than the mouth portion IA and there is no need to operate the fuel suction pump 17, and step 8 Then, the solenoid valve 21 is switched to the bypass piping 22 side. As a result, return piping 1
Excess oil from 6 is passed through a solenoid valve 21 to a bypass pipe 22.
Then, the operation of the fuel suction pump 17 is stopped.

Further, when it is determined as rYESJ in step 4, it indicates that the remaining amount of fuel A in the sub-tank section 3 is low, and that when the fuel suction pump 17 is operated, air may be sucked in as well, causing abnormal noise. Therefore, the process moves to step 8 and the solenoid valve 21 is switched to the bypass piping 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, when rYESJ is determined in step 6, this indicates a state where the temperature of fuel A is 50°C or higher and there is a risk that a large amount of vapor will be generated in the return pipe 16.
Proceeding to step 9, the elapsed time S of the soft timer that started counting in step 1 is the set time S0 (3 minutes)
It is determined whether or not the period has elapsed, and when it is determined that rYESJ, the process moves to step 7 and the above-mentioned control is performed to operate the fuel suction pump 17. If it is determined in step 9 that it is rNOJ, 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, the fuel suction pump 17 does not need to be operated and the fuel suction pump 17 is in a state where abnormal noise is likely to occur, that is, the liquid level of the fuel A in the fuel tank 1 is lower than the opening part IA. When located above the
When the fuel A in the sub-tank 3 is almost empty, or when starting or starting the engine when the temperature of the fuel A is high, the signals from the sensors 23, 24 and the engine switch 26 Since the electromagnetic valve control device 25 controls the electromagnetic valve 21 to appropriately activate or deactivate the fuel suction pump 17, it is possible to reliably prevent the fuel suction pump 17 from generating abnormal noise.

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. Therefore, it is possible to prevent the power consumption from increasing (or increase), 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, bypass piping 2 is connected to the outflow boat 21C of the solenoid valve 21.
2, the bypass pipe 22 may be provided as necessary, and the bypass pipe 22 may be provided directly into the fuel tank 1 from the outflow bow 21C.

Furthermore, the electromagnetic valve control device 25 may not be configured as a software such as a microcomputer, but may be configured as a hardware such as a relay circuit.

[Effects of the Invention] As detailed above, according to the present invention, the solenoid valve installed in the middle of the return pipe, the liquid level sensor provided in the sub-tank, and the temperature of the fuel in the fuel tank are detected. and a solenoid valve control device that controls the solenoid valve based on signals from the liquid level sensor and the fuel temperature sensor. The solenoid valve control device controls the solenoid valves based on signals from each sensor to stop the fuel suction pump when the fuel suction pump is in a weak condition, thereby reliably preventing abnormal noise from occurring in the fuel suction pump. In addition, 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, FIG. 1 is an overall configuration diagram of a fuel injection device, and FIG. 2 is a circuit configuration of a solenoid valve, a sensor, a solenoid valve control device, etc. in FIG. 1. FIG. 3 is an explanatory diagram showing the configuration of the storage area in the storage circuit, FIG. 4 is a flowchart showing the control processing operation of the solenoid valve control device, and FIG. 5 is an overall diagram of the conventional fuel injection device. FIG.

Claims (1)

[Claims] A fuel tank consisting of a main tank and a sub-tank, a fuel pump provided on the main tank side of the fuel tank, a supply pipe that supplies fuel discharged from the fuel pump to the injection valve, and a fuel tank intervening in the middle of the supply pipe. A pressure regulator is installed to adjust the internal fuel pressure, a return pipe is provided to return excess oil from the pressure regulator to the main tank side of the fuel tank, and a return pipe is provided at the tip side of the return pipe to control the return flow of the excess oil. In the fuel injection device, the fuel injection device includes a fuel suction pump that sucks the fuel in the sub-tank into the main tank side using the fuel suction pump. a solenoid valve having a switching position and another switching position that connects the inflow side directly to the main tank;
A liquid level sensor provided in the sub-tank to detect the height of the liquid level in the sub-tank, a fuel temperature sensor to detect the temperature of the fuel stored in the fuel tank, and from the liquid level sensor and the fuel temperature sensor. When the fuel temperature in the sub-tank is low and the fuel temperature is below a predetermined temperature by the signal, the solenoid valve is set to one switching position, and even if the sub-tank is in a low liquid level state and the fuel temperature is above the predetermined temperature, the solenoid valve is set to one of the switching positions. A fuel injection device comprising: a solenoid valve control device that sets the solenoid valve to the other switching position for a certain period of time after starting the engine.