JP2000008997A - Variable displacement high pressure fuel pump and fuel supply control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable displacement high pressure fuel pump and a fuel supply control method, capable of reducing the driving power of a fuel pump, and of feeding fuel even in case where a flow controlling electromagnetic valve is inoperative, by controlling a flow rate of high pressure fuel supplied according to the fuel injection quantity of an injector. SOLUTION: A suction heck valve 111, a discharge check valve 112 and an electromagnetic valve 113 are provided in a plunger type fuel pump, and this electromagnetic valve 113 is opened or closed and thereby communicating and noncommunicating between a suction passage 103 and a pump case 100 or a discharge passage 104 and the pump case 100 are switched, whereby a fuel flow rate to the discharge passage 104 is controlled. In the case where on-off operations for the electromagnetic valve 113 are not performed, a constant flow rate of high pressure fuel is discharged to the discharge passage 104 by operations of both these suction and discharge check valves 111 and 112.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel pump for supplying fuel to an injector of an automobile engine, in particular, a cylinder injection engine at a high pressure, and more particularly to a flow rate of a high-pressure fuel supplied according to a fuel injection amount of the injector. The present invention relates to a variable flow high pressure fuel pump capable of reducing the driving power of the fuel pump by changing the pressure.

[0002]

2. Description of the Related Art Conventionally, as a high-pressure pump with a variable flow rate,
For example, one described in JP-A-1-73166 is known.

Japanese Patent Application Laid-Open No. 1-73166 discloses a cylinder, a fuel pressurizing member built in the cylinder and driven by an engine, and a fuel pressurizing member defined by the fuel pressurizing member for pressurizing fuel in the cylinder. And a solenoid valve facing the pump chamber and fixed to the cylinder.The solenoid valve includes a seat portion of a passage for communicating high-pressure fuel in the pump chamber to the low-pressure side. By closing the valve body of this solenoid valve during energization, high-pressure fuel in the pump chamber is pumped into the common rail where high-pressure fuel is stored, and the amount of fuel discharged to the common rail is controlled according to the energization period. The valve body of the solenoid valve penetrates the seat and protrudes into the pump chamber, and when the valve is closed,
The entire lower end surface of the valve body protruding toward the pump chamber receives the high-pressure fuel pressure in the pump chamber as a pressing force in the valve closing direction, so that the valve body closes the seat portion and retains the high-pressure fuel in the pump chamber. A variable displacement high pressure pump configured as an external opening valve is described.

[0004]

By changing the flow rate of the fuel pump and controlling the flow rate discharged from the fuel pump in accordance with the injection amount from the injector, the excess amount returned to a low pressure without being injected from the injector is obtained. It is possible to reduce the power of the engine consumed for increasing the pressure of the fuel, and to improve the fuel efficiency.

Particularly, in the case of a high-pressure fuel pump such as a cylinder injection engine which is used to boost fuel to a high pressure of several tens to hundreds of atmospheres or more, the driving torque of the pump required for the pressure increase is large. , The effect of reducing the pump driving power accompanying the reduction of the surplus flow rate is large.

In addition, high reliability is required for a fuel pump used for an automobile engine. When the engine stops, the auxiliary equipment driven by the engine, such as a hydraulic pump that supplies hydraulic pressure to the power steering and brakes, stops, so that the vehicle can be moved to a safe place and stopped as well as traveling. It becomes difficult. Therefore, it is necessary for safety that the function of supplying high-pressure fuel to the injector can be maintained even if the function of controlling the discharge flow rate is lost due to a failure or the like in the variable flow rate fuel pump.

However, in the above-mentioned prior art, it is difficult to maintain the function of the fuel pump for supplying high-pressure fuel when the operation of the flow control valve becomes impossible. In each of the solenoid valves described in JP-A-1-73166, a force in the valve opening direction is urged to the valve body by a spring or the like, and the valve body is closed by an electromagnetic force generated by energizing the electromagnetic coil. It has a structure to make a valve.

The most frequent problem with the solenoid valve having this structure is that the solenoid coil cannot be energized due to disconnection or poor contact of the connector. At this time, the valve body remains open due to the urging force. , The valve cannot be closed.

When the solenoid valve is kept open, the fuel is once sucked into the pump chamber by the plunger of the pump descending from the top dead center, and subsequently the pump is moved by the plunger rising from the bottom dead center. The fuel in the chamber flows backward through the opened electromagnetic valve, and the fuel in the pump chamber is not pressurized and is not discharged from the discharge port.

That is, in the prior art, when the solenoid valve provided for variable flow rate cannot be energized, not only the flow rate cannot be controlled but also the function of discharging fuel is lost. There was a case that had to be stopped until.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and the driving power of a fuel pump is controlled by controlling the flow rate of high-pressure fuel supplied according to the fuel injection amount of an injector. It is an object of the present invention to provide a variable flow high-pressure fuel pump and a fuel supply control method that can reduce the amount of fuel and can supply fuel even when the flow control solenoid valve cannot operate.

[0012]

In order to achieve the above object, a variable flow high pressure fuel pump according to the present invention is characterized in that a suction flow is controlled by opening and closing a solenoid valve provided in a suction passage or a discharge passage. When switching the communication and non-communication between the passage and the pump chamber or between the discharge passage and the pump chamber to control the fuel flow rate and supply it to the injector, while the solenoid valve is not energized and does not open and close In the suction check valve provided in the suction flow path, the fuel corresponding to the reciprocating movement of the plunger is sucked from the suction flow path into the pump chamber, and the discharge check valve provided in the discharge flow path,
The object of the present invention is to discharge fuel from a pump chamber to a discharge channel and supply the fuel to an injector according to reciprocation of a plunger.

Specifically, the present invention provides the following apparatus and method.

The present invention has a suction flow path for sucking fuel into a pump chamber, and a discharge flow path for discharging the fuel from the pump chamber, and uses a plunger reciprocating in the pump chamber to suction and discharge fuel. And a variable flow high-pressure fuel pump for supplying to the injector, wherein the suction flow path is provided with a suction check valve and the discharge flow path is provided with a discharge check valve, and the fuel flow rate is provided in the suction flow path or the discharge flow path. An electromagnetic valve that performs control of the electromagnetic valve, the electromagnetic valve opens and closes the electromagnetic valve to switch between communication and non-communication between the suction passage and the pump chamber or the discharge passage and the pump chamber, When the fuel flow is controlled and the solenoid valve is not energized and does not open or close, the suction check valve operates at a constant flow rate corresponding to the reciprocating motion of the plunger. And the discharge check valve discharges a constant flow rate of fuel from the pump chamber to the discharge passage according to the reciprocation of the plunger. A variable flow high pressure fuel pump is provided.

[0015] Preferably, the solenoid valve is provided in the suction flow passage, and returns fuel from the pump chamber to the suction flow passage by switching between communication and non-communication between the suction flow passage and the pump chamber. Alternatively, the operation of stopping the intake of fuel from the intake passage into the pump chamber is performed to control the fuel flow rate.

Preferably, the solenoid valve is provided in a discharge flow path, and performs an operation of returning fuel from the discharge flow path to the pump chamber by switching between communication and non-communication between the discharge flow path and the pump chamber. To control the fuel flow.

Preferably, the solenoid valve has a normally open structure in which the solenoid valve is opened when non-energized and closed when energized, and the suction check is provided between the suction passage and the pump chamber. It is arranged in series with the valve.

Preferably, the solenoid valve has a normally closed structure in which the valve is closed when not energized and is opened when energized, and the suction check is provided between the suction passage and the pump chamber. It is arranged in parallel with the valve.

Preferably, the solenoid valve has a normally closed structure in which the solenoid valve is closed when not energized and is opened when energized, and the discharge check is provided between the pump chamber and the discharge passage. It is arranged in parallel with the valve.

Preferably, the solenoid valve is provided in the suction passage.
The discharge flow path includes the discharge check valve,
The solenoid valve is configured such that, when the power is not supplied, a valve body is opened by a negative pressure in the pump chamber with respect to the suction flow passage generated when the plunger descends from top dead center, By opening the body, a constant flow rate of fuel according to the reciprocating motion of the plunger is sucked into the pump chamber from the suction flow path, and the discharge check valve is configured to discharge the constant flow rate of fuel according to the reciprocating motion of the plunger. Discharge from the pump chamber to the discharge flow path.

Preferably, the suction flow path includes the suction check valve, and the discharge flow path includes the solenoid valve.
The suction check valve draws a constant flow rate of fuel from the suction flow path into the pump chamber according to the reciprocating motion of the plunger. The valve body is configured to be opened by a positive pressure in the pump chamber with respect to the discharge flow path generated when the valve body rises from a predetermined flow rate. Discharge from the pump chamber to the discharge flow path.

The present invention also relates to a fuel supply control method for discharging fuel sucked from a suction flow path to a discharge flow path by a plunger reciprocating in a fuel pump chamber and supplying the fuel to an injector. When the solenoid valve provided in the passage is energized and the solenoid valve performs an opening / closing operation, the solenoid valve communicates the suction passage with the fuel pump chamber or the discharge passage with the fuel pump chamber. And the non-communication is switched, the flow rate of the fuel is controlled and supplied to the injector, while, when the solenoid valve is not energized and does not perform the opening and closing operation, the fuel valve is provided in the suction passage. A suction check valve sucks a constant flow rate of fuel from the suction passage into the fuel pump chamber in accordance with the reciprocation of the plunger, and discharges the fuel from the discharge passage provided in the discharge passage. The click valve provides a fuel supply control method comprising supplying a fuel of a constant flow rate corresponding to reciprocation of the plunger in the injector discharge to the discharge flow path from the fuel pump chamber.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A variable flow high pressure fuel pump and a fuel supply control method according to an embodiment of the present invention will be described below with reference to the drawings.

[First Embodiment] FIG. 1 is a configuration diagram of a fuel supply system of an automobile engine equipped with a variable flow high-pressure fuel pump according to a first embodiment of the present invention.

The fuel supply system shown in FIG.
A feed pump 2 for transferring the fuel, a low-pressure pressure regulator 3 for adjusting a discharge pressure of the feed pump 2,
Fuel pump 10 capable of controlling the flow rate of fuel discharged while further pressurizing the fuel discharged from feed pump 2
0, a controller 4 for controlling the fuel pump 100,
An injector 5 for injecting fuel discharged from the fuel pump 100 into the engine, a pressure sensor 6 for measuring a fuel pressure applied to the injector 5, and a fuel pressure lower when the fuel pressure applied to the injector 5 exceeds a predetermined pressure. And a relief valve 8 for releasing.

Here, the feed pump 2 and the low-pressure pressure regulator 3 are provided mainly for preventing cavitation when the fuel pump 100 sucks fuel, and may not be mounted depending on the conditions under which the fuel pump 100 operates. It is possible.

The fuel pump 100 has a suction passage 103 for sucking fuel into the pump chamber 102 and a discharge passage 104 for discharging fuel from the pump chamber 102. The plunger 106 is reciprocated by the plunger 106.

The suction passage 103 and the discharge passage 10
4 is provided with a suction check valve 111 and a discharge check valve 112, respectively. An electromagnetic valve 113 is provided in the suction passage 103, and the opening and closing operation of the electromagnetic valve 113 can be controlled by an electromagnetic valve drive signal input from the controller 4 to the electromagnetic valve 113.

In many cases, it is necessary to adjust the fuel pressure applied to the injector 5 according to the operating condition of the engine. In FIG. 1, the host controller determines the operating state of the engine based on values from various sensors such as the throttle opening and the engine speed.

Then, the host controller determines an appropriate fuel pressure and an injection amount of the injector 5 according to the operation state of the engine, and instructs the controller 4 and the injector drive circuit of the required pressure and the required injection amount. Output a signal.

The controller 4 controls the discharge flow rate of the fuel pump 100 by feeding back a signal from the pressure sensor 6 so that the fuel pressure applied to the injector 5 becomes the required pressure from the host controller. At this time, the controller 4 refers to the rotation angle of the cam 105 of the fuel pump 100 output from the rotation angle sensor 7 and
13 is controlled to be energized and de-energized.

When the discharge flow rate of the fuel pump 100 is controlled to adjust a value other than the fuel pressure, another sensor is provided instead of or in addition to the pressure sensor 6.

As the rotation angle sensor 7, a crank angle sensor provided in the engine can be used. Alternatively, the signal from the rotation angle sensor 7 is
The solenoid valve 113 is used only to detect a reference position (for example, the top dead center or the bottom dead center of the plunger 106) of the rotation angle of 05.
The timing of energization / de-energization to the motor can be controlled not by the rotation angle but by the time using a timer or the like in the controller 4.

In FIG. 1, the host controller, the injector drive circuit, and the controller 4 are depicted as separate blocks. However, actually, it is possible to install them in one controller, and it is also possible to perform the above-mentioned control with one arithmetic circuit.

The first embodiment is an example in which the variable flow high-pressure fuel pump of the present invention is applied to a direct injection gasoline engine. In a cylinder injection gasoline engine, it is required to inject fuel into a high-pressure atmosphere of a cylinder during a compression stroke or to inject a predetermined fuel into a cylinder in a limited short injection period. The discharge pressure of the pump needs to be much higher than the conventional port injection engine, from several tens of atmospheres to more than one hundred atmospheres.

Here, if the high-pressure fuel pump is made to have a variable flow rate and the flow rate discharged from the high-pressure fuel pump is controlled in accordance with the injection amount from the injector, surplus fuel that is not injected from the injector and returned to low pressure can be obtained. The power of the engine consumed for increasing the pressure can be reduced, and the fuel efficiency can be improved.

In particular, in the case of a high-pressure fuel pump such as a direct injection gasoline engine that boosts the fuel to a high pressure, since the driving torque of the pump required for the boosting is large, it is necessary to control the flow rate to reduce the excess flow rate. The effect of reducing the pump driving power, i.e., the effect of improving fuel efficiency, is great.

On the other hand, a fuel pump used for an automobile engine is required to have high reliability. When the fuel supply from the fuel pump stops and the engine stops, the hydraulic pumps for power steering and brakes, as well as the auxiliary equipment driven by the engine, stop. It is also difficult to move the vehicle to a stop.

Therefore, it is necessary for safety that the function of supplying high-pressure fuel to the injector can be maintained even if the function of controlling the discharge flow rate is lost in the variable flow high-pressure fuel pump.

In FIG. 1, the solenoid valve 113 is connected to the suction passage 103 and the pump chamber 1 so as to be in series with the suction check valve 111.
02, and the structure of the solenoid valve 113 has a so-called normally open structure in which the valve is opened when no power is supplied and closed when power is supplied.

Therefore, when the solenoid valve 113 stops operating due to the failure of energization due to disconnection or the like, the solenoid valve 113 of the variable flow high pressure fuel pump of this embodiment remains open. At this time, the fuel discharge amount cannot be controlled.

However, since the solenoid valve 113 is open,
Without blocking the suction passage 103, during the suction stroke,
Fuel can be sucked into the pump chamber 102 from the suction channel 103 through the suction check valve 111. In the discharge stroke, fuel can be supplied from the pump chamber 102 to the injector 5 through the discharge check valve 112.

In other words, the variable flow high pressure fuel pump of the first embodiment can be used as a fixed flow high pressure fuel pump even when the solenoid valve 113 does not operate and the function of controlling the discharge flow is lost. The function of supplying high-pressure fuel to the injector 5 can be maintained.

When operating as a fixed-capacity high-pressure fuel pump, if the amount of fuel injected from the injector 5 is small, the pump continues to discharge fuel, and the pressure of fuel supplied to the injector 5 continues to rise. May be damaged.

In the first embodiment, the relief valve 8 shown in FIG.
Is provided, and when the fuel pressure applied to the injector 5 exceeds a predetermined pressure (relief pressure), the fuel is released to a low pressure. That is, even when the solenoid valve 113 does not operate and functions as a high-pressure fuel pump with a fixed capacity, high-pressure fuel at the relief pressure set by the relief valve 8 can be supplied to the injector 5.

Next, the flow control operation of the variable flow high pressure fuel pump shown in FIG. 1 will be described with reference to FIG. In the first embodiment, in order to reduce the discharge flow rate of the fuel pump 100, the plunger 106 is moved during a partial period (a period of FIG. 2B) of a suction stroke in which the plunger 106 descends from a top dead center to a bottom dead center. Solenoid valve 11
3 is closed. Hereinafter, operations in the suction stroke and the discharge stroke will be sequentially described.

The period (a) in FIG. 2 is in the suction stroke. The solenoid valve 113 is opened, the suction check valve 111 is opened as the plunger 106 is lowered, and the fuel flows into the suction passage 103.
From the pump chamber 102. Since the solenoid valve 113 is a normally open type, in the period (a), there is no solenoid valve drive signal from the controller 4 and the solenoid valve 113 is in a non-energized state.

Although the period (b) in FIG. 2 is still in the suction stroke, the solenoid valve 113 is energized and closed by the solenoid valve drive signal from the controller 4. Therefore,
Even if the plunger 106 moves down, fuel is not sucked into the pump chamber 102. At this time, when the negative pressure in the pump chamber 102 caused by the lowering of the plunger 106 becomes equal to or lower than the saturated vapor pressure of the fuel, fuel bubbles are generated in the pump chamber 102.

The period (c) in FIG. 2 is in the discharge stroke. At this time, the solenoid valve 113 is energized by the solenoid valve drive signal from the controller 4 and is closed. Plunger 1
06 is a stroke which rises from the bottom dead center, but the plunger 106
Is acted upon by a lifting force.

That is, the work spent by the plunger 106 for generating the negative pressure in the pump chamber 102 in the period (b) is recovered as the work for moving the plunger 106 in the period (c). When the plunger 106 rises, bubbles generated in the pump chamber 102 during the period (b) are crushed, and the pressure in the pump chamber 102 rises.

In the period (d) of FIG. 2, the discharge stroke is continued after the period (c), but the pressure in the pump chamber 102 increases until the discharge check valve 112 is opened, and the fuel is discharged from the pump chamber 102 through the discharge check valve. Discharged through 112.

As described above, in the variable flow high pressure fuel pump according to the first embodiment, the discharge amount of fuel can be reduced by closing the solenoid valve 113 during a part of the suction stroke. is there. Further, the amount of decrease in the fuel discharge amount can be controlled by the length of the valve closing period.

Further, in the first embodiment, since the fuel does not flow while the solenoid valve 113 is closed for controlling the discharge amount, no loss occurs due to the fluid resistance.

FIG. 2 shows a case where the solenoid valve 113 is opened during the first half of the suction stroke, and the solenoid valve 113 is closed during the second half of the suction stroke. In the variable flow high-pressure fuel pump according to the first embodiment, the discharge amount can be controlled by closing the solenoid valve 113 during an arbitrary period of the suction stroke.

FIG. 3 shows an example of the structure of the variable flow high pressure fuel pump shown in FIG. The fuel pump 100 includes a pump chamber 10
A suction passage 103 for sucking fuel into the pump chamber 102;
Pump chamber 1 having a discharge flow path 104 for discharging fuel from the pump chamber 1
In 02, a plunger 106 reciprocated by a rotating cam 105 is provided.

A cam follower 107 is disposed between the cam 105 and the plunger 106, and converts the rotational motion of the cam 105 into reciprocating motion and transmits the reciprocating motion to the plunger 106. Since a sliding portion is interposed between the contact surface between the cam 105 and the cam follower 107, the cam follower 107 is made of a material having durability against sliding. May be supplied.

Cam follower 107 and pump body 108
And a spring 109 is inserted between them.
Is set so that a force pressing the cam 105 is applied to the cam follower 107 so that the cam follower 107 follows the movement of the cam 105 without separating.

The plunger 106 and the pump body 1
08, a spring 110 is inserted.
0 applies a force pressing the cam follower 107 to the plunger 106 so that the plunger 106
It is set so as to follow the movement of 07 without leaving.

The plunger 106 and the cam follower 1
07 may have an integral structure, in which case either one of the spring 109 and the spring 110 may not be used. The suction check valve 1 is provided in the suction passage 103.
The discharge flow path 104 is provided with a discharge check valve 112.

An electromagnetic valve 113 is provided in the suction passage 103, and the opening and closing operation of the electromagnetic valve 113 can be controlled by an electromagnetic valve drive signal input from the outside to the electromagnetic valve 113.
The electromagnetic valve 113 includes an electromagnetic valve body 114, an electromagnetic coil 11
5, an electromagnetic core 116, a valve body 117, and a spring 118 as an example of an elastic member.

FIG. 3 shows the non-energized state of the solenoid valve 113. The valve element 117 is opened apart from the seat portion 119 by the spring force of the spring 118. Electromagnetic coil 115
When power is supplied to the valve element 117, the electromagnetic force overcomes the spring force and
Is attracted to the electromagnetic core 116, and the valve body 117 is
The solenoid valve 113 is closed in close contact with 19.

That is, the solenoid valve 113 shown in FIG.
It has a normally open structure.

The solenoid valve 113 communicates with the suction passage 103 and the pump chamber 102 so that the port 120 communicates with the suction check valve 111 and the port 121 communicates with the pump chamber 102 so that the port 121 communicates with the suction check valve 111 in series. It is arranged in between. Therefore, the fuel pump 100 shown in FIG. 3 uses the solenoid valve 1 to control the discharge flow rate described above with reference to FIGS.
13 is possible.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a configuration diagram of a fuel supply system of an automobile engine equipped with a variable flow high-pressure fuel pump according to a second embodiment of the present invention.

The fuel supply system shown in FIG.
The configuration is the same as that shown in FIG. 1 except for the configuration of the solenoid valve, suction check valve, and discharge check valve of No. 0.

In the fuel pump 200 shown in FIG. 4, the solenoid valve 213 is disposed between the suction passage 103 and the pump chamber 102 so as to be in parallel with the suction check valve 111. Further, the structure of the solenoid valve 213 has a so-called normally closed structure in which the valve is closed when not energized and is opened when energized.

Therefore, when the solenoid valve 213 does not operate due to the failure of energization due to disconnection or the like, the solenoid valve 213 of the variable flow high pressure fuel pump of this embodiment cannot be opened. At this time, the fuel discharge amount cannot be controlled.

However, since the suction check valve 111 is provided in parallel with the solenoid valve 213, the suction passage 103 is not blocked. In the suction stroke, the suction check valve 1
The fuel from the suction passage 103 through the pump chamber 102
Can be inhaled.

In the discharge stroke, fuel can be supplied from the pump chamber 102 to the injector 5 through the discharge check valve 112.

That is, in the variable flow high pressure fuel pump according to the second embodiment, as in the first embodiment, the solenoid valve 213 does not operate and the function of controlling the discharge flow is lost. In some cases, as a fixed flow high pressure fuel pump,
High-pressure fuel having a relief pressure set by the relief valve 8 can be supplied to the injector 5.

Next, the flow control operation of the variable flow high pressure fuel pump shown in FIG. 4 will be described with reference to FIG. In the second embodiment, in order to reduce the discharge flow rate of the fuel pump 100, the plunger 106 is moved from a bottom dead center to a top dead center during a partial period (a period of FIG. 5B) of a discharge stroke. Solenoid valve 21
3 is opened. Hereinafter, operations in the suction stroke and the discharge stroke will be sequentially described.

The period (a) in FIG. 5 is the suction stroke. At this time, regardless of whether the solenoid valve 213 is closed or open, fuel is sucked into the pump chamber 102 from the suction passage 103 as the plunger 106 descends.

That is, when the solenoid valve 213 is in the closed state, the suction check valve 111 is opened as the plunger 106 is lowered, and fuel flows from the suction passage 103 to the pump chamber 10.
Inhaled into 2. When the solenoid valve 213 is open, fuel is sucked from the suction passage 103 into the pump chamber 102 through the solenoid valve 213.

Therefore, in the second embodiment, when it is desired to reduce the power consumption of the solenoid valve 213, the period
In (a), the energization of the solenoid valve 213 can be stopped.

When it is desired to reduce the fluid resistance when the fuel is sucked into the pump chamber 102, the solenoid valve 213 is energized during the period (a), and the fuel is sucked through the opened solenoid valve 213. Thus, the fluid resistance (pressure loss) at the suction check valve 111 can be reduced.

When the pressure loss at the suction check valve 111 is reduced, the suction work of the fuel pump 200 can be reduced, and cavitation of fuel suction can be easily prevented.

Since the solenoid valve 213 is a normally closed type, when the solenoid valve 213 is opened during the period (a), a solenoid valve drive signal is output from the controller 4 to make the solenoid valve 213 conductive. .

The period (b) in FIG. 5 is a discharge stroke, and the solenoid valve 213 is driven by a solenoid valve driving signal from the controller 4.
Is energized and is open. At this time, even if the plunger 106 rises, the fuel is still supplied from the pump chamber 102 to the solenoid valve 2.
The pressure in the pump chamber 102 does not rise, only being returned to the suction channel 103 through 13. Therefore, the discharge check valve 112 does not open, and no fuel is discharged toward the injector during the period (b).

The period (c) in FIG. 2 is still in the discharge stroke. At this time, the solenoid valve drive signal from the controller 4 to the solenoid valve 213 is cut off, and the solenoid valve 213 is de-energized and closed. When the plunger 106 rises, the pressure in the pump chamber 102 increases until the discharge check valve 112 is opened, and fuel is discharged from the pump chamber 102 to the discharge check valve 112.
Is discharged through.

As described above, in the variable flow high pressure fuel pump according to the second embodiment, the fuel discharge amount can be reduced by opening the solenoid valve 213 during a part of the discharge stroke. is there. Further, the amount of decrease in the fuel discharge amount can be controlled by the length of the valve opening period.

In FIG. 5, the solenoid valve 213 is opened in the first half of the discharge stroke, and the solenoid valve 213 is opened in the second half of the discharge stroke.
Is shown, the variable flow high-pressure fuel pump of the second embodiment controls the discharge amount by opening the solenoid valve 213 during an arbitrary period of the discharge stroke. Is possible.

FIG. 6 shows an example of the structure of the variable flow high pressure fuel pump shown in FIG. The fuel pump 200 is different from the example of the structure of the variable flow high-pressure fuel pump of the first embodiment shown in FIG. Therefore, the description of the same structural parts as in FIG. 3 will be omitted below.

The fuel pump 200 controls the suction passage 103 so that the solenoid valve 213 is in parallel with the suction check valve 111.
And the pump chamber 102. Solenoid valve 213
Are a solenoid valve body 214, an electromagnetic coil 215, an electromagnetic iron core 216, a valve body 217, and a spring 218 as an example of an elastic member.
Consists of

FIG. 6 shows the non-energized state of the solenoid valve 213, and the valve body 217 is closed by the spring force of the spring 218. When the electromagnetic coil 215 is energized, the electromagnetic force overcomes the spring force, the valve element 217 is attracted to the electromagnetic core 216, and the electromagnetic valve 213 opens. That is, the solenoid valve 213 shown in FIG. 6 has a normally closed structure.

The solenoid valve 213 has a port 220 communicating with the inlet of the suction check valve 111, and a port 221 communicating with the outlet of the suction check valve 111 in the pump chamber 102, and is in parallel with the suction check valve 111. Is arranged between the suction passage 103 and the pump chamber 102 as described above. Therefore,
In the fuel pump 200 of FIG. 6, the control of the discharge flow rate described above with reference to FIGS. 4 and 5 can be performed by controlling the opening and closing of the solenoid valve 213.

FIG. 7 shows another example of the structure of the variable flow high pressure fuel pump according to the second embodiment. Fuel pump 20
0 is different from the example of the structure of the variable flow rate high pressure fuel pump shown in FIG. 6 in the communication between the ports 220 and 221 of the solenoid valve 213, the inflow passage 103, and the pump chamber 102.

In the fuel pump 200 shown in FIG.
3, the port 221 communicates with the inlet of the suction check valve 111, and the port 220 communicates with the outlet of the suction check valve 111 in the pump chamber 102.
1 and the suction channel 103 and the pump chamber 102
It is arranged between.

Therefore, the fuel pump 200 shown in FIG.
As described above, the control of the discharge flow rate described above with reference to FIGS. 4 and 5 can be performed by controlling the opening and closing of the solenoid valve 213.

The difference between the fuel pump shown in FIG. 7 and the fuel pump shown in FIG. 6 is that the direction of the fuel pressure acting on the valve element 217 of the solenoid valve 213 in the compression stroke and the suction stroke is reversed. That is, in FIG. 7, in the compression stroke, the solenoid valve 213
When the valve is closed, the pressure in the pump chamber 102 becomes high,
3 has a low pressure, the fuel pressure causes the valve 217
Has the advantage that a force in the closing direction (downward in FIG. 7) acts to secure the fuel seal.

When the solenoid valve 213 is opened during the suction stroke, the inside of the pump chamber 102 has a negative pressure as compared with the suction passage 103, so that the fuel pressure causes the valve 217 to open (FIG. 7). Then, there is an advantage that the force of (upward) acts to easily open the valve body 217.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a configuration diagram of a fuel supply system of an automobile engine provided with a variable flow high-pressure fuel pump according to a third embodiment of the present invention.

The fuel supply system shown in FIG.
The configuration is the same as that shown in FIG.

In the fuel pump 300 shown in FIG. 8, the solenoid valve 313 is arranged in the suction passage 103. Solenoid valve 31
The structure of No. 3 has a so-called normally closed structure in which the valve is in a closed state when de-energized and is opened when energized.

The spring force of the solenoid valve 313 is set so that the solenoid valve 313 is opened by a negative pressure in the pump chamber 102 generated during the suction stroke when the power is not supplied.

Therefore, when the solenoid valve 313 is de-energized due to disconnection or the like and cannot be energized, the discharge amount of the fuel cannot be controlled. It functions to transfer fuel from the suction passage 103 through the solenoid valve 313 to the pump chamber 10.
2 can be inhaled. In the discharge stroke, the pump 5 is discharged from the pump chamber 102 through the discharge check valve 112.
Can be supplied with fuel.

That is, similarly to the first and second embodiments, the variable flow high-pressure fuel pump of the third embodiment is also fixed even if the function of controlling the discharge flow is lost. As a high-pressure fuel pump with a flow rate, high-pressure fuel at a relief pressure set by the relief valve 8 can be supplied to the injector 5.

Next, the flow rate control operation of the variable flow rate high pressure fuel pump shown in FIG. 8 will be described with reference to FIG. In the third embodiment, similarly to the second embodiment, in order to reduce the discharge flow rate of the fuel pump 300, the plunger 10
6 opens the solenoid valve 313 during a partial period (period in FIG. 9B) of the discharge stroke in which the ascending stroke rises from the bottom dead center to the top dead center.

The period (a) in FIG. 9 is the suction stroke. At this time, the solenoid valve 313 is energized by the solenoid valve drive signal from the controller 4 and opens, and fuel is sucked from the suction passage 103 into the pump chamber 102 through the solenoid valve 313.

The period (b) in FIG. 9 is the discharge stroke, and the solenoid valve 313 is driven by the solenoid valve driving signal from the controller 4.
Is energized and is open. At this time, even if the plunger 106 rises, the fuel is supplied from the pump chamber 102 to the solenoid valve 3.
The pressure in the pump chamber 102 does not rise, only being returned to the suction channel 103 through 13. Therefore, the discharge check valve 112 does not open, and no fuel is discharged toward the injector during the period (b).

The period (c) in FIG. 9 is still in the discharge stroke. At this time, the solenoid valve drive signal from the controller 4 to the solenoid valve 313 is cut off, and the solenoid valve 313 is de-energized and closed. When the plunger 106 rises, the pressure in the pump chamber 102 increases until the discharge check valve 112 is opened, and fuel is discharged from the pump chamber 102 to the discharge check valve 112.
Is discharged through.

As described above, in the variable flow high pressure fuel pump according to the third embodiment, the solenoid valve 313 is opened during a part of the discharge stroke, as in the second embodiment. It is possible to reduce the amount of fuel discharged. Further, it is also possible to control the amount of decrease in the fuel discharge amount depending on the length of the valve opening period in an arbitrary period of the discharge stroke.
This is the same as the embodiment.

FIG. 10 shows an example of the structure of the variable flow high pressure fuel pump shown in FIG. The fuel pump 300 is different from the example of the structure of the variable flow rate high pressure fuel pump of the second embodiment shown in FIG. 6 in that the suction check valve 111 is not provided and the structure and arrangement of the electromagnetic valve 313 are different. In the following, FIG.
The description of the same structural parts as those described above is omitted.

The fuel pump 300 has an electromagnetic valve 313 disposed between the suction passage 103 and the pump chamber 102. The electromagnetic valve 313 includes an electromagnetic valve body 314, the electromagnetic coil 31
5, an electromagnetic core 316, a valve body 317, and a spring 318 which is an example of an elastic member.

FIG. 10 shows a state in which the solenoid valve 313 is not energized, and the valve element 317 uses the spring force of the spring 318 (FIG. 10).
The valve is closed by the action of middle and upward. Electromagnetic coil 3
When power is supplied to the solenoid valve 15, the electromagnetic force (acting downward in FIG. 10) overcomes the spring force, and the valve element 317 is attracted to the electromagnetic iron core 316, and the electromagnetic valve 313 closes. That is, the solenoid valve 313 shown in FIG. 10 has a normally closed structure.

The solenoid valve 313 has a port 320 communicating with the suction passage 103 and a port 321 connected to the pump chamber 102.
It is arranged between the suction channel 103 and the pump chamber 102 so as to communicate with each other. Therefore, in the fuel pump 300 of FIG. 6, the control of the discharge flow rate described above with reference to FIGS. 8 and 9 can be performed by controlling the opening and closing of the solenoid valve 313.

The spring 318 of the solenoid valve 313 acts on the valve body 317 due to the imbalance between the pressure of the port 320 and the negative pressure in the pump chamber 102 generated during the suction stroke (in the figure,
The spring force is set so as to open the valve by acting downward.

When the solenoid valve 313 is de-energized, during the suction stroke, the de-energized solenoid valve 313 plays the same role as the suction check valve, and transfers fuel from the suction passage 103 to the pump chamber 102 through the solenoid valve 313. Can be inhaled.

In the discharge stroke, the valve body 317 moves upward due to a rise in pressure in the pump chamber 102 and closes, and the discharge check valve 112 opens to discharge fuel toward the injector.

The same operation as that of the structure shown in FIG. 10 can also be realized by removing the suction check valve 111 from the fuel pump having the structure shown in FIG.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a configuration diagram of a fuel supply system of an automobile engine including a variable flow high pressure fuel pump according to a fourth embodiment of the present invention.

The fuel supply system shown in FIG.
The configuration is the same as that of the first to third embodiments except for the configuration of the solenoid valve, suction check valve, and discharge check valve of No. 00.

In the fuel pump 400 shown in FIG. 11, the solenoid valve 413 is disposed between the pump chamber 102 and the discharge passage 104 so as to be in parallel with the discharge check valve 112. Further, the structure of the solenoid valve 413 has a so-called normally-closed structure in which the valve is closed when non-energized and opened when energized.

When the solenoid valve 413 is de-energized,
Since the discharge check valve 112 is provided in parallel with the electromagnetic valve 413, the discharge flow path 104 is not blocked.

In the suction stroke, fuel can be sucked into the pump chamber 102 from the suction passage 103 through the suction check valve 111. In the discharge stroke, the discharge check valve 112
The fuel can be supplied from the pump chamber 102 to the injector 5 through the pump chamber 102.

That is, in the variable flow high-pressure fuel pump of the fourth embodiment, similarly to the first to third embodiments, the solenoid valve 413 cannot be energized and the discharge flow is controlled. Even when the function is lost, high-pressure fuel at a relief pressure set by the relief valve 8 can be supplied to the injector 5 as a high-pressure fuel pump with a fixed flow rate.

Next, the flow control operation of the variable flow high pressure fuel pump shown in FIG. 11 will be described with reference to FIG. In the fourth embodiment, in order to reduce the discharge flow rate of the fuel pump 400, the plunger 106 is moved from a top dead center to a bottom dead center during a partial period (a period of FIG. 12A) of a suction stroke. The solenoid valve 413 is opened. Hereinafter, operations in the suction stroke and the discharge stroke will be sequentially described.

The period (a) in FIG. 12 is in the suction stroke. At this time, the solenoid valve 413 is opened by the solenoid valve drive signal from the controller 4. Then, the plunger 106
The fuel is sucked into the pump chamber 102 from the discharge flow path 104 through the electromagnetic valve 413 as the pressure decreases.

[0118] The fuel which has been discharged at a high pressure in a discharge stroke described later is returned to the pump chamber 102 again, and a force for lowering the plunger 106 acts on the plunger 106 by the high-pressure fuel.

That is, in the fourth embodiment, by the operation of returning the high-pressure fuel, a part of the power consumed for increasing the fuel pressure in the discharge stroke is recovered.

In the period (b) in FIG. 12, the suction stroke is continued, but the solenoid valve drive signal from the controller 4 is cut off to close the solenoid valve 413. At this time, the plunger 106
Due to the negative pressure in the pump chamber 102 caused by the
This time, the suction check valve 111 is opened, and the suction flow path 10
From 3, fuel is sucked into the pump chamber 102.

Since the fuel once discharged is returned in the above-mentioned period (a), the amount of suction in the period (b) is changed to the next discharge stroke (period).
The amount of fuel actually discharged together with (c)).

The period (c) in FIG. 12 is a discharge stroke. At this time, regardless of whether the solenoid valve 413 is in the valve closed state or the valve open state, fuel is discharged from the discharge passage 104 toward the injector 5 as the plunger 106 rises. That is, when the solenoid valve 413 is in the closed state, the pressure in the pump chamber 102 increases with the rise of the plunger 106, the discharge check valve 112 opens, and fuel is discharged from the discharge passage 104. When the solenoid valve 413 is in the open state, fuel is discharged from the discharge passage 104 through the solenoid valve 413.

Therefore, in the fourth embodiment, when it is desired to reduce the power consumption of the solenoid valve 413, the period
In (a), the energization of the solenoid valve 413 can be stopped.

When it is desired to reduce the fluid resistance when the fuel is discharged from the pump chamber 102, the solenoid valve 413 is energized during the period (a) and the fuel is discharged through the opened solenoid valve 413. Thus, the fluid resistance (pressure loss) at the discharge check valve 112 can be reduced.

As described above, in the variable flow high-pressure fuel pump according to the fourth embodiment, the discharge amount of fuel can be reduced by opening the solenoid valve 413 during a part of the suction stroke. is there. Further, the amount of decrease in the fuel discharge amount can be controlled by the length of the valve opening period.

FIG. 13 shows an example of the structure of the variable flow high pressure fuel pump shown in FIG. The structure and arrangement of the solenoid valve 413 of the fuel pump 400 are different from those of the structure examples of the variable flow high pressure fuel pump of the first to third embodiments. In the following, description of the same structural part will be omitted.

The fuel pump 400 is arranged such that the solenoid valve 413 is in parallel with the discharge check valve 112 so that the pump chamber 102
And the discharge channel 104. Solenoid valve 413
Are an electromagnetic valve body 414, an electromagnetic coil 415, an electromagnetic iron core 416, a valve body 417, and a spring 418 which is an example of an elastic member.
It is composed of

FIG. 13 shows the non-energized state of the solenoid valve 413, and the valve element 417 is closed by the spring force of the spring 418. When the electromagnetic coil 415 is energized, the electromagnetic force overcomes the spring force, the valve element 417 is attracted to the electromagnetic core 416, and the electromagnetic valve 413 is closed. That is, the solenoid valve 413 shown in FIG. 13 has a normally closed structure.

In the solenoid valve 413, the port 420 communicates with the outlet, and the port 421 communicates with the inlet of the discharge check valve 112 in the pump chamber 102.
Are arranged between the discharge flow path 104 and the pump chamber 102 so as to be in parallel. Therefore, the fuel pump 400 shown in FIG.
The control of the discharge flow rate described above with reference to FIGS. 11 and 13 can be performed by controlling the opening and closing of the solenoid valve 413.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 14 is a configuration diagram of a fuel supply system of an automobile engine equipped with a variable flow high-pressure fuel pump according to a fifth embodiment of the present invention.

The fuel supply system shown in FIG. 14 is different from the fuel supply system shown in FIG.
Except for the arrangement of No. 3, it is the same as the fourth embodiment shown in FIG.

In the fuel pump 500 shown in FIG. 14, an electromagnetic valve 513 is provided in the discharge passage 104. Solenoid valve 5
The structure of No. 13 has a so-called normally closed structure in which the valve is in a closed state when de-energized and is opened when energized.

The spring force of the solenoid valve 513 is set so that the solenoid valve 513 is opened when power is not supplied to the solenoid valve 513 due to an increase in the pressure in the pump chamber 102 generated during the discharge stroke.

Therefore, when the solenoid valve 513 is de-energized due to a power failure due to disconnection or the like, the fuel discharge amount cannot be controlled. However, during the suction stroke, the fuel is injected into the pump chamber 102 through the suction check valve 111. Can be inhaled. In the discharge stroke, the non-energized solenoid valve 5
13 serves the same role as the discharge check valve,
The fuel can be discharged from the discharge passage 104 toward the injector 5 through the discharge passage 104.

That is, similarly to the first to fourth embodiments, the variable flow high-pressure fuel pump of the fifth embodiment is also fixed even if the function of controlling the discharge flow is lost. As a high-pressure fuel pump with a flow rate, high-pressure fuel at a relief pressure set by the relief valve 8 can be supplied to the injector 5.

Next, the flow control operation of the variable flow high pressure fuel pump shown in FIG. 14 will be described with reference to FIG.

In the fifth embodiment, similarly to the fourth embodiment, in order to reduce the discharge flow rate of the fuel pump 500, the plunger 106 is moved from the top dead center to the bottom dead center during the suction stroke. The solenoid valve 513 is opened during a partial period (the period of FIG. 15A).

The period (a) in FIG. 15 is the suction stroke. At this time, the solenoid valve 513 has been opened by the solenoid valve drive signal from the controller 4, and the solenoid valve 513 shown in FIG.
The same operation as described in the period (a) of 2 is performed.

In the period (b) of FIG. 15, the suction stroke is continued, but the solenoid valve drive signal from the controller 4 is cut off to close the solenoid valve 513. At this time, the same operation as that described in the period (b) of FIG. 12 of the fourth embodiment is performed.

The period (c) in FIG. 15 is a discharge stroke. At this time, the solenoid valve 513 is opened by the solenoid valve drive signal from the controller 4, and fuel is discharged from the discharge passage 104 to the injector 5 through the solenoid valve 513 as the plunger 106 rises.

As described above, also in the variable flow high pressure fuel pump of the fifth embodiment, as in the fourth embodiment, the solenoid valve 513 is opened during a part of the suction stroke, as in the case of the fourth embodiment. It is possible to reduce the amount of fuel discharged.

FIG. 16 shows an example of the structure of the variable flow high pressure fuel pump shown in FIG. The fuel pump 500 is different from the structure example of the variable flow rate high pressure fuel pump of the fourth embodiment in that the discharge check valve 112 is not provided and the solenoid valve 51
3 is different.

In the fuel pump 500, an electromagnetic valve 513 is arranged between the pump chamber 102 and the discharge passage 104.
The configuration of the solenoid valve 513 is the same as that of the solenoid valve 413 of the fourth embodiment shown in FIG. 13, and has a normally closed structure.

The port 520 communicates with the discharge channel 104, and the port 521 communicates with the pump chamber 102. With this configuration, the fuel pump 500 in FIG. 16 can control the discharge flow rate described above with reference to FIGS. 14 and 15 by controlling the opening and closing of the solenoid valve 513.

The spring 418 of the solenoid valve 513 is opened by a force acting on the valve body 417 (upward in the figure) due to an imbalance between the pressure of the port 520 and the pressure in the pump chamber 102 which rises during the discharge stroke. The spring force is set so as to valve.

When the solenoid valve 513 is de-energized, in the discharge stroke, the de-energized solenoid valve 513 plays the same role as the discharge check valve, and directs the fuel from the discharge passage 105 through the solenoid valve 513 to the injector. Can be ejected.
In the suction stroke, the valve element 5
17 moves downward to close the valve, and the suction check valve 111 opens to move fuel from the suction passage 104 to the pump chamber 1.
Inhalation at 02.

[0147]

According to the present invention, the driving power of the fuel pump can be reduced by controlling the discharge flow rate of the high-pressure fuel supplied to the injector by the fuel pump according to the fuel injection amount of the injector. Further, even when the flow control electromagnetic valve becomes inoperable, high-pressure fuel can be supplied to the injector, so that the reliability of the variable flow high-pressure fuel pump can be improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a fuel supply system of an automobile engine including a variable flow high-pressure fuel pump according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a flow control operation of the variable flow high-pressure fuel pump of FIG.

FIG. 3 is a diagram showing an example of the structure of the variable flow high-pressure fuel pump of FIG. 1;

FIG. 4 is a configuration diagram of a fuel supply system of an automobile engine including a variable flow high-pressure fuel pump according to a second embodiment of the present invention.

FIG. 5 is an explanatory diagram of a flow rate control operation of the variable flow rate high pressure fuel pump of FIG.

6 is a diagram showing an example of the structure of the variable flow high pressure fuel pump of FIG.

FIG. 7 is a diagram showing another example of the structure of the variable flow high-pressure fuel pump according to the second embodiment.

FIG. 8 is a configuration diagram of a fuel supply system of an automobile engine including a variable flow high-pressure fuel pump according to a third embodiment of the present invention.

9 is an explanatory diagram of a flow rate control operation of the variable flow rate high pressure fuel pump of FIG.

FIG. 10 is a diagram showing an example of the structure of the variable flow high pressure fuel pump of FIG.

FIG. 11 is a configuration diagram of a fuel supply system of an automobile engine including a variable flow high-pressure fuel pump according to a fourth embodiment of the present invention.

12 is an explanatory diagram of a flow rate control operation of the variable flow rate high pressure fuel pump of FIG.

FIG. 13 is a diagram showing an example of the structure of the variable flow high pressure fuel pump of FIG.

FIG. 14 is a configuration diagram of a fuel supply system of an automobile engine including a variable flow high-pressure fuel pump according to a fifth embodiment of the present invention.

15 is an explanatory diagram of a flow rate control operation of the variable flow rate high pressure fuel pump of FIG.

FIG. 16 is a diagram showing an example of the structure of the variable flow high-pressure fuel pump of FIG.

[Explanation of symbols]

4 ... Controller, 5 ... Injector, 6 ... Pressure sensor, 7 ... Rotation angle sensor, 8 ... Relief valve, 100,2
00, 300, 400, 500 ... fuel pump, 102 ...
Pump chamber, 103: suction flow path, 104: discharge flow path, 10
5 cam, 106 plunger, 111 suction check valve, 112 discharge check valve, 113, 213, 31
3,413,513 ... Solenoid valve

Continued on the front page (72) Inventor Tadahiko Nogami 502, Kandachicho, Tsuchiura-shi, Ibaraki Machinery Research Laboratory, Hitachi, Ltd. Within the business division (72) Kenji Hirako 502 Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. Machinery Research Laboratory, Hitachi, Ltd. Term (Reference) 3G066 AA02 AB02 AD12 BA12 BA17 BA29 BA33 CA01S CA03 CA04T CA04U CA05T CA08 CA09 CA19 CA20U CA22T CC01 CD26 CE02 CE13 CE22 DC04 DC09 DC18 3G301 HA01 HA04 HA06 JA02 JB02 LA01 LB04 LB16 LC01 MA28 ND02 PZZ08

Claims (9)

[Claims] A suction passage for sucking fuel into a pump chamber; and a discharge passage for discharging the fuel from the pump chamber.
A variable flow high-pressure fuel pump that performs suction and discharge of fuel by a plunger that reciprocates in the pump chamber and supplies the fuel to an injector, comprising: a suction check valve in the suction passage; and a discharge check valve in the discharge passage. Further, an electromagnetic valve for controlling a fuel flow rate is provided in the suction flow passage or the discharge flow passage, and the electromagnetic valve opens and closes the electromagnetic valve to open the suction flow passage and the pump chamber or the discharge flow passage. The fuel flow rate is controlled by switching between communication and non-communication with the pump chamber, and when the solenoid valve is not energized and does not open or close, the suction check valve is connected to the plunger. A constant flow rate of fuel is drawn into the pump chamber from the suction flow path according to the reciprocating motion, and the discharge check valve is driven at a constant flow rate according to the reciprocating motion of the plunger. Variable flow high-pressure fuel pump, characterized in that for discharging the fuel from the pump chamber to the discharge flow channel. 2. The suction valve according to claim 1, wherein the solenoid valve is provided in the suction flow passage, and switches between communication and non-communication between the suction flow passage and the pump chamber, so that the pump chamber is connected to the suction flow passage. A variable flow high-pressure fuel pump that controls the fuel flow by returning the fuel or stopping the suction of the fuel from the suction flow path into the pump chamber. 3. The fuel supply system according to claim 1, wherein the solenoid valve is provided in a discharge flow passage, and switches fuel communication from the discharge flow passage to the pump chamber by switching communication between the discharge flow passage and the pump chamber. A variable flow high pressure fuel pump characterized by controlling the fuel flow by performing a return operation. 4. The solenoid valve according to claim 2, wherein the solenoid valve has a normally open structure in which the solenoid valve is opened when not energized and closed when energized, and is provided between the suction passage and the pump chamber. A variable flow high pressure fuel pump, which is arranged in series with said suction check valve. 5. The solenoid valve according to claim 2, wherein the solenoid valve has a normally closed structure that is closed when not energized and is opened when energized, and between the suction passage and the pump chamber. 3. The variable flow high pressure fuel pump according to claim 1, wherein said variable flow high pressure fuel pump is arranged in parallel with said suction check valve. 6. The solenoid valve according to claim 3, wherein the solenoid valve has a normally closed structure that is closed when not energized and opened when energized, and between the pump chamber and the discharge passage. The variable flow high pressure fuel pump is arranged in parallel with the discharge check valve. 7. The apparatus according to claim 1, wherein the solenoid valve is provided in the suction passage, and the discharge check valve is provided in the discharge passage. A valve element is configured to open by a negative pressure in the pump chamber with respect to the suction flow path generated when descending from the dead center, and a constant flow rate of fuel corresponding to the reciprocating motion of the plunger by opening the valve element. Wherein the discharge check valve discharges a constant flow rate of fuel from the pump chamber to the discharge flow path according to the reciprocation of the plunger. High pressure fuel pump. 8. The apparatus according to claim 1, wherein the suction flow path includes the suction check valve, and the discharge flow path includes the solenoid valve. The suction check valve has a constant flow rate according to the reciprocating motion of the plunger. The solenoid valve sucks fuel from the suction flow path into the pump chamber, and the solenoid valve, in the absence of the energization, causes a positive pressure in the pump chamber with respect to the discharge flow path generated when the plunger rises from bottom dead center. A variable flow rate characterized by discharging a constant flow rate of fuel from the pump chamber to the discharge flow path in accordance with the reciprocation of the plunger by opening the valve body. High pressure fuel pump. 9. A fuel supply control method for discharging fuel sucked from a suction flow path by a plunger reciprocating in a fuel pump chamber to a discharge flow path and supplying the fuel to an injector, wherein the fuel supply control method is provided in the suction flow path or the discharge flow path. When the solenoid valve is energized and the solenoid valve performs an opening and closing operation, the solenoid valve establishes communication and non-communication between the suction passage and the fuel pump chamber or the discharge passage and the fuel pump chamber. Switching, controlling the flow rate of the fuel and supplying the fuel to the injector. On the other hand, when the solenoid valve is not energized and does not perform the opening / closing operation, the suction check valve provided in the suction passage is used. A constant flow rate of fuel corresponding to the reciprocation of the plunger is sucked into the fuel pump chamber from the suction passage, and a discharge check valve provided in the discharge passage. Fuel supply control method comprising supplying a fuel of a constant flow rate corresponding to reciprocation of the plunger in the injector discharge to the discharge flow path from the fuel pump chamber.