JP3428443B2 - Variable flow high pressure fuel pump and fuel supply control method - Google Patents

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 at high pressure to an injector of an automobile engine, especially a cylinder injection engine, and more particularly to a flow rate of high-pressure fuel supplied according to the fuel injection amount of the injector. The present invention relates to a variable flow rate high pressure fuel pump capable of reducing the driving power of the fuel pump by changing

[0002]

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

Japanese Laid-Open Patent Publication No. 1-73166 discloses a cylinder, a fuel pressurizing member built in the cylinder and driven by an engine, and for pressurizing fuel in the cylinder defined by the fuel pressurizing member. And a solenoid valve fixed to the cylinder and facing the pump chamber, wherein the solenoid valve has a seat portion of a passage communicating high pressure fuel in the pump chamber to the low pressure side. By closing the valve element of this solenoid valve when energized, high-pressure fuel in the pump chamber is pumped into the common rail where high-pressure fuel is accumulated, and the amount of fuel discharged to the common rail is controlled according to the energization period. Then, the valve body of the solenoid valve penetrates the seat portion and projects toward the inside of the pump chamber.
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. There is described a variable discharge high pressure pump configured as an open valve.

[0004]

By changing the flow rate of the fuel pump and controlling the flow rate discharged by the fuel pump according to the injection amount from the injector, the surplus amount returned to low pressure without being injected from the injector. It is possible to reduce the power of the engine used to boost the pressure of fuel and improve fuel efficiency.

In particular, in the case of a high pressure fuel pump used for boosting the fuel from several tens to a high pressure of hundreds of atmospheres or more, such as a cylinder injection engine, since the driving torque of the pump required for boosting is large, the flow rate is increased. The effect of reducing the pump drive power is large due to controlling the flow rate and reducing the excess flow rate.

In addition, a fuel pump used in an automobile engine is required to have high reliability. When the engine stops, the auxiliary machinery driven by the engine, such as the hydraulic pump that supplies hydraulic pressure to the power steering and brakes, also stops, so it is possible to move the vehicle to a safe place and stop it. It will be difficult. Therefore, it is necessary for safety in the variable flow rate fuel pump that the function of supplying the high pressure fuel to the injector can be maintained even if the function of controlling the discharge flow rate is lost due to a malfunction such as a failure.

However, in the above-mentioned prior art, it was difficult to maintain the function of the fuel pump that supplies 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 valve opening force is applied 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 that makes it open.

The most likely problem with the solenoid valve having this structure is that the solenoid coil cannot be energized due to disconnection, poor contact of the connector, etc. At this time, the valve body remains open due to the biasing force. , It becomes impossible to close the valve.

When the solenoid valve remains open, the plunger of the pump descends from the top dead center so that fuel is once drawn into the pump chamber, but then the plunger rises from the bottom dead center to cause the pump to move. The fuel in the chamber flows back through the opened solenoid 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, if 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. Sometimes there was no choice but to stop.

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

[0012]

To achieve the above object, the variable flow rate high-pressure fuel pump of the present invention is characterized in that the intake flow is controlled by opening and closing an electromagnetic valve provided in the intake flow path or the discharge flow path. When the passage and the pump chamber or the discharge passage and the pump chamber are switched between communication and non-communication, the fuel flow rate is controlled and supplied to the injector, while the solenoid valve is not energized and the solenoid valve does not open and close. Includes a suction check valve provided in the suction passage, sucking fuel corresponding to the reciprocating movement of the plunger from the suction passage into the pump chamber, and a discharge check valve provided in the discharge passage,
It is to discharge the fuel corresponding to the reciprocating movement of the plunger from the pump chamber to the discharge passage and supply it to the injector.

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

The present invention has a suction flow passage for sucking fuel into the pump chamber and a discharge flow passage for discharging the fuel from the pump chamber, and the fuel suction / discharge is performed by a plunger reciprocating in the pump chamber. In the variable-flow high-pressure fuel pump that supplies the fuel to the injector, an intake check valve is provided in the intake passage, a discharge check valve is provided in the discharge passage, and an electromagnetic valve that controls the fuel flow rate in the intake passage is provided. A valve, the solenoid valve is arranged in series with the suction check valve between the suction passage and the pump chamber, and the solenoid valve opens and closes the solenoid valve to connect to the suction passage. By switching between communication and non-communication with the pump chamber, the fuel flow rate is controlled, and when the solenoid valve is not energized and the solenoid valve does not open and close, the suction check valve is A constant flow rate of fuel corresponding to the reciprocating movement of the plunger is sucked into the pump chamber from the suction flow passage, and the discharge check valve discharges a constant flow rate of fuel from the pump chamber according to the reciprocating movement of the plunger. Provided is a variable flow high-pressure fuel pump which is characterized by discharging to a flow path.

Further , the present invention has a suction flow passage for sucking fuel into the pump chamber and a discharge flow passage for discharging the fuel from the pump chamber, and the fuel suction is performed by a plunger reciprocating in the pump chamber. In a variable flow high-pressure fuel pump that performs discharge and supplies the fuel to an injector, an intake check valve is provided in the intake passage, a discharge check valve is provided in the discharge passage, and a fuel flow rate is controlled in the intake passage. A solenoid valve for performing the suction flow is provided between the suction passage and the pump chamber in parallel with the suction check valve, and the solenoid valve opens and closes the solenoid valve. By switching between communication and non-communication between a passage and the pump chamber, sucking fuel from the suction passage to the pump chamber, or returning fuel from the pump chamber to the suction passage, or When the operation of stopping the intake of fuel to the pump chamber is performed to control the fuel flow rate, and the solenoid valve is not energized and the solenoid valve does not open and close, the suction check valve is the plunger A constant flow rate of fuel corresponding to the reciprocating movement of the plunger to the pump chamber, and the discharge check valve causes a constant flow rate of fuel corresponding to the reciprocating movement of the plunger from the pump chamber to the discharge flow channel. Disclosed is a variable flow high-pressure fuel pump which is characterized in that

Further , the present invention has a suction flow passage for sucking fuel into the pump chamber and a discharge flow passage for discharging the fuel from the pump chamber, and sucks the fuel by a plunger reciprocating in the pump chamber. In a variable flow high-pressure fuel pump that discharges and supplies to an injector, an intake check valve is provided in the intake passage, a discharge check valve is provided in the discharge passage, and a fuel flow rate is controlled in the discharge passage. An electromagnetic valve is provided for controlling the fuel flow rate by energizing the electromagnetic valve by opening and closing the electromagnetic valve to switch between communication and non-communication between the discharge passage and the pump chamber. In the case where the solenoid valve does not open and close, the suction check valve sucks a constant flow rate of fuel from the suction passage into the pump chamber according to the reciprocating movement of the plunger, Serial discharge check valve provides a variable flow high-pressure fuel pump, characterized in that for discharging the fuel of a constant flow rate corresponding to reciprocation of the plunger from the pump chamber to the discharge flow channel.

[0017] Preferably, the placing only the solenoid valve to the suction channel, the electromagnetic valve, wherein when energization is not,
By configuring the valve body to open due to the negative pressure in the pump chamber with respect to the suction flow passage generated when the plunger descends from the top dead center, the suction check valve also has a function.

[0018] Preferably, only the electromagnetic valve arranged in the discharge flow channel, the electromagnetic valve, wherein when energization is not,
By configuring the valve body to open due to the positive pressure in the pump chamber with respect to the discharge flow path generated when the plunger rises from the bottom dead center, the discharge check valve also functions.

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

Further , according to the present invention, in the fuel supply control method for supplying the fuel sucked from the suction flow passage to the discharge flow passage by the plunger reciprocating in the fuel pump chamber and supplying the fuel to the injector, the suction flow passage is provided. When the solenoid valve arranged in the suction passage is energized in series with the suction check valve and the solenoid valve opens and closes, the solenoid valve connects the suction passage and the fuel pump chamber. When the solenoid valve is not energized and the solenoid valve does not open / close, the intake check valve causes the plunger to operate. A constant flow rate of fuel according to the reciprocating movement of the fuel into the fuel pump chamber from the suction flow passage, and a discharge check valve provided in the discharge flow passage, To provide a fuel supply control method characterized by the fuel of a constant flow rate corresponding to the reciprocation of the feed to the injector discharge to the discharge flow path from the fuel pump chamber.

Further , according to the present invention, in the fuel supply control method for supplying the fuel sucked from the suction flow passage to the discharge flow passage by the plunger reciprocating in the fuel pump chamber and supplying the fuel to the injector, the suction flow passage is provided. When the solenoid valve disposed in the suction passage in parallel with the suction check valve is energized and the solenoid valve opens and closes, the solenoid valve allows communication between the suction passage and the fuel pump chamber. And switching the non-communication to perform an operation of sucking fuel from the suction passage into the pump chamber, returning fuel from the pump chamber to the suction passage, or stopping suction of fuel into the pump chamber. And supplies the fuel to the injector by controlling the flow rate of the fuel, and when the solenoid valve is not energized and the solenoid valve does not open and close,
The suction check valve sucks a constant flow rate of fuel according to the reciprocating movement of the plunger from the suction flow passage into the fuel pump chamber, and the discharge check valve provided in the discharge flow passage causes the plunger to reciprocate. There is provided a fuel supply control method characterized in that a constant flow rate of fuel according to the movement is discharged from the fuel pump chamber to the discharge passage and supplied to an injector.

Further , according to the present invention, in the fuel supply control method for supplying the fuel sucked from the suction flow passage to the discharge flow passage by the plunger reciprocating in the fuel pump chamber and supplying the fuel to the injector, the discharge flow passage is provided. When the solenoid valve is energized and the solenoid valve opens and closes, the solenoid valve switches between communication and non-communication between the discharge flow path and the fuel pump chamber, and controls the flow rate of the fuel to inject the fuel. On the other hand, when the solenoid valve is not energized and the solenoid valve does not open and close, the suction check valve provided in the suction flow passage causes a constant flow rate according to the reciprocating movement of the plunger. Of the fuel is sucked into the fuel pump chamber from the suction flow passage, and a discharge check valve provided in the discharge flow passage causes a constant flow rate of the fuel to flow according to the reciprocating movement of the plunger. The providing fuel supply control method characterized by supplying to the injector discharges into the discharge flow path from the fuel pump chamber.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION 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 rate high-pressure fuel pump according to a first embodiment of the present invention.

The fuel supply system shown in FIG.
A feed pump 2 that transfers more, a low-pressure pressure regulator 3 that adjusts the discharge pressure of the feed pump 2,
A fuel pump 10 capable of further pressurizing the fuel discharged from the feed pump 2 and controlling the flow rate of the discharged fuel.
0, and a controller 4 that controls the fuel pump 100,
The injector 5 that injects the fuel discharged from the fuel pump 100 into the engine, the pressure sensor 6 that measures the fuel pressure applied to the injector 5, and the fuel is reduced to a low pressure when the fuel pressure applied to the injector 5 exceeds a predetermined pressure. The relief valve 8 for escaping is included.

The feed pump 2 and the low-pressure pressure regulator 3 are provided mainly for the purpose of preventing cavitation when the fuel pump 100 sucks in fuel, and may not be attached depending on the operating conditions of the fuel pump 100. 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. Inside the pump chamber 102, a rotating cam 105 is provided. A plunger 106 that is reciprocated by is provided.

Further, the suction passage 103 and the discharge passage 10
4 has an intake check valve 111 and a discharge check valve 112, respectively. An electromagnetic valve 113 is provided in the intake passage 103, and the opening / 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, the fuel pressure applied to the injector 5 needs to be adjusted according to the operating state of the engine. In FIG. 1, the host controller determines the operating state of the engine based on values from various sensors such as throttle opening and engine speed.

Then, the host controller determines the appropriate fuel pressure and the injection amount of the injector 5 according to the operating 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 the 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 that 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 refers to the solenoid valve 1
The timing of energization / de-energization of 13 is controlled.

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

As the rotation angle sensor 7, it is possible to use a crank angle sensor provided in the engine. Alternatively, the signal from the rotation angle sensor 7 is sent to the cam 1
The solenoid valve 113 is used only to detect the reference position of the rotation angle of 05 (for example, the top dead center or the bottom dead center of the plunger 106).
The timing of energizing / de-energizing can be controlled not by the rotation angle but by time by 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 shown as separate blocks. However, in practice, 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 cylinder injection gasoline engine. In a cylinder injection gasoline engine, it is required to inject fuel into the high pressure atmosphere of the cylinder during the compression stroke and to inject a predetermined fuel into the cylinder within a limited short injection period. The discharge pressure of the pump needs to be much higher than that of the conventional port injection engine, from several tens of atmospheres to 100 atmospheres or more.

If the flow rate of the high-pressure fuel pump is made variable and the flow rate discharged by the high-pressure fuel pump is controlled according to the injection amount from the injector, the surplus fuel returned to the low pressure without being injected from the injector is used. It is possible to reduce the power of the engine spent for boosting the pressure and improve fuel efficiency.

In particular, in the case of a high pressure fuel pump for boosting fuel to a high pressure such as a cylinder injection gasoline engine, since the pump driving torque required for boosting is large, the flow rate should be controlled to reduce the surplus flow rate. The effect of reducing the pump driving power, that is, the effect of improving fuel efficiency is great.

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

Therefore, in the variable flow rate high pressure fuel pump, 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 FIG. 1, the solenoid valve 113 is connected to the suction check valve 111 so as to be in series with the suction passage 103 and the pump chamber 1.
The solenoid valve 113 has a so-called normally open type structure in which the solenoid valve 113 is opened when not energized and closed when energized.

Therefore, when the solenoid valve 113 does not operate due to inability to energize due to disconnection or the like, the solenoid valve 113 of the variable flow rate high pressure fuel pump of this embodiment remains open. At this time, the amount of fuel discharged cannot be controlled.

However, since the solenoid valve 113 is open,
In the suction stroke, without blocking the suction flow path 103,
Fuel can be sucked into the pump chamber 102 from the suction passage 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.

That is, the variable-flow high-pressure fuel pump of the first embodiment is 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 fuel injection amount from the injector 5 is small, the pump continues to discharge fuel, so that the fuel pressure supplied to the injector 5 continues to rise and the fuel pipe May be damaged.

In the first embodiment, the relief valve 8 shown in FIG. 1 is provided so that such a dangerous situation does not occur.
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 having a fixed capacity, the high-pressure fuel having the 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 of 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 lowered from the top dead center to the bottom dead center during a part of the intake stroke (the period of FIG. 2B). Solenoid valve 11
Close valve 3. The operation in the suction stroke and the discharge stroke will be sequentially described below.

The period (a) in FIG. 2 is in the inhalation stroke. The solenoid valve 113 is open, and the intake check valve 111 opens as the plunger 106 descends, and the fuel flows through the intake passage 103.
Is sucked into 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 the non-energized state.

The period (b) in FIG. 2 is still in the intake stroke, but the solenoid valve 113 is energized by the solenoid valve drive signal from the controller 4 and is closed. Therefore,
Fuel is not drawn into the pump chamber 102 even if the plunger 106 descends. 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 fuel, bubbles of fuel 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 and closed by the solenoid valve drive signal from the controller 4. Plunger 1
06 is a stroke that rises from the bottom dead center, but due to the negative pressure in the pump chamber 102 generated in the period (b), the plunger 106
The force to raise acts on.

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

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

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

Further, in the first embodiment, there is no fuel flow while the electromagnetic valve 113 is closed for controlling the discharge amount, so that loss due to fluid resistance does not occur.

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

FIG. 3 shows an example of the structure of the variable flow high-pressure fuel pump of FIG. The fuel pump 100 has a pump chamber 10
2, a suction passage 103 for sucking fuel, and a pump chamber 102
Has a discharge flow path 104 for discharging fuel from the pump chamber 1
A plunger 106 that is reciprocally moved by a rotating cam 105 is provided in 02.

A cam follower 107 is arranged between the cam 105 and the plunger 106, and converts the rotational movement of the cam 105 into a reciprocating motion and transmits it to the plunger 106. Since the sliding portion is present on 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, and a lubricating oil is applied to the sliding portion to improve durability. May be supplied.

Cam follower 107 and pump body 108
The spring 109 is inserted between the
Is set so that a force for 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.

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

The plunger 106 and the cam follower 1
It is also possible to have 07 as an integral structure, and in that case, either spring 109 or spring 110 need not be used. A suction check valve 1 is provided in the suction passage 103.
11 is provided, and the discharge flow path 104 is provided with a discharge check valve 112.

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

FIG. 3 shows a non-energized state of the solenoid valve 113. The valve body 117 is opened apart from the seat portion 119 by the spring force of the spring 118. Electromagnetic coil 115
When energized, the electromagnetic force overcomes the spring force and the valve body 117
Is attracted to the electromagnetic core 116, and the valve element 117 is seated on the seat portion 1.
The solenoid valve 113 is closed by closely contacting with 19.

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

In the solenoid valve 113, the port 120 communicates with the suction check valve 111, and the port 121 communicates with the pump chamber 102 so that the suction flow valve 103 and the pump chamber 102 are connected in series. It is arranged in between. Therefore, in the fuel pump 100 shown in FIG. 3, the control of the discharge flow rate described above with reference to FIGS.
This is possible by controlling the opening and closing of 13.

[Second Embodiment] Next, a second embodiment of the present invention will be described with reference to FIGS. 4 to 6. FIG. 4 is a configuration diagram of a fuel supply system of an automobile engine equipped with a variable flow rate 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 configurations of the solenoid valve 0, the suction check valve, and the discharge check valve.

In the fuel pump 200 shown in FIG. 4, the solenoid valve 213 is arranged 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 it is closed when not energized and opened when energized.

Therefore, when the solenoid valve 213 does not operate due to inability to energize due to disconnection or the like, the solenoid valve 213 of the variable flow rate high pressure fuel pump of this embodiment cannot be opened. At this time, the amount of fuel discharged 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 intake stroke, intake check valve 1
Fuel from the suction passage 103 through the pump chamber 102
Can be inhaled into.

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, also in the variable flow rate high-pressure fuel pump of the second embodiment, the solenoid valve 213 does not operate and the function of controlling the discharge flow rate is lost, as in the first embodiment. Also, as a high-pressure fuel pump with a fixed flow rate,
High-pressure fuel having 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 of 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 lifted from the bottom dead center to the top dead center in a part of the discharge stroke (the period of FIG. 5B). Solenoid valve 21
Open valve 3. The operation in the suction stroke and the discharge stroke will be sequentially described below.

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

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

Therefore, in the second embodiment, when it is desired to reduce the power consumption of the solenoid valve 213,
It is possible to stop the energization of the solenoid valve 213 in (a).

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 in the period (a) to suck the fuel 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 in the suction check valve 111 is reduced, the suction work of the fuel pump 200 can be reduced and the occurrence of cavitation in fuel suction can be easily prevented.

Since the solenoid valve 213 is a normally closed type, when the solenoid valve 213 is opened in the period (a), a solenoid valve drive signal is output from the controller 4 and the solenoid valve 213 is energized. .

The period (b) in FIG. 5 is the discharge stroke, but the solenoid valve 213 is driven by the solenoid valve drive signal from the controller 4.
Is energized and is open. At this time, fuel is pumped from the pump chamber 102 to the solenoid valve 2 even if the plunger 106 rises.
The pressure in the pump chamber 102 does not rise because it is simply returned to the suction flow path 103 through 13. Therefore, the discharge check valve 112 does not open, and fuel is not 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 rises until the discharge check valve 112 is opened, and the fuel flows 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 of the second embodiment, it is possible to reduce the fuel discharge amount by opening the solenoid valve 213 during a part of the discharge stroke. is there. Further, the reduction amount of 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 latter half of the discharge stroke.
Although the variable flow rate high-pressure fuel pump of the second embodiment is controlled by closing the solenoid valve 213 at an arbitrary period of the discharge stroke, the discharge amount is controlled. Is possible.

FIG. 6 shows an example of the structure of the variable flow rate high pressure fuel pump of 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. 3 in the structure and arrangement of the solenoid valve 213. Therefore, in the following, description of the same structural parts as in FIG. 3 will be omitted.

In the fuel pump 200, the suction passage 103 is arranged so that the solenoid valve 213 is in parallel with the suction check valve 111.
And the pump chamber 102. Solenoid valve 213
Is a solenoid valve body 214, a solenoid coil 215, a solenoid core 216, a valve body 217, and a spring 218 which is an example of an elastic member.
Composed of.

FIG. 6 shows a 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 body 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.

In the solenoid valve 213, the port 220 is in communication with the inlet of the intake check valve 111, and the port 221 is in communication with the outlet of the intake check valve 111 in the pump chamber 102, and is in parallel with the intake check valve 111. Thus, it is arranged between the suction passage 103 and the pump chamber 102. 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 the opening / closing control of the solenoid valve 213.

FIG. 7 shows another example of the structure of the variable flow rate high pressure fuel pump of 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 that the ports 220 and 221 of the solenoid valve 213 are in communication with the inflow passage 103 and the pump chamber 102.

In the fuel pump 200 of FIG. 7, the solenoid valve 21
3, the port 221 communicates with the inlet of the intake check valve 111, and the port 220 communicates with the outlet of the intake check valve 111 in the pump chamber 102.
1 and the suction passage 103 and the pump chamber 102 in parallel with each other.
It is arranged between.

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

The difference between the fuel pump of FIG. 7 and the fuel pump of FIG. 6 is that the directions of the fuel pressures acting on the valve element 217 of the solenoid valve 213 are opposite in the compression stroke and the suction stroke. That is, in FIG. 7, the solenoid valve 213 is used in the compression stroke.
When the valve is closed, the pressure in the pump chamber 102 is high, and the suction flow path 10
Since the inside of 3 becomes a low pressure, the valve body 217 is changed by the fuel pressure.
Has an advantage that a force in the closing direction (downward in FIG. 7) acts to firmly seal the fuel.

Further, when the solenoid valve 213 is opened during the intake stroke, the inside of the pump chamber 102 is at a negative pressure as compared with the intake passage 103, so the fuel pressure causes the valve body 217 to open (see FIG. 7). Then, there is an advantage that the valve body 217 can be easily opened by the action of the upward force.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. 8 to 10. FIG. 8 is a configuration diagram of a fuel supply system of an automobile engine equipped with a variable flow high-pressure fuel pump according to the third embodiment of the present invention.

The fuel supply system shown in FIG.
The structure is the same as that shown in FIG. 4 except the structure of the solenoid valve of No. 0.

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 3 has a so-called normally closed structure in which the valve is closed when not energized and opened when energized.

Further, the solenoid valve 313 is set to have a spring force so as to be opened by a negative pressure in the pump chamber 102 generated in the suction stroke when the solenoid valve 313 is not energized.

Therefore, when the solenoid valve 313 is de-energized due to the fact that the solenoid valve 313 is de-energized due to a disconnection or the like, the fuel discharge amount cannot be controlled. It plays a role of supplying 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 fueled.

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

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

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

The period (b) in FIG. 9 is the discharge stroke, but the solenoid valve 313 is driven by the solenoid valve drive signal from the controller 4.
Is energized and is open. At this time, even if the plunger 106 rises, the fuel flows from the pump chamber 102 to the solenoid valve 3
The pressure in the pump chamber 102 does not rise because it is simply returned to the suction flow path 103 through 13. Therefore, the discharge check valve 112 does not open, and fuel is not 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 rises until the discharge check valve 112 is opened, and the fuel flows 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 of the third embodiment, as in the second embodiment, the solenoid valve 313 is opened during a part of the discharge stroke. It is possible to reduce the amount of fuel discharged. In addition, it is possible to control the amount of decrease in the fuel discharge amount by adjusting the length of the valve opening period in any period of the discharge stroke.
This is the same as the embodiment described above.

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

In the fuel pump 300, the solenoid valve 313 is arranged between the suction passage 103 and the pump chamber 102. The solenoid valve 313 includes a solenoid valve body 314, a solenoid 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 the solenoid valve 313 in the non-energized state, and the valve body 317 is the spring force of the spring 318 (see FIG. 10).
The valve is closed by the action (inward and upward). Electromagnetic coil 3
When electricity is applied to 15, the electromagnetic force (acting downward in FIG. 10) overcomes the spring force, the valve element 317 is attracted to the electromagnetic core 316, and the electromagnetic valve 313 closes. That is, the solenoid valve 313 shown in FIG. 10 has a normally closed structure.

In the solenoid valve 313, the port 320 communicates with the suction flow passage 103, and the port 321 has the pump chamber 102.
It is in communication with each other and is arranged between the suction passage 103 and the pump chamber 102. 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 the opening / closing control of the solenoid valve 313.

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

When the solenoid valve 313 is de-energized, the non-energized solenoid valve 313 plays the same role as the suction check valve in the suction stroke, and the fuel is supplied 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 and closes due to the pressure increase in the pump chamber 102, and the discharge check valve 112 opens to discharge the fuel toward the injector.

The same operation as that of the structure shown in FIG. 10 can be realized also by removing the intake 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. 11 to 13. FIG. 11 is a configuration diagram of a fuel supply system of an automobile engine equipped with a variable flow rate high pressure fuel pump according to a fourth embodiment of the present invention.

The fuel supply system shown in FIG.
No. 00 solenoid valve, intake check valve, and discharge check valve are the same as in the first to third embodiments.

In the fuel pump 400 shown in FIG. 11, the solenoid valve 413 is arranged 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 not energized and opened when energized.

Even when the solenoid valve 413 is de-energized,
Since the discharge check valve 112 is provided in parallel with the solenoid 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 flow passage 103 through the suction check valve 111. In the discharge stroke, the discharge check valve 112
Fuel can be supplied from the pump chamber 102 to the injector 5 through the through.

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

Subsequently, the flow rate control operation of the variable flow rate high pressure fuel pump of 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 lowered from the top dead center to the bottom dead center during a part of the intake stroke (the period of FIG. 12 (a)). The solenoid valve 413 is opened. The operation in the suction stroke and the discharge stroke will be sequentially described below.

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

This is one in which the fuel, which has been once made high in pressure in the discharge stroke to be described later, is returned to the inside of the pump chamber 102, and the high-pressure fuel acts on the plunger 106 to lower the plunger 106.

That is, in the fourth embodiment, the operation of returning the high-pressure fuel recovers a part of the motive power spent for increasing the pressure of the fuel in the discharge stroke.

In the period (b) of FIG. 12, the suction stroke continues, 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 that accompanies the descent of
This time, the suction check valve 111 opens and the suction flow path 10
Fuel is sucked into the pump chamber 102 from 3.

In the above period (a), since the discharged fuel is returned, the intake amount in the period (b) is the next discharge stroke (period).
It is the amount of fuel actually discharged together with (c)).

The period (c) in FIG. 12 is the discharge stroke. At this time, fuel is discharged from the discharge flow path 104 toward the injector 5 as the plunger 106 moves upward, whether the electromagnetic valve 413 is closed or open. That is, when the solenoid valve 413 is closed, the pressure inside the pump chamber 102 rises as the plunger 106 rises, the discharge check valve 112 opens, and the fuel is discharged from the discharge passage 104. Further, when the solenoid valve 413 is in the open state, the 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,
It is possible to stop the energization of the solenoid valve 413 in (a).

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 in the period (a) to discharge the fuel 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 rate high pressure fuel pump of the fourth embodiment, the discharge amount of fuel can be reduced by opening the solenoid valve 413 during a part of the intake stroke. is there. Further, the reduction amount of 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 rate high pressure fuel pump of FIG. The fuel pump 400 differs from the structural examples of the variable-flow high-pressure fuel pumps of the first to third embodiments in the structure and arrangement of the solenoid valve 413. In the following, description of the same structural parts will be omitted.

In the fuel pump 400, the pump chamber 102 is arranged so that the solenoid valve 413 is in parallel with the discharge check valve 112.
And the discharge flow path 104. Solenoid valve 413
Is a solenoid valve body 414, a solenoid coil 415, a solenoid core 416, a valve body 417, and a spring 418 which is an example of an elastic member.
It consists of

FIG. 13 shows a 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 to communicate with the pump chamber 102.
It is arranged between the discharge channel 104 and the pump chamber 102 so as to be in parallel with. Therefore, the fuel pump 400 of FIG.
The control of the discharge flow rate described above with reference to FIGS. 11 and 13 can be performed by the opening / closing control of the solenoid valve 413.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described with reference to FIGS. 14 to 16. FIG. 14 is a configuration diagram of a fuel supply system of an automobile engine equipped with a variable flow rate high pressure fuel pump according to a fifth embodiment of the present invention.

The fuel supply system shown in FIG. 14 has no discharge check valve 112 and the solenoid valve 51 of the fuel pump 500.
The arrangement is the same as that of the fourth embodiment shown in FIG. 11 except the arrangement of No. 3.

In the fuel pump 500 shown in FIG. 14, an electromagnetic valve 513 is arranged in the discharge flow passage 104. Solenoid valve 5
The structure of 13 has a so-called normally closed structure in which the valve is closed when not energized and opened when energized.

Further, the solenoid valve 513 is set with a spring force so as to open when the pressure inside the pump chamber 102 increases during the discharge stroke when the solenoid valve 513 is not energized.

Therefore, when the solenoid valve 513 is de-energized due to inability to energize due to disconnection or the like, the fuel discharge amount cannot be controlled, but in the intake stroke, the fuel is introduced into the pump chamber 102 through the intake check valve 111. Can be inhaled. In the discharge stroke, the non-energized solenoid valve 5
13 plays the same role as the discharge check valve, and the solenoid valve 513
Through this, the fuel can be discharged from the discharge passage 104 toward the injector 5.

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

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

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

The period (a) in FIG. 15 is the inhalation stroke. At this time, the solenoid valve 513 is 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 continues, but the solenoid valve drive signal from the controller 4 is turned off to close the solenoid valve 513. At this time, the same operation as described in the period (b) of FIG. 12 of the fourth embodiment is performed.

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

As described above, also in the variable-flow high-pressure fuel pump of the fifth embodiment, the solenoid valve 513 is opened during a part of the intake stroke as in 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 of FIG. The fuel pump 500 is different from the structural 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 that the solenoid valve 51 is provided.
The arrangement of 3 is different.

In the fuel pump 500, the electromagnetic valve 513 is arranged between the pump chamber 102 and the discharge passage 104.
The structure 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 type structure.

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

The spring 418 of the solenoid valve 513 is opened by the force (acting upward in the figure) acting on the valve element 417 due to the imbalance between the pressure in the port 520 and the pressure in the pump chamber 102 that rises in the discharge stroke. Spring force is set to valve.

When the solenoid valve 513 is de-energized, the non-energized solenoid valve 513 plays the same role as the discharge check valve in the discharge stroke, directing the fuel from the discharge passage 105 to the injector through the solenoid valve 513. Can be discharged.
In the suction stroke, the negative pressure in the pump chamber 102 causes the valve element 5 to
17 moves downward and closes, and the intake check valve 111 opens to allow fuel to flow from the intake passage 104 to the pump chamber 1.
Inhale 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 solenoid valve for controlling the flow rate becomes inoperable, the high pressure fuel can be supplied to the injector, so that the reliability of the variable flow rate high pressure fuel pump can be improved.

[Brief description of drawings]

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.

2 is an explanatory diagram of a flow rate control operation of the variable flow rate 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.

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

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 rate 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 rate 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.

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

FIG. 11 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 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.

13 is a diagram showing an example of a structure of the variable flow rate 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 rate 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.

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 channel, 104 ... Discharge channel, 10
5 ... Cam, 106 ... Plunger, 111 ... Intake check valve, 112 ... Discharge check valve, 113, 213, 31
3,413,513 ... Solenoid valve

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Yukio Takahashi 2520 Takaba, Hitachinaka City, Ibaraki Prefecture Hitachi Ltd. Automotive Equipment Division (72) Inventor Kenji Hirako 502 Kintachicho, Tsuchiura City, Ibaraki Hitachi Ltd. Mfg. Co., Ltd., Mechanical Research Laboratory (72) Inventor Isao Hayase, 502 Jinmachi, Tsuchiura City, Ibaraki Prefecture Hitachi Co., Ltd., Mechanical Research Laboratory (56) Reference JP-A-11-200990 (JP, A) JP-A-10-318060 (JP) , A) JP-A-1-73166 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02M 59/20 F02M 59/02 F02M 59/34 F02M 59/36 F02M 51/00

Claims (9)

(57) [Claims] 1. A suction flow passage for sucking fuel into a pump chamber, and a discharge flow passage for discharging the fuel from the pump chamber,
A variable-flow high-pressure fuel pump that sucks and discharges fuel by a plunger that reciprocates in the pump chamber and supplies the fuel to an injector, wherein a suction check valve is provided in the suction passage and a discharge check valve is provided in the discharge passage. An electromagnetic valve for controlling a fuel flow rate is provided in the intake passage, the electromagnetic valve is arranged in series with the intake check valve between the intake passage and the pump chamber, and the electromagnetic valve is provided. Controls the fuel flow rate by opening and closing the solenoid valve to switch between communication and non-communication between the suction flow path and the pump chamber, and the solenoid valve is opened and closed without energization. If not, the suction check valve sucks a constant flow rate of fuel into the pump chamber from the suction flow passage according to the reciprocating movement of the plunger, and the discharge check valve is A variable-flow high-pressure fuel pump, wherein a constant flow rate of fuel is discharged from the pump chamber to the discharge flow path according to the reciprocating movement of the plunger. 2. A suction flow passage for sucking fuel into the pump chamber, and a discharge flow passage for discharging the fuel from the pump chamber,
A variable-flow high-pressure fuel pump that sucks and discharges fuel by a plunger that reciprocates in the pump chamber and supplies the fuel to an injector, wherein a suction check valve is provided in the suction passage and a discharge check valve is provided in the discharge passage. An electromagnetic valve for controlling the fuel flow rate is provided in the intake passage, the electromagnetic valve is arranged in parallel with the intake check valve between the intake passage and the pump chamber, and the electromagnetic valve is provided. Is configured to open and close the solenoid valve to switch communication and non-communication between the suction flow passage and the pump chamber, thereby sucking fuel from the suction flow passage into the pump chamber, or from the pump chamber to the suction flow. The fuel flow rate is controlled by returning the fuel to the passage or stopping the fuel suction into the pump chamber, and the solenoid valve is opened and closed without energizing the solenoid valve. If not performed, the suction check valve sucks a constant flow rate of fuel into the pump chamber from the suction flow passage according to the reciprocating movement of the plunger, and the discharge check valve causes reciprocating movement of the plunger. A variable flow high-pressure fuel pump, which discharges a constant flow rate of fuel from the pump chamber to the discharge flow path. 3. A suction flow passage for sucking fuel into the pump chamber, and a discharge flow passage for discharging the fuel from the pump chamber,
A variable-flow high-pressure fuel pump that sucks and discharges fuel by a plunger that reciprocates in the pump chamber and supplies the fuel to an injector, wherein a suction check valve is provided in the suction passage and a discharge check valve is provided in the discharge passage. Further, an electromagnetic valve for controlling the fuel flow rate is provided in the discharge flow path, and the electromagnetic valve opens and closes the electromagnetic valve to switch communication and non-communication between the discharge flow path and the pump chamber. When the fuel flow rate is controlled and the solenoid valve is not energized and the solenoid valve does not open and close, the intake check valve supplies a constant flow rate of fuel according to the reciprocating movement of the plunger to the intake passage. Is sucked into the pump chamber from the pump chamber, and the discharge check valve discharges a constant flow rate of fuel from the pump chamber to the discharge passage according to the reciprocating movement of the plunger. Variable flow high-pressure fuel pump to. 4. The method according to claim 1 or 2, wherein only the solenoid valve is arranged in the suction passage, and when the solenoid valve is not energized, the plunger is lowered from a top dead center. A variable-flow high-pressure fuel pump having the function of the suction check valve, which is configured so that the valve body is opened by a negative pressure in the pump chamber with respect to the suction flow path generated in the above. 5. The method of claim 3, wherein the the discharge passage the solenoid valve only place, the electromagnetic valve, wherein when energization is not, the discharge generated when the plunger is raised from the bottom dead center A variable-flow high-pressure fuel pump, wherein the valve body is configured to open by positive pressure in the pump chamber with respect to a flow path, thereby having a function of the discharge check valve. 6. The solenoid valve according to claim 3, wherein the solenoid valve has a normally closed structure in which a valve is closed when not energized and opened when energized, and between the pump chamber and the discharge passage. And a variable-flow high-pressure fuel pump, which is arranged in parallel with the discharge check valve. 7. A fuel supply control method for supplying fuel, which is sucked from a suction flow passage to a discharge flow passage and is supplied to an injector, by a plunger reciprocating in a fuel pump chamber, wherein a suction check valve provided in the suction flow passage is provided. On the other hand, when the solenoid valve arranged in the intake passage is energized in series and the solenoid valve opens and closes, the solenoid valve establishes communication and non-communication between the intake passage and the fuel pump chamber. The flow rate of the fuel is switched to supply the fuel to the injector. On the other hand, when the solenoid valve is not energized and the solenoid valve does not open and close, the suction check valve causes the plunger to reciprocate. According to the reciprocating movement of the plunger by a discharge check valve provided in the discharge flow path. Fuel supply control method characterized by supplying to the injector discharges into the discharge flow channel of the fuel at a constant flow rate from the fuel pump chamber has. 8. A fuel supply control method for supplying fuel, which is sucked from a suction flow passage to a discharge flow passage by a plunger that reciprocates in a fuel pump chamber and supplies the fuel to an injector, a suction check valve provided in the suction flow passage. On the other hand, when the solenoid valves arranged in parallel in the intake passage are energized and the solenoid valve opens and closes, the solenoid valve establishes communication and non-communication between the intake passage and the fuel pump chamber. By switching, the fuel is sucked into the pump chamber from the suction flow path, the fuel is returned from the pump chamber to the suction flow path, or the operation of stopping the fuel suction from the pump chamber is performed. The flow rate is controlled and supplied to the injector. On the other hand, when the solenoid valve is not energized and the solenoid valve does not open / close, the suction check valve causes A constant flow rate of fuel corresponding to the reciprocating movement of the plunger is sucked into the fuel pump chamber from the suction flow passage, and a constant flow rate of the constant flow rate corresponding to the reciprocating movement of the plunger is provided by the discharge check valve provided in the discharge flow passage. A method of controlling fuel supply, characterized in that fuel is discharged from the fuel pump chamber to the discharge passage and supplied to an injector. 9. A fuel supply control method for supplying fuel, which is sucked from a suction flow passage to a discharge flow passage by a plunger that reciprocates in a fuel pump chamber and supplies the fuel to an injector, a solenoid valve provided in the discharge flow passage. When the solenoid valve is energized and opens and closes, the solenoid valve switches between communication and non-communication between the discharge passage and the fuel pump chamber, and controls the flow rate of the fuel to supply it to the injector, On the other hand, when the solenoid valve is not energized and the solenoid valve does not open / close, the suction check valve provided in the suction passage supplies a constant flow of fuel according to the reciprocating movement of the plunger. The fuel is sucked into the fuel pump chamber from the suction flow passage, and a discharge check valve provided in the discharge flow passage provides a constant flow rate of fuel according to the reciprocating movement of the plunger. Fuel supply control method characterized by supplying to the injector discharged from flop chamber to the discharge flow channel.