JP2006220112A - High pressure fuel supply device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate air in a delivery pipe in an engine having an in-cylinder injector.
A high-pressure fuel supply device includes high-pressure delivery communication pipes 500 and 510 for supplying high-pressure fuel from a high-pressure pump to a high-pressure delivery pipe 112A, and a plurality of in-cylinder injectors 110 provided on the high-pressure delivery pipe 112A. The high-pressure delivery pipe 112A and the high-pressure delivery pipe 112B provided with the electromagnetic relief valve 114 are connected to each other. The electromagnetic relief valve 114 is provided at least above the high-pressure delivery pipe 112. The electromagnetic relief valve 114 is opened when the engine is stopped to bring the high-pressure delivery pipe 112B into communication with the fuel tank.
[Selection] Figure 3

Description

  The present invention injects fuel into an intake passage or an intake port in addition to an internal combustion engine having a fuel injection means (in-cylinder injector) for injecting fuel at a high pressure into the cylinder. The present invention relates to a high-pressure fuel supply device for an internal combustion engine including a fuel injection means (intake passage injection injector), and particularly to an internal combustion engine that accurately prevents leakage of fuel from an in-cylinder injector when the internal combustion engine is stopped. The present invention relates to a high-pressure fuel supply device.

  In general, in an automobile engine, fuel is supplied from a fuel tank to an engine (internal combustion engine) via a fuel pump and a fuel pipe, and the fuel is injected into the engine via an injector.

  At this time, in order to improve the high temperature restartability at the time of starting the engine, it is necessary to prevent vapor from being generated in the fuel in the fuel pipe. Therefore, in a conventional fuel injection control device for an internal combustion engine, a check valve is provided on the discharge port side of the fuel pump, and a high fuel pressure is maintained without reducing the residual fuel pressure in the fuel pipe even when the engine is stopped. It is configured as follows.

  However, if the fuel pressure in the fuel pipe is kept high while the engine is stopped, fuel may leak from the injector into the intake pipe. The fuel pressure maintained at a high pressure even when the engine is stopped decreases to an atmospheric pressure equivalent value (= 0.1 [MPa]) in about 60 minutes, but the gasoline leakage during that period is about 20 mcc per fuel pipe. Also reach.

  Such fuel leakage causes unburned HC (toxic gas) in the exhaust gas to increase at the next engine start. It can be seen that the amount of HC emission at the start becomes very large within a time of about 1 second. In addition, since the amount of fuel leakage from the injector cannot be managed, the exhaust gas component at the time of engine start varies.

  Furthermore, the fuel leaking into the intake pipe also increases the fuel evaporation gas from the automobile. Such a state has become an unacceptable level with respect to exhaust gas regulations that are becoming increasingly strict in recent years.

  Japanese Patent Laying-Open No. 2002-317669 (Patent Document 1) discloses a fuel injection control device for an internal combustion engine that reliably prevents fuel leakage from an injector while the engine is stopped. The control device includes various sensors for detecting an operating state of the internal combustion engine, a fuel pump and a fuel pipe for supplying fuel in the fuel tank to the internal combustion engine, an injector for injecting fuel into the internal combustion engine, and an internal combustion engine An engine stop detecting means for detecting a stop state, a fuel temperature estimating means for estimating a fuel temperature in the fuel pipe, and a fuel pressure reducing means for reducing the fuel pressure in the fuel pipe. The fuel pressure in the fuel pipe is reduced according to the estimated fuel temperature value by the fuel temperature estimating means after the stop.

  According to this fuel injection control device for an internal combustion engine, various sensors for detecting the operating state of the internal combustion engine, a fuel pump and a fuel pipe for supplying the fuel in the fuel tank to the internal combustion engine, and fuel injection into the internal combustion engine A fuel pressure reduction means comprising: an injector; an engine stop detection means for detecting a stop state of the internal combustion engine; a fuel temperature estimation means for estimating a fuel temperature in the fuel pipe; and a fuel pressure reduction means for reducing the fuel pressure in the fuel pipe. Since the means reduces the fuel pressure in the fuel pipe in accordance with the estimated fuel temperature value by the fuel temperature estimating means after the internal combustion engine is stopped, fuel leakage from the injector can be reliably prevented while the engine is stopped.

  In the fuel supply device for supplying fuel to the internal combustion engine, the fuel in the fuel tank is pumped to the injector through the delivery pipe. Gases such as air and fuel vapor collected in the delivery pipe are finally injected together with fuel from each injector. Therefore, particularly when the engine is restarted from a high temperature state, the generation of fuel vapor in the delivery pipe increases. As a result, the amount of fuel injected from each injector is less than the expected amount, and the air-fuel ratio is disturbed, which may deteriorate the engine startability.

  Japanese Patent Laid-Open No. 8-189434 (Patent Document 2) discloses an internal combustion engine that prevents a fuel from being injected into a fuel injected from an injector and reducing its fuel amount in a returnless type fuel supply device. A fuel supply apparatus is disclosed. This internal combustion engine fuel supply device discharges fuel in a tank by a pump and pumps the fuel to an injector through a delivery pipe, and adjusts the fuel pressure by a pressure regulator provided upstream from the delivery pipe. A fuel supply device for an internal combustion engine configured to return surplus fuel to the tank from the pressure regulator by adjustment, and is provided at the upper part of the delivery pipe, and a collection chamber for collecting gas that enters or is generated in the pipe A collecting means for collecting the gas collected in the collecting chamber from the delivery pipe, a communicating path for communicating between the collecting chamber and the collecting means, an opening / closing means for opening and closing the communicating path, and an internal combustion engine Control means for controlling the opening and closing means to flow the gas collected in the collection chamber during the stop to the collecting means before starting the internal combustion engine; Provided.

According to the fuel supply device for an internal combustion engine, the gas that has entered or generated in the delivery pipe while the internal combustion engine is stopped is collected in the collection chamber. Then, before the internal combustion engine is started, the control means controls the opening / closing means to open the communication path, whereby the gas collected in the collection chamber flows to the recovery means through the communication path and is recovered. For this reason, no gas is mixed into the fuel injected from the injector when the internal combustion engine is started. Furthermore, since the gas discharged from the delivery pipe is recovered by the recovery means, the gas is never released to the atmosphere.
JP 2002-317669 A JP-A-8-189434

  By the way, a first fuel injection valve (in-cylinder injector) for injecting fuel into the combustion chamber of a gasoline engine and a second fuel injection valve (for intake passage injection) for injecting fuel into the intake passage. 2. Description of the Related Art An engine that includes an injector) and injects fuel by using an in-cylinder injector and an intake passage injector according to the engine speed and the load on the internal combustion engine is known. Further, a direct engine including only a fuel injection valve (in-cylinder injector) for injecting fuel into a combustion chamber of a gasoline engine is also known. In a high-pressure fuel system including an in-cylinder injector, fuel whose fuel pressure has been increased by a high-pressure fuel pump is supplied to the in-cylinder injector via a delivery pipe, and the in-cylinder injector is connected to each cylinder of the internal combustion engine. High pressure fuel is injected into the combustion chamber.

  A diesel engine having a common rail fuel injection system is also known. In this common rail fuel injection system, fuel whose fuel pressure has been increased by a high pressure fuel pump is stored in a common rail, and high pressure fuel is injected from the common rail into the combustion chamber of each cylinder of a diesel engine by opening and closing an electromagnetic valve.

  In order to bring the fuel in such an internal combustion engine into a high pressure state, a high pressure fuel pump that drives a cylinder by a cam provided on a drive shaft connected to a crankshaft of the internal combustion engine is used. The fuel pressure of the high-pressure fuel system having such a configuration is pressurized to a very high pressure of about 14 [MPa].

  For this reason, as described in Patent Document 1, when the fuel pressure in the fuel pipe is reduced after the internal combustion engine is stopped, the fuel pressure during operation of the internal combustion engine is very high. As a result, air is generated in the delivery pipe, or air is leaked into the delivery pipe from the relief valve gap to generate air in the delivery pipe. When air generated in such a delivery pipe is injected from the injector into the fuel chamber, the air-fuel ratio is disturbed when the internal combustion engine is started next time.

  For this reason, as in the fuel supply device for an internal combustion engine disclosed in Patent Document 2, a returnless type collecting chamber for collecting gas such as fuel vapor, a canister including activated carbon as a collecting means, a collecting chamber and a canister It is conceivable to provide a switching valve for switching between a communication state and a non-communication state, and a pipe from the canister to the intake manifold. However, these configurations lead to an increase in cost due to an increase in the number of parts. In addition, a space for mounting these components is required.

  The present invention has been made to solve the above-described problems, and its object is to increase the cost for attaching new components in an internal combustion engine having a fuel injection means for directly injecting fuel into a cylinder. An object of the present invention is to provide a high-pressure fuel supply device for an internal combustion engine that does not require a large space and can eliminate air in a delivery pipe.

  A high-pressure fuel supply device for an internal combustion engine according to a first aspect supplies high-pressure fuel to an internal combustion engine having fuel injection means for injecting fuel into a cylinder. This device is driven by an internal combustion engine and pressurizes fuel supplied from a fuel tank, a delivery pipe for supplying fuel from the high-pressure fuel pump to fuel injection means, and a delivery pipe at a position higher than the delivery pipe. A relief valve provided on the pipe communicating with the pipe and connected to the pipe communicating with the fuel tank.

  According to the first invention, when the relief valve is opened after the internal combustion engine is stopped, the fuel returns to the fuel tank, and there is no fuel leakage from the fuel injection means for injecting the fuel into the cylinder. At this time, the pressure is reduced from a very high pressure to a low pressure (about the pressure in the fuel tank). For this reason, air is generated in the delivery pipe due to reduced-pressure boiling caused by lowering the fuel pressure in the delivery pipe. This air collects in a relief valve provided at a position higher than the delivery pipe. Since the relief valve communicates with the fuel tank, the air collected here moves to the fuel tank. The relief valve becomes an air vent hole. Thereby, it is no longer injected into the fuel chamber from the injector in the delivery pipe, and it is possible to suppress disturbance of the air-fuel ratio at the next start of the internal combustion engine. As a result, in an internal combustion engine having a fuel injection means for directly injecting fuel into a cylinder, high cost fuel for the internal combustion engine that eliminates the need for high cost and wide space for mounting new parts and eliminates air in the delivery pipe. A feeding device can be provided.

  A high-pressure fuel supply apparatus for an internal combustion engine according to a second aspect of the invention is an apparatus for supplying high-pressure fuel to an internal combustion engine having fuel injection means for injecting fuel into a cylinder. This device is provided by a high-pressure fuel pump driven by an internal combustion engine and pressurizing fuel supplied from a fuel tank, a delivery pipe for supplying fuel from the high-pressure fuel pump to the fuel injection means, and an uppermost part of the delivery pipe. And a relief valve connected to a pipe communicating with the fuel tank.

  According to the second invention, when the relief valve is opened after the internal combustion engine is stopped, the fuel returns to the fuel tank, and there is no fuel leakage from the fuel injection means for injecting the fuel into the cylinder. At this time, the pressure is reduced from a very high pressure to a low pressure (about the pressure in the fuel tank). For this reason, air is generated in the delivery pipe due to reduced-pressure boiling caused by lowering the fuel pressure in the delivery pipe. This air collects in a relief valve provided at the top of the delivery pipe. Since the relief valve communicates with the fuel tank, the air collected here moves to the fuel tank. The relief valve becomes an air vent hole. Thereby, it is no longer injected into the fuel chamber from the injector in the delivery pipe, and it is possible to suppress disturbance of the air-fuel ratio at the next start of the internal combustion engine. As a result, in an internal combustion engine having a fuel injection means for directly injecting fuel into a cylinder, high cost fuel for the internal combustion engine that eliminates the need for high cost and wide space for mounting new parts and eliminates air in the delivery pipe. A feeding device can be provided.

  The high pressure fuel supply device for an internal combustion engine according to the third invention further includes a control means for controlling the open / close state of the relief valve in addition to the configuration of the first or second invention. The relief valve is a valve whose open / closed state is switched based on at least one of an electric signal and a hydraulic signal from the control means.

  According to the third aspect of the invention, the control means closes the relief valve (especially fully closed) during operation of the internal combustion engine, opens the relief valve (especially fully open) when the internal combustion engine stops, and delivers the delivery pipe. And the fuel tank in communication with each other, the fuel pressure can be lowered to eliminate fuel leakage from the fuel injection means when the internal combustion engine is stopped. Air generated by boiling under reduced pressure by lowering the fuel pressure is collected in a relief valve provided above the delivery pipe and moved to the fuel tank, so it does not stay in the delivery pipe. Air is no longer ejected from the means.

  The high pressure fuel supply device for an internal combustion engine according to the fourth aspect of the invention further includes control means for controlling the open / close state of the relief valve in addition to the configuration of the first or second aspect of the invention. The relief valve is a valve that is switched between an open state and a closed state based on at least one of an electric signal and a hydraulic signal from the control means.

  According to the fourth aspect of the invention, the control means closes the relief valve when the internal combustion engine is in operation, opens the relief valve when the internal combustion engine stops, and connects the delivery pipe and the fuel tank to make the fuel pressure open. The fuel leakage from the fuel injection means when the internal combustion engine is stopped can be eliminated. Air generated by boiling under reduced pressure by lowering the fuel pressure is collected in a relief valve provided above the delivery pipe and moved to the fuel tank, so it does not stay in the delivery pipe. Air is no longer ejected from the means.

  The high pressure fuel supply device for an internal combustion engine according to the fifth aspect of the invention further includes control means for controlling the open / close state of the relief valve in addition to the configuration of the first or second aspect of the invention. The relief valve is a valve that can set the opening degree between the fully open state and the fully closed state based on at least one of an electric signal and a hydraulic pressure signal from the control means.

  According to the fifth invention, the control means closes the relief valve during operation of the internal combustion engine, and opens the relief valve when the internal combustion engine stops. When this open state is set, for example, the opening of the relief valve may be controlled so as to change linearly so that the fuel pressure changes gradually, and the generation of air due to reduced-pressure boiling may be suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  FIG. 1 shows an engine fuel supply system 10 according to an embodiment of the present invention. This engine is a V-type 8-cylinder gasoline engine, and includes an in-cylinder injector 110 that injects fuel into the cylinder of each cylinder, and an intake passage injector 120 that injects fuel into the intake passage of each cylinder. Have The present invention is not limited to such an engine and may be applied to other types of gasoline engines such as gasoline engines having at least in-cylinder injectors 110 and common rail diesel engines. Good. Furthermore, the number of high-pressure fuel pumps is not limited to two. Further, the type of engine is not limited to the V-type 8-cylinder, and may be a V-type 6-cylinder, an in-line 4 cylinder, an in-line 6 cylinder, or the like.

  As shown in FIG. 1, the fuel supply system 10 is provided in a fuel tank, and is driven by a feed pump 100 that supplies fuel at a low pressure (pressure regulator pressure of about 400 kPa) and a first cam 210. The high-pressure fuel is supplied to the second high-pressure fuel pump 300 driven by the second cam 310 and the in-cylinder injector 110 that are different in discharge phase from the first high-pressure fuel pump 200 and the first cam 210. High pressure delivery pipe 112 provided for each of the left and right banks, four in-cylinder injectors 110 for each of the left and right banks provided in the high pressure delivery pipe 112, and an intake passage injection injector 120. A low pressure delivery pipe 122 provided for each of the left and right banks for supplying fuel, and the low pressure delivery pipe 12 And a left and right banks intake manifold injectors 120 for each of the four provided.

  The discharge port of the fuel tank feed pump 100 is connected to a low-pressure supply pipe 400, and the low-pressure supply pipe 400 branches into a first low-pressure delivery communication pipe 410 and a pump supply pipe 420. The first low-pressure delivery communication pipe 410 becomes a second low-pressure delivery communication pipe 430 on the downstream side of the branch point with the low-pressure delivery pipe 122 of one bank of the V-shaped bank, and the low-pressure delivery pipe 122 of the other bank. It is connected to the.

  The pump supply pipe 420 is connected to the inlets of the first high-pressure fuel pump 200 and the second high-pressure fuel pump 300, respectively. A first pulsation damper 220 is provided in front of the entrance of the first high-pressure fuel pump 200, and a second pulsation damper 320 is provided in front of the entrance of the second high-pressure fuel pump 300, respectively. The fuel pulsation is reduced.

  The discharge port of the first high-pressure fuel pump 200 is connected to the first high-pressure delivery communication pipe 500, and the first high-pressure delivery communication pipe 500 is connected to the high-pressure delivery pipe 112 of one bank of the V-shaped bank. . The discharge port of the second high-pressure fuel pump 300 is connected to the second high-pressure delivery communication pipe 510, and the second high-pressure delivery communication pipe 510 is connected to the high-pressure delivery pipe 112 of the other bank of the V-shaped bank. The The high-pressure delivery pipe 112 of one bank of the V-type bank and the high-pressure delivery pipe 112 of the other bank are connected by a high-pressure communication pipe 520.

  The electromagnetic relief valve 114 provided in the high pressure delivery pipe 112 is connected to the high pressure fuel pump return pipe 600 via the high pressure delivery return pipe 610. Return ports of the high-pressure fuel pump 200 and the high-pressure fuel pump 300 are connected to a high-pressure fuel pump return pipe 600. The high-pressure fuel pump return pipe 600 is connected to the return pipe 620 and the return pipe 630, and is connected to the fuel tank.

  FIG. 2 shows an enlarged view of the vicinity of the first high-pressure fuel pump 200 of FIG. The same applies to the second high-pressure fuel pump 300, but the cam phase is different and the discharge timing phase is shifted to suppress the occurrence of pulsation. The characteristics of the first high-pressure fuel pump 200 and the second high-pressure fuel pump 300 may be the same or different.

  The high-pressure fuel pump 200 includes a pump plunger 206 that is driven by a cam 210 and slides up and down, an electromagnetic spill valve 202, and a check valve 204 with a leak function as main components.

  When the pump plunger 206 is moved downward by the cam 210 and the electromagnetic spill valve 202 is open, fuel is introduced (sucked), and the pump plunger 206 is moved upward by the cam 210. When the electromagnetic spill valve 202 is closed, the timing for closing the electromagnetic spill valve 202 is changed to control the amount of fuel discharged from the high pressure fuel pump 200. The earlier the timing for closing the electromagnetic spill valve 202 during the pressurization stroke in which the pump plunger 206 is moving upward, the more fuel is discharged, and the slower the fuel is discharged, the slower. The driving duty of the electromagnetic spill valve 202 when discharging the most is 100%, and the driving duty of the electromagnetic spill valve 202 when discharging the least is 0%. When the drive duty of the electromagnetic spill valve 202 is 0%, the electromagnetic spill valve 202 remains open without closing, and as long as the first cam 210 is rotating (as long as the engine is rotating). ) The pump plunger 206 slides in the vertical direction, but the fuel is not pressurized because the electromagnetic spill valve 202 does not close.

  The pressurized fuel is pushed open to the high pressure delivery pipe 112 via the first high pressure delivery communication pipe 500 by pushing open the check valve 204 with a leak function (set pressure of about 60 kPa). At this time, the fuel pressure is feedback controlled by a fuel pressure sensor provided in the high pressure delivery pipe 112. Further, as described above, the high pressure delivery pipe 112 of one bank of the V type and the high pressure delivery pipe 112 of the other bank are communicated by the high pressure communication pipe 520.

  In the high-pressure fuel supply apparatus according to the present embodiment, when the engine is stopped, the electromagnetic relief valve 114 provided in the high-pressure delivery pipe 112 is opened by an engine ECU (Electronic Control Unit) and the high-pressure delivery pipe 112 and the fuel tank are opened. And the fuel pressure is lowered to avoid fuel leakage from the in-cylinder injector 110. In this way, air is generated by reduced-pressure boiling caused by lowering the fuel pressure in the high-pressure delivery pipe 112. In the present embodiment, the installation position of the electromagnetic relief valve 114 is the uppermost part of the high-pressure delivery pipe 112 itself. Further, the electromagnetic relief valve 114 may be installed in a pipe communicating with the high-pressure delivery pipe 112 so that the installation position is above the high-pressure delivery pipe 112. In the following description, the latter case will be described.

  The position of the electromagnetic relief valve 114 will be described with reference to FIGS. 3 (A) and 3 (B).

  As shown in FIGS. 3A and 3B, in the present embodiment, the high pressure delivery pipe 112 is provided with a high pressure delivery pipe 112A connected to the in-cylinder injector and an electromagnetic relief valve 114. The high-pressure delivery pipe 112B, and the pipe 112C that connects the high-pressure delivery pipe 112A and the high-pressure delivery pipe 112B.

  The electromagnetic relief valve 114 is provided in the high pressure delivery pipe 112B, and the position of the electromagnetic relief valve 114 is higher than the position of the high pressure delivery pipe 112A. That is, since the electromagnetic relief valve 114A is closed when the engine is in operation, the fuel supplied from the high-pressure pump to the high-pressure delivery pipe 112A from the high-pressure delivery communication pipes 500 and 510 is transferred from the in-cylinder injector 110 to the combustion chamber. Direct fuel injection.

  On the other hand, when the engine is stopped, the electromagnetic relief valve 114 is opened, and the electromagnetic relief valve 114A communicates with the fuel tank via the high-pressure delivery return pipe 610 and the return pipes 620 and 630, so the fuel in the delivery pipe 112A is It returns to the fuel tank from the electromagnetic relief valve 114 through the pipe 112C. At this time, the fuel pressure is rapidly reduced. Air is generated by boiling under reduced pressure in the high-pressure delivery pipe 112A. Air generated in the high-pressure delivery pipe 112A moves to the high-pressure delivery pipe 112B through the pipe 112C.

  This is because, in the delivery pipe 112, the high pressure delivery pipe 112A to which the in-cylinder injector 110 is connected is lower than the high pressure delivery pipe 112B in which the electromagnetic relief valve 114 is provided (the high pressure delivery pipe 112B is located at the high pressure delivery pipe 112A). This is because the air generated in the high-pressure delivery pipe 112A gathers in the vicinity of the electromagnetic relief valve 114 because the electromagnetic relief valve 114 is at the uppermost position. Since the electromagnetic relief valve 114 is open when the engine is stopped, the air moves to the fuel tank. In this way, the fuel pressure in the high-pressure delivery pipe 112A is lowered until it becomes the same as the pressure in the fuel tank, and fuel leakage from the in-cylinder injector 110 to the combustion chamber can be prevented.

  As described above, the electromagnetic relief valve 114 may be configured to be provided at the uppermost portion of the high-pressure delivery pipe 112A so that the pipe 112C and the high-pressure delivery pipe 112B are not provided.

  A control structure of a program executed by the engine ECU that controls the high-pressure fuel supply apparatus according to the present embodiment will be described with reference to FIG.

  In step (hereinafter step is abbreviated as S) 100, the engine ECU determines whether or not the ignition is turned off. If the ignition is turned off (YES in S100), the process proceeds to S200. If not (NO in S100), the process returns to S100 and waits until the ignition switch is turned off.

  In S200, engine ECU transmits an open signal to electromagnetic relief valve 114. In S300, the engine ECU detects a fuel pressure P that is the pressure of the fuel in the high-pressure delivery pipe. At this time, the fuel pressure P is detected based on a signal input to the engine ECU from the fuel pressure sensor shown in FIG. It is determined whether or not the detected fuel pressure P is lower than a P threshold value that is a predetermined threshold value for the fuel pressure P. If fuel pressure P <P threshold value (YES in S400), the process proceeds to S500. If not (NO in S400), the process proceeds to S600.

  In S500, the engine ECU transmits a close signal to electromagnetic relief valve 114.

  In S600, the engine ECU performs an abnormality process. In this abnormality process, for example, a diagnosis indicating that the electromagnetic relief valve 114 is abnormal is stored in the memory.

  The operation of the fuel supply device according to the present embodiment based on the above-described structure and flowchart will be described.

  When a vehicle equipped with an engine having an in-cylinder injector 110 is running, a high-pressure fuel is supplied from the high-pressure pump to the high-pressure delivery pipe 112 with the electromagnetic relief valve 114 closed, and the combustion chamber is supplied from the in-cylinder injector 110. The fuel is directly injected into the tank. Further, depending on the engine speed and load, fuel is injected only from the in-cylinder injector 110, fuel is injected only from the intake manifold injector 120, or fuel is injected from both of these injectors. .

  When the vehicle stops and the ignition switch is turned off (YES in S100), an open signal that opens electromagnetic relief valve 114 is transmitted. As a result, the electromagnetic relief valve 114 is changed from the closed state to the open state. Since the electromagnetic relief valve 114 communicates the high pressure delivery pipe 112 with the fuel tank, the fuel pressure in the high pressure delivery pipe 112 is greatly reduced.

  At this time, when the electromagnetic relief valve 114 is opened, the fuel pressure in the high-pressure delivery pipe is greatly reduced, and air may be generated due to boiling under reduced pressure. The air generated in the high pressure delivery pipe 112 is moved to the fuel tank through the electromagnetic relief valve 114. Therefore, air does not remain in the high-pressure delivery pipe, and a factor that disturbs the air-fuel ratio control by injecting air from the in-cylinder injector 110 at the time of restart can be avoided.

  When the fuel pressure is detected by the fuel pressure sensor provided in the high pressure delivery pipe 112 (S300) and the fuel pressure P has decreased to a value lower than the threshold (YES in S400), the electromagnetic relief valve 114 is closed. A signal is transmitted (S500), and the electromagnetic relief valve 114 is closed.

  As described above, according to the high-pressure fuel supply apparatus according to the present embodiment, the high-pressure delivery pipe is provided with the electromagnetic relief valve that is opened when the engine is stopped and that brings the fuel tank and the high-pressure delivery pipe into communication. The position of the electromagnetic relief valve was set to be higher than at least the high-pressure delivery pipe. Therefore, even if air is generated in the high-pressure delivery pipe by boiling under reduced pressure, the air is moved to the fuel tank through the electromagnetic relief valve. For this reason, air does not remain in the high-pressure delivery pipe, and air-fuel ratio control can be stabilized without injecting air from the in-cylinder injector when the engine is restarted. In addition, since the fuel pressure in the high-pressure delivery pipe can be reduced, fuel leakage from the in-cylinder injector can be avoided. Furthermore, since the fuel pressure in the high-pressure delivery pipe has been abnormally high (such as when the pressure exceeds 14 MPa), an electromagnetic relief valve has been provided instead of a relief valve (relief valve) that allows the fuel to escape. In particular, no new space is required.

  The opening degree of the electromagnetic relief valve 114A may be linearly controlled by the engine ECU.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall schematic diagram of a fuel supply system for a gasoline engine controlled by a control device according to an embodiment of the present invention. It is the elements on larger scale of FIG. FIG. 2 is a partial perspective view of FIG. 1. It is a flowchart which shows the control structure of the program performed in the control apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel supply system, 100 Feed pump, 110 In-cylinder injector, 112 High pressure delivery pipe, 114 Electromagnetic relief valve, 120 Intake passage injection injector, 122 Low pressure delivery pipe, 200 1st high pressure fuel pump, 202 Electromagnetic spill valve 204, check valve with leak function, 206 pump plunger, 210 first cam, 220 first pulsation damper, 300 second high pressure fuel pump, 310 second cam, 320 second pulsation damper, 400 Low pressure supply pipe, 410 First low pressure delivery communication pipe, 420 Pump supply pipe, 430 Second low pressure delivery communication pipe, 500 First high pressure delivery communication pipe, 510 Second high pressure delivery communication pipe, 520 High pressure communication Pipe, 600 high pressure fuel pump return pipe, 610 high pressure delivery return pipe, 620, 630 return pipe.

Claims (5)

A high-pressure fuel supply device for an internal combustion engine having fuel injection means for injecting fuel into a cylinder,
A high pressure fuel pump driven by the internal combustion engine and pressurizing fuel supplied from a fuel tank;
A delivery pipe for supplying fuel from the high-pressure fuel pump to the fuel injection means;
A high-pressure fuel supply device for an internal combustion engine, comprising a relief valve provided in a pipe communicating with the delivery pipe at a position higher than the delivery pipe and connected to the pipe communicating with the fuel tank. A high-pressure fuel supply device for an internal combustion engine having fuel injection means for injecting fuel into a cylinder,
A high pressure fuel pump driven by the internal combustion engine and pressurizing fuel supplied from a fuel tank;
A delivery pipe for supplying fuel from the high-pressure fuel pump to the fuel injection means;
A high-pressure fuel supply device for an internal combustion engine, comprising: a relief valve provided at an uppermost portion of the delivery pipe and connected to a pipe communicating with the fuel tank. The high-pressure fuel supply device further includes a control means for controlling an open / close state of the relief valve,
3. The high-pressure fuel supply device for an internal combustion engine according to claim 1, wherein the relief valve is a valve whose open / close state is switched based on at least one of an electric signal and a hydraulic pressure signal from the control means. The high-pressure fuel supply device further includes a control means for controlling an open / close state of the relief valve,
3. The high-pressure fuel supply for an internal combustion engine according to claim 1, wherein the relief valve is a valve that is switched between an open state and a closed state based on at least one of an electric signal and a hydraulic signal from the control means. apparatus. The high-pressure fuel supply device further includes a control means for controlling an open / close state of the relief valve,
The internal combustion engine according to claim 1 or 2, wherein the relief valve is a valve capable of setting an opening degree between a fully open state and a fully closed state based on at least one of an electric signal and a hydraulic pressure signal from the control means. High pressure fuel supply system for engines.

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