JP2012188960A - Fuel supply device for internal combustion engine and high pressure pump for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the fuel pressure on the downstream side of an ejection valve in a high pressure passage to an appropriate level during normal operation of a high pressure pump and to restrain stall of the engine at an abnormal operation of the high pressure pump.SOLUTION: The fuel supply device comprises an ejection valve 19 provided in a high pressure passage to be opened when the fuel pressure from a compression chamber is the same as or higher than the ejection pressure for allowing pressure feed of the fuel to the fuel injection valve side; a relief valve 30 provided in a relief passage 40 for detouring the ejection valve 19 in the high pressure passage to be opened when the downstream side fuel pressure being the pressure of the fuel on the downstream side of the ejection valve 19 is the same as or higher than the relief pressure for relieving a part of the fuel to the upstream side of the ejection valve 19, and a holding mechanism (A) for holding the relief valve 30 in an open state when the downstream side fuel pressure is the same as or higher than an abnormal pressure higher than the maximum value of a range of the downstream side fuel pressure during normal operation of the high pressure pump.

Description

  The present invention relates to a fuel supply device for a direct injection internal combustion engine and a high pressure pump for the internal combustion engine.

  Conventionally, as a fuel supply device for this type of internal combustion engine and a high-pressure pump for the internal combustion engine, for example, there is one disclosed in Patent Document 1. In the conventional general fuel supply apparatus including the one described in Patent Document 1, the fuel stored in the fuel tank is pressurized by the feed pump and is pumped to the high pressure pump via the low pressure passage. The fuel further pressurized by the high-pressure pump is pumped to the fuel injection valve through the high-pressure passage, and is directly injected into the cylinder from the fuel injection valve.

  Here, the high-pressure pump includes a plunger that reciprocates in the pressurizing chamber by an engine-driven cam, and the fuel sucked into the pressurizing chamber is pressurized by the plunger. Further, an electromagnetically driven spill valve is provided between the low pressure passage and the pressurizing chamber, and the suction is taken into the pressurizing chamber by changing the opening / closing timing of the spill valve with respect to the reciprocating motion of the plunger. The amount of fuel, that is, the discharge amount discharged from the pressurizing chamber to the high-pressure passage is changed.

  In addition, a discharge valve is provided in the high-pressure passage, and when the pressure of fuel from the pressurizing chamber becomes equal to or higher than a predetermined discharge pressure, the discharge valve opens to keep the fuel pressure downstream of the discharge valve constant. Has been.

JP 2009-103101 A

  By the way, at the time of high temperature restart, for example, the temperature of the fuel pipe constituting the high pressure passage is high, and the temperature of the fuel in the fuel pipe is high. For this reason, the pressure of the fuel becomes excessively high, and there is a possibility that the fuel injection control cannot be performed accurately.

  In addition, when an abnormality occurs in the high pressure pump, such as a broken spill valve needle, the amount of fuel discharged by the high pressure pump is fixed to the maximum discharge amount. In this case, if the pressure of the fuel in the high pressure passage further increases, the fuel injection valve cannot be opened, and the operation of the internal combustion engine may stop.

  The present invention has been made in view of such circumstances, and its purpose is to maintain the pressure of the fuel downstream of the discharge valve in the high pressure passage at an appropriate level when the high pressure pump is normal, and An object of the present invention is to provide a fuel supply device for an internal combustion engine and a high-pressure pump for the internal combustion engine that can suppress the engine stop when an abnormality occurs.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
The invention according to claim 1 is provided with a high pressure pump that sucks low pressure fuel supplied through the low pressure passage and pressurizes the low pressure fuel in the pressurizing chamber and pumps the low pressure fuel to the fuel injection valve through the high pressure passage. A fuel supply device for an internal combustion engine comprising: a discharge valve that opens when the pressure of the fuel from the pressurizing chamber side becomes equal to or higher than a predetermined discharge pressure, and allows the fuel to be pumped to the fuel injection valve side; A valve provided in a relief passage that bypasses the discharge valve in the high-pressure passage and opens when a downstream fuel pressure, which is a pressure of fuel downstream of the discharge valve, becomes equal to or higher than a relief pressure, and part of the fuel is opened. A relief valve that relieves upstream of the discharge valve, and holds the relief valve open when the downstream fuel pressure exceeds the abnormal pressure that is higher than the maximum value that can be taken when the high-pressure pump is normal Do And an injection control unit that controls the fuel injection valve to inject the low-pressure fuel from the fuel injection valve when the relief valve is held in the open state by the holding mechanism. The gist of this is.

  According to this configuration, when the high-pressure pump is operating normally, the urging force of the spring and the back pressure, which is the pressure of the fuel from the pressurizing chamber, act on the valve body of the relief valve in the valve closing direction. Fuel pressure acts in the valve opening direction. In the high pressure pump, the pressure of the fuel in the pressurizing chamber is increased and the back pressure increases, so that the force acting on the valve body in the valve closing direction always exceeds the force acting on the valve opening direction. It becomes like this. Therefore, the relief valve does not open.

  In the suction stroke of the high pressure pump, the fuel pressure in the pressurizing chamber is lower than the downstream fuel pressure. Here, when the temperature of the fuel pipe that constitutes the high-pressure passage is high as in the high temperature restart, the temperature of the fuel in the fuel pipe is high, and the fuel pressure increases accordingly, The downstream fuel pressure may be higher than the relief pressure. In this case, the force acting in the valve closing direction on the valve body of the relief valve is less than the force acting in the valve opening direction. For this reason, the relief valve is opened, the fuel is relieved, and the downstream fuel pressure decreases.

  As described above, the relief valve is basically closed, but when the downstream side fuel pressure becomes equal to or higher than the relief pressure, the relief side valve is opened during the intake stroke to maintain the downstream side fuel pressure at an appropriate level. Will be able to.

  On the other hand, when an abnormality occurs in which the fuel discharge amount by the high-pressure pump is fixed to the maximum discharge amount, and the downstream side fuel pressure becomes higher than the abnormal pressure higher than the maximum value that can be taken when the high-pressure pump is normal, The valve is held open. For this reason, the low-pressure fuel supplied to the pressurizing chamber via the low-pressure passage is pumped to the fuel injection valve via the relief valve and the high-pressure passage without being pressurized. The operation of the internal combustion engine can be continued by controlling the valve opening time of the fuel injection valve in accordance with the low fuel pressure.

  Therefore, when the high pressure pump is normal, the pressure of the fuel downstream of the discharge valve in the high pressure passage can be maintained at an appropriate level, and the engine operation can be continued even when the high pressure pump is abnormal.

  According to a second aspect of the present invention, in the fuel supply device for an internal combustion engine according to the first aspect, the holding mechanism mechanically restricts movement of the valve body of the relief valve and opens the relief valve. The gist of the invention is that it is configured to be held at the same time.

According to this configuration, since an electrical configuration or a magnetic configuration for holding the relief valve in the open state is unnecessary, the holding mechanism can be easily realized.
According to a fuel supply device for an internal combustion engine according to a second aspect of the present invention, as in the invention according to the third aspect, the holding mechanism includes a recess formed in a peripheral surface of the valve body and a peripheral surface of the valve body. A restricting portion that is biased toward the valve body, and when the displacement amount of the valve body increases to a predetermined amount, the restricting portion is fitted into a concave portion of the valve body to move the valve body. The embodiment can be embodied in such a manner that it is configured to mechanically limit. In this case, when the displacement amount of the valve body increases to become a predetermined amount, the movement of the valve body is mechanically restricted by fitting the restriction portion into the concave portion of the valve body. . Therefore, the holding mechanism can have a simple configuration.

  According to a fourth aspect of the present invention, in the fuel supply device for an internal combustion engine according to any one of the first to third aspects, the relief valve is integrally formed with the high-pressure pump. Yes.

According to this configuration, the configuration of the entire fuel supply device can be simplified.
The invention according to claim 5 is a high-pressure pump that sucks low-pressure fuel supplied through the low-pressure passage, pressurizes the low-pressure fuel in the pressurizing chamber, and pumps the low-pressure fuel to the fuel injection valve through the high-pressure passage. An internal combustion engine having a discharge valve that opens when the pressure of the fuel from the pressurizing chamber side becomes equal to or higher than a predetermined discharge pressure and allows the fuel to be pumped to the fuel injection valve side. A valve provided in a relief passage that bypasses the discharge valve in the high-pressure passage and opens when a downstream fuel pressure, which is a pressure of fuel downstream of the discharge valve, becomes equal to or higher than a relief pressure, and part of the fuel is opened. A relief valve that relieves upstream of the discharge valve, and holds the relief valve open when the downstream fuel pressure exceeds the abnormal pressure that is higher than the maximum value that can be taken when the high-pressure pump is normal You A holding mechanism, in that it comprises has as its gist.

  According to this configuration, when the high-pressure pump is normal, the pressure of the fuel downstream of the discharge valve is maintained at an appropriate level in the high-pressure passage, and when the high-pressure pump is abnormal, the pressure is supplied to the pressurizing chamber via the low-pressure passage. The low pressure fuel can be pumped to the fuel injection valve via the high pressure passage without being pressurized. If the valve opening time of the fuel injection valve is controlled according to such a low fuel pressure, the operation of the internal combustion engine can be continued.

1 is a schematic diagram showing a schematic configuration of a fuel supply device for an internal combustion engine according to an embodiment of the present invention. Sectional drawing which shows the cross-section of the relief valve of the valve closing state in the embodiment. Sectional drawing which shows the cross-section of the relief valve of the valve opening state in the embodiment.

  Hereinafter, an embodiment of a fuel supply device for an internal combustion engine according to the present invention will be described in detail with reference to FIGS. Note that the internal combustion engine of the present embodiment is a cylinder injection internal combustion engine.

  As shown in FIG. 1, in the fuel supply device 1, an electric feed pump 3 is disposed in a fuel tank 2, and a low pressure fuel supply pipe 4 is connected to the feed pump 3. The fuel stored in the fuel tank 2 is sucked by the feed pump 3 and pressurized to a predetermined feed pressure PF (for example, several hundred kPa) and is pumped to the low pressure fuel supply pipe 4 as a low pressure fuel.

  A high pressure pump 10 is connected to the downstream side of the low pressure fuel supply pipe 4. A return pipe 5 is branched and connected to the low pressure fuel supply pipe 4. A pressure regulating valve 6 is provided in the middle of the return pipe 5, and the pressure regulating valve 6 is opened when the fuel pressure in the low pressure fuel supply pipe 4 becomes equal to or higher than the feed pressure PF. As a result, part of the fuel discharged from the feed pump 3 is returned to the fuel tank 2 via the return pipe 5 so that the pressure of the fuel in the low-pressure fuel supply pipe 4 is maintained at a predetermined level. It has become.

  Inside the casing 11 of the high-pressure pump 10, a suction passage 12 connected to the downstream side of the low-pressure fuel supply pipe 4, a cylinder 13 connected to the downstream side of the suction passage 12, and a downstream side of the cylinder 13 are connected. A discharge passage 14 is formed.

  The cylinder 13 has a substantially cylindrical shape, and an inlet 21 for sucking low-pressure fuel is formed at an upstream end portion (upper end portion in FIG. 1), and a side surface thereof (right side surface in FIG. 1). Is formed with a discharge port 22 for discharging high-pressure fuel. A plunger 15 is provided in the cylinder 13 so as to reciprocate. A pressurizing chamber 16 is defined by the inner wall of the cylinder 13 and the top surface of the plunger 15. The discharge port 22 is formed so as to communicate with the pressurizing chamber 16.

  In the cylinder 13, a valve body 23 of the spill valve 20 that opens and closes the suction port 21 is provided. The valve body 23 is provided so as to be movable along the axial direction of the cylinder 13 via a needle 23a. The spill valve 20 is a so-called normally open valve, and is urged in a direction to open the suction port 21 by the urging force of the spring 25. The spill valve 20 is sucked in a direction to close the suction port 21 by energizing the solenoid 24. When the solenoid 24 is not energized, the valve body 23 is biased in the direction away from the suction port 21 (downward in FIG. 1) by the biasing force of the spring 25, and the suction port 21 is opened. On the other hand, when the solenoid 24 is energized, the valve body 23 is sucked by the solenoid 24 in a direction close to the suction port 21 (upward in FIG. 1), and the suction port 21 is closed. Such energization control of the solenoid 24 is performed by the electronic control unit 90.

  The plunger 15 is driven by the rotation of the crankshaft of the internal combustion engine. Specifically, the intake camshaft 51 is rotationally driven by the rotation of the crankshaft, and the plunger 15 reciprocates as the cam 52 fixed to the intake camshaft 51 rotates. A lifter 17 is provided below the plunger 15, and the lifter 17 is maintained in contact with the cam surface of the cam 52 by the biasing force of the spring 18.

  In the high-pressure pump 10, when the plunger 15 descends and the volume of the pressurizing chamber 16 increases, the electronic control device 90 sets the solenoid 24 in a non-energized state and opens the suction port 21, whereby the low-pressure fuel supply pipe 4 and Low-pressure fuel from the suction passage 12 is sucked into the pressurizing chamber 16 (intake stroke).

  Further, when the plunger 15 moves up and the volume of the pressurizing chamber 16 decreases, the electronic control device 90 energizes the solenoid 24 to close the suction port 21 so that the fuel in the pressurizing chamber 16 is pressurized. Then, the high pressure fuel having a predetermined pressure (for example, 35 MPa) is discharged from the discharge port 22 to the discharge passage 14. Further, by adjusting the energization timing of the solenoid 24, that is, the closing timing of the suction port 21, the fuel intake amount is adjusted.

  A high pressure fuel supply pipe 7 is connected to the outside of the high pressure pump 10 and downstream of the discharge passage 14, and a delivery pipe 8 is connected to the downstream side of the high pressure fuel supply pipe 7. A fuel injection valve 9 for injecting and supplying fuel into each cylinder is connected to the delivery pipe 8. The drive control of the fuel injection valve 9 is performed by the electronic control unit 90.

  A discharge valve 19 for making the pressure of the fuel supplied to the high-pressure fuel supply pipe 7 constant is provided in the middle of the discharge passage 14. When the pressure of the fuel acting on the valve body 19a of the discharge valve 19 from the pressurizing chamber 16 side becomes equal to or higher than a predetermined discharge pressure PD (for example, 20 MPa), a spring 19b that biases the valve body 19a in the valve closing direction is attached. Displacement of the valve body 19a against the force causes the discharge valve 19 to open. As a result, the fuel is allowed to be pumped to the fuel injection valve 9 side.

  Inside the high-pressure pump 10 of the present embodiment, a relief passage 40 that is branched and connected to the discharge passage 14 and bypasses the discharge valve 19 is provided. A relief valve 30 is provided in the middle of the relief passage 40. ing.

Next, the configuration of the relief valve 30 will be described in detail.
As shown in FIG. 2, a valve body accommodating portion 33 that is a substantially cylindrical space is formed in the casing 11, and one end (right end in FIG. 2) of the valve body accommodating portion 33 is provided with a discharge valve 19. A relief passage 40 connected to the downstream side is open. A relief passage 40 connected to the upstream side of the discharge valve 19 is opened on the inner peripheral surface on the other end side (left side in FIG. 2) of the valve body housing portion 33. In addition, a spring accommodating portion 34 that is a substantially columnar space and has a diameter smaller than that of the valve element accommodating portion 33 is formed in communication with the other end of the valve element accommodating portion 33.

  A substantially cylindrical valve element 35 is accommodated in the valve element accommodating part 33 so as to be displaceable along the central axis direction of the valve element accommodating part 33. In addition, a spring 36 is provided in the spring accommodating portion 34, and the valve body 35 is urged by the spring 36 in a direction to close one end side of the valve element accommodating portion 33, that is, one end side opening. That is, the urging force of the spring 36 and the back pressure that is the pressure of the fuel from the pressurizing chamber 16 act on the valve body 35 in the valve closing direction, while the downstream fuel pressure Px acts in the valve opening direction. Here, when the downstream side fuel pressure Px becomes equal to or higher than the relief pressure PR (for example, 25 MPa) higher than the upper limit value Pth1 (for example, 22 MPa) of the range in which the fuel injection valve 9 can be opened, the valve body 35 starts to be displaced in the valve opening direction. Thus, the spring coefficient of the spring 36 is set.

  In the present embodiment, a pin housing portion 37 that is a substantially columnar space is formed in communication with the inner peripheral surface of the valve body housing portion 33 so as to be oriented in the radial direction. Further, a substantially cylindrical pin 38 is inserted into the pin housing portion 37, and this pin 38 is urged toward the valve body housing portion 33 by a spring 39.

A concave portion 35 a into which the pin 38 can be fitted is formed on the outer peripheral surface of the valve body 35.
As shown in FIG. 3, when the amount of displacement of the valve body 35 in the valve opening direction increases to a predetermined amount L, the pin 38 is fitted into the recess 35 a of the valve body 35. This predetermined amount L is the amount of displacement of the valve body 35 from the fully closed position when the downstream fuel pressure Px becomes the abnormal pressure Pth2 due to an abnormality occurring in the high-pressure pump 10. Here, the abnormal pressure Pth2 is higher than the maximum value Pmax of the range that can be taken when the high-pressure pump 10 is normal (Pmax <Pth2). Therefore, in the relief valve 30, when the downstream fuel pressure Px becomes equal to or higher than the abnormal pressure Pth2 due to an abnormality such as breakage of the needle 23a that supports the valve body 23 of the high pressure pump 10, the holding mechanism A The pin 38 is fitted into the concave portion 35a of the functioning valve body 35. As a result, the relief valve 30 is kept open thereafter. Incidentally, the relief pressure PR is set lower than the maximum value Pmax (PR <Pmax). When the relief valve 30 is held in the open state by the holding mechanism A, the low pressure fuel is injected from the fuel injection valve 9 through the electronic control unit 90. The valve opening time is controlled.

Next, the operation of this embodiment will be described.
In the normal pressure-feeding stroke of the high-pressure pump 10, the pressure of the fuel in the pressurizing chamber 16 is increased and the back pressure increases, so that the force acting on the valve body 35 in the valve closing direction acts in the valve opening direction. It will always exceed the power. Therefore, the relief valve 30 does not open.

  Further, in the intake stroke of the high pressure pump 10, the fuel pressure in the pressurizing chamber 16 is lower than the downstream fuel pressure Px. Here, when the temperature of the delivery pipe 8 is high as in the high temperature restart, the temperature of the fuel in the delivery pipe 8 is high, and the fuel pressure rises accordingly, so the downstream side fuel pressure Px May exceed the relief pressure PR. In this case, the force acting in the valve closing direction on the valve body 35 of the relief valve 30 becomes lower than the force acting in the valve opening direction. For this reason, the relief valve 30 is opened, the fuel is relieved, and the downstream fuel pressure Px decreases. Thus, although the relief valve 30 is basically closed, when the downstream side fuel pressure Px becomes equal to or higher than the relief pressure PR, the relief valve is opened during the intake stroke, so that the downstream side fuel pressure Px is reduced. It is maintained at an appropriate size.

  On the other hand, an abnormality occurs in which the amount of fuel discharged by the high-pressure pump 10 is fixed to the maximum discharge amount, and the downstream fuel pressure Px is higher than the abnormal-time pressure Pth2 that is higher than the maximum value Pmax that can be taken when the high-pressure pump 10 is normal. When this happens, the relief valve 30 is held in the open state by the holding mechanism A. For this reason, the low-pressure fuel supplied to the pressurizing chamber 16 via the low-pressure fuel supply pipe 4 and the suction passage 12 is not pressurized, and the discharge passage 14, the relief passage 40, the relief valve 30, the high-pressure fuel supply pipe 7, The fuel is fed to the fuel injection valve 9 through the delivery pipe 8. The operation of the internal combustion engine is continued by controlling the valve opening time of the fuel injection valve 9 according to such a low fuel pressure.

  The low pressure fuel supply pipe 4 and the suction passage 12 correspond to the low pressure passage according to the present invention. Further, the discharge passage 14, the high-pressure fuel supply pipe 7, and the delivery pipe 8 correspond to the high-pressure passage according to the present invention. The electronic control device 90 corresponds to the injection control unit according to the present invention. The pin 38 corresponds to the limiting unit according to the present invention.

According to the fuel supply device for an internal combustion engine according to the present embodiment described above, the following effects can be obtained.
(1) The fuel supply device 1 pressurizes the low-pressure fuel supplied through the low-pressure fuel supply pipe 4 and the suction passage 12 in the pressurizing chamber 16 by the reciprocation of the plunger 15, the discharge passage 14, and the high-pressure fuel supply pipe 7. And a high-pressure pump 10 that pumps the fuel to the fuel injection valve 9 via the delivery pipe 8. Further, a discharge valve 19 is provided which is provided in the discharge passage 14 and opens when the pressure of the fuel from the pressurizing chamber 16 side becomes equal to or higher than a predetermined discharge pressure PD and allows the fuel to be pumped to the fuel injection valve 9 side. ing. Further, the valve is provided in a relief passage 40 that bypasses the discharge valve 19 in the discharge passage 14 and opens when the downstream fuel pressure Px, which is the pressure of the fuel downstream of the discharge valve 19, becomes equal to or higher than the relief pressure PR. A relief valve 30 is provided to relieve part of the fuel upstream of the discharge valve 19. Further, a holding mechanism A is provided that holds the relief valve 30 in the open state when the downstream side fuel pressure Px becomes equal to or higher than the abnormal pressure Pth2 that is higher than the maximum value Pmax that can be taken when the high pressure pump 10 is normal. . Further, the electronic control unit 90 is configured to control the fuel injection valve 9 so as to inject low-pressure fuel from the fuel injection valve 9 when the relief valve 30 is held in the open state by the holding mechanism A. ing.

  According to such a configuration, the relief valve 30 is basically closed, but when the downstream side fuel pressure Px becomes equal to or higher than the relief pressure PR, the relief valve 30 is opened during the intake stroke, so that the downstream side fuel pressure Px is appropriately set. It will be possible to maintain a large size. On the other hand, an abnormality occurs in which the amount of fuel discharged by the high-pressure pump 10 is fixed to the maximum discharge amount, and the downstream fuel pressure Px is higher than the abnormal-time pressure Pth2 that is higher than the maximum value Pmax that can be taken when the high-pressure pump 10 is normal. When this happens, the relief valve 30 is held open. For this reason, the low-pressure fuel supplied to the pressurizing chamber 16 via the low-pressure fuel supply pipe 4 and the suction passage 12 is not pressurized, and the discharge passage 14, the relief passage 40, the relief valve 30, the high-pressure fuel supply pipe 7, The fuel is fed to the fuel injection valve 9 through the delivery pipe 8. The operation of the internal combustion engine can be continued by controlling the valve opening time or the like of the fuel injection valve 9 according to such a low fuel pressure. Accordingly, when the high-pressure pump 10 is normal, the downstream side fuel pressure Px is maintained at an appropriate level, and the engine operation can be continued even when the high-pressure pump 10 is abnormal.

  (2) The holding mechanism A is configured to mechanically limit the movement of the valve body 35 of the relief valve 30 and hold the relief valve 30 in the open state. According to such a configuration, the holding mechanism A can be easily realized because an electrical configuration or a magnetic configuration for holding the relief valve 30 in the open state is unnecessary.

  (3) The holding mechanism A includes a recess 35a formed on the peripheral surface of the valve body 35 and a pin 38 that is biased toward the peripheral surface of the valve body 35, and the displacement amount of the valve body 35 increases. Thus, the pin 38 is fitted into the recess 35a of the valve body 35 when the predetermined amount L is reached. According to such a configuration, when the displacement amount of the valve body 35 increases to a predetermined amount L, the pin 38 is fitted into the recess 35a of the valve body 35, so that the movement of the valve body 35 is mechanically performed. Be restricted. Therefore, the holding mechanism A can have a simple configuration.

(4) The relief valve 30 is formed integrally with the high-pressure pump 10. According to such a configuration, the overall configuration of the fuel supply device 1 can be simplified.
The fuel supply device for an internal combustion engine and the high-pressure pump for the internal combustion engine according to the present invention are not limited to the configurations exemplified in the above-described embodiments, and are implemented as, for example, the following forms appropriately modified. You can also.

  In the above embodiment, the relief pressure PR of the relief valve 30 is set higher than the upper limit value Pth1 of the range in which the fuel injection valve 9 can be opened. Instead, the relief pressure is set lower than the upper limit value Pth1. It can also be set.

  -Although illustrated about what the relief valve 30 is integrally formed with the high pressure pump 10, the structure of a relief valve is not limited to this. Any high pressure pump may be used as long as it opens when the downstream fuel pressure Px is equal to or higher than the relief pressure PR and relieves part of the fuel downstream of the discharge valve 19 between the pressurizing chamber 16 and the discharge valve 19. It is good also as what is provided outside.

  -The structure of a holding mechanism is not limited to what was illustrated in the said embodiment. In addition, for example, by using a ratchet mechanism, the displacement of the valve body in the valve opening direction is allowed, while the displacement of the valve body in the valve closing direction is prohibited when the displacement amount of the valve body exceeds a predetermined amount. May be.

  In the above embodiment and the modification, the holding mechanism that mechanically restricts the movement of the valve body of the relief valve has been illustrated, but instead, the valve body of the relief valve is restricted by an electrical or magnetic configuration. It is good also as what to do.

  DESCRIPTION OF SYMBOLS 1 ... Fuel supply apparatus, 2 ... Fuel tank, 3 ... Feed pump, 4 ... Low pressure fuel supply pipe (low pressure passage), 5 ... Return pipe, 6 ... Pressure regulating valve, 7 ... High pressure fuel supply pipe (high pressure passage), 8 ... Delivery pipe (high pressure passage), 9 ... fuel injection valve, 10 ... high pressure pump, 11 ... casing, 12 ... suction passage (low pressure passage), 13 ... cylinder, 14 ... discharge passage (high pressure passage), 15 ... plunger, 16 ... Pressure chamber, 17 ... Lifter, 18 ... Spring, 19 ... Discharge valve, 19a ... Valve body, 19b ... Spring, 20 ... Spill valve, 21 ... Suction port, 22 ... Discharge port, 23 ... Valve body, 23a ... Needle, 24 ... Solenoid, 25 ... Spring, 30 ... Relief valve, 33 ... Valve body housing portion, 34 ... Spring housing portion, 35 ... Valve body, 35a ... Recess, 36 ... Spring, 37 ... Pin housing portion, 38 ... Pin, 39 ... Spring, 40 ... Relief passage, 51 ... Air camshaft, 52 ... cam, 90 ... electronic control unit, the holding mechanism A.

Claims (5)

A high-pressure pump that sucks in the low-pressure fuel supplied through the low-pressure passage and pressurizes the fuel in the pressurizing chamber and pumps it to the fuel injection valve through the high-pressure passage; and is provided in the high-pressure passage and from the pressurizing chamber side In a fuel supply device for an internal combustion engine, comprising a discharge valve that opens when the pressure of the fuel is equal to or higher than a predetermined discharge pressure and allows the fuel to be pumped to the fuel injection valve side,
A valve provided in a relief passage that bypasses the discharge valve in the high-pressure passage and opens when a downstream fuel pressure, which is a pressure of fuel downstream of the discharge valve, becomes equal to or higher than a relief pressure, and part of the fuel is opened. A relief valve that relieves upstream of the discharge valve;
A holding mechanism that holds the relief valve in an open state when the downstream side fuel pressure is equal to or higher than an abnormal pressure higher than a maximum value of a range that can be taken when the high-pressure pump is normal;
An injection control unit that controls the fuel injection valve so as to inject the low-pressure fuel from the fuel injection valve when the relief valve is held in the open state by the holding mechanism. A fuel supply device for an internal combustion engine. The fuel supply device for an internal combustion engine according to claim 1,
The fuel supply device for an internal combustion engine, wherein the holding mechanism is configured to mechanically limit movement of the valve body of the relief valve to hold the relief valve in an open state. The fuel supply apparatus for an internal combustion engine according to claim 2,
The holding mechanism includes a recess formed in the peripheral surface of the valve body and a restricting portion biased toward the peripheral surface of the valve body, and the displacement amount of the valve body increases to a predetermined amount. A fuel supply device for an internal combustion engine, wherein the restriction portion is configured to be fitted into the concave portion of the valve body when it becomes. The fuel supply apparatus for an internal combustion engine according to any one of claims 1 to 3,
The fuel supply device for an internal combustion engine, wherein the relief valve is integrally formed with the high-pressure pump. A high-pressure pump that sucks low-pressure fuel supplied through a low-pressure passage and pressurizes the fuel in a pressurizing chamber and pressure-feeds the fuel injection valve through a high-pressure passage. In a high-pressure pump of an internal combustion engine comprising a discharge valve that opens when the pressure of the fuel from the fuel reaches a predetermined discharge pressure or higher and allows the fuel to be pumped to the fuel injection valve side,
A valve provided in a relief passage that bypasses the discharge valve in the high-pressure passage and opens when a downstream fuel pressure, which is a pressure of fuel downstream of the discharge valve, becomes equal to or higher than a relief pressure, and part of the fuel is opened. A relief valve that relieves upstream of the discharge valve;
A holding mechanism that holds the relief valve in an open state when the downstream side fuel pressure becomes equal to or higher than an abnormal pressure higher than a maximum value of a range that can be taken when the high-pressure pump is normal. Engine high pressure pump.

Images