JP7040301B2 - Fuel supply device - Google Patents

Description

The present invention relates to a fuel supply device that supplies fuel to an internal combustion engine.

Patent Document 1 discloses a fuel supply device provided with a check valve in a passage for supplying fuel from a feed pump to a high-pressure pump. The check valve is configured to open when the pressure on the feed pump side is high. If such a check valve is provided, the check valve closes the fuel pipe when the feed pump is stopped. Therefore, it is possible to prevent the fuel from coming out of the fuel pipe. In addition, this device has a detour passage that bypasses the check valve and returns fuel to the fuel tank in order to prevent the check valve from closing due to the pulsation of fuel that occurs on the downstream side of the check valve. It is provided on the downstream side of the valve. The detour passage is provided with a switching valve for switching between communication and interruption of the detour passage.

When the check valve closes due to the propagation of pulsation from the downstream side of the check valve, the valve body of the check valve may repeatedly close and open due to the pulsation. This could cause noise and vibration of the piping. According to the fuel supply device disclosed in Patent Document 1, by opening the switching valve, it is possible to suppress the repetition of closing and opening of the check valve due to the propagation of pulsation, and noise. And vibration of piping can be suppressed.

Japanese Unexamined Patent Publication No. 2016-44598

It has been required to suppress the noise and the vibration of the pipe generated when the check valve is closed due to the propagation of pulsation without providing the detour passage and the switching valve as disclosed in Patent Document 1.

Fuel supply devices for solving the above problems are provided in a feed pump that discharges fuel pumped from a fuel tank, a low-pressure fuel pipe through which the fuel discharged from the feed pump flows, and the low-pressure fuel pipe. From the high-pressure pump, which has a check valve and a pulsation damper that attenuates the pulsation propagating to the low-pressure fuel pipe due to elastic deformation of the diaphragm, and pressurizes the fuel supplied from the low-pressure fuel pipe, and the high-pressure pump. A high-pressure fuel pipe through which the discharged fuel flows, an injector for injecting fuel from the high-pressure fuel pipe, and a pump control unit for controlling the drive of the feed pump are provided, and the check valve is on the high-pressure pump side. It is equipped with a mechanism for suppressing valve closure due to pulsation from the pump, and the pump control unit executes a pump stop process when stopping the discharge of fuel by the feed pump, and in the pump stop process, the feed pump is stopped. By increasing the rotation speed of the feed pump from the start of execution of the pump stop process, the low pressure side fuel pressure, which is the internal pressure of the low pressure fuel pipe, is increased from the start of execution of the pump stop process. That is the gist.

In the above configuration, the check valve is suppressed from closing even if the pulsation propagates from the high pressure pump side. Therefore, even if the pulsation propagates from the high-pressure pump side, the repetition of opening and closing the check valve is suppressed. On the other hand, when the feed pump is stopped, the pump control unit executes a pump stop process for increasing the low pressure side fuel pressure before the feed pump is stopped. When the low-pressure side fuel pressure increases, the amount of deformation of the diaphragm of the pulsation damper due to the fuel discharged from the feed pump being supplied to the high-pressure pump increases. This makes it possible to increase the amount of fuel that travels through the low pressure fuel pipe and returns to the check valve side when the feed pump is stopped and the diaphragm is restored. Therefore, when the feed pump is stopped, the valve body of the check valve can be pushed in the direction of shutting off the low-pressure fuel pipe. By increasing the low-pressure side fuel pressure and closing the check valve, the low-pressure side fuel pressure is maintained in a high state, so that the check valve can be maintained in the closed state. That is, it is possible to prevent the fuel from escaping from the low-pressure fuel pipe by closing the check valve by utilizing the restoring force of the pulsation damper.

In short, according to the above configuration, the check valve is opened and closed by propagating pulsation from the downstream side of the check valve while realizing the function as a check valve without providing a detour passage and a switching valve. It is possible to suppress repetition with the valve, and it is possible to suppress the generation of noise and vibration of the pipe.

Examples of the fuel supply device include a feed pump that discharges fuel pumped from a fuel tank, a low-pressure fuel pipe through which the fuel discharged from the feed pump flows, and a check valve provided in the low-pressure fuel pipe. A high-pressure pump that pressurizes the fuel supplied from the low-pressure fuel pipe, a high-pressure fuel pipe through which the fuel discharged from the high-pressure pump flows, and an injector that injects fuel from the high-pressure fuel pipe. In the check valve, the valve body of the check valve is provided on the high pressure pump side of the check valve seat in the low pressure fuel pipe, and the force in the direction of opening the check valve is the valve. It has a valve opening mechanism that acts on the body and maintains a valve opening state when the pressure on the high pressure pump side of the check valve in the low pressure fuel pipe is lower than the specified pressure.

According to the above configuration, when the pressure on the high-pressure pump side of the check valve in the low-pressure fuel pipe is lower than the specified pressure, the open state of the check valve is maintained. On the other hand, if the pressure is equal to or higher than the specified pressure, the check valve closes. That is, even if the pulsation propagates from the high pressure pump side, the closing of the check valve is suppressed. Therefore, even if the pulsation propagates from the high-pressure pump side, it is possible to suppress the repetition of opening and closing of the check valve, and it is possible to suppress the generation of noise and vibration of the pipe.

The schematic which shows one Embodiment of a fuel supply device. The schematic diagram which shows the check valve which the fuel supply device which concerns on this embodiment has. The flowchart which shows the processing routine of the pump stop processing in the fuel supply apparatus which concerns on the same embodiment. The figure which shows the transition between the low pressure side fuel pressure and the pump rotation speed when the pump stop processing is executed. The schematic diagram which shows the check valve of the fuel supply device as a comparative example. The figure which shows the modification example of a fuel supply device. The figure which shows the other modification example of a fuel supply device. The figure which shows the other modification example of a fuel supply device.

Hereinafter, an embodiment of the fuel supply device will be described with reference to FIGS. 1 to 4.
As shown in FIG. 1, the fuel supply device 10 includes a fuel tank 11 for storing fuel of an internal combustion engine. The fuel tank 11 is provided with a feed pump 12 for pumping fuel stored in the fuel tank 11. The fuel supply device 10 includes a first low-pressure fuel pipe 14 through which the fuel discharged from the feed pump 12 flows.

The feed pump 12 uses a motor as a drive source. By changing the rotation speed of the motor and changing the pump rotation speed Nfp of the feed pump 12, the amount of fuel discharged to the first low-pressure fuel pipe 14 can be controlled per unit time.

A pressure regulator 13 connected to the first low-pressure fuel pipe 14 is provided in the fuel tank 11. When the fuel pressure in the first low-pressure fuel pipe 14 becomes equal to or higher than the specified valve opening pressure, the pressure regulator 13 opens the valve and the fuel in the first low-pressure fuel pipe 14 is discharged to the fuel tank 11.

A check valve 40 is provided in the first low-pressure fuel pipe 14. The check valve 40 is provided in the curved portion 15 of the first low-pressure fuel pipe 14.
The fuel supply device 10 includes a low-pressure injector 17 that injects fuel. The low pressure injector 17 is provided in the low pressure delivery pipe 16 connected to the first low pressure fuel pipe 14. Four low-pressure injectors 17 are connected to the low-pressure delivery pipe 16. The low pressure injector 17 injects fuel into the intake port of the internal combustion engine.

The fuel supply device 10 includes a high pressure pump 20. The fuel supply device 10 includes a second low-pressure fuel pipe 18 that connects the first low-pressure fuel pipe 14 and the high-pressure pump 20. The end of the second low-pressure fuel pipe 18 opposite to the high-pressure pump 20 is connected between the check valve 40 and the low-pressure delivery pipe 16 in the first low-pressure fuel pipe 14. The first low-pressure fuel pipe 14 and the second low-pressure fuel pipe 18 are formed of a material that allows elastic deformation according to the fuel pressure flowing inside. For example, a first low-pressure fuel pipe 14 and a second low-pressure fuel pipe 18 molded of nylon, metal, or the like can be adopted.

The high-pressure pump 20 includes a pulsation damper 21 in which fuel is introduced from the second low-pressure fuel pipe 18. The pulsation damper 21 includes a diaphragm 22 capable of elastic deformation. The pulsation damper 21 is configured to attenuate the pulsation of fuel in the first low-pressure fuel pipe 14 and the second low-pressure fuel pipe 18 by changing the internal volume by elastic deformation of the diaphragm 22.

The high-pressure pump 20 includes a pressurizing chamber 25 into which the fuel that has passed through the pulsation damper 21 is introduced. The high-pressure pump 20 includes a solenoid valve 26 that switches between communication and disconnection between the pulsation damper 21 and the pressurizing chamber 25.

The high-pressure pump 20 includes a plunger 24 for compressing the fuel in the pressurizing chamber 25 and a cylinder 23 in which the plunger 24 is housed. The plunger 24 is driven by a cam 92 provided on the camshaft 91 of the internal combustion engine. The volume of the pressurizing chamber 25 changes as the plunger 24 slides in the cylinder 23. The high-pressure pump 20 can suck and discharge fuel by changing the volume of the pressurizing chamber 25 and opening and closing the solenoid valve 26.

The high-pressure pump 20 includes a high-pressure fuel pipe 31 through which the fuel discharged from the pressurizing chamber 25 passes. The high-pressure fuel pipe 31 is provided with a check valve 32. The high-pressure fuel pipe 31 is connected to the high-pressure delivery pipe 35. In the check valve 32, the fuel pressure of the high-pressure fuel pipe 31 on the high-pressure pump 20 side of the check valve 32 is the specified valve opening difference with respect to the fuel pressure of the high-pressure fuel pipe 31 on the high-pressure delivery pipe 35 side of the check valve 32. It is set to open when the pressure is higher than the pressure. The high-pressure fuel pipe 31 is provided with a relief passage 33 through which the fuel flowing back from the high-pressure delivery pipe 35 to the high-pressure pump 20 side passes. A relief valve 34 is provided in the relief passage 33. In the relief valve 34, when the fuel pressure of the relief passage 33 on the high pressure delivery pipe 35 side of the relief valve 34 is higher than the fuel pressure of the relief passage 33 on the high pressure pump 20 side of the relief valve 34 or more. It is set to open the valve. Four high-pressure injectors 36 are connected to the high-pressure delivery pipe 35 as injectors. The high-pressure injector 36 injects fuel into the combustion chamber of the internal combustion engine.

A first pressure sensor 81 is attached to the low pressure delivery pipe 16. A second pressure sensor 82 is attached to the high pressure delivery pipe 35.
As shown in FIG. 1, the fuel supply device 10 includes a control device 50.

A detection signal from the first pressure sensor 81 is input to the control device 50. The first pressure sensor 81 outputs a signal corresponding to the internal pressure of the low pressure delivery pipe 16. In the present embodiment, the internal pressure of the low-pressure delivery pipe 16 is treated as the internal pressure of the first and second low-pressure fuel pipes 14, 18. That is, the low pressure side fuel pressure PL, which is the internal pressure of the first low pressure fuel pipe 14, is detected based on the first pressure sensor 81.

A detection signal from the second pressure sensor 82 is input to the control device 50. The second pressure sensor 82 outputs a signal corresponding to the internal pressure of the high pressure delivery pipe 35. Based on the second pressure sensor 82, the high pressure side fuel pressure, which is the internal pressure of the high pressure fuel pipe 31, is detected.

The control device 50 includes an injection control unit 51 and a pump control unit 52 as functional units.
The injection control unit 51 controls the amount of fuel injected from the low pressure injector 17 and the high pressure injector 36. The injection control unit 51 calculates the required injection amount as the amount of fuel to be injected from each injector based on the rotation speed of the internal combustion engine and the intake air amount.

The injection control unit 51 calculates the target fuel pressure PLt as the target value of the low pressure side fuel pressure PL in order to control the discharge amount from the feed pump 12 based on the required injection amount.
Further, the injection control unit 51 operates the opening and closing of the solenoid valve 26 to control the discharge amount from the high pressure pump 20.

The pump control unit 52 controls the pump rotation speed Nfp, which is the rotation speed of the feed pump 12, by controlling the duty of the voltage supplied to the motor of the feed pump 12. More specifically, the discharge amount of the feed pump 12 is controlled by controlling the pump rotation speed Nfp of the feed pump 12 so that the low pressure side fuel pressure PL follows the target fuel pressure PLt.

Further, the pump control unit 52 executes a pump stop process when the drive of the feed pump 12 is stopped.
The curved portion 15 and the check valve 40 will be described in detail with reference to FIG. In FIG. 2, an arrow indicating a vertical direction is displayed. As shown in FIG. 2, the curved portion 15 of the first low-pressure fuel pipe 14 has a linear vertical portion 15A having both ends pointing in the vertical direction in a state where the fuel supply device 10 is mounted on the vehicle. is doing. In the first low-pressure fuel pipe 14, the vertically upper end of the vertical portion 15A is connected to the fuel tank 11 side. The vertically lower end of the vertical portion 15A is connected to the high pressure pump 20 side.

The check valve 40 is arranged in the vertical portion 15A of the curved portion 15. The check valve 40 has a valve seat 42. A valve hole 43 is opened in the valve seat 42. A stopper 44 is provided vertically below the valve seat 42. The stopper 44 is arranged as a partition wall that separates the fuel passage formed by the vertical portion 15A from the upstream side and the downstream side. A plurality of communication holes 44A are formed in the stopper 44. Fuel can flow on the upstream side and the downstream side of the stopper 44 through the communication hole 44A.

The check valve 40 has a spherical valve body 41. The valve body 41 is housed between the valve seat 42 and the stopper 44. The diameter of the valve body 41 is larger than the diameter of the valve hole 43. When the valve body 41 is seated on the valve seat 42, the valve hole 43 is closed. The diameter of the valve body 41 is larger than the diameter of the communication hole 44A. Further, the valve body 41 is made of a material having a specific gravity larger than that of the fuel, and is designed to sink in the fuel.

The valve body 41 moves between the valve seat 42 and the stopper 44 due to the pressure received from the fuel flowing through the first low-pressure fuel pipe 14. When the pulsation of the fuel by the high-pressure pump 20 propagates to the first low-pressure fuel pipe 14, a force is applied to the valve body 41 to move the fuel from the stopper 44 side to the valve seat 42 side. However, the valve body 41 is acted on by its own weight so as to face vertically downward, that is, toward the stopper 44 side. Therefore, a large force enough to move the valve body 41 vertically upward against the weight of the valve body 41 is a high pressure pump on the fuel tank 11 side of the valve body 41 and on the valve body 41 due to the pulsation of the fuel. As long as the pressure difference generated on the 20 side does not act on the valve body 41, the valve body 41 does not block the valve hole 43. In the check valve 40, the weight of the valve body 41 acting in the valve opening direction is a force for suppressing valve closing due to pulsation from the high pressure pump 20 side. In short, in the check valve 40, the valve body 41 that sinks in the fuel is applied, and the valve seat 42 located on the fuel tank 11 side is provided vertically above, which suppresses the valve closing due to pulsation from the high pressure pump 20 side. It is a mechanism to do. In the configuration, "a force in the direction of opening the check valve acts on the valve body, and the pressure on the high pressure pump side is lower than the specified pressure than the check valve in the low pressure fuel pipe. Sometimes it is also a valve opening mechanism that maintains the valve opening state. The "force in the direction of opening the check valve" corresponds to the own weight of the valve body 41 acting in the valve opening direction. The "specified pressure" in this case is a pressure having a magnitude commensurate with the own weight of the valve body 41 acting in the valve opening direction. The specific gravity and size of the material constituting the valve body 41 are designed so that the check valve 40 does not close due to the pulsation from the high pressure pump 20 side when the feed pump 12 is driven to supply fuel. Has been done.

The pump stop process executed by the pump control unit 52 will be described with reference to FIG. This process is executed when the drive of the feed pump 12 is stopped.
When the execution of this processing routine is started, first, in step S101, the low pressure side fuel pressure PL increasing processing is executed by the pump control unit 52. In this process, the pre-stop fuel pressure EPLt, which is a value higher than the target fuel pressure PLt, is set as the target value of the low pressure side fuel pressure PL. The pump control unit 52 controls the drive of the feed pump 12 so that the low-pressure side fuel pressure PL follows the fuel pressure EPLt before stopping. Specifically, the discharge amount of the feed pump 12 is increased by increasing the pump rotation speed Nfp.

When the low pressure side fuel pressure PL is increased based on the pre-stop fuel pressure EPLt, the process shifts to step S102.
In step S102, the drive of the feed pump 12 is stopped. After that, this processing routine is terminated.

The operation and effect of this embodiment will be described.
First, a check valve 440 as a comparative example will be described with reference to FIG. In FIG. 5, an arrow indicating a vertical direction is displayed. The check valve 440 is arranged in a low pressure fuel pipe extending in the vertical direction. The upper part of the pipe is connected to the high pressure pump side and the lower part is connected to the fuel tank side. The valve body 441 of the check valve 440 is housed between the valve seat 442 and the stopper 444 located vertically above the valve seat 442. A plurality of communication holes 444A are formed in the stopper 444. The valve body 441 is designed to sink in the fuel like the valve body 41, and the valve body 441 moves toward the valve seat 442 side by its own weight. Therefore, when the feed pump is stopped and the pressure does not act from the fuel tank side, the valve body 441 closes the valve hole 443 and the check valve 440 closes.

That is, the check valve 440 has a function of suppressing the fuel from coming out of the pipe by closing the valve due to the weight of the valve body 441 when the feed pump 12 is stopped. However, in this check valve 440, the weight of the valve body 441 acts in the valve closing direction to promote the valve closing due to the pulsation from the high pressure pump side. Therefore, when the pulsation propagates from the high pressure pump side, the check valve 440 The valve closing and opening of the valve are repeated.

On the other hand, in the check valve 40, since its own weight acts in the valve opening direction, the valve closing due to pulsation is suppressed. On the other hand, the check valve 40 does not have a function of closing the valve by its own weight of the valve body 41.

Therefore, in the fuel supply device 10, when the drive of the feed pump 12 is stopped, the pump stop process described with reference to FIG. 3 is executed. As a result, the check valve 40 can be closed.

With reference to FIG. 4, changes in the low pressure side fuel pressure PL and the pump rotation speed Nfp when the pump stop process is executed will be described.
In FIG. 4, the low pressure side fuel pressure PL increase process is executed at the timing t1 (S101). When the target value of the low-pressure side fuel pressure PL is raised to the pre-stop fuel pressure EPLt by the low-pressure side fuel pressure PL increase process, as shown in FIG. 4 (b), after timing t1, the pump is pumped more than when the pump stop process is started. The rotation speed Nfp is increased. Then, as shown in FIG. 4A, the low pressure side fuel pressure PL increases following the pre-stop fuel pressure EPLt. That is, after the timing t1, the low pressure side fuel pressure PL is increased as compared with the time when the execution of the pump stop process is started. After that, the drive of the feed pump 12 is stopped at the timing t2 (S102).

In this way, when the drive of the feed pump 12 is stopped, the pump rotation speed Nfp is increased before the feed pump 12 is stopped by executing the pump stop process, so that the low pressure side fuel pressure PL pumps. It increases from the start of execution of the stop process. When the low-pressure side fuel pressure PL increases, the amount of deformation of the diaphragm 22 of the pulsation damper 21 due to the fuel discharged from the feed pump 12 being supplied to the high-pressure pump 20 increases. As a result, when the drive of the feed pump 12 is stopped, the diaphragm 22 of the pulsation damper 21 is restored, so that the diaphragm 22 returns to the check valve 40 side through the second low-pressure fuel pipe 18 and the first low-pressure fuel pipe 14. The amount of fuel can be increased.

In the fuel supply device 10, when the feed pump 12 is stopped in this way, the check valve 40 is closed by increasing the force acting on the valve body 41 from the high pressure pump 20 side. That is, by executing the pump stop process, when the feed pump 12 is stopped, the valve body 41 of the check valve 40 can be pushed toward the valve seat 42 in the direction of shutting off the first low-pressure fuel pipe 14. ing. Since the check valve 40 is closed by increasing the low pressure side fuel pressure PL, when the check valve 40 is closed, the low pressure side fuel pressure PL on the high pressure pump 20 side is higher than the pressure on the fuel tank 11 side than the check valve 40. High condition is maintained. Therefore, the check valve 40 can be maintained in a closed state.

That is, according to the fuel supply device 10, the pulsation propagates from the downstream side of the check valve 40 while realizing the function of suppressing the fuel from coming out from the first low-pressure fuel pipe 14 when the feed pump 12 is stopped. As a result, it is possible to suppress the repetition of opening and closing of the check valve 40, and it is possible to suppress the generation of noise and vibration of the pipe.

Further, in the fuel supply device 10, the first low-pressure fuel pipe 14 and the second low-pressure fuel pipe 18 can be elastically deformed according to the pressure of the fuel flowing inside. That is, when the low-pressure side fuel pressure PL increases due to the execution of the pump stop process, the first low-pressure fuel pipe 14 and the second low-pressure fuel pipe 18 expand. Therefore, when the feed pump 12 is stopped, a force acting on the valve body 41 from the high pressure pump 20 side is also generated by the restoration of the first low pressure fuel pipe 14 and the second low pressure fuel pipe 18. Therefore, in the fuel supply device 10, when the pump stop process is executed, in addition to the fuel that moves to the check valve 40 side due to the restoration of the diaphragm 22, the first low-pressure fuel pipe 14 and the second low-pressure fuel pipe 14 are used. The valve body 41 of the check valve 40 can be pushed toward the valve seat 42 by the fuel that moves to the check valve 40 side with the restoration of 18.

The pre-stop fuel pressure EPLt in the low-pressure side fuel pressure PL increase process is subjected to elastic deformation required to generate a force necessary for closing the check valve 40 when the feed pump 12 is stopped. 1 The size is set so that it can be generated in the low pressure fuel pipe 14 and the second low pressure fuel pipe 18.

Hereinafter, the correspondence between the matters in the above-described embodiment and the matters described in the above-mentioned "means for solving the problem" column will be described.
The "low-pressure fuel pipe through which the fuel discharged from the feed pump flows" corresponds to the first low-pressure fuel pipe 14. The "injector that injects fuel from the high-pressure fuel pipe" corresponds to the high-pressure injector 36.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-In the above embodiment, when the feed pump 12 is stopped, the pump stop process is executed to increase the low pressure side fuel pressure PL, so that the valve body of the check valve is pushed into the valve seat side. Even if such a pump stop process is not executed, when the feed pump 12 is stopped, the force generated by the restoration of the elastically deformable first low-pressure fuel pipe 14 and the second low-pressure fuel pipe 18 is applied from the high-pressure pump 20 side to the valve body. It acts on 41. If the force acting on the valve body 41 from the high-pressure pump 20 side is equal to or greater than the force in the direction of opening the check valve 40, the first low-pressure fuel pipe 14 and the second low-pressure fuel pipe 18 can be restored. The fuel moving to the check valve 40 side can push the valve body 41 of the check valve 40 toward the valve seat 42 side. As described above, even if the pump stop process is not executed, it may be possible to realize a function of suppressing fuel from coming out of the first low-pressure fuel pipe 14 when the feed pump 12 is stopped.

-In the above embodiment, the check valve 40 arranged in the curved portion 15 is exemplified. The form of the check valve is not limited to that arranged in the curved portion 15.
In the example shown in FIG. 6, the first low-pressure fuel pipe 14 includes a bent portion 115, and the bent portion 115 has a horizontal portion 115A. In FIG. 6, an arrow indicating the horizontal direction is displayed. The horizontal portion 115A is a linear portion in which both end portions are oriented in the horizontal direction when the fuel supply device 10 is mounted on the vehicle. The check valve 140 arranged in the bent portion 115 having the horizontal portion 115A may be adopted instead of the check valve 40 arranged in the curved portion 15.

The check valve 140 has a valve seat 142 arranged on the fuel tank 11 side. The valve seat 142 has a valve hole 143. The check valve 140 has a stopper 144 arranged on the high pressure pump 20 side. A communication hole 144A is formed in the stopper 144. In the check valve 140, the valve body 141 is accommodated between the valve seat 142 and the stopper 144.

In the check valve 140, the valve seat 142 is located horizontally with respect to the valve body 141. The weight of the valve body 141 does not act in the direction of closing the check valve 140. The force enough to move the valve body 141 to the valve seat 142 side is generated by the pressure difference between the fuel tank 11 side of the valve body 141 and the high pressure pump 20 side of the valve body 141 due to the pulsation of the fuel. As long as it does not act on 141, the valve hole 143 is unlikely to be blocked by the valve body 141. That is, the check valve 140 is unlikely to be closed even if the pulsation of the fuel by the high-pressure pump 20 propagates to the first low-pressure fuel pipe 14. Similar to the check valve 40 in the above embodiment, the check valve 140 has a configuration for suppressing valve closing due to pulsation propagating from the high pressure pump 20 side.

Even when the check valve 140 is adopted, the check valve 140 can be closed as in the above embodiment by executing the pump stop process by the pump control unit 52.
That is, according to the check valve 140, it is possible to suppress repeated opening and closing of the check valve 140 due to pulsation propagating from the high pressure pump 20 side as in the above embodiment, and noise and piping can be suppressed. It is possible to suppress the occurrence of vibration.

The check valve 240 shown in FIG. 7 may be adopted. The check valve 240 is arranged at a linear portion of the first low-pressure fuel pipe 14 in which both ends are oriented in the vertical direction in a state where the fuel supply device 10 is mounted on the vehicle.

The check valve 240 has a valve seat 242 arranged on the fuel tank 11 side. The valve seat 242 has a valve hole 243. The check valve 240 has a stopper 244 arranged on the high pressure pump 20 side. A communication hole 244A is formed in the stopper 244. In the check valve 240, the valve body 241 is accommodated between the valve seat 242 and the stopper 244. That is, the valve seat 242 is located vertically below the valve body 241.

As shown in FIG. 7, the valve body 241 is a hollow spherical shape. The valve body 241 is designed so that when it is present in the fuel, a buoyancy is generated and a force that moves the valve body 241 vertically upward acts.

Since the buoyancy acts on the valve body 241, a large force enough to move the valve body 241 vertically downward against the buoyancy force is applied to the fuel tank 11 side and the valve from the valve body 241 due to the pulsation of the fuel. The valve hole 243 is not blocked by the valve body 241 unless the pressure difference generated on the high pressure pump 20 side of the body 241 acts on the valve body 241. In the check valve 240, the buoyancy of the valve body 241 acting in the valve opening direction is a force for suppressing valve closing due to pulsation from the high pressure pump 20 side. That is, the check valve 240 is suppressed from closing even if the pulsation of the fuel by the high pressure pump 20 propagates to the first low pressure fuel pipe 14. Similar to the above embodiment, the check valve 240 has a configuration for suppressing valve closing due to pulsation propagating from the high pressure pump 20 side. In the configuration, "a force in the direction of opening the check valve acts on the valve body, and the pressure on the high pressure pump side is lower than the specified pressure than the check valve in the low pressure fuel pipe. Sometimes it is also a valve opening mechanism that maintains the valve opening state. The "force in the direction of opening the check valve" corresponds to the buoyancy of the valve body 241 acting in the valve opening direction. The "specified pressure" in this case is a pressure having a magnitude commensurate with the buoyancy of the valve body 241.

Even when the check valve 240 is adopted, the check valve 240 can be closed as in the above embodiment by executing the pump stop process by the pump control unit 52. Specifically, the check valve 240 closes when the low-pressure side fuel pressure PL rises and a force exceeding the buoyancy of the valve body 241 is applied from the high-pressure pump side.

That is, according to the check valve 240, it is possible to suppress repeated opening and closing of the check valve 240 due to pulsation propagating from the high pressure pump 20 side as in the above embodiment, and noise and piping can be suppressed. It is possible to suppress the occurrence of vibration.

Further, instead of forming the valve body in a hollow shape as in the valve body 241, the valve body may be formed of a material having a specific gravity smaller than that of the fuel. Further, by connecting a float to the valve body, buoyancy may be applied to the valve body to suppress the seating of the valve body on the valve seat.

The check valve 340 shown in FIG. 8 may be adopted. In the check valve 340, the valve body 341 is suspended from the stopper 344 by a tension coil spring 345. A communication hole 344A is formed in the stopper 344. A valve seat 342 having a valve hole 343 is arranged vertically below the valve body 341.

The length and tension of the tension coil spring 345 suppresses the seating of the valve body 341 on the valve seat 342 when the pressure difference between the fuel tank 11 side of the valve body 341 and the high pressure pump 20 side of the valve body 341 is small. Is set to be done. In this check valve 340, the tension of the tension coil spring 345 acting in the valve opening direction is a force for suppressing valve closing due to pulsation from the high pressure pump 20 side. That is, the check valve 340 is suppressed from closing even if the pulsation of the fuel by the high pressure pump 20 propagates to the first low pressure fuel pipe 14. The check valve 340 has a configuration for suppressing valve closing due to pulsation propagating from the high pressure pump 20 side, as in the above embodiment. In the configuration, "a force in the direction of opening the check valve acts on the valve body, and the pressure on the high pressure pump side is lower than the specified pressure than the check valve in the low pressure fuel pipe. Sometimes it is also a valve opening mechanism that maintains the valve opening state. The "force in the direction of opening the check valve" corresponds to the tension of the tension coil spring 345 acting in the valve opening direction. The "specified pressure" in this case is a pressure having a magnitude commensurate with the tension of the tension coil spring 345.

Even when the check valve 340 is adopted, the check valve 340 can be closed as in the above embodiment by executing the pump stop process by the pump control unit 52. Specifically, when the tension coil spring 345 is extended by increasing the low pressure side fuel pressure PL, the valve body 341 can be seated on the valve seat 342.

That is, according to the check valve 340, it is possible to suppress repeated opening and closing of the check valve 340 due to pulsation propagating from the high pressure pump 20 side as in the above embodiment, and noise and piping can be suppressed. It is possible to suppress the occurrence of vibration.

-For each of the above check valves, the shapes of the valve seat, valve body and stopper can be changed as appropriate. The check valve is configured to suppress valve closing due to pulsation propagating from the high-pressure pump 20 side by the arrangement direction of the check valve, the tension coil spring, etc., and the check valve can be closed by executing the pump stop process. Just do it.

10 ... Fuel supply device, 11 ... Fuel tank, 12 ... Feed pump, 13 ... Pressure regulator, 14 ... First low pressure fuel pipe, 15 ... Curved part, 15A ... Vertical part, 16 ... Low pressure delivery pipe, 17 ... Low pressure injector, 18 ... 2nd low pressure fuel pipe, 20 ... high pressure pump, 21 ... pulsation damper, 22 ... diaphragm, 23 ... cylinder, 24 ... plunger, 25 ... pressurizing chamber, 26 ... electromagnetic valve, 31 ... high pressure fuel pipe, 32 ... Check valve, 33 ... relief passage, 34 ... relief valve, 35 ... high pressure delivery pipe, 36 ... high pressure injector, 40 ... check valve, 41 ... valve body, 42 ... valve seat, 43 ... valve hole, 44 ... stopper, 44A ... Communication hole, 50 ... Control device, 51 ... Injection control unit, 52 ... Pump control unit, 81 ... First pressure sensor, 82 ... Second pressure sensor, 91 ... Cam shaft, 92 ... Cam.

Claims (2)

A feed pump that discharges the fuel pumped from the fuel tank,
A low-pressure fuel pipe through which the fuel discharged from the feed pump flows, and
The check valve provided in the low-pressure fuel pipe and
A high-pressure pump that pressurizes the fuel supplied from the low-pressure fuel pipe, and
The high-pressure fuel pipe through which the fuel discharged from the high-pressure pump flows, and
It is equipped with an injector that injects fuel from the high-pressure fuel pipe.
The check valve comprises a valve body having a higher specific density than the fuel.
The valve body is provided on the high-pressure pump side of the check valve in the low-pressure fuel pipe and vertically below the valve seat .
The check valve opens when the pressure on the high-pressure pump side of the check valve in the low-pressure fuel pipe is lower than the pressure equal to the own weight of the valve body acting in the valve opening direction. The state is maintained
Fuel supply device. The high-pressure pump having a pulsation damper that attenuates the pulsation propagating to the low-pressure fuel pipe due to the elastic deformation of the diaphragm, and the high-pressure pump.
A pump control unit that controls the drive of the feed pump is provided.
When the discharge of fuel by the feed pump is stopped, the pump control unit executes the pump stop process, and in the pump stop process, the pump stop process is performed before the feed pump is stopped, rather than at the start of the execution of the pump stop process. By increasing the rotation speed of the feed pump, the low-pressure side fuel pressure, which is the internal pressure of the low-pressure fuel pipe, is increased from the time when the execution of the pump stop process is started.
The fuel supply device according to claim 1.

Images