JP2018059436A - High pressure pump device and fuel supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To receive necessary and sufficient supply of low pressure fuel from a low pressure pump, pressurize it, and output to a common rail unit the low pressure fuel as high pressure fuel.SOLUTION: A high pressure pump device includes: a pressurization chamber 56 configured to pressurize low pressure fuel, pumped up from a fuel tank 2 by a low pressure pump 3, by a cam mechanism; a suction valve 55 configured to suction low pressure fuel to the pressurization chamber; a discharge valve 57 configured to discharge high pressure fuel pressurized in the pressurization chamber; a pressure control valve 72 communicating with a cam chamber 51a storing the cam mechanism, and configured to keep pressure of low pressure fuel supplied to the cam chamber by the low pressure pump 3 constant; and a fuel supply passage 17 connecting between the pressure control valve and the suction valve for feeding part of low pressure fuel into the pressurization chamber, the low pressure fuel subjected to overflow in order to keep pressure of the cam chamber constant by the pressure control valve in a case where a supply amount of low pressure fuel supplied to the cam chamber increases.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a high-pressure pump device and a fuel supply system, and more particularly, to a high-pressure pump device and a fuel supply system that pressurize fuel and pump it to an injector.

  Conventionally, as a fuel supply to an internal combustion engine such as a diesel engine, a plurality of injectors are connected and a common rail for storing high-pressure fuel is provided, and a high-pressure pump pressurizes and supplies fuel to the common rail. A common rail system that stores fuel (hereinafter, also referred to as “high pressure fuel”) and enables injection control of high pressure fuel from an injector attached to each cylinder of the engine is known (for example, a patent) (See reference 1.)

  Such a common rail system is attached to the engine via a flange attached to the pump housing, and transmits the driving force from the engine drive shaft to the camshaft of the high-pressure pump inserted into the flange. The fuel is pressurized.

  A low-pressure pump is connected to the upstream side of the high-pressure pump so that low-pressure fuel (hereinafter also referred to as “low-pressure fuel”) is sucked from the fuel tank and supplied to the high-pressure pump.

  Specifically, as shown in FIG. 3, in the conventional common rail system 100, a fuel tank 101, a mechanical high pressure pump assembly 110, and a common rail and an injector (not shown) connected to the high pressure pump assembly 110. Etc. Here, the description will be given mainly focusing on the fuel tank 101 and the high pressure pump assembly 110.

  The fuel tank 101 is a tank for storing diesel oil for a diesel engine, and one end of a low-pressure fuel passage 102 and one end of a fuel circulation passage 108 are connected to the fuel tank 101. A manual priming pump 104 and a prefilter 105 are connected on the line of the low-pressure fuel path 102.

  The high pressure pump assembly 110 includes a low pressure pump 111, a high pressure pump 121, a mechanical relief valve 131, and the like. The low-pressure pump 111 is a mechanical fuel pump that is driven by an engine (not shown), sucks up fuel stored in the fuel tank 101, and then supplies the fuel to the high-pressure pump 121 through the main filter 116.

  The low-pressure pump 111 has a configuration in which a low-pressure feed pump main body 112, a pressure control valve 113, and a bypass valve 114 are connected in parallel. The low-pressure fuel supplied from the low-pressure feed pump main body 112 of the low-pressure pump 111 is supplied to the cam chamber 121 a of the high-pressure pump 121 and also to the proportional control valve 117.

The high-pressure pump 121 includes a camshaft 122 connected to a drive shaft of an engine (not shown), a cam 122a integrated with the camshaft 122, a tappet 123 that transmits the rotational motion of the cam 122a as a linear motion, Plunger 124 that moves in the vertical direction according to linear motion, suction valve 125 that sucks in low-pressure fuel supplied through proportional control valve 117, and pressurization chamber 126 that pressurizes low-pressure fuel sucked in through suction valve 125 A discharge valve 127 is provided for pressure-feeding the high-pressure fuel pressurized in the pressurizing chamber 126 to a common rail (not shown).

  In this case, the low-pressure fuel sucked into the pressurizing chamber 126 through the proportional control valve 117 and the suction valve 125 is pressurized according to the movement of the plunger 124 and then from the discharge valve 127 through the high-pressure fuel passage 107. Pumped to the common rail.

  The camshaft 122 of the high-pressure pump 121 is housed in a cam chamber 121a, and the camshaft 122 is pivotally supported via a bearing 128 attached to a housing forming the cam chamber 121a.

  The mechanical components that form the cam mechanism such as the cam shaft 122, the cam 122a, and the bearing 128 of the high-pressure pump 121 are housed in the cam chamber 121a, and these mechanical configurations are formed by the low-pressure fuel supplied from the low-pressure pump 111. Parts are lubricated.

  The cam chamber 121 a of the high-pressure pump 121 is connected to the relief valve 131, and the pressure in the cam chamber 121 a is held constant by the relief valve 131. Therefore, the low-pressure fuel supplied to the cam chamber 121a is permeated into a slight gap (clearance) between the cam shaft 122 and the bearing 128 by the pressure of the cam chamber 121a held by the relief valve 131, and the lubricity thereof is increased. It is secured.

  The clearance between the camshaft 122 and the bearing 128 leads to the fuel circulation path 108, and the difference between the pressure in the cam chamber 121a and the pressure in the fuel circulation path 108 is maintained at a predetermined magnitude. Then, after a part of the low-pressure fuel passes through the clearance and functions as the lubricating oil, it is returned to the fuel tank 101 via the fuel circulation path 108.

  Here, when a large amount of low-pressure fuel is sucked up from the low-pressure pump 111 according to the accelerator opening, a large amount of low-pressure fuel is sucked into the pressurizing chamber 126 through the proportional control valve 117 and the suction valve 125. At the same time, a large amount of low-pressure fuel from the low-pressure pump 111 increases the pressure in the cam chamber 121 a and pushes down the piston 132 of the relief valve 131 against the urging force of the spring 133. At this time, the low-pressure fuel that has overflowed from the cam chamber 121 a is returned to the fuel tank 101 via the relief valve 131 and the fuel circulation path 108.

JP 2001-214821 A

  In the common rail system 100 configured as described above, the minimum amount of low-pressure fuel is supplied to the cam chamber 121a even when the accelerator opening is small in order to always lubricate the clearance between the camshaft 122 and the bearing 128.

  However, in this common rail system 100, even when the accelerator opening becomes large, the pressure in the cam chamber 121a is kept constant, so that the low pressure fuel corresponding to the increased accelerator opening overflows from the relief valve 131. Thus, the overflowed low-pressure fuel is returned to the fuel tank 101.

For this reason, more low-pressure fuel than the amount actually injected from the common rail has to be supplied from the low-pressure pump 111 to the high-pressure pump 121 side, and the supply amount of low-pressure fuel is useless and inefficient.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to receive a supply of necessary and sufficient low-pressure fuel from a low-pressure pump, pressurize it, and output it to a common rail unit as high-pressure fuel. It is to provide a pump device and a fuel supply system.

  In order to achieve the above object, a high-pressure pump device according to the present invention includes a pressurizing chamber that pressurizes low-pressure fuel sucked up from a fuel tank by a low-pressure pump by a cam mechanism, and an intake that sucks the low-pressure fuel into the pressurizing chamber. A valve, a discharge valve that discharges the high-pressure fuel pressurized in the pressurizing chamber, and a cam chamber that houses the cam mechanism, and the low-pressure fuel supplied to the cam chamber by the low-pressure pump A pressure control valve that keeps the pressure constant, and the low pressure that causes the pressure control valve to overflow to keep the pressure in the cam chamber constant when the supply amount of the low-pressure fuel supplied to the cam chamber increases A fuel supply path connected between the pressure control valve and the suction valve is provided for supplying a part of the fuel to the pressurizing chamber.

  In the high-pressure pump device according to the present invention, the low-pressure pump is an electromagnetic low-pressure feed pump, and sucks low-pressure fuel at a desired flow rate and supplies it to the cam chamber by energization control by an electronic control unit. .

In the high-pressure pump device according to the present invention, even when the supply amount of the low-pressure fuel supplied to the cam chamber by the low-pressure pump decreases, the minimum amount of the low-pressure fuel for lubricating the cam mechanism is reduced. It is supplied to the cam chamber.

  In the high-pressure pump device according to the present invention, the low-pressure pump supplies a minimum amount of the low-pressure fuel for lubricating the cam mechanism even when the supply amount of the low-pressure fuel supplied to the cam chamber decreases. It supplies to the said cam chamber, It is characterized by the above-mentioned.

  The fuel supply system according to the present invention includes a low-pressure pump that sucks low-pressure fuel from a fuel tank, and a high-pressure pump device that pressurizes the low-pressure fuel supplied from the low-pressure pump and pumps it as a high-pressure fuel to a common rail unit, The high-pressure pump device is pressurized in the pressurizing chamber that pressurizes the low-pressure fuel sucked up by the low-pressure pump by a cam mechanism, an intake valve that sucks the low-pressure fuel into the pressurizing chamber, and the pressurizing chamber. A pressure control valve that communicates with a discharge valve that discharges high-pressure fuel, a cam chamber that houses the cam mechanism, and that maintains a constant pressure of the low-pressure fuel supplied to the cam chamber by the low-pressure pump; When the supply amount of the low-pressure fuel supplied to the cam chamber increases, the pressure control valve causes an overflow in order to keep the pressure in the cam chamber constant. And having a fuel supply path connected between said pressure control valve and the suction valve for supplying a portion of the low pressure fuel to the pressurizing chamber.

  According to the present invention, it is possible to realize a high-efficiency high-pressure pump device and a fuel supply system that receive supply of necessary and sufficient low-pressure fuel from a low-pressure pump, pressurize it, and output it as high-pressure fuel to a common rail unit.

1 is a schematic conceptual diagram showing an overall configuration of a common rail system according to an embodiment of the present invention. It is an approximate line figure showing the whole common rail system composition concerning other embodiments of the present invention. It is a basic diagram which shows the structure of the conventional common rail system.

<Embodiment>
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

<Overall configuration of common rail system>
As shown in FIG. 1, a common rail system 1 as a fuel supply system is mainly used as a system for injecting fuel into a cylinder of a diesel engine.

The common rail system 1 includes a fuel tank 2, a low pressure pump 3, an ECU (Electronic Control Unit) 4 as an electronic control unit, a high pressure pump assembly 5 as a high pressure pump device, a common rail unit 7, and a plurality of injectors 8a. , 8b,..., 8n, etc. are provided as main components.

  The fuel tank 2 stores light oil that is a fuel of the diesel engine, and one end of the low-pressure fuel passage 12 and one end of the fuel circulation passage 18 are connected to the fuel tank 2.

  A pre-filter 15 is provided on the line of the low-pressure fuel path 12 and between the fuel tank 2 and the low-pressure pump 3. The pre-filter 15 is a filter that collects foreign matter that is not sucked into the low-pressure pump 3 when foreign matter is mixed in the fuel stored in the fuel tank 2.

  The low-pressure pump 3 is an in-line type provided on the line of the low-pressure fuel path 12, and sucks low-pressure fuel from the fuel tank 2 through the low-pressure fuel path 12 and supplies the low-pressure fuel to the high-pressure pump assembly 5. This is a low pressure feed pump. The low-pressure pump 3 is not limited to the in-line type, and may be an in-tank type.

  The low-pressure pump 3 sucks low-pressure fuel at a flow rate corresponding to the accelerator opening from the fuel tank 2 and supplies the low-pressure pump 3 to the high-pressure pump assembly 5 by energization control by the ECU 4 having a microcomputer configuration.

  A main filter 16 is provided on the line of the low pressure fuel passage 12 between the low pressure pump 3 and the high pressure pump assembly 5. The main filter 16 is also a filter that collects foreign matters mixed in the fuel supplied to the high pressure pump assembly 5 by the low pressure pump 3.

  The high-pressure pump assembly 5 includes a high-pressure pump main body 51 and a mechanical pressure regulating valve (relief valve) 6. The high-pressure pump main body 51 and the common rail unit 7 are high-pressure fuel for pumping high-pressure fuel. They are connected by a path 59.

  The high-pressure pump main body 51 includes a cam chamber 51a, a cam shaft 52, a cam 52a integrated with the cam shaft 52, a tappet 53 that transmits the rotational motion of the cam 52a as a linear motion, and the linear motion of the tappet 53. A plunger 54 that moves in the vertical direction, a suction valve 55 that sucks in the low-pressure fuel supplied through the mechanical relief valve 6, a pressurization chamber 56 that pressurizes the low-pressure fuel sucked in through the suction valve 55, A discharge valve 57 that outputs high-pressure fuel pressurized by the vertical movement of the plunger 54 in the pressure chamber 56 to the common rail unit 7 is provided. A high pressure fuel passage 59 is connected to the discharge valve 57.

In this case, the low pressure fuel sucked into the pressurizing chamber 56 via the suction valve 55 is transferred to the camshaft 52.
After being pressurized to a high pressure of, for example, about 200 MPa by the movement of the plunger 54 in accordance with the rotation of the gas, it is discharged to the common rail unit 7 via the discharge valve 57 and the high-pressure fuel path 59.

  The camshaft 52 of the high-pressure pump main body 51 is pivotally supported via a bearing 58 attached to a housing forming a cam chamber 51a.

  The mechanical components constituting the cam mechanism such as the cam shaft 52, the cam 52a, the tappet 53, the plunger 54, and the bearing 58 of the high-pressure pump main body 51 are housed in the cam chamber 51a and supplied from the low-pressure pump 3. These machine components are lubricated by the low pressure fuel. That is, the common rail system 1 is a fuel lubrication type that lubricates with fuel.

  The cam chamber 51 a of the high-pressure pump main body 51 is connected to the relief valve 6 via the low-pressure fuel passage 12, and the pressure in the cam chamber 51 a is held constant by the relief valve 6. Therefore, the low-pressure fuel supplied to the cam chamber 51a is permeated into a slight clearance between the cam shaft 52 and the bearing 58 by the pressure of the pressurizing chamber 56 held by the relief valve 6, and the lubricity thereof is ensured. ing.

  The clearance between the camshaft 52 and the bearing 58 communicates with the fuel circulation passage 18, and the difference between the pressure in the cam chamber 51a and the pressure in the fuel circulation passage 18 is maintained at a predetermined magnitude, Part of the low-pressure fuel passes through the clearance of the bearing 58 and is discharged to the fuel circulation passage 18, functions as a lubricating oil, and then returned to the fuel tank 2.

  The relief valve 6 is a pressure adjusting valve that keeps the pressure of the low-pressure fuel supplied to the cam chamber 51 a of the high-pressure pump main body 51 constant, and includes a cylinder 61, a piston 62, a spring 63, and an orifice 64.

  The cylinder 61 has a bottomed cylindrical shape, and is provided with a suction port 61 a that receives supply of low-pressure fuel from the cam chamber 51 a via the low-pressure fuel path 12 at one end in the longitudinal direction. Is provided with a discharge port 61b for discharging low-pressure fuel. A fuel supply path 17 is connected to the discharge port 61b.

  The piston 62 has a bottomed cylindrical shape with one closed and the other opened, and is slidable along the inner peripheral surface of the cylinder 61. The spring 63 is an elastic body that biases the piston 62 toward the suction port 61a of the cylinder 61 along the inner peripheral surface of the cylinder 61, and is attached so as to bias one end surface of the piston 62 from the inner peripheral side. Yes.

  The orifice 64 is a throttle in which the pipe of the fuel supply path 17 is partially reduced in diameter in order to limit the flow rate of the fuel supply path 17 attached to the other end of the cylinder 61 in the longitudinal direction. Is provided in order to keep the pressure at a constant. The fuel supply path 17 is connected to a suction valve 55 that constitutes the high-pressure pump main body 51, and merges with the fuel supply path 17 connected to the discharge port 61 b of the cylinder 61.

  The common rail unit 7 accumulates high-pressure fuel pumped from the discharge valve 57 of the high-pressure pump main body 51 via the high-pressure fuel path 59, and a plurality of injectors 8 a and 8 b connected via the high-pressure fuel path 59. ..., high pressure fuel is supplied to 8n.

A rail pressure sensor 71 and a pressure control valve 72 are attached to the common rail unit 7. The sensor output of the rail pressure sensor 71 is output to the ECU 4, and a control signal corresponding to the sensor output is sent from the ECU 4 to the pressure control valve. 72. Specifically, the ECU 4
Receives the sensor output of the actual rail pressure detected by the rail pressure sensor 71 of the common rail unit 7, and outputs a control signal for controlling the valve opening degree of the pressure control valve 72 so that the actual rail pressure becomes the target rail pressure. .

<Operation and effect>
In the above configuration, in the common rail system 1, the low-pressure fuel sucked up through the pre-filter 15 and the low-pressure pump 3 in the idling state where the accelerator opening is the smallest, for example, is sent through the main filter 16 to the high-pressure pump of the high-pressure pump assembly 5. It is supplied to the cam chamber 51 a of the main body 51.

At this time, the low-pressure fuel is supplied from the cam chamber 51a of the high-pressure pump main body 51 through the low-pressure fuel passage 12 into the cylinder 61 of the relief valve 6. However, even in the idling state, a slight amount of about 10 mm ³ / st is provided. Since the injection amount and the return fuel to be returned from the plurality of injectors 8a to 8n to the fuel tank 2 are necessary, the piston 62 does not completely block the suction port 61a of the cylinder 61. However, when the vehicle is traveling in inertia with the accelerator opening being set to 0, the injection amount from the plurality of injectors 8a to 8n is 0, so that the piston 62 is moved to the cylinder 61 by the urging force of the spring 63. The suction port 61a is temporarily completely closed. However, even in this case, since the low pressure fuel for lubricating the mechanical components of the cam mechanism is necessary, the corresponding low pressure fuel is discharged from the low pressure pump 3 and returned from the bearing 58 to the fuel tank 2. .

  Therefore, in this case, after the mechanical components of the cam mechanism are lubricated by the low-pressure fuel in the cam chamber 51 a, the low-pressure fuel used for the lubrication passes through the clearance between the camshaft 52 and the bearing 58 and then returns to the fuel circulation channel 18. To the fuel tank 2.

  Thereafter, when the accelerator opening increases, the low pressure pump 3 supplies the low pressure fuel sucked from the fuel tank 2 to the cam chamber 51 a of the high pressure pump main body 51 in accordance with a control signal from the ECU 4. The supply amount of the low-pressure fuel supplied at this time is increased as compared with the idling state.

  At this time, low-pressure fuel is supplied from the cam chamber 51a of the high-pressure pump main body 51 to the cylinder 61 of the relief valve 6 through the low-pressure fuel passage 12, but the biasing force of the spring 63 is increased by the increase of the pressure in the cam chamber 51a. Against this, the piston 62 moves away from the suction port 61a of the cylinder 61.

  When the piston 62 is separated and the discharge port 61b of the cylinder 61 is opened, an increase exceeding the minimum amount of low-pressure fuel necessary for maintaining the pressure in the cam chamber 51a is constant from the discharge port 61b. The air is sucked into the pressurizing chamber 56 by the suction valve 55 of the high pressure pump main body 51 through the supply path 17.

  That is, as the accelerator opening increases, all of the increased low pressure fuel overflowed from the cam chamber 51a passes through the relief valve 6 and the fuel supply passage 17 from the intake valve 55 of the high pressure pump main body 51 to the pressurizing chamber 56. Will be inhaled.

  As a result, there is no need to return the low pressure fuel overflowed from the cam chamber 51a to the fuel tank 2 from the relief valve 6 as in the prior art, and the fuel supply passage 17 is routed from the relief valve 6 to the pressurizing chamber 56 of the high pressure pump body 51. The low-pressure fuel can be directly supplied via the pressure chamber 56 and pressurized in the pressurizing chamber 56, and then can be efficiently pumped to the common rail unit 7 as the high-pressure fuel.

In this way, there is no need to return the low-pressure fuel overflowed from the cam chamber 51a from the relief valve 6 to the fuel tank 2 as in the prior art, so that the low-pressure pump 3 can lubricate the cam mechanism in the cam chamber 51a. Need only be returned to the fuel tank 2. That is, low-pressure fuel other than lubricating the cam mechanism in the cam chamber 51 a is directly supplied to the pressurizing chamber 56 of the high-pressure pump main body 51 via the relief valve 6 and the fuel supply path 17, and is supplied via the low-pressure pump 3 to the high-pressure pump. There is no need to supply the assembly 5 again.

  This leads to an improvement in energy efficiency when the low-pressure pump 3 sucks the low-pressure fuel from the fuel tank 2, and the power consumption by the low-pressure pump 3 can be reduced by that much, so the size of the battery mounted on the vehicle The vehicle can be reduced in size to reduce the weight of the entire vehicle, and fuel saving can be promoted.

  Furthermore, in the common rail system 1, since the low pressure pump 3 is not a mechanical type but an electromagnetic low pressure feed pump controlled by the ECU 4, there is no mechanical friction loss and a desired supply corresponding to the accelerator opening degree. An amount of low-pressure fuel can be efficiently supplied to the high-pressure pump assembly 5.

  Thus, it is possible to realize an efficient high-pressure pump assembly 5 and common rail system 1 that can receive supply of necessary and sufficient low-pressure fuel from the low-pressure pump 3, pressurize it, and output it as high-pressure fuel to the common rail unit 7.

<Other embodiments>
In the above-described embodiment, the case where an electromagnetic low-pressure feed pump that controls the suction amount of low-pressure fuel by energization control by the ECU 4 is used as the low-pressure pump 3 of the common rail system 1 has been described. However, the present invention is not limited to this, and a mechanical low-pressure pump unit 91 may be used in the common rail system 80, as shown in FIG.

  In this case, the low-pressure pump unit 91 includes a low-pressure feed pump 92, an overflow valve 93, a bypass valve 94, and a flow rate control valve 95. The overflow valve 93 and the bypass valve 94 are mounted in parallel with the low pressure feed pump 92, and the flow control valve 95 is mounted on the line of the low pressure fuel path 12 between the low pressure feed pump 92 and the prefilter 15.

  The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the common rail system 1 according to the above-described embodiment, and all aspects included in the concept of the present invention and the scope of the claims. including. In addition, the respective configurations may be selectively combined as appropriate so as to achieve at least part of the above-described problems and effects. For example, the shape, material, arrangement, size, and the like of each component in the above embodiment can be changed as appropriate according to the specific usage mode of the present invention.

  The high-pressure pump device and fuel supply system of the present invention can be used not only in a diesel engine for vehicles such as automobiles but also in the field of industrial diesel engines such as agricultural machinery, construction machinery, and ships. .

1, 80, 100 Common rail system (fuel supply system)
2, 101 Fuel tank 3, 111 Low pressure pump 4 ECU
5 High pressure pump assembly 6, 131 Relief valve (pressure regulating valve)
7 Common rail unit 8 (8a to 8n) Injectors 12, 102 Low pressure fuel passages 15, 105 Pre-filter 16, 116 Main filter 17 Fuel supply passage 18 Fuel ring passage 51 High pressure pump body 51a, 121a Cam chamber 52, 122 Cam shaft 52a, 122a Cam 53, 123 Tappet 54, 124 Plunger 55, 125 Suction valve 56, 126 Pressurization chamber 57, 127 Discharge valve 58, 128 Bearing 59, 107 High pressure fuel path 61 Cylinder 61a Suction port 61b Discharge port 62, 132 Piston 63, 133 Spring 64 Orifice 71 Rail pressure sensor 72 Pressure control valve 91 Low pressure pump unit 92 Low pressure feed pump 93 Overflow valve 94, 114 Bypass valve 95 Flow control valve 121 High pressure pump

Claims (4)

A pressurizing chamber for pressurizing low pressure fuel sucked from the fuel tank by a low pressure pump by a cam mechanism;
A suction valve for sucking the low-pressure fuel into the pressurizing chamber;
A discharge valve for discharging high-pressure fuel pressurized in the pressurizing chamber;
A pressure regulating valve that communicates with the cam chamber housing the cam mechanism and that maintains a constant pressure of the low-pressure fuel supplied to the cam chamber by the low-pressure pump;
When the supply amount of the low-pressure fuel supplied to the cam chamber increases, a part of the low-pressure fuel that is caused to overflow in order to keep the pressure in the cam chamber constant by the pressure adjusting valve is supplied to the pressurization chamber. And a fuel supply path connected between the pressure regulating valve and the suction valve. 2. The high-pressure pump device according to claim 1, wherein the low-pressure pump is an electromagnetic low-pressure feed pump, and sucks low-pressure fuel at a desired flow rate and supplies the cam chamber with energization control by an electronic control unit. . The low-pressure pump supplies the cam chamber with a minimum amount of the low-pressure fuel for lubricating the cam mechanism even when the supply amount of the low-pressure fuel supplied to the cam chamber decreases. The high-pressure pump device according to claim 1 or 2. A low pressure pump that draws low pressure fuel from the fuel tank;
A high-pressure pump device that pressurizes the low-pressure fuel supplied from the low-pressure pump and pumps it as a high-pressure fuel to a common rail unit;
The high-pressure pump device includes:
A pressurizing chamber for pressurizing the low-pressure fuel sucked up by the low-pressure pump by a cam mechanism;
A suction valve for sucking the low-pressure fuel into the pressurizing chamber;
A discharge valve for discharging high-pressure fuel pressurized in the pressurizing chamber;
A pressure regulating valve that communicates with the cam chamber housing the cam mechanism and that maintains a constant pressure of the low-pressure fuel supplied to the cam chamber by the low-pressure pump;
When the supply amount of the low-pressure fuel supplied to the cam chamber increases, a part of the low-pressure fuel that is caused to overflow in order to keep the pressure in the cam chamber constant by the pressure adjusting valve is supplied to the pressurization chamber. And a fuel supply path connected between the pressure regulating valve and the suction valve.