JP6769816B2 - High pressure pumping system and fuel supply system - Google Patents

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 common rail is provided in which a plurality of injectors are connected and high-pressure fuel is stored, and the fuel is pressurized and supplied by a high-pressure pump to increase the high pressure in the common rail. A common rail system is known that can store fuel (hereinafter, also referred to as "high pressure fuel") and inject and control high pressure fuel from injectors attached to each cylinder of an engine (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 by transmitting the driving force from the drive shaft of the engine to the camshaft of the high pressure pump inserted in the flange. It pressurizes the fuel.

A low-pressure pump is connected to the upstream side of the high-pressure pump, and low-pressure fuel (hereinafter, also referred to as "low-pressure fuel") is sucked up 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 are not shown. Etc. Here, the fuel tank 101 and the high pressure pump assembly 110 will be mainly described.

The fuel tank 101 is a tank for storing light oil for a diesel engine, and one end of a low-pressure fuel passage 102 and one end of a fuel ring flow path 108 are connected to the fuel tank 101. A manual priming pump 104 and a pre-filter 105 are connected on the line of the low-pressure fuel passage 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 driven by an engine (not shown), sucks up the fuel stored in the fuel tank 101, and then supplies the fuel to the high-pressure pump 121 via 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 121a 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, and a tappet 123. A plunger 124 that moves in the vertical direction according to a linear motion, a suction valve 125 that sucks low-pressure fuel supplied through the proportional control valve 117, and a pressurizing chamber 126 that pressurizes the low-pressure fuel sucked through the suction valve 125. A discharge valve 127 for pumping the pressurized high-pressure fuel in the pressurizing chamber 126 to a common rail (not shown) is provided.

In this case, the low-pressure fuel sucked into the pressurizing chamber 126 via the proportional control valve 117 and the suction valve 125 is pressurized according to the movement of the plunger 124, and then is pressurized from the discharge valve 127 via the high-pressure fuel passage 107. It is 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 forming the cam mechanism such as the cam shaft 122, the cam 122a, and the bearing 128 of the high-pressure pump 121 are housed inside the cam chamber 121a, and these mechanical components are provided by the low-pressure fuel supplied from the low-pressure pump 111. The parts are lubricated.

The cam chamber 121a of the high-pressure pump 121 is connected to the relief valve 131, and the pressure of the cam chamber 121a is held constant by the relief valve 131. Therefore, the low-pressure fuel supplied to the cam chamber 121a permeates into a slight gap (clearance) between the cam shaft 122 and the bearing 128 due to the pressure of the cam chamber 121a held by the relief valve 131, and its lubricity is improved. 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 size. After a part of the low-pressure fuel passes through the clearance and functions as a 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 degree, a large amount of low-pressure fuel is sucked into the pressurizing chamber 126 via 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 raises the pressure in the cam chamber 121a 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 overflowing from the cam chamber 121a is returned to the fuel tank 101 via the relief valve 131 and the fuel circulation path 108.

Japanese Unexamined Patent Publication No. 2001-214821

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

However, in this common rail system 100, even when the accelerator opening is increased, 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. The structure is such that the overflowed low-pressure fuel is returned to the fuel tank 101.

Therefore, a larger amount of low-pressure fuel than the injection amount actually injected from the common rail must be supplied from the low-pressure pump 111 to the high-pressure pump 121 side, and the supply amount of the low-pressure fuel is wastefully large and inefficient.

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

In order to achieve the above object, the high pressure pump device of the present invention has a pressurizing chamber that pressurizes the low pressure fuel sucked up from the fuel tank by the low pressure pump by a cam mechanism, and a suction chamber that sucks the low pressure fuel into the pressurizing chamber. The low-pressure fuel that communicates with the valve, the discharge valve that discharges the high-pressure fuel pressurized in the pressurizing chamber, and the cam chamber that houses the cam mechanism, and is supplied to the cam chamber by the low-pressure pump. The pressure control valve that keeps the pressure constant, and the low pressure that overflows to keep the pressure in the cam chamber constant by the pressure control valve when the supply amount of the low pressure fuel supplied to the cam chamber increases. It is characterized by including a fuel supply path connected between the pressure control valve and the suction valve in order to supply a part of 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 is characterized in that low-pressure fuel of a desired flow rate is sucked up and supplied 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 used. It is characterized in that it is supplied to the cam chamber.

In the high-pressure pump device according to the present invention, the low-pressure pump uses the 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 is reduced. It is characterized by supplying to the cam chamber.

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 to a common rail unit as high-pressure fuel. The high-pressure pump device was pressurized in the 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, and the pressurizing chamber. A pressure control valve that communicates with a discharge valve that discharges high-pressure fuel and a cam chamber that houses the cam mechanism and maintains a constant pressure of the low-pressure fuel that is 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 overflows in order to keep the pressure in the cam chamber constant is supplied to the pressurizing chamber by the pressure control valve. Therefore, it is characterized by having a fuel supply path connected between the pressure control valve and the suction valve.

According to the present invention, it is possible to realize a high-efficiency high-pressure pump device and a fuel supply system capable of receiving a necessary and sufficient low-pressure fuel supply from a low-pressure pump, pressurizing it, and outputting it as high-pressure fuel to a common rail unit.

It is a schematic conceptual diagram which shows the whole structure of the common rail system which concerns on embodiment of this invention. It is a schematic diagram which shows the whole structure of the common rail system which concerns on other embodiment of this invention. It is a schematic 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, the 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, which is a fuel for a diesel engine, and one end of a low-pressure fuel passage 12 and one end of a fuel ring flow path 18 are connected to the fuel tank 2.

A pre-filter 15 is provided between the fuel tank 2 and the low-pressure pump 3 on the line of the low-pressure fuel passage 12. The pre-filter 15 is a filter that collects foreign substances so that they are not sucked into the low-pressure pump 3 when foreign substances are 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 passage 12, and is an electromagnetic type that sucks low-pressure fuel from the fuel tank 2 through the low-pressure fuel passage 12 and supplies the low-pressure fuel to the high-pressure pump assembly 5. Low pressure feed pump. The low-pressure pump 3 is not limited to the in-line type, but may be an in-tank type.

The low-pressure pump 3 sucks low-pressure fuel at a flow rate corresponding to the accelerator opening degree from the fuel tank 2 and supplies it 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 matter 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, and the high-pressure pump main body 51 and the common rail unit 7 are used to pump high-pressure fuel. It is connected by road 59.

The high-pressure pump main body 51 responds to the cam chamber 51a, the cam shaft 52, the cam 52a integrated with the cam shaft 52, the 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 low-pressure fuel supplied via a mechanical relief valve 6, a pressurizing chamber 56 that pressurizes the low-pressure fuel sucked through the suction valve 55, and the addition. A discharge valve 57 is provided in the compression chamber 56 to output high-pressure fuel pressurized by the vertical movement of the plunger 54 to the common rail unit 7. 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 the camshaft 52.
After being pressurized to a high pressure of, for example, about 200 MPa by moving the plunger 54 in accordance with the rotation of the fuel, the plunger 54 is discharged to the common rail unit 7 via the discharge valve 57 and the high pressure fuel passage 59.

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

Mechanical components that make up the cam mechanism, such as the cam shaft 52, cam 52a, tappet 53, plunger 54, and bearing 58 of the high-pressure pump main body 51, are housed inside the cam chamber 51a and are supplied from the low-pressure pump 3. Low pressure fuel lubricates these mechanical components. That is, the common rail system 1 is a fuel lubrication type that lubricates with fuel.

The cam chamber 51a 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 51a 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 camshaft 52 and the bearing 58 by the pressure of the pressurizing chamber 56 held by the relief valve 6, and its lubricity is ensured. ing.

The clearance between the camshaft 52 and the bearing 58 is connected to the fuel ring flow path 18, and the difference between the pressure in the cam chamber 51a and the pressure in the fuel ring flow path 18 is maintained at a predetermined size. A part of the low-pressure fuel passes through the clearance of the bearing 58, is discharged to the fuel ring flow path 18, functions as a lubricating oil, and is 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 51a 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 61a for receiving low-pressure fuel from the cam chamber 51a via the low-pressure fuel passage 12 at one end in the longitudinal direction, and is provided with an outer peripheral surface of the cylinder 61. 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 in which one is closed and the other is open, and the piston 62 is slidably provided along the inner peripheral surface of the cylinder 61. The spring 63 is an elastic body that urges the piston 62 to the suction port 61a of the cylinder 61 along the inner peripheral surface of the cylinder 61, and is attached so as to urge one end surface of the piston 62 from the inner peripheral side. There is.

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 in the longitudinal direction of the cylinder 61. It is provided to keep the pressure constant. The fuel supply path 17 is connected to the suction valve 55 constituting the high-pressure pump main body 51, and joins the fuel supply path 17 connected to the discharge port 61b of the cylinder 61.

The common rail unit 7 stores high-pressure fuel that is pumped from the discharge valve 57 of the high-pressure pump main body 51 via the high-pressure fuel passage 59, and a plurality of injectors 8a and 8b connected via the high-pressure fuel passage 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 output from the ECU 4 to the pressure control valve. It is output to 72. Specifically, 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 is pumped through the main filter 16 in the high-pressure pump assembly 5 in the idling state where the accelerator opening is the smallest. It is supplied to the cam chamber 51a of the main body 51.

At this time, low-pressure fuel is supplied from the cam chamber 51a of the high-pressure pump main body 51 into the cylinder 61 of the relief valve 6 via the low-pressure fuel passage 12, but even in the idling state, it is as small as about 10 mm ³ / st. Since the injection amount and the return fuel returned from the plurality of injectors 8a to 8 to the fuel tank 2 are required, the piston 62 does not completely block the suction port 61a of the cylinder 61. However, when the vehicle is traveling by inertia with the accelerator opening set to 0 while the vehicle is traveling, the injection amount from the plurality of injectors 8a to n becomes 0, so that the piston 62 is moved to the cylinder 61 by the urging force of the spring 63. The suction port 61a of the above is temporarily completely closed. However, even in this case, since the low-pressure fuel that lubricates the mechanical components of the cam mechanism is required, the low-pressure fuel corresponding to that amount 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 51a, the low pressure fuel used for the lubrication is passed through the clearance between the cam shaft 52 and the bearing 58 to the fuel ring flow path 18 Is returned to the fuel tank 2.

After that, when the accelerator opening degree becomes large, the low-pressure pump 3 supplies the low-pressure fuel sucked up from the fuel tank 2 to the cam chamber 51a of the high-pressure pump main body 51 according to the control signal from the ECU 4. The amount of low-pressure fuel supplied at this time is increased as compared with the case of the idling state.

At this time, low-pressure fuel is supplied from the cam chamber 51a of the high-pressure pump main body 51 into the cylinder 61 of the relief valve 6 via the low-pressure fuel passage 12, but the urging force of the spring 63 due to the increase in pressure in the cam chamber 51a. The piston 62 is separated from the suction port 61a of the cylinder 61 against the above.

When the pistons 62 are separated from each other and the discharge port 61b of the cylinder 61 is opened, an increase exceeding the minimum amount of low-pressure fuel required to maintain a constant pressure in the cam chamber 51a is fueled from the discharge port 61b. It is sucked into the pressurizing chamber 56 by the suction valve 55 of the high pressure pump main body 51 via the supply path 17.

That is, all of the increased low-pressure fuel overflowing from the cam chamber 51a as the accelerator opening becomes larger passes from the suction valve 55 of the high-pressure pump main body 51 to the pressurizing chamber 56 via the relief valve 6 and the fuel supply path 17. Will be inhaled to.

As a result, it is not necessary to return the low-pressure fuel overflowing from the cam chamber 51a from the relief valve 6 to the fuel tank 2 as in the conventional case, and the fuel supply path 17 is provided from the relief valve 6 to the pressurizing chamber 56 of the high-pressure pump main body 51. The low-pressure fuel can be directly supplied via the pressurizing chamber 56, and then the high-pressure fuel can be efficiently pumped to the common rail unit 7.

In this way, it is not necessary to return the low-pressure fuel overflowing from the cam chamber 51a from the relief valve 6 to the fuel tank 2 as in the conventional case, so that the low-pressure pump 3 is a low-pressure fuel that lubricates the cam mechanism in the cam chamber 51a. Only need to be returned to the fuel tank 2. That is, low-pressure fuel other than lubricating the cam mechanism in the cam chamber 51a 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 to the high-pressure pump 56 via the low-pressure pump 3. There is no need to supply the assembly 5 again.

This leads to improvement of energy efficiency when the low-pressure pump 3 sucks low-pressure fuel from the fuel tank 2, and the power consumption by the low-pressure pump 3 can be reduced by that amount, so that the size of the battery mounted on the vehicle It is possible to reduce the size of the vehicle to reduce the weight of the entire vehicle and promote fuel efficiency.

Further, in the common rail system 1, since the low pressure pump 3 is not a mechanical type but an electromagnetic type low pressure feed pump controlled by the ECU 4, there is no mechanical friction loss and a desired supply according to the accelerator opening degree. A large 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 a common rail system 1 that can receive a necessary and sufficient low-pressure fuel supply 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, a 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. 2 in which the corresponding portions corresponding to those in FIG. 1 are designated by the same reference numerals.

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 passage 12 between the low pressure feed pump 92 and the prefilter 15.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the common rail system 1 according to the above embodiment, and all aspects included in the concept of the present invention and the scope of claims. including. In addition, each configuration may be selectively combined as appropriate so as to achieve at least a part of the above-mentioned problems and effects. For example, the shape, material, arrangement, size, etc. of each component in the above embodiment can be appropriately changed depending on 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 the field of diesel engines 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-8n) Injectors 12, 102 Low-pressure fuel passages 15, 105 Pre-filters 16, 116 Main filters 17 Fuel supply passages 18 Fuel ring flow paths 51 High-pressure pump bodies 51a, 121a Cam chambers 52, 122 Camshafts 52a, 122a Cam 53, 123 Tappet 54, 124 Plunger 55, 125 Suction valve 56, 126 Pressurizing chamber 57, 127 Discharge valve 58, 128 Bearing 59, 107 High pressure fuel passage 61 Cylinder 61a Suction port 61b Discharge port 62, 132 Piston 63, 133 Spring 64 Injector 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 that pressurizes the low-pressure fuel sucked up from the fuel tank by a low-pressure pump by a cam mechanism,
An intake valve that sucks the low-pressure fuel into the pressurizing chamber,
A discharge valve that discharges high-pressure fuel pressurized in the pressurizing chamber,
A pressure regulating valve that communicates with the cam chamber that houses the cam mechanism and maintains the pressure of the low-pressure fuel supplied to the cam chamber by the low-pressure pump at a constant level.
When the supply amount of the low-pressure fuel supplied to the cam chamber increases, a part of the low-pressure fuel that overflows in order to keep the pressure in the cam chamber constant is supplied to the pressurizing chamber by the pressure regulating valve. A fuel supply path connected between the pressure regulating valve and the suction valve is provided for this purpose .
High-pressure pump device is the low pressure fuel from the cam chamber, characterized in Rukoto supplied to the pressure chamber via the pressure regulating valve. The high-pressure pump device according to claim 1, wherein the low-pressure pump is an electromagnetic low-pressure feed pump, and sucks up low-pressure fuel at a desired flow rate by energization control by an electronic control unit and supplies the low-pressure fuel to the cam chamber. .. The low-pressure pump is characterized by supplying the cam chamber with the 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 is reduced. The high-pressure pump device according to claim 1 or 2. A low-pressure pump that sucks low-pressure fuel from the fuel tank,
It is provided with a high-pressure pump device that pressurizes the low-pressure fuel supplied from the low-pressure pump and pumps it to the common rail unit as high-pressure fuel.
The high-pressure pump device
A pressurizing chamber that pressurizes the low-pressure fuel sucked up by the low-pressure pump by a cam mechanism, and
An intake valve that sucks the low-pressure fuel into the pressurizing chamber,
A discharge valve that discharges high-pressure fuel pressurized in the pressurizing chamber,
A pressure regulating valve that communicates with the cam chamber that houses the cam mechanism and maintains the pressure of the low-pressure fuel supplied to the cam chamber by the low-pressure pump at a constant level.
When the supply amount of the low-pressure fuel supplied to the cam chamber increases, a part of the low-pressure fuel that overflows in order to keep the pressure in the cam chamber constant is supplied to the pressurizing chamber by the pressure regulating valve. wherein possess connected a fuel supply passage between the pressure regulating valve and the suction valve in order to,
The fuel supply system according to claim Rukoto said low pressure fuel from the cam chamber is supplied to the pressure chamber via the pressure regulating valve.