JP2020143585A - Pressure control unit - Google Patents

Abstract

To provide a pressure control unit for enabling appropriate pressure reducing control of fuel in a high-pressure channel of a fuel injection system and the cooling of structural members.SOLUTION: A passage forming member 10 is provided in a high-pressure pipe as part of the high-pressure channel, and has a fuel passage 60 communicating the high-pressure channel with a low-pressure channel. A flow amount regulation part 20 is provided in a part of the fuel passage 60 for regulating the flow amount of fuel to be discharged from the high-pressure channel to the low-pressure channel. A cooling passage 80 is provided in the passage forming member 10, where fuel having a lower temperature than the fuel flowing the high-pressure channel flows. A joint passage is a passage where the fuel flowing out of the flow amount regulation part 20 and the fuel flowing in the cooling passage 80 are joined. The pressure control unit is constructed so that a flow amount change of the fuel flowing out of the flow amount regulation part 20 to the joint passage is suppressed with respect to a flow amount change of the fuel flowing out of the cooling passage 80 to the joint passage.SELECTED DRAWING: Figure 2

Description

The present invention relates to a pressure adjusting device for reducing the pressure of fuel in a high pressure path of a fuel injection system.

Conventionally, a common rail system is known as a control system for a fuel injection system of a diesel engine. In the common rail system, the fuel boosted by the supply pump is accumulated in the common rail, and the fuel is injected into each cylinder of the engine at an appropriate time and at an appropriate time from a plurality of injectors connected to the common rail.

In the common rail system, a pressure regulator that stably discharges fuel from a high-pressure path such as a common rail to a low-pressure path such as a fuel tank with a stable minute flow rate within a certain range, and reduces the pressure of the high-pressure fuel in the common rail to an appropriate pressure. Is provided. In the following description, the fuel discharged from the high pressure path such as the common rail to the low pressure path is referred to as "relief fuel".

In the pressure adjusting device described in Patent Document 1, the fuel of the common rail passes through the flow path in the intermediate throttle after the flow rate is throttled in the gap between the end of the first valve piston and the first valve seat. 2 It is configured to be discharged to the low pressure path from the opening between the valve seat and the ball valve. Fuel that is returned to the fuel tank without being boosted by the supply pump (hereinafter referred to as "pump return fuel") flows through the low-pressure path. Therefore, the relief fuel discharged from the opening between the second valve seat and the ball valve merges with the pump return fuel and flows into the fuel tank.

Specifically, in the pressure adjusting device described in Patent Document 1, the first valve piston is provided so as to be reciprocally movable in the housing of the first valve unit. The first valve piston moves in the housing of the first valve unit according to the fuel pressure of the common rail, and changes the gap between the end portion of the first valve piston and the first valve seat. On the other hand, the ball valve is pressed toward the second valve seat side by the second valve piston. The second valve piston is provided so as to be reciprocally movable in the housing of the second valve unit. The valve opening pressure of the ball valve is adjusted by a compression spring and an adjusting screw that urge the second valve seat so that the fuel pressure of the common rail becomes equal to or higher than the pressure required for idling of the engine.

German Patent Application Publication No. 10108202A1

However, in the pressure adjusting device described in Patent Document 1, the direction in which the pump return fuel flowing in the low pressure path flows is orthogonal to the opening direction of the ball valve with respect to the second valve seat. Therefore, in this pressure adjusting device, when the flow rate of the pump return fuel increases, it is conceivable that the ball valve is displaced from the flow path axis of the second valve seat to the downstream side of the pump return fuel. In that case, the flow velocity of the fuel flowing at a position far from the flow path wall surface in the opening formed between the ball valve and the second valve seat becomes faster, and the flow rate of the relief fuel (hereinafter referred to as "relief flow rate"). Increases. As a result, when the fuel pressure of the common rail drops more than necessary, the amount of fuel injected from the injector connected to the common rail to each cylinder of the engine decreases. As described above, in the pressure adjusting device described in Patent Document 1, since the relief flow rate varies according to the change in the flow rate of the pump return fuel, the relief flow rate cannot be stably reduced within a certain range, and the fuel for the common rail There is a problem that the pressure cannot be adjusted to reduce the pressure properly.

Further, the pressure adjusting device described in Patent Document 1 has a configuration in which only one surface of a member forming the second valve seat is cooled by the pump return fuel. Therefore, when the fuel whose flow rate is throttled in the gap between the end of the first valve piston and the first valve seat generates heat due to the reduced pressure, it is considered that the fuel deteriorates and a deposit is generated in the relief fuel. When the deposit adheres to the sliding part between the inner wall of the housing of the first valve unit and the first valve piston, the sliding part between the inner wall of the housing of the second valve unit and the second valve piston, etc., those operations occur. Getting worse. Even in such a case, the pressure adjusting device described in Patent Document 1 cannot limit the relief flow rate to a stable minute flow rate within a certain range, and cannot appropriately reduce the fuel pressure of the common rail.

In view of the above points, it is an object of the present invention to provide a pressure adjusting device capable of appropriately reducing the pressure of fuel in the high pressure path of the fuel injection system and cooling the constituent members.

In order to achieve the above object, according to the invention of claim 1, the pressure adjusting device for reducing the pressure of the fuel flowing in the high pressure path of the fuel injection system of the engine includes a passage forming member (10) and a flow rate regulating unit (20). , A cooling passage (80) and a confluence passage (64, 67, 75, 121). The passage forming member is provided in the high pressure pipe (103) constituting the high pressure path, and has a fuel passage (60) communicating the high pressure path and the low pressure path. The flow rate control unit is provided in a part of the fuel passage and regulates the flow rate of the fuel discharged from the high pressure path to the low pressure path. The cooling passage is provided in the passage forming member, and fuel having a lower temperature than the fuel flowing in the high pressure path flows. The merging passage is a passage where the fuel flowing out from the flow rate regulating unit and the fuel flowing through the cooling passage merge. The pressure adjusting device is configured so that the change in the flow rate of the fuel flowing out from the flow rate regulating unit to the merging passage is suppressed with respect to the change in the flow rate of the fuel flowing out from the cooling passage to the merging passage.

As a result, the change in the relief flow rate is suppressed with respect to the change in the flow rate of the fuel flowing through the cooling passage (hereinafter referred to as "cooling fuel"). Therefore, it is possible to suppress the variation in the relief flow rate and set the relief flow rate to a stable minute flow rate within a certain range. Therefore, this pressure regulator makes it possible to control the fuel injection amount from the injector connected to the high-pressure path to each cylinder of the engine with high accuracy by properly reducing the fuel pressure in the high-pressure path. To do.

In addition, the relief fuel flowing through the flow rate regulating section generates heat due to decompression due to the flow rate regulation. On the other hand, this pressure regulator can cool the passage forming member, the flow rate regulating unit, and the relief fuel by the cooling fuel. Therefore, it is possible to suppress a decrease in the viscosity of the relief fuel and set the relief flow rate to a stable minute flow rate within a certain range. In addition, it is possible to prevent thermal deterioration of the relief fuel and prevent deposits from being generated in the relief fuel.

The high-pressure path refers to a fuel path from the discharge valve of the supply pump provided in the fuel injection system to the injection hole of the injector via the common rail. The low-pressure path refers to a fuel path from the fuel tank provided in the fuel injection system to the pump chamber of the supply pump, and a path communicating with the fuel tank.

The reference reference numerals in parentheses attached to each component or the like indicate an example of the correspondence between the component or the like and the specific component or the like described in the embodiment described later.

It is a block diagram of the common rail system which uses the pressure adjusting apparatus which concerns on 1st Embodiment. It is sectional drawing of the pressure adjusting apparatus which concerns on 1st Embodiment. It is an enlarged view of the part III of FIG. It is sectional drawing of the pressure adjusting apparatus which concerns on 2nd Embodiment. It is an enlarged view of the V part of FIG. It is sectional drawing which shows a part of the pressure adjustment apparatus of the comparative example. FIG. 6 is a cross-sectional view showing a valve body open state when the flow rate of the cooling fuel is small in the cross section of the line VII-VII of FIG. FIG. 6 is a cross-sectional view showing a valve body open state when the flow rate of cooling fuel is large in the cross section of the line VII-VII of FIG. It is sectional drawing of the pressure adjusting apparatus which concerns on 3rd Embodiment. It is an enlarged view of the X part of FIG. It is sectional drawing of the pressure adjusting apparatus which concerns on 4th Embodiment. It is sectional drawing of the pressure adjusting apparatus which concerns on 5th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the following embodiments, the same or equal parts are designated by the same reference numerals, and the description thereof will be omitted.

(First Embodiment)
The first embodiment will be described with reference to the drawings. The pressure adjusting device 1 of the present embodiment is used in the common rail system 100 of a diesel engine.

First, the common rail system 100 will be described.
As shown in FIG. 1, the common rail system 100 includes a fuel tank 101, a supply pump 102, a common rail 103, an injector 104, an electronic control unit (hereinafter, referred to as “ECU”) 105, and the like. Liquid fuel such as light oil stored in the fuel tank 101 is pumped by a low-pressure pump (not shown) and sucked into the supply pump 102 via the low-pressure fuel pipe 106 and the fuel filter 107. The supply pump 102 is, for example, a plunger pump driven by an engine. The supply pump 102 boosts the fuel sucked into the pump chamber (not shown) to, for example, about 200 to 300 MPa, and pumps it to the common rail 103. The supply pump 102 is provided with a fuel regulating valve 108 for adjusting the fuel to be boosted in the pump chamber.

The fuel boosted by the supply pump 102 passes through the high-pressure fuel pipe 112 and is stored in the common rail 103. The common rail 103 is a long and thin tubular high-pressure pipe. A plurality of injectors 104 are connected to the common rail 103 via a plurality of distribution pipes 113. Therefore, the fuel accumulated in the common rail 103 is supplied to the plurality of injectors 104 via the plurality of distribution pipes 113. The injector 104 injects an appropriate amount of fuel into each cylinder of the engine at an appropriate time based on a control signal input from the ECU 105. A part of the fuel supplied from the common rail 103 to the injector 104 is returned to the fuel tank 101 through the leak pipe 114 and the return pipe 111.

An overflow pipe 109 is connected to the fuel tank 101. A part of the fuel supplied from the fuel tank 101 to the supply pump 102 via the low pressure fuel pipe 106 flows to the overflow pipe 109 without being boosted. Therefore, a fuel having a lower temperature and a lower pressure than the high pressure fuel pumped from the supply pump 102 to the common rail 103 flows through the overflow pipe 109. The fuel is returned from the overflow pipe 109 to the fuel tank 101 via the cooling passage 80 in the pressure adjusting device 1 shown in FIG. 2 and the relief pipe 110 and the return pipe 111 shown in FIG.

A fuel pressure sensor 115 for detecting the fuel pressure inside is attached to the common rail 103. The information detected by the fuel pressure sensor 115 is input to the ECU 105. The ECU 105 is composed of a processor that performs control processing and arithmetic processing, a microcomputer that includes a storage unit such as a ROM and a RAM that stores programs and data, and peripheral circuits thereof. The ECU 105 controls the drive of the fuel regulating valve 108 and the injector 104 of the supply pump 102.

The common rail 103 is provided with a pressure adjusting device 1 for adjusting the internal fuel pressure to reduce the pressure. The pressure adjusting device 1 discharges the high-pressure fuel in the common rail 103 to a low-pressure path such as a fuel tank 101 at a minute flow rate. Therefore, a part of the fuel in the common rail 103 is returned from the pressure adjusting device 1 to the fuel tank 101 via the relief pipe 110 and the return pipe 111. As a result, the pressure adjusting device 1 prevents the fuel pressure from being accumulated more than necessary in the common rail 103 during the operation of the engine, optimizes the fuel injection amount injected from the injector 104, and generates noise. It can be suppressed. Further, the pressure adjusting device 1 prevents the fuel pressure from being accumulated more than necessary in the common rail 103 while the engine is stopped, and adjusts the fuel injection amount injected from the injector 104 at the start of the next operation. , It is possible to suppress the generation of noise.

The position where the pressure adjusting device 1 is provided is not limited to the common rail 103, and may be any location on the high-pressure path of the fuel injection system of the engine. The high-pressure path refers to a fuel path from the discharge valve of the supply pump 102 to the injection hole of the injector 104 via the common rail 103. As a result, the pressure adjusting device 1 can adjust the decompression of the fuel flowing in the high pressure path of the fuel injection system of the engine. The low-pressure path refers to a fuel path from the fuel tank 101 provided in the fuel injection system to the pump chamber of the supply pump 102, and a low-pressure pipe communicating with the fuel tank 101. That is, the low pressure path includes the above-mentioned overflow pipe 109, the cooling passage 80 in the pressure adjusting device 1, the relief pipe 110, the return pipe 111, and the like.

Next, the configuration of the pressure adjusting device 1 of the first embodiment will be described.
As shown in FIGS. 2 and 3, the pressure adjusting device 1 of the first embodiment includes a passage forming member 10, a flow rate regulating unit 20, a cooling passage 80, a connecting passage 67 as a merging passage, and the like. ..

The passage forming member 10 is provided at one end of the common rail 103 in the longitudinal direction. At the end of the common rail 103, a mounting hole 116 for mounting the passage forming member 10 is provided. The mounting hole 116 communicates with a rail chamber 117 formed inside the common rail 103. The inner diameter of the mounting hole 116 is larger than the inner diameter of the rail chamber 117. Therefore, a contact portion 118 with which the passage forming member 10 abuts is provided at the step portion between the mounting hole 116 and the rail chamber 117.

The passage forming member 10 is composed of a first passage forming member 11 and a second passage forming member 12. The first passage forming member 11 is arranged on the rail chamber 117 side in the mounting hole 116. The first passage forming member 11 has a shoulder portion 13 that abuts on the contact portion 118 of the common rail 103, and a protruding portion 14 that protrudes from the shoulder portion 13 into the rail chamber 117. A bottomed tubular filter 50 is fitted to the outer wall of the protruding portion 14. The filter 50 has a plurality of pores 51. The filter 50 collects foreign substances contained in the fuel by having the plurality of pores 51 thereof.

The second passage forming member 12 is provided on the side opposite to the rail chamber 117 with the first passage forming member 11 interposed therebetween. The second passage forming member 12 has a holding portion 15 that holds the first passage forming member 11 outside the diameter of the first passage forming member 11. The holding portion 15 regulates the radial movement of the first passage forming member 11. The male screw 16 provided on the outer wall of the second passage forming member 12 is screwed into the female screw 119 provided on the inner wall of the mounting hole 116 of the common rail 103. Due to the axial force at that time, the second passage forming member 12 and the first passage forming member 11 are brought into close contact with each other, and the shoulder portion 13 of the first passage forming member 11 comes into contact with the abutting portion 118 of the common rail 103. As a result, the first passage forming member 11 and the second passage forming member 12 are attached to the mounting holes 116 of the common rail 103. A seal ring 17 is provided between the inner wall of the mounting hole 116 of the common rail 103 and the second passage forming member 12. The seal ring 17 is made of, for example, rubber or an elastomer, and prevents fuel from leaking from the gap between the mounting hole 116 of the common rail 103 and the second passage forming member 12.

A fuel passage 60 is formed inside the first passage forming member 11 and the second passage forming member 12. In the following description, the fuel passage 60 formed inside the first passage forming member 11 is referred to as a first fuel passage 61, and the fuel passage 60 formed inside the second passage forming member 12 is referred to as a second fuel passage 62. May be called. The first fuel passage 61 communicates with the rail chamber 117 of the common rail 103, which is a part of the high-pressure path of the fuel injection system of the engine. On the other hand, the second fuel passage 62 communicates with the relief pipe 110 which is a part of the low pressure path. The first fuel passage 61 and the second fuel passage 62 communicate with each other. Therefore, the fuel passage 60 included in the passage forming member 10 communicates the high pressure path and the low pressure path of the fuel injection system of the engine.

The first fuel passage 61 has an inlet passage 63 and a valve hole 21 from the rail chamber 117 side. The inlet passage 63 is a passage for introducing fuel from the rail chamber 117 through the filter 50. The valve hole 21 is formed to have a smaller flow path area than the inlet passage 63, and is a flow path that regulates the flow of fuel. The pressure of the fuel introduced from the inlet passage 63 decreases as it passes through the valve hole 21. The inner diameter of the valve hole 21 is set to be larger than the cutting limit value (for example, a diameter of 0.05 mm). The inner diameter of the valve hole 21 is, for example, about 0.06 to 0.12 mm or 0.08 to 0.1 mm. As a result, the relief flow rate can be limited to a stable minute flow rate within a certain range, and clogging of the valve hole 21 due to foreign matter contained in the fuel can be suppressed. The length of the flow path of the valve hole 21 is shorter than the length of the inlet passage 63. The flow path area of the valve hole 21 is larger than the flow path area of the pore 51 of the filter 50. Therefore, even when a fine foreign matter passes through the plurality of pores 51 of the filter 50, the foreign matter flows to the relief pipe 110 side without clogging the valve hole 21. Therefore, it is possible to suppress clogging of the valve hole 21 due to foreign matter contained in the fuel.

The flow rate regulating unit 20 of the first embodiment includes a valve mechanism 30, a valve hole 21, and an orifice member 40. Further, the valve mechanism 30 has a valve seat 31, a ball valve 32, a guide member 33, a stopper portion 69, and a spring 34.

A valve seat 31 is provided at a position on the relief pipe 110 side of the valve hole 21 in the first fuel passage 61. The valve seat 31 is formed in a tapered shape in which the inner diameter gradually decreases from the second fuel passage 62 side toward the valve hole 21. A ball valve 32 as a valve body is provided on the valve seat 31 so that it can be seated and taken off. The valve body is not limited to the ball valve 32, and various poppet valves can be adopted.

The second fuel passage 62 has a valve mechanism passage 64, an orifice passage 65, a throttle hole 41, a holding passage 66, and a connecting passage 67 from the first fuel passage 61 side. Since the orifice passage 65 of the first embodiment is provided on the low pressure path side with respect to the valve hole 21, it may be referred to as a low pressure side orifice passage 65.

The valve mechanism passage 64 is provided with a guide member 33 that supports a portion of the ball valve 32 opposite to the valve seat 31. The guide member 33 is provided with an outer wall on the outer side in the radial direction so as to be slidable on the inner wall of the valve mechanism passage 64. The outer wall of the guide member 33 on the outer side in the radial direction and the inner wall of the valve mechanism passage 64 can be in line contact with each other. The flow path area of the valve mechanism passage 64 is larger than the flow path area of the orifice passage 65. Therefore, a stopper portion 69 as a stepped surface is provided between the valve mechanism passage 64 and the orifice passage 65. The movable range of the guide member 33 is set by the stopper portion 69.

The guide member 33 has a large lift amount of the ball valve 32 even when the fuel pressure in the rail chamber 117 (hereinafter referred to as “rail pressure”) becomes abnormally high pressure or when abnormal pressure pulsation occurs in the fuel. , Prevents the ball valve 32 from rampaging in the direction intersecting the flow path axis Ax1. Therefore, the guide member 33 can prevent the ball valve 32 from falling off from the valve seat 31, and can prevent the spring 34 that urges the guide member 33 toward the valve seat 31 from being damaged.

A plurality of orifice members 40 are continuously provided in the orifice passage 65. The plurality of orifice members 40 have throttle holes 41 that regulate the relief flow rate. Specifically, two orifice members 40 are continuously provided in the low pressure side orifice passage 65. The number of orifice members 40 is not limited to two, and is appropriately set by experiments or the like so that the relief flow rate becomes an appropriate amount.
In addition, "a plurality of orifice members 40 are continuously provided" means that, in addition to being provided in a state where the plurality of orifice members 40 are in contact with each other, the plurality of orifice members 40 are provided as washers or seal members. It also includes the fact that it is provided on both sides.

The plurality of orifice members 40 are arranged so that the flow path axes Ax1 of the throttle holes 41 of the respective orifice members 40 coincide with each other. As a result, the relief flow rate can be kept within a certain range.
If the flow path axes Ax1 of the respective throttle holes 41 of the plurality of orifice members 40 are deviated, the fuel flow collides with the wall surface of the orifice member 40 in the flow path axis Ax1 direction, and the plurality of throttle holes 41 are formed. The pressure loss of the passing fuel varies. Therefore, it becomes difficult to keep the relief flow rate within a certain range.

On the other hand, as in the first embodiment, by matching the flow path axes Ax1 of the throttle holes 41 of the plurality of orifice members 40, it is possible to suppress the variation in the pressure loss of the fuel flow. Therefore, with this configuration, the relief flow rate can be limited to a stable minute flow rate within a certain range, and the rail pressure can be appropriately reduced and adjusted.

A spring 34 as an urging member is provided between the orifice member 40 and the guide member 33. One end of the spring 34 is in contact with the guide member 33, and the other end is in contact with the orifice member 40. The spring 34 is a compression coil spring, and urges the guide member 33 and the ball valve 32 toward the valve seat 31 side. The valve opening pressure of the ball valve 32 is set by adjusting the urging force of the spring 34. The valve opening pressure of the ball valve 32 is set so that the rail pressure is equal to or higher than the pressure required for idling of the engine.

The valve seat 31, ball valve 32, guide member 33, stopper portion 69, and spring 34 described above constitute a valve mechanism 30 that holds the rail pressure at a pressure higher than that required for idling. The flow rate regulating unit 20 is composed of the valve mechanism 30, the valve hole 21, and the orifice member 40. The flow rate regulating unit 20 regulates the relief flow rate discharged from the rail chamber 117 to the relief pipe 110.

The holding passage 66 is provided on the relief pipe 110 side with respect to the orifice passage 65. The flow path area of the holding passage 66 is smaller than the flow path area of the orifice passage 65. Therefore, a step portion 70 is formed between the orifice passage 65 and the holding passage 66. The orifice member 40 is fixed to the step portion 70. The spring 34 constituting the valve mechanism 30 described above presses the orifice member 40 against the step portion 70. Therefore, the spring 34 also has a function as a fixing member for fixing the orifice member 40 to the orifice passage 65. In this way, when the spring 34 is used as the fixing member, it is possible to absorb the variation in the length of the second fuel passage 62 in the flow path axis Ax1 direction and reliably press the orifice member 40 against the step portion 70. It is possible. Therefore, it is possible to prevent fuel leakage between the orifice member 40 and the step portion 70.

The inner diameter of the throttle hole 41 included in the orifice member 40 is set to be larger than the limit value for cutting (for example, 0.05 mm in diameter). The inner diameter of the aperture hole 41 is, for example, about 0.06 to 0.12 mm or 0.08 to 0.1 mm. As a result, the relief flow rate can be limited to a stable minute flow rate within a certain range, and clogging of the throttle hole 41 due to foreign matter contained in the fuel can be suppressed. The flow path area of the throttle hole 41 is larger than the flow path area of the pore 51 of the filter 50. Therefore, even when a fine foreign matter passes through the plurality of pores 51 of the filter 50, the foreign matter flows to the relief pipe 110 side without clogging the throttle hole 41. Therefore, it is possible to suppress clogging of the throttle hole 41 due to foreign matter contained in the fuel. Tapered surfaces 42 are formed at both ends of the throttle hole 41.

The connecting passage 67 is provided on the relief pipe 110 side of the holding passage 66. The flow path area of the connecting passage 67 is larger than the flow path area of the holding passage 66. A tip portion (not shown) of the relief pipe 110 is connected to the connection passage 67. In this embodiment, the flow path axis Ax1 of the throttle hole 41 of the orifice member 40 and the flow path axis Ax1 of the connection passage 67 are in the same direction.

The common rail 103 is provided with a cooling fuel inlet portion 120 to which the overflow pipe 109 is connected. Fuel having a lower temperature and lower pressure than the high pressure fuel accumulated in the common rail 103 is supplied to the cooling fuel inlet portion 120 from the overflow pipe 109. In the following description, the fuel supplied from the overflow pipe 109 to the cooling fuel inlet portion 120 is referred to as cooling fuel.

A cooling fuel chamber 121 is formed between the inner wall of the mounting hole 116 of the common rail 103 and the outer wall of the passage forming member 10. The cooling fuel chamber 121 is formed so as to surround the radial outer side of the passage forming member 10. The cooling fuel supplied from the overflow pipe 109 to the cooling fuel inlet portion 120 flows into the cooling fuel chamber 121. The flow path shaft Ax2 of the cooling fuel inlet portion 120 is directed to the radial outer wall surface of the passage forming member 10. Therefore, the cooling fuel flowing into the cooling fuel chamber 121 from the cooling fuel inlet portion 120 collides with the radial outer wall surface of the passage forming member 10. Therefore, the passage forming member 10 is cooled with high efficiency by increasing the flow rate of the cooling fuel in contact with the radial outer wall surface of the passage forming member 10 and increasing the heat exchange efficiency between the passage forming member 10 and the cooling fuel. Can be done.

The second passage forming member 12 is provided with a plurality of cooling passages 80 for communicating the cooling fuel chamber 121 and the connecting passage 67. The cooling fuel that has flowed into the cooling fuel chamber 121 from the cooling fuel inlet portion 120 passes through the plurality of cooling passages 80 and flows into the connection passage 67. The plurality of cooling passages 80 are provided inside the second passage forming member 12 so as to surround the radial outside of the plurality of orifice members 40. The plurality of cooling passages 80 are provided so as to pass between the flow rate regulating portion 20 and the seal ring 17 inside the second passage forming member 12.

The cooling fuel flowing out from the cooling passage 80 and the relief fuel flowing out from the flow rate regulating unit 20 merge in the connecting passage 67. Therefore, in the first embodiment, the connection passage 67 in the fuel passage 60 corresponds to a “merging passage” in which the cooling fuel flowing out from the cooling passage 80 and the relief fuel decompressed by the flow rate regulating unit 20 merge. ..

The flow path shaft Ax3 of the cooling passage 80 is provided so as to go from the upstream side to the downstream side and approach the flow path shaft Ax1 of the fuel passage 60 provided in the second passage forming member 12. Therefore, the flow path shaft Ax3 of the cooling passage 80 and the flow path shaft Ax1 of the connection passage 67 are configured to have an acute angle. As a result, the change in the flow rate of the relief fuel flowing out from the flow rate regulating unit 20 to the connection passage 67 is suppressed with respect to the change in the flow rate of the cooling fuel flowing out from the cooling passage 80 to the connection passage 67.

In this specification, the fact that the flow path axis Ax3 of the cooling passage 80 and the flow path axis Ax1 of the merging passage are parallel or acute is referred to as "the cooling passage 80 and the merging passage are parallel". That is, in the first embodiment, the cooling passage 80 and the connecting passage 67 as a confluence passage are parallel to each other.

The flow rate of the relief fuel flowing from the flow rate regulating unit 20 to the connection passage 67 is set to be equal to or less than the flow rate of the cooling fuel flowing from the cooling passage 80 to the connection passage 67. Specifically, the flow rate of the relief fuel is, for example, 200 cc / min or less. On the other hand, the flow rate of the cooling fuel is, for example, 200 cc / min or more. As a result, the passage forming member 10, the flow rate regulating unit 20, and the relief fuel can be sufficiently cooled by the cooling fuel flowing through the cooling passage 80.

The pressure adjusting device 1 of the first embodiment described above has the following effects.
(1) In the first embodiment, the change in the flow rate of the relief fuel flowing out from the flow rate regulating unit 20 to the connecting passage 67 is suppressed with respect to the change in the flow rate of the cooling fuel flowing out from the cooling passage 80 to the connecting passage 67. It is configured in. As a result, it is possible to suppress variations in the relief flow rate and set the relief flow rate to a stable minute flow rate within a certain range. Therefore, the pressure adjusting device 1 appropriately controls the fuel pressure in the high-pressure path by appropriately reducing the pressure, thereby controlling the fuel injection amount from the injector 104 connected to the high-pressure path to each cylinder of the engine with high accuracy. Make it possible.

(2) Further, when the fuel flowing through the flow rate regulating unit 20 passes through the throttle hole 41 of the orifice member 40, the pressure energy is converted into heat energy by decompression, and heat is generated. On the other hand, the pressure adjusting device 1 can cool the passage forming member 10, the flow rate regulating unit 20, and the relief fuel by the cooling fuel flowing through the cooling passage 80. Therefore, it is possible to suppress a decrease in the viscosity of the fuel and set the relief flow rate to a stable minute flow rate within a certain range. In addition, it is possible to prevent thermal deterioration of the relief fuel and prevent deposits from being generated in the relief fuel.

(3) In the first embodiment, the flow path shaft Ax3 of the cooling passage 80 and the flow path shaft Ax1 of the connection passage 67 as a confluence passage are configured in parallel. The flow path shaft Ax1 of the connection passage 67 and the flow path shaft Ax1 of the throttle hole 41 of the orifice member 40 are in the same direction.
As a result, the cooling fuel flowing out from the cooling passage 80 to the connection passage 67 does not obstruct the flow of the relief fuel flowing out from the throttle hole 41 of the orifice member 40 to the connection passage 67. Therefore, the change in the relief flow rate is suppressed with respect to the change in the flow rate of the cooling fuel flowing through the cooling passage 80, and the relief flow rate can be set to a stable minute flow rate within a certain range. Therefore, the pressure adjusting device 1 can appropriately reduce the fuel pressure in the high pressure path.

(4) Further, in the first embodiment, since the flow path axis Ax3 of the cooling passage 80 and the flow path axis Ax1 of the connection passage 67 are configured to have an acute angle, in the connection passage 67, The fuel flowing out from the cooling passage 80 and the relief fuel flowing out from the flow rate regulating unit 20 are quickly mixed. Therefore, the generation of deposit can be further suppressed.

(5) In the first embodiment, the cooling passage 80 is provided so as to pass between the flow rate regulating portion 20 and the seal ring 17 inside the second passage forming member 12.
As a result, it is possible to suppress the heat generated by the decompression of the fuel of the flow rate regulating unit 20 from being transferred to the seal ring 17 via the second passage forming member 12. As a result, thermal deterioration of the seal ring 17 can be prevented and the product life can be extended.

(6) In the first embodiment, a cooling fuel chamber 121 into which cooling fuel flows in from the cooling fuel inlet portion 120 is formed between the inner wall of the mounting hole 116 of the common rail 103 and the passage forming member 10.
As a result, the passage forming member 10 and the relief fuel can be cooled by the cooling fuel supplied to the cooling fuel chamber 121.

(7) In the first embodiment, the flow path shaft Ax2 of the cooling fuel inlet portion 120 is configured to face the radial outer wall surface of the passage forming member 10.
As a result, the cooling fuel flowing into the cooling fuel chamber 121 from the cooling fuel inlet portion 120 collides with the radial outer wall surface of the passage forming member 10. Therefore, the passage forming member 10 is cooled with high efficiency by increasing the flow rate of the cooling fuel in contact with the radial outer wall surface of the passage forming member 10 and increasing the heat exchange efficiency between the passage forming member 10 and the cooling fuel. Can be done.

(8) In the first embodiment, the cooling passage 80 is provided inside the passage forming member 10 and outside the orifice member 40 in the radial direction.
Thereby, the cooling fuel flowing through the cooling passage 80 can efficiently cool the passage forming member 10, the orifice member 40, and the relief fuel passing through the throttle hole 41 of the orifice member 40.

(9) In the first embodiment, the flow path shaft Ax3 of the cooling passage 80 is provided so as to approach the flow path shaft Ax1 of the fuel passage 60 provided in the passage forming member 10 from the upstream side to the downstream side.
As a result, the flow path shaft Ax3 of the cooling passage 80 and the flow path shaft Ax1 of the connection passage 67 are configured to have an acute angle. Therefore, in the connection passage 67, the cooling fuel flowing out from the cooling passage 80 and the relief fuel flowing out from the flow rate regulating unit 20 are quickly mixed, so that the generation of deposit can be further suppressed.

(10) In the first embodiment, the flow rate of the relief fuel flowing from the flow rate regulating unit 20 to the connection passage 67 is set to be equal to or less than the flow rate of the cooling fuel flowing from the cooling passage 80 to the connection passage 67.
As a result, the passage forming member 10, the flow rate regulating unit 20, and the relief fuel can be sufficiently cooled by the cooling fuel flowing through the cooling passage 80.

(Second Embodiment)
The second embodiment is different from the first embodiment because the configuration of the flow rate regulating unit 20 and the cooling passage 80 is changed from the first embodiment, and the other parts are the same as those of the first embodiment. Only the part will be described.

As shown in FIGS. 4 and 5, in the second embodiment, the first fuel passage 61 formed in the first passage forming member 11 has an orifice passage 71, a throttle hole 41, and a valve hole from the rail chamber 117 side. Has 21. Since the orifice passage 71 of the second embodiment is provided on the high pressure path side with respect to the valve mechanism 30, it may be referred to as a high pressure side orifice passage 71.

A plurality of orifice members 40 are continuously provided in the high-pressure side orifice passage 71. Specifically, three orifice members 40 are continuously provided in the high-pressure side orifice passage 71. The number of orifice members 40 is not limited to three, and is appropriately set by experiments or the like so that the relief flow rate becomes an appropriate amount.
The plurality of orifice members 40 are arranged so that the flow path axes Ax1 of the throttle holes 41 of the respective orifice members 40 coincide with each other. As a result, the relief flow rate can be limited to a stable minute flow rate within a certain range, and the rail pressure can be appropriately reduced.

The flow path area of the high-pressure side orifice passage 71 is larger than the flow path area of the valve hole 21. Therefore, a step portion 72 is formed between the high-pressure side orifice passage 71 and the valve hole 21. The plurality of orifice members 40 are fixed to the step portion 72.

A spring 36 and a spacer member 37 as fixing members are provided between the plurality of orifice members 40 and the inner wall of the filter 50. The spacer member 37 is spherical and is in contact with the inner wall of the filter 50. One end of the spring 36 is in contact with the spacer member 37, and the other end is in contact with the orifice member 40. The spring 36 is a compression coil spring, and urges a plurality of orifice members 40 to the step portion 72. As a result, the plurality of orifice members 40 are fixed to the step portion 72.

When the spring 36 is used as the fixing member, the variation in the length of the filter 50 and the first fuel passage 61 in the flow path axis Ax1 direction is absorbed, and the plurality of orifice members 40 are surely pressed against the step portion 72. Is possible. Therefore, it is possible to prevent fuel leakage between the orifice member 40 and the step portion 72.

The plurality of orifice members 40 included in the pressure adjusting device 1 of the second embodiment include a throttle hole 41 that regulates the flow of fuel and an open chamber 43 having a larger flow path area and a fixed volume than the throttle hole 41. Have. The inner diameter of the drawing hole 41 is set to be larger than the limit value for cutting (for example, 0.05 mm in diameter). The inner diameter of the aperture hole 41 is, for example, about 0.06 to 0.12 mm or 0.08 to 0.1 mm. The length of the flow path of the throttle hole 41 is, for example, about 1/2 to 1/4 of the length of one orifice member 40. On the other hand, the inner diameter of the opening chamber 43 is, for example, about 10 to 100 times that of the throttle hole 41. The plurality of orifice members 40 are in contact with each other. Therefore, the volume of the open chamber 43 of the orifice member 40 is fixed.

Since the plurality of orifice members 40 are continuously provided, the plurality of throttle holes 41 and the plurality of open chambers 43 are alternately arranged. With this configuration, the pressure of the relief fuel is gradually reduced each time it passes through the plurality of throttle holes 41 one by one. Therefore, as compared with the case where one orifice member 40 having one long throttle hole 41 is used, the configuration of the second embodiment can reduce the relief flow rate. Therefore, the pressure adjusting device 1 can appropriately reduce the rail pressure.

Further, as compared with using one orifice member 40 having one long throttle hole 41, the configuration of the second embodiment is to increase the inner diameter of the diaphragm hole 41 of each of the plurality of orifice members 40. Is possible. Therefore, it is possible to prevent the throttle hole 41 from being clogged by foreign matter contained in the fuel.
Further, the pores 51 of the filter 50 provided on the upstream side of the orifice member 40 may be smaller than the cross-sectional area of the plurality of throttle holes 41. Therefore, clogging of the aperture holes 41 can be prevented without using the filter 50 having extremely small pores 51.

Further, since the pressure of the relief fuel gradually decreases each time it passes through each of the throttle holes 41 of the plurality of orifice members 40, the flow velocity of the fuel also decreases accordingly. Therefore, the pressure adjusting device 1 can suppress the occurrence of cavitation in the fuel and prevent the occurrence of erosion on the surface of the orifice member 40.

In the second embodiment, the relief fuel flows through the valve hole 21 after being sufficiently depressurized by the plurality of orifice members 40. Therefore, the flow path area of the valve hole 21 of the second embodiment may be larger than the flow path area of the valve hole 21 described in the first embodiment. Even in such a case, by appropriately setting the number of the plurality of orifice members 40, it is possible to limit the relief flow rate to a stable minute flow rate within a certain range and appropriately reduce the rail pressure. .. Therefore, in the second embodiment, the valve hole 21 can be easily machined.

Further, in the second embodiment, since the relief fuel flows through the valve hole 21 after being sufficiently decompressed by the plurality of orifice members 40, the force that the fuel pressure of the valve hole 21 acts on the ball valve 32 is the first embodiment. It will be smaller than the one due to the configuration of the form. Therefore, in the second embodiment, the urging force of the spring 34 that urges the ball valve 32 and the guide member 33 toward the valve seat 31 can be reduced, so that the valve opening pressure of the valve mechanism 30 can be set accurately.

Further, in the second embodiment, since the force that the fuel pressure of the valve hole 21 acts on the ball valve 32 becomes small, the distance between the outer wall on the radial outer side of the guide member 33 and the inner wall of the valve mechanism passage 64 is increased. It may be configured. As a result, the guide member 33 can be miniaturized. Further, in the second embodiment, the stopper portion 69 on the downstream side of the guide member 33 described in the first embodiment may be abolished. Thereby, the configuration of the valve mechanism passage 64 can be simplified.

The valve seat 31, the ball valve 32, the guide member 33, and the spring 34 described above constitute the valve mechanism 30. The flow rate regulating unit 20 is composed of a plurality of orifice members 40, a valve hole 21, and a valve mechanism 30. The flow rate regulating unit 20 of the second embodiment also regulates the relief flow rate discharged from the rail chamber 117 to the relief pipe 110, similarly to that of the first embodiment.

Next, in the second embodiment, the cooling passage 80 communicates the cooling fuel chamber 121 with the valve mechanism passage 64. The cooling fuel flowing out from the cooling passage 80 and the relief fuel flowing out from the flow rate regulating unit 20 merge in the valve mechanism passage 64. Therefore, in the second embodiment, the valve mechanism passage 64 in the fuel passage 60 corresponds to a “merging passage” in which the cooling fuel flowing out from the cooling passage 80 and the relief fuel decompressed by the flow rate regulating unit 20 merge. To do.

In the second embodiment, the flow path shaft Ax3 of the cooling passage 80 is configured to face downstream of the ball valve 32 and the guide member 33 in the valve mechanism passage 64. The cooling fuel flowing out from the cooling passage 80 to the valve mechanism passage 64 flows downstream of the ball valve 32 and the guide member 33. As a result, the cooling fuel flowing out from the cooling passage 80 to the valve mechanism passage 64 does not collide with the ball valve 32 and the guide member 33. Therefore, even when the flow rate of the cooling fuel flowing out from the cooling passage 80 to the valve mechanism passage 64 increases, it is possible to prevent the ball valve 32 and the guide member 33 from deviating from the flow path axis Ax1 of the valve seat 31. Therefore, the pressure adjusting device 1 of the second embodiment also suppresses the variation in the relief flow rate due to the change in the flow rate of the cooling fuel flowing through the cooling passage 80, and makes the relief flow rate a stable minute flow rate within a certain range. The fuel pressure of 117 can be appropriately reduced and adjusted.

Here, the pressure adjusting device of the comparative example will be described for comparison with the pressure adjusting device 1 of the second embodiment described above.

As shown in FIG. 6, the pressure adjusting device 2 of the comparative example is configured such that the flow path shaft Ax3 of the cooling passage 80 faces the guide member 33 in the valve mechanism passage 64. Therefore, the cooling fuel flowing out from the cooling passage 80 to the valve mechanism passage 64 collides with the guide member 33 and is configured to flow toward the ball valve 32 side along the wall surface thereof.

In the configuration of the pressure adjusting device 2 of this comparative example, the relationship between the relief fuel and the cooling fuel when the ball valve 32 is opened will be described with reference to FIGS. 7 and 8. In addition, each of FIG. 7 and FIG. 8 shows the state of the ball valve 32 at the time of opening in the VII-VII line cross section of FIG.

FIG. 7 shows the positional relationship between the ball valve 32 and the valve seat 31 when the flow rate of the cooling fuel is relatively small when the ball valve 32 is opened. In this case, even if the cooling fuel flowing out from the cooling passage 80 to the valve mechanism passage 64 collides with the guide member 33, the dynamic pressure of the cooling fuel is small, so that the influence on the guide member 33 and the ball valve 32 is small. Therefore, as shown in FIG. 7, the center 321 of the ball valve 32 is on the flow path axis Ax1 of the valve seat 31. Therefore, in the opening 310 formed between the ball valve 32 and the valve seat 31, the distance between the ball valve 32 and the valve seat 31 is kept substantially the same over the entire circumference. As a result, the relief fuel flowing through the opening 310 has a stable flow rate within a certain range.

On the other hand, FIG. 8 shows the positional relationship between the ball valve 32 and the valve seat 31 when the flow rate of the cooling fuel is relatively large when the ball valve 32 is opened. In this case, when the cooling fuel flowing out from the cooling passage 80 to the valve mechanism passage 64 collides with the guide member 33, the guide member 33 and the ball valve 32 may be displaced due to the dynamic pressure of the cooling fuel. As shown in FIG. 8, the center 321 of the ball valve 32 is displaced from the flow path axis Ax1 of the valve seat 31 to the downstream side in the flow direction of the cooling fuel. Therefore, the opening 310 formed between the ball valve 32 and the valve seat 31 has a large area on the upstream side in the flow direction of the cooling fuel and a small area on the downstream side in the flow direction of the cooling fuel. As a result, as shown by the broken line S in FIG. 8, there is a place in the opening 310 that is far from the wall surfaces of both the ball valve 32 and the valve seat 31. At the location indicated by the broken line S, the flow velocity of the relief fuel becomes high. As a result, the relief flow rate passing through the opening 310 increases.

As described above, according to the configuration of the pressure adjusting device 2 of the comparative example, the relief flow rate varies according to the change in the flow rate of the cooling fuel flowing through the cooling passage 80. Therefore, there is a problem that the relief flow rate cannot be set to a stable minute flow rate within a certain range, and the fuel pressure of the common rail 103 cannot be appropriately reduced and adjusted.

In contrast to the pressure adjusting device 2 of the comparative example described above, in the pressure adjusting device 1 of the second embodiment, the cooling fuel flowing out from the cooling passage 80 to the valve mechanism passage 64 is on the downstream side of the ball valve 32 and the guide member 33. It is configured to flow to. Therefore, even when the flow rate of the cooling fuel flowing through the cooling passage 80 increases, it is possible to prevent the ball valve 32 and the guide member 33 from being displaced from the flow path axis Ax1 of the valve seat 31. That is, regardless of the change in the flow rate of the cooling fuel, the opening 310 formed between the ball valve 32 and the valve seat 31 keeps the distance between the ball valve 32 and the valve seat 31 substantially the same over the entire circumference. Is done. Therefore, the pressure adjusting device 1 of the second embodiment suppresses the variation in the relief flow rate due to the change in the flow rate of the cooling fuel, and makes the relief flow rate a stable minute flow rate within a certain range to reduce the fuel pressure in the rail chamber 117. The decompression can be adjusted appropriately.

(Third Embodiment)
The third embodiment is a modification of the configuration of the second fuel passage 62 and the like with respect to the second embodiment, and is the same as the second embodiment except for the parts different from the second embodiment. explain.

As shown in FIGS. 9 and 10, in the third embodiment, the second fuel passage 62 formed in the second passage forming member 12 includes a valve mechanism passage 64, a spring passage 73, and a continuous passage 74. Have.

The valve mechanism passage 64 is provided with a guide member 33 that supports a portion of the ball valve 32 opposite to the valve seat 31. The guide member 33 is provided with an outer wall on the outer side in the radial direction so as to be slidable on the inner wall of the valve mechanism passage 64. The flow path area of the valve mechanism passage 64 is larger than the flow path area of the spring passage 73. Therefore, a stopper portion 69 as a stepped surface is provided between the valve mechanism passage 64 and the spring passage 73. The movable range of the guide member 33 is set by the stopper portion 69.

The spring passage 73 is provided with a spring 34 that urges the guide member 33 and the ball valve 32 toward the valve seat 31. The spring passage 73 and the connection passage 67 are not directly connected. That is, the spring passage 73 has a dead end shape (that is, a dead end).

In the third embodiment, a plurality of communication passages 74 for communicating the valve mechanism passage 64 and the cooling fuel chamber 121 are provided on the radial outer side of the guide member 33. Therefore, when the ball valve 32 is opened, the relief fuel flows into the valve mechanism passage 64 from the first fuel passage 61 side, and then flows through the communication passage 74 to the cooling fuel chamber 121. The relief fuel merges with the cooling fuel flowing into the cooling fuel chamber 121 from the cooling fuel inlet 120 in the cooling fuel chamber 121, and then flows from the cooling fuel chamber 121 through the cooling passage 80 to the connection passage 67. Therefore, in the third embodiment, the cooling fuel chamber 121 corresponds to a "merging passage" in which the cooling fuel flowing out from the cooling passage 80 and the relief fuel decompressed by the flow rate regulating unit 20 merge.

As described above, in the third embodiment, the relief fuel flowing out from the flow rate regulating unit 20 is configured to flow from the valve mechanism passage 64 to the cooling fuel chamber 121 through the communication passage 74. Further, the spring passage 73 has a dead end shape. Therefore, the cooling fuel in the cooling fuel chamber 121 does not flow into the valve mechanism passage 64, but flows through the cooling passage 80 to the connection passage 67 together with the relief fuel that has flowed into the cooling fuel chamber 121 from the communication passage 74. Therefore, the cooling fuel flowing through the cooling passage 80 does not affect the positions of the ball valve 32 and the guide member 33. Therefore, even with the configuration of the third embodiment, it is possible to suppress the change in the flow rate of the relief fuel flowing out from the flow rate regulating unit 20 with respect to the change in the flow rate of the cooling fuel flowing through the cooling passage 80. Therefore, the pressure adjusting device 1 of the third embodiment can also exert the same action and effect as those of the first and second embodiments.

(Fourth Embodiment)
In the fourth embodiment, the configurations of the passage forming member 10, the flow rate regulating unit 20, the cooling passage 80, and the like are changed from those in the first embodiment, and the other parts are the same as those in the first embodiment. Only the part different from one embodiment will be described.

As shown in FIG. 11, in the fourth embodiment, the passage forming member 10 is composed of a single member. A fuel passage 60 is formed inside the passage forming member 10. The fuel passage 60 has an orifice passage 65, a holding passage 66, an intermediate passage 75, and a connecting passage 67 from the rail chamber 117 side.

A plurality of orifice members 40 are continuously provided in the orifice passage 65. The number of orifice members 40 is appropriately set by experiments or the like so that the relief flow rate becomes an appropriate amount. The plurality of orifice members 40 have a throttle hole 41 that regulates the flow of fuel, and an open chamber 43 that has a larger flow path area and a fixed volume than the throttle hole 41. Since the plurality of orifice members 40 are continuously provided, the plurality of throttle holes 41 and the plurality of open chambers 43 are alternately arranged. With this configuration, the pressure of the relief fuel is gradually reduced each time it passes through the plurality of throttle holes 41 one by one. Therefore, as compared with using one orifice member 40 having one long throttle hole 41, the configuration of the fourth embodiment can reduce the relief flow rate. Therefore, the pressure adjusting device 1 can appropriately reduce the rail pressure.

In the fourth embodiment, the flow rate regulating unit 20 is composed of only a plurality of orifice members 40. Even in this configuration, the flow rate regulating unit 20 can regulate the relief flow rate discharged from the rail chamber 117 to the relief pipe 110.

The holding passage 66 is provided on the relief pipe 110 side with respect to the orifice passage 65. The flow path area of the holding passage 66 is smaller than the flow path area of the orifice passage 65. Therefore, a step portion 70 is formed between the orifice passage 65 and the holding passage 66. The orifice member 40 is fixed to the step portion 70.

A spring pin 35 and a spring 36 as fixing members for fixing the plurality of orifice members 40 are provided on the upstream side of the plurality of orifice members 40 in the orifice passage 65. The spring pin 35 is sometimes called a split washer. The spring pin 35 is provided with a cut extending in the axial direction at one position in the circumferential direction of the cylindrical member. The outer diameter of the spring pin 35 is formed to be larger than the inner diameter of the orifice passage 65 before being assembled to the orifice passage 65. Then, the spring pin 35 is fixed to the inner wall of the orifice passage 65 by press fitting in a state of being compressed in the radial direction. Therefore, even if the inner diameter of the orifice passage 65 is expanded by the fuel flowing through the orifice passage 65, the spring pin 35 follows the expansion of the inner diameter of the orifice passage 65 and adjusts the outer diameter of the spring pin 35 itself. It can be expanded.

One end of the spring 36 is in contact with the spring pin 35, and the other end is in contact with the orifice member 40. The spring 36 is a compression coil spring, and urges a plurality of orifice members 40 to the step portion 70. As a result, the plurality of orifice members 40 are fixed to the step portion 70.

In the fourth embodiment, a plurality of orifice members 40 are provided on the rail chamber 117 side with respect to the step portion 70. Therefore, the orifice member 40 is pressed against the step portion 70 by the rail pressure, so that the orifice member 40 and the step portion 70 are surely in contact with each other. Further, even when the rail pressure is relatively low, such as when the engine is started, the orifice member 40 is pressed against the step portion 70 by the spring 36, so that the orifice member 40 and the step portion 70 are surely in contact with each other. .. Therefore, it is possible to prevent fuel leakage between the orifice member 40 and the step portion 70. Therefore, the pressure adjusting device 1 can limit the relief flow rate so as to be a stable minute flow rate within a certain range, and can appropriately reduce the rail pressure.

The intermediate passage 75 is formed between the holding passage 66 and the connecting passage 67. The inner diameter of the intermediate passage 75 is formed to be larger than the inner diameter of the holding passage 66 and smaller than the inner diameter of the connecting passage 67.

Also in the fourth embodiment, the cooling fuel chamber 121 is formed between the inner wall of the mounting hole 116 of the common rail 103 and the outer wall of the passage forming member 10. The cooling fuel chamber 121 is formed so as to surround the radial outer side of the passage forming member 10. The cooling fuel supplied from the overflow pipe 109 to the cooling fuel inlet portion 120 flows into the cooling fuel chamber 121. The flow path shaft Ax2 of the cooling fuel inlet portion 120 is directed to the radial outer wall surface of the passage forming member 10. Therefore, the cooling fuel flowing into the cooling fuel chamber 121 from the cooling fuel inlet portion 120 collides with the radial outer wall surface of the passage forming member 10. Therefore, the passage forming member 10 is cooled with high efficiency by increasing the flow rate of the cooling fuel in contact with the radial outer wall surface of the passage forming member 10 and increasing the heat exchange efficiency between the passage forming member 10 and the cooling fuel. Can be done.

The passage forming member 10 is provided with a plurality of cooling passages 80 for communicating the cooling fuel chamber 121 and the connecting passage 67. The cooling fuel that has flowed into the cooling fuel chamber 121 from the cooling fuel inlet 120 passes through the cooling passage 80 and flows into the connection passage 67. The cooling passage 80 is provided inside the passage forming member 10 on the radial outer side of the plurality of orifice members 40. The cooling passage 80 is provided inside the passage forming member 10 so as to pass between the plurality of orifice members 40 and the seal ring 17.

The cooling fuel flowing out from the cooling passage 80 and the relief fuel flowing out from the flow rate regulating unit 20 merge in the connecting passage 67. Therefore, in the fourth embodiment, the connection passage 67 in the fuel passage 60 corresponds to a “merging passage” in which the cooling fuel flowing out from the cooling passage 80 and the relief fuel decompressed by the flow rate regulating unit 20 merge. ..

In the fourth embodiment, the flow path axis Ax3 of the cooling passage 80 and the flow path axis Ax1 of the connection passage 67 are configured to be parallel to each other. That is, the cooling passage 80 and the connection passage 67 are provided in parallel. The flow path shaft Ax1 of the connection passage 67 and the flow path shaft Ax1 of the throttle hole 41 of the orifice member 40 are in the same direction. As a result, the relief fuel flowing out from the throttle hole 41 of the orifice member 40 to the connecting passage 67 via the holding passage 66 and the intermediate passage 75, and the cooling fuel flowing out from the cooling passage 80 to the connecting passage 67 It flows in parallel in the connecting passage 67. Therefore, the cooling fuel flowing out from the cooling passage 80 to the connecting passage 67 does not obstruct the flow of the relief fuel. Therefore, the change in the relief flow rate is suppressed with respect to the change in the flow rate of the cooling fuel flowing through the cooling passage 80, and the relief flow rate can be set to a stable minute flow rate within a certain range. Therefore, the pressure adjusting device 1 can appropriately reduce the fuel pressure in the high pressure path.

Also in the fourth embodiment, it is possible to cool the passage forming member 10, the flow rate regulating unit 20, and the relief fuel by the cooling fuel flowing through the cooling passage 80. Therefore, it is possible to suppress a decrease in the viscosity of the fuel and set the relief flow rate to a stable minute flow rate within a certain range. In addition, it is possible to prevent thermal deterioration of the relief fuel flowing through the fuel passage 60 and to prevent a deposit from being generated in the relief fuel. In addition, thermal deterioration of the seal ring 17 can be prevented and the product life can be extended.
In addition, the pressure adjusting device 1 of the fourth embodiment can also exert the same action and effect as those of the first to third embodiments.

(Fifth Embodiment)
The fifth embodiment is a modification of the configuration of the fixing member, the cooling passage 80, and the like with respect to the fourth embodiment, and the other parts are the same as those of the fourth embodiment. Only explain.

As shown in FIG. 12, in the fifth embodiment, the fixing member for fixing the plurality of orifice members 40 to the orifice passage 65 is composed of a spacer member 37 and a spring 36. The spacer member 37 is in contact with the inner wall of the filter 50. One end of the spring 36 is in contact with the spacer member 37, and the other end is in contact with the orifice member 40. The spring 36 is a compression coil spring, and urges a plurality of orifice members 40 to the step portion 70. As a result, the plurality of orifice members 40 are fixed to the step portion 70.

In the fifth embodiment, the cooling passage 80 communicates the cooling fuel chamber 121 with the intermediate passage 75. The cooling fuel flowing from the cooling fuel inlet 120 into the cooling fuel chamber 121 flows through the cooling passage 80 to the intermediate passage 75 and then to the connecting passage 67. The cooling passage 80 is provided inside the passage forming member 10 on the radial outer side of the plurality of orifice members 40. The cooling passage 80 is provided inside the passage forming member 10 so as to pass between the plurality of orifice members 40 and the seal ring 17.

The cooling fuel flowing out from the cooling passage 80 and the relief fuel flowing out from the flow rate regulating unit 20 merge in the intermediate passage 75. Therefore, in the fifth embodiment, the intermediate passage 75 of the fuel passage 60 corresponds to a “merging passage” in which the cooling fuel flowing out from the cooling passage 80 and the relief fuel decompressed by the flow rate regulating unit 20 merge.

Also in the fifth embodiment, the cooling passage 80 and the intermediate passage 75 are provided in parallel. Specifically, the flow path axis Ax3 of the cooling passage 80 is provided so as to approach the flow path axis Ax1 of the intermediate passage 75 from the upstream side to the downstream side. That is, the flow path axis Ax3 of the cooling passage 80 and the flow path axis Ax1 of the intermediate passage 75 are configured to have an acute angle. The flow path shaft Ax1 of the intermediate passage 75 and the flow path shaft Ax1 of the throttle hole 41 of the orifice member 40 are in the same direction. As a result, the fuel flowing out from the cooling passage 80 to the intermediate passage 75 and the relief fuel flowing out from the throttle hole 41 of the orifice member 40 to the intermediate passage 75 via the holding passage 66 are parallel to each other in the intermediate passage 75. It flows. Therefore, the fuel flowing out from the cooling passage 80 to the intermediate passage 75 does not obstruct the flow of the relief fuel flowing out from the holding passage 66 to the intermediate passage 75. Therefore, the change in the relief flow rate is suppressed with respect to the change in the flow rate of the cooling fuel flowing through the cooling passage 80, and the relief flow rate can be set to a stable minute flow rate within a certain range. Therefore, the pressure adjusting device 1 can appropriately reduce the fuel pressure in the high pressure path.

Further, in the fifth embodiment, since the flow path axis Ax3 of the cooling passage 80 and the flow path axis Ax1 of the intermediate passage 75 are configured to have an acute angle, in the intermediate passage 75 and the connection passage 67, The cooling fuel and relief fuel mix quickly. Therefore, in the fifth embodiment, the generation of deposit can be further suppressed.
In addition, the pressure adjusting device 1 of the fifth embodiment can also exert the same action and effect as those of the first to third embodiments.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and can be appropriately modified within the scope of the claims. Further, the above-described embodiments are not unrelated to each other, and can be appropriately combined unless the combination is clearly impossible. Further, in each of the above embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential except when it is clearly stated that they are essential and when they are clearly considered to be essential in principle. No. Further, in each of the above embodiments, when numerical values such as the number, numerical values, amounts, and ranges of the constituent elements of the embodiment are mentioned, when it is clearly stated that they are particularly essential, and in principle, the number is clearly limited to a specific number. It is not limited to the specific number except when it is done. In addition, in each of the above embodiments, when referring to the shape, positional relationship, etc. of a component or the like, the shape, unless otherwise specified or limited in principle to a specific shape, positional relationship, etc. It is not limited to the positional relationship.

(1) In each of the above embodiments, the pressure adjusting device 1 has been described as being attached to the common rail 103 as a high pressure path, but the present invention is not limited to this. The pressure adjusting device 1 may be provided at any place on the high pressure path. Specifically, the pressure adjusting device 1 may be provided at any location of the fuel path from the discharge valve of the supply pump 102 to the injection hole of the injector 104 or the fuel path communicating therewith.

(2) In each of the above embodiments, the common rail 103 is exemplified as the high pressure pipe constituting the high pressure path, but the present invention is not limited to this. The high-pressure pipe that constitutes the high-pressure path may be any member that constitutes the fuel path from the discharge valve of the supply pump 102 to the injection hole of the injector 104 or the fuel path that communicates with the fuel path.

(3) In each of the above embodiments, the passage forming member 10, the common rail 103, and the relief pipe 110 included in the pressure adjusting device 1 are composed of separate members, but the present invention is not limited to this. The passage forming member 10 included in the pressure adjusting device 1 may be integrally formed with other members adjacent thereto. Specifically, the passage forming member 10 and the common rail 103 may be integrally formed. Alternatively, the passage forming member 10 and the relief pipe 110 may be integrally formed.

(4) In each of the above embodiments, the orifice member 40 is provided in either the low pressure side orifice passage 65 or the high pressure side orifice passage 71, but the present invention is not limited to this. The orifice member 40 may be provided in both the low pressure side orifice passage 65 and the high pressure side orifice passage 71.

(5) In the first embodiment, the flow path shaft Ax3 of the cooling passage 80 and the flow path shaft Ax1 of the connection passage 67 are configured to have an acute angle, but for connection with the flow path shaft Ax3 of the cooling passage 80. It may be configured in parallel with the flow path axis Ax1 of the passage 67.

(6) In the fourth embodiment, the flow path axis Ax3 of the cooling passage 80 and the flow path axis Ax1 of the connection passage 67 are configured to be parallel to each other, but for connection with the flow path axis Ax3 of the cooling passage 80. It may be configured at an acute angle with the flow path axis Ax1 of the passage 67.

(7) In the fifth embodiment, the flow path axis Ax3 of the cooling passage 80 and the flow path axis Ax1 of the intermediate passage 75 are configured to have an acute angle, but the flow path axis Ax3 of the cooling passage 80 and the intermediate passage 75 It may be configured in parallel with the flow path axis Ax1 of.

(8) In each of the above embodiments, the pressure adjusting device 1 is provided with a plurality of cooling passages 80, but the pressure adjusting device 1 is not limited to this. Only one cooling passage 80 may be used.

1 Pressure regulator 10 Passage forming member 20 Flow control unit 60 Fuel passage 64 Valve mechanism passage 67 Connection passage 75 Intermediate passage 80 Cooling passage 103 Common rail 121 Cooling fuel chamber

Claims (10)

A pressure regulator that adjusts the pressure of fuel flowing in the high-pressure path of the fuel injection system of an engine.
A passage forming member (10) provided in the high pressure pipe (103) constituting the high pressure path and having a fuel passage (60) communicating the high pressure path and the low pressure path.
A flow rate regulating unit (20) provided in a part of the fuel passage and regulating the flow rate of fuel discharged from the high pressure path to the low pressure path,
A cooling passage (80) provided in the passage forming member and through which a fuel having a temperature lower than that of the fuel flowing in the high pressure path flows,
A confluence passage (64, 67, 75, 121) at which the fuel flowing out from the flow rate regulating unit and the fuel flowing through the cooling passage merge is provided.
A pressure adjusting device configured to suppress a change in the flow rate of fuel flowing out from the flow rate regulating unit to the merging passage with respect to a change in the flow rate of fuel flowing out from the cooling passage to the merging passage. The flow rate regulating unit includes a valve seat (31) provided on the inner wall of the fuel passage, a valve body (32) configured to be seated and detached from the valve seat, and the valve seat among the valve bodies. It has a guide member (33) that supports a portion on the opposite side and an urging member (34) that urges the guide member to the valve seat side.
The pressure adjusting device according to claim 1, wherein the flow path shaft (Ax3) of the cooling passage is configured to face the downstream side of the valve body and the guide member. The pressure adjusting device according to claim 1 or 2, wherein the flow path shaft of the cooling passage and the flow path shaft (Ax1) of the confluence passage are configured in parallel. A seal ring (17) provided between the inner wall of the mounting hole (116) of the high-pressure pipe and the passage forming member is provided.
The pressure adjusting device according to any one of claims 1 to 3, wherein the cooling passage is provided so as to pass between the flow rate regulating portion and the seal ring inside the passage forming member. The flow rate regulating unit has an orifice member (40) provided with a throttle hole (41) that regulates the flow rate of fuel discharged from the high pressure path to the low pressure path.
The pressure adjusting device according to any one of claims 1 to 4, wherein the cooling passage is provided inside the passage forming member and outside in the radial direction of the orifice member. The high-pressure pipe is provided with a cooling fuel inlet (120) to which fuel having a temperature lower than that of the fuel flowing in the high-pressure path is supplied.
A cooling fuel chamber (121) into which fuel flows in from the cooling fuel inlet portion is formed between the inner wall of the mounting hole of the high-pressure pipe and the passage forming member.
The pressure adjusting device according to any one of claims 1 to 5, wherein the cooling passage communicates the cooling fuel chamber and the confluence passage. The pressure adjusting device according to claim 6, wherein the flow path shaft (Ax2) of the cooling fuel inlet portion is configured to face the radial outer wall surface of the passage forming member. Any one of claims 1 to 7, wherein the flow path shaft of the cooling passage is provided so as to approach the flow path shaft (Ax1) of the fuel passage provided in the passage forming member from the upstream side to the downstream side. The pressure regulator according to one. The flow rate regulating unit is set so that the flow rate of fuel flowing from the high pressure path to the merging passage via the flow rate regulating section is equal to or less than the flow rate of fuel flowing from the cooling passage to the merging passage. The pressure adjusting device according to any one of claims 1 to 8. The flow rate of fuel flowing from the high-pressure path to the confluence passage via the flow rate regulating unit is 200 cc / min or less.
The pressure adjusting device according to any one of claims 1 to 9, wherein the flow rate of fuel flowing from the cooling passage to the merging passage is 200 cc / min or more.

Images