阅读说明：本技术 压力控制装置 (Pressure control device ) 是由 西胁正 久野耕平 于 2020-03-02 设计创作，主要内容包括：一种压力控制装置,其构造为对在发动机燃料喷射系统中的高压通道中流动的燃料进行减压和控制。该压力控制装置包括：通道形成构件(10、51、52),其形成连通高压通道和低压通道的燃料通道(13)；和设置在燃料通道中的流率规制器(20、201、202),其构造为规制从高压通道流向低压通道的燃料的流率。多个孔口管道(22)以及多个释放室(23、23a、23b)在流率规制器中交替设置,每个孔口管道都构造为规制燃料流动,每个释放室的通道面积都大于孔口管道的通道面积,并且具有固定容积。(A pressure control device is configured to depressurize and control fuel flowing in a high-pressure passage in a fuel injection system of an engine. The pressure control device includes: a passage forming member (10, 51, 52) that forms a fuel passage (13) that communicates a high-pressure passage and a low-pressure passage; and a flow rate regulator (20, 201, 202) provided in the fuel passage, configured to regulate a flow rate of the fuel flowing from the high-pressure passage to the low-pressure passage. A plurality of orifice tubes (22), each configured to regulate fuel flow, and a plurality of relief chambers (23, 23a, 23b), each having a larger passage area than the orifice tubes and having a fixed volume, are alternately arranged in the flow rate regulator.)

1. A pressure control device configured to depressurize and control fuel flowing in a high-pressure passage in a fuel injection system of an engine, the pressure control device comprising:

a passage forming member (10, 51, 52) that forms a fuel passage (13) that communicates the high-pressure passage to a low-pressure passage; and

a flow rate regulator (20, 201, 202) disposed in the fuel passage and configured to regulate a flow rate of the fuel flowing from the high pressure passage to the low pressure passage, wherein,

the flow rate regulator has a plurality of orifice tubes (22) each configured to regulate the flow of the fuel and a plurality of relief chambers (23, 23a, 23b) each having a passage area larger than that of the orifice tube and having a fixed volume, and

the plurality of orifice tubes and the plurality of relief chambers are alternately arranged in the flow rate regulator.

2. The pressure control device of claim 1,

the flow rate regulator comprises a plurality of orifice members (21) placed in series and each orifice member comprising the orifice conduit and the release chamber.

3. The pressure control device according to claim 2,

the fuel passage includes:

an orifice channel (14, 141, 142) housing the plurality of orifice members,

a holding passage (15, 151, 152) having a passage cross-sectional area smaller than that of the orifice member and placed on the high-pressure passage side or the low-pressure passage side with respect to the orifice passage, and

a step (17, 171, 172) placed between the orifice channel and the retaining channel, an

The orifice member is secured to the step.

4. The pressure control device of claim 3,

the orifice passage is longer than the retention passage.

5. The pressure control device according to claim 3 or 4,

the holding channel is placed on the side of the high-pressure channel with respect to the orifice channel, and

the step is placed on the high-pressure passage side with respect to the plurality of orifice members.

6. The pressure control device according to claim 3 or 4,

the holding passage is placed on the side of the low pressure passage with respect to the orifice passage, and

the step is placed on the low-pressure passage side with respect to the plurality of orifice members.

7. The pressure control device according to claim 3 or 4, further comprising:

a fixing member (30) that presses the plurality of orifice members toward the step from a side of the plurality of orifice members opposite the step and fixes the plurality of orifice members in the orifice passage.

8. The pressure control device of claim 7,

the fixing member is at least one of a spring (31), a bushing (32), a spring bushing (33), a spring washer (38), a wave washer (39), and a screw member (34).

9. The pressure control device according to any one of claims 1 to 4, further comprising:

a filter (40) placed upstream of the flow rate regulator, wherein,

the cross-sectional area of the orifice conduit in the flow rate gauge is greater than the cross-sectional area of the aperture (41) in the filter.

10. The pressure control device of claim 9, further comprising:

a valve mechanism (60) disposed between the filter and the flow rate regulator, wherein,

the valve mechanism is configured to: the valve mechanism opens in a case where a pressure difference between a fuel pressure between the flow rate regulator and the valve mechanism and a fuel pressure of the high-pressure passage becomes greater than a predetermined pressure.

Technical Field

The present disclosure relates to a pressure control device that depressurizes and controls fuel in a high-pressure passage of a fuel injection system.

Background

A known control system for a diesel engine fuel injection system is a common rail system. The common rail system accumulates fuel, which has been pressurized by a supply pump, in a common rail, and injects the fuel from a plurality of injectors connected to the common rail to cylinders of an engine for a certain period of time at an appropriate timing.

The pulsation damping device in patent document 1 is provided between the common rail and the injector. The pulsation damping device includes two plates each having an orifice, and the two plates are disposed in parallel with each other inside a container through which fuel flows. The pulsation damping device further includes springs which are respectively located in a space formed by the inner wall of the container and the plates, which will be referred to as a first space hereinafter, and in a space formed between the plates, which will be referred to as a second space hereinafter. The pulsation damping device damps fuel pulsation caused by fuel injection of the injector by the first space and the second space according to a volume change of expansion and contraction of the spring during supply of the fuel from the common rail to the injector at a flow rate required for the fuel injection through the orifice located on the plate. Therefore, the pulsation damping device suppresses noise generated by the common rail and fluctuation in the fuel injection amount of the injector by attenuating pulsation of fuel transmitted from the injector to the common rail.

(patent document 1)

EP1435455A1

In the common rail system, if the accumulated fuel pressure exceeds the pressure required for the common rail during the stop of the engine, the amount of fuel injected from the injector at the start of the next operation of the engine may increase, and noise may be caused. Therefore, the common rail system includes a pressure control device. During engine stop, the pressure control device depressurizes the high-pressure fuel in the common rail, and controls the pressure of the fuel to an appropriate pressure by discharging the fuel from a high-pressure passage such as the common rail to a low-pressure passage such as a fuel tank at a minute flow rate.

The above-described pulsation damping device disclosed in patent document 1 cannot be used as a pressure control device. As described above, the pulsation damping device in patent document 1 damps fuel pulsation caused by fuel injection from the injector during supply of fuel from the common rail to the injector at a flow rate required for the injection of the fuel. Thus, the holes in the plate are sized to supply fuel at the flow rate required for fuel injection. A predetermined gap is provided between the two plates and the inner wall of the container so that the two plates move in the container as the springs expand and contract. Therefore, the pulsation damper device cannot discharge the fuel from the high-pressure passage to the low-pressure passage at a minute flow rate. In the case where the pulsation damping device in patent document 1 is used as the pressure control device, a large amount of fuel is discharged from the common rail to the low-pressure passage, and the pressure of the fuel in the common rail is reduced more than necessary. Therefore, the injector cannot inject fuel.

Disclosure of Invention

An object of the present disclosure is to produce a pressure control device configured to appropriately depressurize and control fuel in a high-pressure passage of a fuel injection system.

According to an aspect of the present disclosure, a pressure control device is configured to depressurize and control fuel flowing in a high-pressure passage of a fuel injection system of an engine. The pressure control device includes a passage forming member and a flow rate gauge. The passage forming member forms a fuel passage that communicates the high-pressure passage with the low-pressure passage. A flow rate regulator is disposed in the fuel passage and is configured to regulate a fuel flow rate from the high-pressure passage to the low-pressure passage. In the flow rate regulator, a plurality of orifice pipes each configured to regulate the flow of the fuel and a plurality of relief chambers each having a passage area larger than that of the orifice pipe and having a fixed volume are alternately provided.

According to this structure, the plurality of orifice pipes and the plurality of relief chambers are alternately provided in the flow rate regulator, and the pressure of the fuel flowing from the high-pressure passage to the low-pressure passage is gradually reduced each time the fuel flows through one orifice pipe. Thus, the flow rate of fuel flowing from the high-pressure passage to the low-pressure passage may be reduced, hereinafter referred to as the pressure relief flow rate, as compared to a configuration in which the flow rate regulator comprises a single long orifice tube. In this aspect of the present disclosure, in the case where the relief flow rate is controlled by a single long orifice tube to decompress and regulate the fuel in the high-pressure passage, the inner diameter of the orifice tube must be smaller than each inner diameter of the orifice tubes in the flow rate regulator. More specifically, unless the inner diameter of the single long orifice tube is less than the machined manufacturing limit, the flow rate regulator is unable to control the flow rate and the fuel pressure of the high pressure passage is reduced more than necessary. However, according to this aspect of the present disclosure, unlike the configuration of the single long orifice tube, the flow rate of the fuel can be reduced without making the inner diameter of the orifice tube smaller than the manufacturing limit of the cut. That is, the pressure control device in the present invention can appropriately decompress and control the fuel in the high-pressure passage.

Further, according to the aspect of the present disclosure, the pressure of the fuel flowing from the high-pressure passage to the low-pressure passage is gradually reduced each time the fuel passes through one orifice pipe, and accordingly, the fuel flow rate is decreased. Therefore, the pressure control device can prevent cavitation of the fuel, and can protect the surface of the structural member of the pressure control device from corrosion.

Further, according to this aspect of the disclosure, the inner diameter of each orifice conduit may be larger than a configuration having a single long orifice conduit. Therefore, the orifice pipe can be prevented from being clogged with foreign matter contained in the fuel. In the case where a filter is provided upstream of the flow rate regulator, the hole contained in the filter is smaller than the cross-sectional area of the orifice pipe. That is, the orifice tube can be prevented from being clogged without using a filter having very small pores.

The high-pressure passage is a fuel passage that communicates from a discharge valve of a supply pump of the fuel injection system to injection holes of the injectors through a common rail. The low-pressure passage includes a fuel passage from a fuel tank of the fuel injection system to a pump chamber of the supply pump and a low-pressure pipe connected to the fuel tank.

Drawings

The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description, which is made with reference to the accompanying drawings. In the drawings:

fig. 1 is a structural diagram showing a common rail system to which a pressure control device of a first embodiment is applied.

Fig. 2 is a sectional view showing a pressure control device according to a first embodiment.

Fig. 3 is a sectional view showing a flow rate gauge provided in the pressure control device according to the first embodiment.

Fig. 4 is a sectional view showing a flow rate gauge provided in a pressure control device according to a comparative example.

Fig. 5 is a graph showing a change in fuel pressure by the flow rate regulator according to the first embodiment and a change in fuel pressure by the flow rate regulator according to the comparative example.

Fig. 6 is a graph showing a relationship between the number of orifice members included in the flow rate regulator and the flow rate according to the first embodiment.

Fig. 7 is a graph showing the relationship between the number of orifice members included in the flow rate regulator, the fuel pressure of the common rail, and the flow rate according to the first embodiment.

Fig. 8 is a sectional view showing a flow rate gauge provided in the pressure control device according to the second embodiment.

Fig. 9 is a sectional view showing a flow rate gauge provided in a pressure control device according to a third embodiment.

Fig. 10 is a sectional view showing a flow rate gauge provided in a pressure control device according to a fourth embodiment.

Fig. 11 is a sectional view showing a pressure control device according to a fifth embodiment.

Fig. 12 is a perspective view showing a fixing member provided in a pressure control apparatus according to a fifth embodiment.

Fig. 13 is a perspective view showing a fixing member provided in a pressure control apparatus according to a sixth embodiment.

Fig. 14 is a sectional view showing a pressure control device according to a seventh embodiment.

Fig. 15 is a sectional view showing a pressure control device according to an eighth embodiment.

Fig. 16 is a sectional view showing a pressure control device according to a ninth embodiment.

Fig. 17 is a perspective view showing a fixing member provided in a pressure control apparatus according to a ninth embodiment.

Fig. 18 is a perspective view showing a fixing member provided in a pressure control apparatus according to a tenth embodiment.

Fig. 19 is a sectional view showing a part of a pressure control apparatus according to an eleventh embodiment.

Fig. 20 is a sectional view showing a part of a pressure control apparatus according to a twelfth embodiment.

Fig. 21 is a sectional view showing a part of a pressure control apparatus according to a thirteenth embodiment.

Fig. 22 is a sectional view showing a part of a pressure control apparatus according to a fourteenth embodiment.

Fig. 23 is a sectional view showing a pressure control device according to a fifteenth embodiment.

Detailed Description

Embodiments of the present invention will be described below with reference to the accompanying drawings. In each embodiment, the same reference numerals are used to designate the structures corresponding to those described in the previous embodiment to avoid the duplicate explanation.

(first embodiment)

The first embodiment will be described with reference to the drawings. The pressure control apparatus 1 of the present embodiment is used for a common rail system 100 of a diesel engine.

First, the common rail system 100 will be described below. As shown in fig. 1, the common rail system 100 includes a fuel tank 101, a supply pump 102, a common rail 103, a plurality of injectors 104, an Electronic Control Unit (ECU)105, and other components. The liquid fuel (e.g., light oil) stored in the fuel tank 101 is pumped up by a low-pressure pump, not shown, and is sent into the supply pump 102 through a low-pressure fuel pipe 106 and a fuel filter 107. The supply pump 102 is, for example, a plunger pump driven by an engine. The supply pump 102 is configured to pressurize fuel, which has been drawn into a pump chamber, not shown, to, for example, about 200 to 300MPa, and to compress and deliver the fuel to the common rail 103 through a high-pressure fuel pipe 112. A fuel control valve 108 is provided to the supply pump 102, and is configured to control the amount of fuel to be pressurized in the pump chamber. A part of the fuel supplied from the fuel tank 101 to the supply pump 102 through the low-pressure fuel pipe 106 is returned to the fuel tank 101 through the overflow pipe 109, a cooling passage not shown in the pressure control device 1, the pressure relief pipe 110, and the return pipe 111.

The fuel that has been pressurized by the supply pump 102 flows through the high-pressure fuel pipe 112 and is accumulated in the common rail 103. The common rail 103 is a high-pressure fuel pipe and has an elongated tubular form. A plurality of distribution pipes 113 connect the common rail 103 to the plurality of injectors 104. Therefore, the fuel accumulated in the common rail 103 is supplied to the plurality of injectors 104 through the plurality of distribution pipes 113. The injector 104 is configured to inject an appropriate amount of fuel to a cylinder of the engine at an appropriate timing based on a control signal input from the ECU 105. 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.

A fuel pressure sensor 115 is attached to the common rail 103, and is configured to detect the fuel pressure in the common rail 103. Information detected by the fuel pressure sensor 115 is input to the ECU 105. The ECU105 includes a processor that performs control processing or arithmetic processing, a ROM that stores programs, data, and the like, a microcomputer including a storage unit such as a RAM, and peripheral circuits thereof. The ECU105 is configured to control the driving of the fuel control valve 108 of the supply pump 102, the injector 104, and the like.

The pressure control device 1 is provided to the common rail 103, and is configured to reduce and control the fuel pressure in the common rail 103. The pressure control device 1 is configured to discharge high-pressure fuel in the common rail 103 to a low-pressure passage, such as the fuel tank 101, at a minute flow rate. That is, a part of the fuel in the common rail 103 is returned from the pressure control device 1 to the fuel tank 101 through the pressure relief pipe 110 and the return pipe 111. Therefore, the pressure control device 1 can protect the inside of the common rail 103 from the accumulated fuel pressure being larger than the pressure required during the engine stop, thereby appropriately adjusting the fuel injection amount of the fuel injected from the injector 104 at the next drive start, and suppressing the generation of noise.

The pressure control device 1 is not limited to being placed at the common rail 103, but may be placed at any position of a high-pressure passage of an engine fuel injection system. The high-pressure passage is a fuel passage from the discharge valve of the supply pump 102 through the common rail 103 up to the injection holes of the injectors 104. Therefore, the pressure control device 1 can decompress and control the fuel flowing in the high-pressure passage of the engine fuel injection system. The low-pressure passage is a fuel passage from a fuel tank 101 in the fuel injection system to a pump chamber of a supply pump 102 and a low-pressure pipe connected to the fuel tank 101.

Next, the structure of the pressure control device 1 in the present embodiment will be described below. As shown in fig. 2, the pressure control device 1 includes a passage forming member 10, a flow rate regulator 20, a fixing member 30, a filter 40, and the like. The passage forming member 10 is located at one end of the common rail 103 in the longitudinal direction. A mounting hole 116 is provided on the end of the common rail 103 to which the passage forming member 10 is attached. The external thread 11 provided on the outer wall of the passage forming member 10 is screwed into the internal thread 117 provided on the inner wall of the mounting hole 116 of the common rail 103. Due to the axial force generated at this point, one end of the passage forming member 10 in the axial direction is axially abutted with the abutment portion 118 on the inner wall of the mounting hole 116, and the passage forming member 10 is connected with the common rail 103. A seal ring or the like, not shown, may be provided between the inner wall of the mounting hole 116 of the common rail 103 and the passage forming member 10.

A fuel passage 13 is formed in the passage forming member 10. One end of the fuel passage 13 is communicated to the rail chamber 119, and the other end of the fuel passage 13 is communicated to the pressure relief pipe 110. The rail chamber 119 is a part of a high-pressure passage of the engine fuel injection system, and the pressure relief pipe 110 is a part of a low-pressure passage. That is, the fuel passage 13 connects a high-pressure passage of the engine fuel injection system to a low-pressure passage.

The fuel passage 13 includes, in order from the high-pressure passage side, an orifice passage 14, a holding passage 15, and a connecting passage 16. A plurality of orifice members 21 are disposed in the orifice passage 14 and form the flow rate regulator 20. The flow rate regulator 20 will be described later. The holding passage 15 is provided on the side of the pressure relief pipe 110 with respect to the orifice passage 14. The channel length of the holding channel 15 is shorter than the channel length of the orifice channel 14, and the cross-sectional area of the channel is smaller than the cross-sectional area of the orifice member 21. Thus, a step 17 is formed between the orifice passage 14 and the retaining passage 15. A plurality of orifice members 21 are fixed to the step 17. The connection passage 16 is provided between the holding passage 15 and the pressure relief pipe 110. The passage cross-sectional area of the connecting passage 16 is larger than that of the holding passage 15. An unillustrated end of the pressure relief pipe 110 is connected to the connection passage 16.

As described above, the flow rate regulator 20 includes a plurality of orifice members provided in the orifice passage 14 of the fuel passage 13. As shown in fig. 2 and 3, the orifice member 21 includes an orifice pipe 22 that regulates the flow of fuel and a relief chamber 23 having a larger passage area than the orifice pipe 22. The inner diameter D1 of the orifice tube 22 is set to be greater than the limit of the cutting process, for example, a diameter of 0.05 mm. For example, the orifice tube 22 has an inner diameter D1 of about 0.06 to 0.12mm, or 0.08 to 0.1 mm. The conduit length L1 of the orifice conduit 22 is, for example, about 1/4 to 1/2 of the entire length L2 of the orifice member 21. The inner diameter D2 of the release chamber 23 is, for example, 10 to 100 times the inner diameter of the orifice tube 22. The plurality of orifice members 21 are in close contact with each other. Thus, the volume of the release chamber 23 included in the orifice member 21 is fixed.

A plurality of orifice members 21 are disposed in series in the flow rate regulator 20. That is, a plurality of orifice tubes 22 and a plurality of relief chambers 23 are alternately disposed in the flow rate regulator 20. Thus, the flow rate regulator 20 can regulate the flow rate of the fuel flowing from the high-pressure passage (e.g., the rail chamber 119) to the low-pressure passage (e.g., the pressure relief pipe 110). The flow rate of the fuel flowing from the high-pressure passage to the low-pressure passage will be referred to as a relief flow rate hereinafter. The number of orifice members 21 is not limited to the example shown in the drawings, and may be appropriately set according to the results of experiments or the like.

As shown in fig. 2, the fixing member 30 is disposed upstream of the plurality of orifice members 21, and fixes the plurality of orifice members 21 in the orifice passage 14. The fixing member 30 in the first embodiment includes a spring 31 and a bush 32.

The bush 32 is a cylindrical member, and is provided on the opposite side of the plurality of orifice members 21 from the step 17, that is, on the side of the rail chamber 119. The bushing 32 is fixed to the inner wall of the orifice passage 14 by press fitting or the like. The spring 31 is disposed between the plurality of orifice members 21 and the bush 32. One end of the spring 31 abuts the orifice member 21, and the other end of the spring 31 abuts the bush 32. The spring 31 is a compression coil spring, and presses the plurality of orifice members 21 toward the step 17. Thus, the plurality of orifice members 21 are fixed to the step 17 in the orifice passage 14.

The passage forming member 10 includes a protrusion 18 protruding toward the rail chamber 119 of the common rail 103. The filter 40 is of tubular form with a bottom and is fitted to the outer wall of the projection 18. That is, the filter 40 is located upstream of the flow rate regulator 20. The filter 40 includes a plurality of holes 41. The filter 40 includes a plurality of holes 41, and traps foreign matter in the fuel flowing from the rail chamber 119 into the fuel passage 13 of the passage forming member 10. The cross-sectional area of the orifice conduit 22 in the orifice member 21 is greater than the cross-sectional area of the hole 41 in the filter 40. Therefore, if fine foreign substances pass through the plurality of holes 41 of the filter 40, the foreign substances flow toward the pressure relief pipe 110 without clogging the orifice pipe 22.

The flow rate regulator 200 provided in the pressure control device in the comparative example will be described below for comparison with the first embodiment described above. As shown in fig. 4, the flow rate regulator 200 provided in the pressure control device in the comparative example includes an orifice member 210. The orifice member 210 in the comparative example has a single long orifice conduit 220. The inner diameter D3 of the orifice tube 220 of the orifice member 210 in the comparative example is assumed to be the same as the inner diameter D1 of the orifice tube 22 in the orifice member 21 in the first embodiment. In addition, the duct length L3 of the orifice duct 220 of the orifice member 210 in the comparative example is assumed to be the same as the total length of the plurality of orifice members 21 in the first embodiment.

The fuel pressure changed by the flow rate regulator 20 in the first embodiment and the fuel pressure changed by the flow rate regulator 200 in the comparative example will be described below with reference to fig. 5.

In fig. 5, the right side of the horizontal axis shows one side of the high pressure passage, and the left side of the horizontal axis shows one side of the low pressure passage. The vertical axis in fig. 5 shows the fuel pressure. In the graph shown in fig. 5, the flow rate regulator 20 of the first embodiment includes six orifice members 21 in series. On the other hand, the duct length L3 of the orifice duct 220 of the flow rate regulator 200 in the comparative example is equal to the total length of the six orifice members 21 in the first embodiment.

As shown by a solid line a in fig. 5, the flow rate regulator 20 in the first embodiment gradually reduces the pressure of the fuel flowing from the high-pressure passage to the low-pressure passage each time the fuel passes through one of the orifice pipes 22 included in the orifice member 21. On the other hand, as shown by a solid line B in fig. 5, when the fuel flows from the high-pressure passage to the low-pressure passage through the orifice pipe 220 (which is a long single pipe), the flow rate regulator 200 in the comparative example continuously reduces the pressure of the fuel flowing from the high-pressure passage to the low-pressure passage. By gradually reducing the fuel pressure by the arrangement structure in which the plurality of orifice pipes 22 and the plurality of relief chambers 23 are alternately arranged, the flow rate regulator 20 can reduce the fuel pressure more than the flow rate regulator 200 in the comparative example. Therefore, the flow rate regulator 20 in the first embodiment can reduce the relief flow rate as compared with the flow rate regulator 200 in the comparative example.

Referring to the graphs in fig. 6 and 7, the setting of the number of orifice members 21 with which the flow rate regulator 20 is equipped in the first embodiment will be described.

The horizontal axis in fig. 6 shows the number of orifice members 21 provided in the flow rate regulator 20. The vertical axis in fig. 6 shows the pressure relief flow rate. As shown in the graph of fig. 6, as the number of orifice members 21 provided in the flow rate regulator 20 increases, the relief flow rate can be reduced.

The horizontal axis in fig. 7 shows the fuel pressure in the rail chamber 119 of the common rail 103, which is referred to as the rail pressure. The vertical axis of fig. 7 shows the relief flow rate. The dashed line D in fig. 7 shows the relationship between the rail pressure and the relief flow rate in the case where the flow rate regulator 20 has two orifice members 21. On the other hand, a solid line E of fig. 7 shows the relationship between the rail pressure and the relief flow rate in the case where the flow rate gauge 20 has 10 orifice members 21. Further, for dotted line D and solid line E in fig. 7, the inner diameter D1 of orifice tube 22 located in orifice member 21 is 0.1 mm. When the flow rate regulator 20 includes the two orifice members 21, the relief flow rate becomes very high as shown by the broken line D in fig. 7 with the rail pressure of 200 MPa. On the other hand, as shown by the solid line in fig. 7, when the flow rate regulator 20 includes 10 orifice members 21, the relief flow rate is controlled to an appropriate value. In the first embodiment, the number of orifice members 21 provided in the flow rate gauge 20 can be arbitrarily set, thereby controlling the relief flow rate suitable for the rail pressure.

The pressure control device 1 in the first embodiment described above produces the operational effects described below.

(1) In the first embodiment, the flow rate regulator 20 with which the pressure control device 1 is equipped includes a plurality of orifice tubes 22 and a plurality of relief chambers 23 that are alternately arranged. Therefore, the pressure of the fuel flowing from the rail chamber 119 of the common rail 103 to the pressure relief pipe 110 is gradually reduced each time the fuel passes through one of the plurality of orifice pipes 22. Thus, the pressure relief flow rate in the first embodiment may be reduced compared to a comparative example where the flow rate regulator 200 comprises one (single) long orifice tube 220.

In the case where the relief flow rate is controlled by the single long orifice pipe 220 to decompress and control the fuel in the high-pressure passage, for example, in the comparative example, the inner diameter of the single long orifice pipe 220 needs to be smaller than the inner diameter D1 of the orifice pipe 22 included in the flow rate regulator 20 in the first embodiment. More specifically, unless the inner diameter D1 of the single long orifice tube 220 is less than a machined manufacturing limit, such as a 0.05mm diameter, the flow rate regulator 200 is unable to control the flow rate and the fuel pressure in the high pressure passage is reduced beyond a desired amount. On the other hand, in the first embodiment, unlike the configuration of the comparative example including the long single long orifice pipe 220, the flow rate of the fuel can still be reduced without making the inner diameter D1 of the orifice pipe 22 smaller than the manufacturing limit of the cut, for example, having a diameter of 0.08 to 0.1mm as the inner diameter of the regular size. That is, the pressure control device 1 in the first embodiment can appropriately decompress and control the fuel in the high-pressure passage.

In addition, in the first embodiment, the pressure of the fuel flowing from the high-pressure passage to the low-pressure passage is gradually reduced each time the fuel passes through one of the orifice pipes 22, and accordingly, the flow rate of the fuel is reduced. Therefore, the pressure control apparatus 1 can restrict the fuel from cavitation, and the surfaces of the structural members of the pressure control apparatus 1 can be protected from corrosion.

Further, in the first embodiment, the inner diameter D1 of each orifice pipe 22 may be set larger than that of the structure having the single long orifice pipe 220 in the comparative example. Therefore, the orifice pipe 22 can be prevented from being clogged with foreign matter included in the fuel. In addition, the aperture 41 included in the filter 40 upstream of the flow rate regulator 20 is smaller than the cross-sectional area of the orifice conduit 22. That is, the orifice tube 22 may be protected from clogging by a filter 40 that does not include extremely small pores 41 and includes, for example, conventionally sized pores 41.

(2) In the first embodiment, the flow rate regulator 20 includes a plurality of orifice members 21 provided in series, and each orifice member includes an orifice tube 22 and a release chamber 23. Therefore, the flow rate regulator 20 can be easily constructed. That is, the number of orifice members 21 constituting the flow rate regulator 20 can be arbitrarily set to control the relief flow rate suitable for the rail pressure. As described above, the plurality of orifice members 21 are provided in series. The plurality of orifice members 21 may be disposed in contact with each other, or may be disposed to sandwich a gasket, a sealing member, or the like.

(3) In the first embodiment, a plurality of orifice members 21 are fixed to the step 17 between the orifice passage 14 and the holding passage 15. Thus, a plurality of orifice members 21 may be fixed in the orifice passage 14.

(4) In the first embodiment, the orifice passage 14 is longer than the holding passage 15. Therefore, by shortening the holding passage 15, it is possible to make the body of the pressure control device 1 small while maintaining the length of the flow rate regulator 20 required to control the fuel pressure in the common rail 103.

(5) In the first embodiment, the holding passage 15 is placed on the side of the pressure relief pipe 110 with respect to the orifice passage 14. The step 17 is provided on one side of the pressure relief pipe 110 with respect to the plurality of orifice members. Therefore, the fuel pressure in the high-pressure passage presses the plurality of orifice members 21 toward the step 17, and the plurality of orifice members 21 are pressed against each other. Therefore, the region between the step 17 and the orifice member 21 and the region between the plurality of orifice members 21 can be sealed.

(6) In the first embodiment, the pressure control device 1 includes the fixing member 30, and the fixing member 30 presses the plurality of orifice members 21 toward the step 17 from the side of the plurality of orifice members 21 opposite to the step 17. The fixing member 30 includes a spring 31 and a bushing 32. Therefore, even in a state where the fuel pressure of the high-pressure passage is relatively low at the time of, for example, engine start, it is possible to firmly fix the plurality of orifice members 21 in the orifice passage 14.

(7) In the first embodiment, the orifice tube 22 included in the flow rate regulator 20 has a cross-sectional area larger than that of the hole 41 in the filter 40 located upstream of the flow rate regulator 20. As described above, in the flow rate regulator 20 of the first embodiment, the inner diameter D1 of the orifice tube 22 can be larger than the configuration having the single long orifice tube 220 such as in the comparative example. Thus, the orifice tube 22 may be protected from clogging by a filter 40, which filter 40 does not include the very small holes 41 and, for example, the filter 40 includes the conventionally sized holes 41 like the filter 40 placed upstream of the flow rate regulator 20.

(second to fourth embodiments)

The pressure control device 1 according to the second to fourth embodiments differs from the first embodiment only in the structure of the flow rate regulator 20, and is otherwise the same as the first embodiment. Hereinafter, only the structure different from the first embodiment will be described.

(second embodiment)

As shown in fig. 8, in the second embodiment, the flow rate regulator 20 includes a plurality of orifice members 21, and each orifice member 21 includes an orifice pipe 22 and two relief chambers 23a, 23 b. The orifice duct 22 is located in the central portion of the orifice member 21 in the channel axis direction. The chain line Ax in the drawing shows the passage axis of the orifice member 21.

The first release chamber 23a of the two release chambers is provided at one end of the orifice pipe 22 in the channel axis direction. The second release chamber 23b of the two release chambers is provided at the other end of the orifice pipe 22 in the channel axis direction. The two release chambers 23a, 23b are respectively formed in a tapered shape, and the inner diameter of each release chamber 23a, 23b is gradually reduced from the outer wall of the orifice member 21 toward the orifice pipe 22. Two release chambers 23a, 23b are formed symmetrically with respect to the orifice duct 22.

In the second embodiment, the flow rate regulator 20 includes a plurality of orifice members 21 arranged in series. That is, in the flow rate regulator 20, the plurality of orifice pipes 22 and the plurality of relief chambers 23 are alternately arranged. Thus, the flow rate regulator 20 is able to control the relief flow rate to a small amount.

In the second embodiment, the two relief chambers 23a, 23b are formed symmetrically with respect to the orifice pipe 22, and in the case where the flow rate gauge 20 includes a plurality of orifice members 21 provided in series, the direction of the passage axis is not limited. That is, in the case where the passage axis direction of the orifice member 21 is directed toward the opposite side, the flow rate regulator 20 has the same function. Therefore, in the second embodiment, the plurality of orifice members 21 can be easily assembled to the orifice passage 14. In addition, the second embodiment has the same operational effects as the first embodiment described above.

(third embodiment)

As shown in fig. 9, in the third embodiment, the flow rate regulator 20 includes a plurality of orifice members 21 each including an orifice tube 22 and two relief chambers 23a, 23 b. The two release chambers 23a, 23b in the third embodiment are different in shape from those in the second embodiment. The two release chambers 23a, 23b respectively include a cylindrical portion 231 and a tapered portion 232. The cylindrical portion 231 is provided on one side of the outer wall of the orifice member 21. The inner diameter of the tapered portion 232 gradually decreases from one end of the cylindrical portion 231 toward the orifice pipe 22. The two release chambers 23a, 23b are symmetrical with respect to the orifice duct 22.

Also in the third embodiment, in the case where the flow rate regulator 20 includes the plurality of orifice members 21 provided in series, the direction of the passage axis direction is not limited. Therefore, also in the third embodiment, it is possible to easily assemble the plurality of orifice members 21 to the orifice passage 14. In addition, the third embodiment has the same operational effects as the first embodiment described above.

(fourth embodiment)

As shown in fig. 10, in the fourth embodiment, the orifice member 21 provided in the flow rate regulator 20 includes a plurality of orifice tubes 22 and a plurality of relief chambers 23 which are alternately provided. Hereinafter, a manufacturing method example of the orifice member 21 will be described. The plurality of orifice ducts 22 and the plurality of relief chambers 23 are formed by cutting two portions 24, 25 which are divided in a plane including the passage axis Ax. Subsequently, the portion 24 is joined to the portion 25. The method of manufacturing the orifice member 21 is not limited to the above method.

In the fourth embodiment, the number of components in the orifice member 21 included in the flow rate regulator 20 can be reduced. In addition, the fourth embodiment has the same operational effects as the first embodiment described above.

(fifth to fourteenth embodiments)

The pressure control device 1 according to the fifth to fourteenth embodiments differs from the pressure control device according to the first embodiment only in the fixing method of fixing the plurality of orifice members 21 in the orifice passage 14 or the like. Hereinafter, only the structure different from the first embodiment will be described.

(fifth embodiment)

As shown in fig. 11 and 12, in the fifth embodiment, a bush 32 having a cylindrical shape forms a fixing member 30 that fixes a plurality of orifice members 21 in the orifice passage 14. A plurality of orifice members 21 are disposed in the orifice passage 14 between the step 17 and the bushing 32. That is, the bushing 32 is located on the side of the rail chamber 119 within the orifice passage 14. The bushing 32 is fixed to the inner wall of the orifice passage 14 by press fitting. The bushing 32 fixes the plurality of orifice members 21 to the step 17 by a load applied during press fitting.

In the fifth embodiment, the number of parts can be reduced from those of the first embodiment by removing the spring 31 located between the bush 32 and the plurality of orifice members 21. In the fifth embodiment, the step 17 is located on the side of the pressure relief pipe 110 with respect to the plurality of orifice members 21. Therefore, the bush 32 and the plurality of orifice members 21 are pressed against the step 17 by the fuel pressure on the rail chamber 119 side, and the plurality of orifice members 21 are pressed against each other. Therefore, the region between the step 17 and the orifice member 21 and the region between the plurality of orifice members 21 can be sealed. In addition, the fifth embodiment has the same operational effects as the first embodiment described above.

(sixth embodiment)

The sixth embodiment is a modification of the fifth embodiment. As shown in fig. 13, in the sixth embodiment, a spring bushing (spritbush)33 forms the fixing member 30 that fixes the plurality of orifice members 21 in the orifice passage 14. The spring bushing 33 is also referred to as a spring pin. The spring bushing 33 is cylindrical and has a cutting line 331 extending in the axial direction at one position in the circumferential direction. In a state before the spring bushing 33 is assembled to the orifice passage 14, the outer diameter of the spring bushing 33 is larger than the inner diameter of the orifice passage 14. The spring bushing 33 in a radially compressed state is fixed to the inner wall of the orifice passage 14 by press fitting. Subsequently, the spring bushing 33 fixes the plurality of orifice members 21 to the step 17 by the load applied during press-fitting.

In the sixth embodiment, even in the case where the inner diameter of the orifice passage 14 is expanded by the pressure of the fuel flowing in the orifice passage 14, the outer diameter of the spring bushing 33 can be expanded as the inner diameter of the orifice passage 14 is expanded. Thus, the spring bushing 33 enables the plurality of orifice members 21 to be firmly fixed to the step 17. In addition, the sixth embodiment has the same operational effects as the first embodiment described above.

(seventh embodiment)

As shown in fig. 14, in the seventh embodiment, the fuel passage 13 formed in the passage forming member 10 includes the orifice passage 14 located downstream of the holding passage 15. That is, the retaining channel 15 is formed between the rail chamber 119 and the orifice duct 14. Thus, the step 17 is provided between the rail chamber 119 and the plurality of orifice members 21.

A plurality of orifice members 21 comprised by the flow rate regulator 20 are disposed in the orifice passage 14. The fixing member 30 is disposed downstream of the plurality of orifice members 21 and fixes the plurality of orifice members 21 in the orifice passage 14. In the seventh embodiment, the fixing member 30 includes a screw member 34. An external thread 35 is formed in an outer wall of the screw member 34. The threaded member 34 includes an axially extending bore 36. The screw member 34 further includes a fitting hole 37, and a fastening tool such as a wrench can be fitted to the fitting hole 37 at one end of the hole 36.

The external thread 35 formed on the outer wall of the screw member 34 as the fixing member 30 is screwed into the internal thread 19 formed on the inner wall of the passage downstream of the orifice passage 14. Thus, the screw member 34 presses the plurality of orifice members 21 against the step 17. Thereby, the plurality of orifice members 21 are fixed in the orifice passage 14. In the seventh embodiment, the screw member 34 is used as the fixing member 30, and the plurality of orifice members 21 are firmly fixed to the step 17. In addition, the seventh embodiment has the same operational effects as the first embodiment described above.

(eighth embodiment)

As shown in fig. 15, in the eighth embodiment, the fuel passage 13 formed in the passage forming member 10 includes a first orifice passage 141 located upstream of the holding passage 15 and a second orifice passage 142 located downstream of the holding passage 15. A first step 171 is formed between the first orifice passage 141 and the retaining passage 15 and a second step 172 is formed between the second orifice passage 142 and the retaining passage 15.

Each of the first and second orifice passages 141, 142 includes a plurality of orifice members 21 that form the flow rate regulator 20. The flow rate regulator 20 disposed in the first orifice passage 141 is referred to as a first flow rate regulator 201, and the flow rate regulator 20 disposed in the second orifice passage 142 is referred to as a second flow rate regulator 202.

Similar to the first embodiment, the fixing member 30 including the spring 31 and the bush 32 presses the first flow rate gauge 201 toward the first step 171. Thus, the first flow rate gauge 201 is secured to the first step 171 in the first orifice passage 141.

On the other hand, similar to the seventh embodiment, the fixed member 30 including the threaded member 34 presses the second flow rate gauge 202 toward the second step 172. Thus, the second flow rate regulator 202 is secured to the second land 172 in the second orifice passage 142. As described above, in the eighth embodiment, the flow rate regulator 20 including the plurality of orifice members 21 may be separately placed at two positions. In addition, the eighth embodiment has the same operational effects as the first embodiment described above.

(ninth embodiment)

As shown in fig. 16 and 17, in the ninth embodiment, the passage forming member 10 includes a first passage forming member 51 on the upstream side and a second passage forming member 52 on the downstream side of the first passage forming member 51.

The first passage forming member 51 is inserted into a mounting hole 116 at an end of the common rail 103. While the second passage forming member 52 holds the first passage forming member 51 from the downstream side of the first passage forming member 51, the external thread 153 formed on the outer wall of the second passage forming member 52 is screwed into the internal thread 117 formed on the inner wall of the mounting hole 116 of the common rail 103. Due to the axial force generated at this point, the axial end of the first passage forming member 51 axially abuts against the abutment portion 118 located on the inner wall of the mounting hole 116. Thus, the common rail 103, the first passage forming member 51, and the second passage forming member 52 are connected. A seal ring or the like, not shown, may be provided between the inner wall of the mounting hole 116 of the common rail 103 and the first passage forming member 51 or the second passage forming member 52.

In the ninth embodiment, the fuel passage 13 formed in the first passage forming member 51 includes the first retaining passage 151 and the orifice passage 14 in this order from the upstream. The inner diameter of the first retaining channel 151 is smaller than the inner diameter of the orifice channel 14. That is, the first step 171 is located between the first retaining channel 151 and the orifice channel 14.

On the other hand, the fuel passage 13 formed in the second passage forming member 52 includes the second retaining passage 152 and the connecting passage 16 in this order from the upstream. The inner diameter of the second holding passage 152 is smaller than the inner diameter of the orifice passage 14 formed in the first passage forming member 51. That is, the second step 172 is located outside the opening of the second retaining channel 152.

The orifice passage 14 formed in the first passage forming member 51 includes a plurality of orifice members 21 forming the flow rate regulator 20. A spring washer 38 as the fixing member 30 is interposed between the plurality of orifice members 21 and the first step 171. The spring washer 38 as the fixing member 30 and the plurality of orifice members 21 are inserted into the orifice passage 14 formed in the first passage forming member 51. Subsequently, the external thread 135 formed on the outer wall of the second passage forming member 52 is screwed into the internal thread 117 formed on the inner wall of the mounting hole 116 of the common rail 103. At this time, the second step 172 of the second passage forming member 52 presses the plurality of orifice members 21 toward the first step 171. Therefore, the plurality of orifice members 21 are pressed toward the second step 172 by the elastic force of the spring washer 38 between the plurality of orifice members 21 and the first step 171, and are fixed in the orifice passage 14.

In the ninth embodiment, the plurality of orifice members 21 are firmly fixed to the orifice passage 14 by using the spring washer 38 as the fixing member 30. In addition, the ninth embodiment has the same operational effects as the first embodiment described above.

(tenth embodiment)

The tenth embodiment is a modification of the ninth embodiment. As shown in fig. 18, in the tenth embodiment, a wave washer 39 is formed in place of the spring washer 38 as the fixing member 30 that fixes the plurality of orifice members 21 in the orifice passage 14. The wave washer 39 has a wave-like shape in the circumferential direction, and can apply a load substantially uniformly to the orifice member 21 as compared with the spring washer 38.

In the tenth embodiment, the plurality of orifice members 21 are firmly fixed to the orifice passage 14 by using the wave washer 39 as the fixing member 30. In addition, the tenth embodiment has the same operational effects as the first embodiment described above.

(eleventh embodiment)

The eleventh embodiment is a modification of the sixth embodiment. As shown in fig. 19, in the eleventh embodiment, the spring bushing 33 forms the fixing member 30 that fixes the plurality of orifice members 21 in the orifice passage 14. The spring bushing 33 is placed on the side of the plurality of orifice members 21 opposite the step 17, i.e., on the side of the rail chamber 119 in the orifice passage 14. The spring bushing 33 is fixed to the inner wall of the orifice passage 14 by press fitting. Thus, the spring bushing 33 fixes the plurality of orifice members 21 to the step 17 by the load applied during press-fitting. In the eleventh embodiment, a part of the spring bushing 33 is exposed from the orifice passage 14.

In the eleventh embodiment, the spring bushing 33 is used as the fixing member 30, and the plurality of orifice members 21 are firmly fixed to the step 17. Further, the eleventh embodiment has the same operational effects as the first embodiment described above.

(twelfth embodiment)

As shown in fig. 20, in the twelfth embodiment, the spring 31 forms the fixing member 30 that fixes the plurality of orifice members 21 in the orifice passage 14. The spring 31 is provided between the plurality of orifice members 21 and the inner wall of the filter 40. One end of the spring 31 abuts against the orifice member 21, and the other end of the spring 31 abuts against the inner wall of the filter 40. The spring 31 is a compression coil spring and presses the plurality of orifice members 21 toward the step 17. Thus, the plurality of orifice members 21 are fixed to the step 17 in the orifice passage 14.

In the twelfth embodiment, a spring 31 is used as the fixing member 30, and the plurality of orifice members 21 are firmly fixed to the orifice passage 14. In addition, the twelfth embodiment has the same operational effects as the first embodiment described above.

(thirteenth embodiment)

As shown in fig. 21, in the thirteenth embodiment, the fixing member 30 that fixes the plurality of orifice members 21 in the orifice passage 14 includes the pin 43 and the spring 31. The pin 43 is disposed inside the filter 40. The spring 31 is disposed between the pin 43 and the plurality of orifice members 21. One end of the spring 31 abuts against the orifice member 21, and the other end of the spring 31 abuts against the pin 43. The spring 31 presses the orifice members 21 toward the step 17. Thus, the plurality of orifice members 21 are fixed to the step 17 in the orifice passage 14.

In the thirteenth embodiment, the pin 43 and the spring 31 are used as the fixing member 30, and the plurality of orifice members 21 are fixed to the orifice passage 14. In addition, the thirteenth embodiment has the same operational effects as the first embodiment described above.

(fourteenth embodiment)

As shown in fig. 22, in the fourteenth embodiment, the fixing member 30 that fixes the plurality of orifice members 21 in the orifice passage 14 includes a ball 44 and a spring 31. The ball 44 is disposed inside the filter 40. The spring 31 is disposed between the ball 44 and the plurality of orifice members 21. One end of the spring 31 abuts against the orifice member 21, and the other end of the spring 31 abuts against the ball 44. The spring 31 presses the orifice members 21 toward the step 17. Thus, the plurality of orifice members 21 are fixed to the step 17 in the orifice passage 14.

In the fourteenth embodiment, the sphere 44 and the spring 31 are used as the fixing member 30, and the plurality of orifice members 21 are fixed to the orifice passage 14. In addition, the fourteenth embodiment has the same operational effects as the first embodiment described above.

(fifteenth embodiment)

The pressure control apparatus 1 of the fifteenth embodiment includes, in addition to the first to fourteenth embodiments, a valve mechanism 60 upstream of the flow rate regulator 20.

As shown in fig. 23, in the fifteenth embodiment, the passage forming member 10 includes a first passage forming member 51 on the upstream side and a second passage forming member 52 on the downstream side of the first passage forming member 51.

The first passage forming member 51 is inserted into a mounting hole 116 at an end of the common rail 103. While the second passage forming member 52 holds the first passage forming member 511 from the downstream side of the first passage forming member 51, the external thread 153 formed on the outer wall of the second passage forming member 52 is screwed into the internal thread 117 formed on the inner wall of the mounting hole 116 of the common rail 103. Due to the axial force generated at this point, the axial end of the first passage forming member 51 axially abuts against the abutment portion 118 provided on the inner wall of the mounting hole 116. Thus, the common rail 103, the first passage forming member 51, and the second passage forming member 52 are connected to each other. A seal ring or the like, not shown, may be provided between the inner wall of the mounting hole 116 of the common rail 103 and the first passage forming member 51 or the second passage forming member 52.

The fuel passage 13 formed in the second passage forming member 52 includes the orifice passage 14, the holding passage 15, and the connecting passage 16. A step 17 is provided between the retaining channel 15 and the orifice channel 14. The orifice passage 14 includes a plurality of orifice members 21 that form a flow rate regulator 20. In fig. 23, the flow rate regulator 20 includes two orifice members 21. However, the number of orifice members 21 is not limited to this value, and it may be appropriately set according to the results of experiments or the like.

On the other hand, the fuel passage 13 is formed in the first passage forming member 51, the first passage forming member 51 is located on the side of the second passage forming member 52 close to the rail chamber 119, and the fuel passage 13 includes the throttle passage 61. The valve seat 62 is disposed downstream of the throttle passage 61. The ball valve 63 is provided so that the ball valve 63 can be seated on the valve seat 62 or lifted from the valve seat 62. A retainer 64 is placed downstream of the ball valve 63 and retains the ball valve 63. The spring 31 is placed between the retainer 64 and the orifice member 21. The valve mechanism 60 includes the valve seat 62, the ball valve 63, the retainer 64, and the spring 31 as described above. The valve mechanism 60 is located between the filter 40 and the flow rate regulator 20. The valve mechanism 60 is configured such that the valve mechanism 60 opens when the pressure difference between the fuel pressure of the passage 26 between the flow rate gauge 20 and the valve mechanism 60 and the fuel pressure of the rail chamber 119 is greater than a predetermined pressure. The predetermined pressure is set, for example, equal to or higher than a rail pressure required for the engine to idle.

In the structure of the fifteenth embodiment, when the valve mechanism 60 is open, the pressure control device 1 is configured to discharge high-pressure fuel in the common rail 103 into a low-pressure passage such as the fuel tank 101 at a minute flow rate. Therefore, the pressure control device 1 can reduce and control the pressure of the high-pressure fuel in the common rail 103 to an appropriate pressure. Therefore, the pressure control device 1 can protect the inside of the common rail 103 from the accumulated fuel pressure exceeding the required pressure during the engine stop, so that it is possible to appropriately adjust the amount of fuel injected from the injector 104 at the start of the next operation and suppress the generation of noise. In addition, the pressure control device 1 in the fifteenth embodiment restricts the rail pressure from decreasing below the predetermined pressure set in the valve mechanism 60. Further, the fifteenth embodiment has the same operational effects as the first embodiment described above.

(other embodiments)

The present disclosure is not limited to the above embodiments and/or modifications, but may be further modified in various ways without departing from the spirit of the invention. The embodiments in the present disclosure are not independent of each other and may be combined appropriately, except where combination is obviously not possible. Elements in the various embodiments are not required except where the elements are specified as particularly necessary or where elements are in principle explicitly required. In addition, even in the case where a number such as an amount, a numerical value, a number, a range is mentioned in each embodiment, the present disclosure is not limited to a specific number unless the number is specified as a particularly necessary number or when the number is clearly defined as a specific number in principle. In addition, even if a specific shape, a specific positional relationship, and the like are mentioned in each embodiment, the present disclosure is not limited to the specific shape, the specific positional relationship, and the like unless the specific shape, the specific positional relationship are specifically defined, or the specific shape, the specific positional relationship are clearly defined in principle.

(1) In the above-described embodiment, the pressure control device 1 is attached to the common rail 103 within the high-pressure passage. However, the present disclosure is not limited to the above structure. The pressure control device 1 may be provided at any position in the fuel passage from the discharge valve of the supply pump 102 to the injection hole of the injector 104 and provided as a high-pressure passage in the fuel injection system, or may be provided in the fuel passage communicating therewith.

(2) In the above-described embodiment, the passage forming member 10, the common rail 103, and the pressure relief pipe 110 with which the pressure control device 1 is equipped are formed separately. However, the present disclosure is not limited to the above. The passage forming member 10 provided in the pressure control apparatus 1 may be integrally formed with other members adjacent to the passage forming member 10. More specifically, the passage forming member 10 may be integrally formed with the common rail 103. In addition, the passage forming member 10 may be integrally formed with the pressure relief pipe 110.