JP2018178995A - Fluid control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid control device capable of detecting variation in pressure in a main flow passage with high precision irrespective of the pressure of fluid flowing through the main flow passage.SOLUTION: A fuel injection device 1 comprises a housing 20, a strain body 70 and a differential pressure sensor 80. The housing 20 has: an inflow port 240 into which fuel in the form of fluid flows; an injection hole 13 out of which the fuel flows, namely, from which the fuel is injected; and a main flow passage 100 which connects the inflow port 240 and injection hole 13 to each other to allow the fuel to flow. The strain body 70 can elastically deform with the pressure difference between a first space S1 and a second space S2 as the first space as a space in contact with one plane 71 communicates with the main flow passage 100 and the second space S2 as a space in contact with another plane 72 communicates with the main flow passage 100. The differential pressure sensor 80 is provided at the strain body 70 and can detect the pressure difference between the first space S1 and second space S2.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a fluid control device.

  BACKGROUND Conventionally, a fluid control device capable of detecting the pressure of a main flow path through which fluid flows is known. For example, the fluid control device of Patent Document 1 is a fuel injection device, and includes a pressure sensor connected to the main flow path. In this fuel injection device, a space in contact with one surface of the strain sensor of the pressure sensor communicates with the main flow passage. The other surface of the strain generating body is in contact with air (atmosphere). In the fluid control device of Patent Document 1, the pressure of the main flow passage at the time of fuel injection is detected by a pressure sensor, and the amount of fuel injected from the injection hole is estimated based on a change in the detected pressure.

JP, 2009-222051, A

  In the fuel injection device of Patent Document 1, since the high pressure fuel is injected, the pressure in the main flow passage becomes high at the time of fuel injection. Therefore, it is necessary to increase the rigidity of the strain sensor of the pressure sensor. In the fuel injection device of Patent Document 1, an absolute pressure sensor having a rigid body with high strain is used. However, although the absolute pressure sensor is high in pressure resistance, the rigidity of the strain generating body is high and it is difficult to distort. Therefore, in the fuel injection device of Patent Document 1, detection of the pressure on the low pressure side is difficult and the pressure is detectable by the pressure sensor. The range may be narrowed. Therefore, it may be difficult to detect changes in pressure in the main flow path with high accuracy.

  An object of the present invention is to provide a fluid control device capable of detecting a change in pressure in a main flow path with high accuracy regardless of the pressure of fluid flowing in the main flow path.

A fluid control device (1) according to a first aspect of the present invention includes a housing (20), a strain generating body (70), and a differential pressure sensor (80).
The housing has an inlet (240) into which the fluid flows, an outlet (13) from which the fluid flows out, and a main channel (100) which connects the inlet and the outlet and through which the fluid flows.
In the strain generating body, a first space (S1) which is a space in contact with one surface (71) communicates with the main flow path, and a second space (S2) which is a space in contact with the other surface (72) is a main flow path It communicates and is elastically deformable by the pressure difference between the first space and the second space.
The differential pressure sensor is provided on the strain generating body, and can detect a pressure difference between the first space and the second space.

  When the fluid flows in the main flow path, the first space in contact with one surface of the strain generating body and the second space in contact with the other surface of the strain generating body are filled with the fluid. Therefore, even when the pressure in the main flow path is high, generation of an excessive pressure difference on both sides of the strain generating body can be suppressed, and the rigidity of the strain generating body can be set low. Thus, the amount of strain of the strain generating body can be increased, and the range of pressure detectable by the differential pressure sensor can be increased. Therefore, regardless of the pressure of the fluid flowing through the main flow channel, the change in pressure of the main flow channel can be detected with high accuracy.

A fluid control system (1) according to a second aspect of the present invention comprises a housing (20), a strain generating body (70), an incompressible fluid (78) and a differential pressure sensor (80).
The housing has an inlet (240) into which the fluid flows, an outlet (13) from which the fluid flows out, and a main channel (100) which connects the inlet and the outlet and through which the fluid flows.
In the strain generating body, a first space (S1), which is a space in contact with one surface (71), communicates with the main flow path, and a second space (S2), which is a space in contact with the other surface (72) It can be elastically deformed by the pressure difference with
The incompressible fluid is provided in the second space.
The differential pressure sensor is provided on the strain generating body, and can detect a pressure difference between the first space and the second space.

  When the fluid flows in the main flow path, the first space in contact with one surface of the strain generating body is filled with the fluid. Here, the second space in contact with the other surface of the strain generating body is filled with the incompressible fluid. Therefore, even when the pressure in the main flow path is high, generation of an excessive pressure difference on both sides of the strain generating body can be suppressed, and the rigidity of the strain generating body can be set low. Thus, the amount of strain of the strain generating body can be increased, and the range of pressure detectable by the differential pressure sensor can be increased. Therefore, regardless of the pressure of the fluid flowing through the main flow channel, the change in pressure of the main flow channel can be detected with high accuracy.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the fluid control apparatus by 1st Embodiment. FIG. 2 is a view showing a strain generating body and a differential pressure sensor of the fluid control system according to the first embodiment, and a cross-sectional view corresponding to a cross section taken along line II-II in FIG. FIG. 2 is a schematic view showing a differential pressure sensor of the fluid control system according to the first embodiment. BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram which shows the fluid control apparatus by 1st Embodiment. (A) shows a pressure change in the first space and a pressure change in the second space of the fluid control system according to the first embodiment, and (B) shows a change in differential pressure between the first space and the second space. Figure. FIG. 7 is a flow chart showing processing concerning correction of the fuel injection amount by the fluid control system according to the first embodiment. Sectional drawing which shows the fluid control apparatus by 2nd Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 2nd Embodiment. Sectional drawing which shows the fluid control apparatus by 3rd Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 3rd Embodiment. Sectional drawing which shows the fluid control apparatus by 4th Embodiment. (A) is a figure which shows the strain generating body and differential pressure sensor of the fluid control apparatus by 4th Embodiment, Comprising: It is sectional drawing corresponding to the XIIA-XIIA line cross section of FIG. 11, (B) is XIIB of (A). -XIIB line sectional view. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 5th Embodiment. Sectional drawing which shows the fluid control apparatus by 6th Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 6th Embodiment. Sectional drawing which shows the fluid control apparatus by 7th Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 7th Embodiment. Sectional drawing which shows the fluid control apparatus by 8th Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 8th Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 9th Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 10th Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 11th Embodiment. FIG. 23 is a cross-sectional view taken along line XXIII-XXIII of FIG. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 12th Embodiment. Sectional drawing which shows the vicinity of the strain body of the fluid control apparatus by 13th Embodiment.

  Hereinafter, fluid control devices according to a plurality of embodiments will be described based on the drawings. In addition, in several embodiment, the same code | symbol is attached | subjected to a substantially identical component, and description is abbreviate | omitted. In addition, substantially the same components in the plurality of embodiments exhibit the same or similar effects.

First Embodiment
A fluid control apparatus according to a first embodiment of the present invention is shown in FIG. A fuel injection device 1 as a fluid control device is used, for example, in a direct injection gasoline engine as an internal combustion engine mounted on a vehicle (not shown), and injects and supplies gasoline as a fuel to the engine. That is, the fuel injection device 1 controls fuel as fluid and supplies it to the engine.

The fuel injection device 1 includes a housing 20, a needle 30, a movable core 40, a fixed core 50, an adjusting pipe 53, a gap forming member 60, a spring 61, a coil 62, a spring seat 63, a spring 64, an elastic body 70, and a difference. A pressure sensor 80, a control unit 91, a pressure change detection unit 92, a flow rate estimation unit 93, a flow rate correction unit 94, and the like are provided.
The housing 20 has a nozzle portion 10, a first cylindrical portion 21, a second cylindrical portion 22, a third cylindrical portion 23, and an inlet portion 24.
The nozzle portion 10 is formed of, for example, a metal such as stainless steel. The nozzle portion 10 is subjected to hardening treatment so as to have a predetermined hardness. The nozzle unit 10 has a nozzle cylinder 11 and a nozzle bottom 12 that closes one end of the nozzle cylinder 11. A plurality of injection holes 13 connecting the surface on the nozzle cylinder 11 side and the surface on the opposite side of the nozzle cylinder 11 are formed in the nozzle bottom 12. Here, the injection hole 13 corresponds to the "outlet". In the present embodiment, a plurality of the injection holes 13 are formed at equal intervals in the circumferential direction of the nozzle bottom 12. Further, an annular valve seat 14 is formed around the injection hole 13 on the surface of the nozzle bottom 12 on the nozzle cylinder 11 side.

  The first cylindrical portion 21, the second cylindrical portion 22 and the third cylindrical portion 23 are all formed in a substantially cylindrical shape. The first cylindrical portion 21, the second cylindrical portion 22, and the third cylindrical portion 23 are arranged to be coaxial (shaft Ax1) in the order of the first cylindrical portion 21, the second cylindrical portion 22, and the third cylindrical portion 23, and Connected

The first cylindrical portion 21 and the third cylindrical portion 23 are made of, for example, a magnetic material such as ferritic stainless steel, and are subjected to a magnetic stabilization process. The second cylindrical portion 22 is formed of, for example, a nonmagnetic material such as austenitic stainless steel.
The end of the nozzle cylinder 11 opposite to the nozzle bottom 12 is joined to the inside of the end of the first cylinder 21 opposite to the second cylinder 22. The first cylindrical portion 21 and the nozzle portion 10 are joined, for example, by welding.

  The inlet portion 24 is formed in a tubular shape, for example, by a metal such as stainless steel. The inlet portion 24 is provided such that one end thereof is joined to the inside of the end portion of the third cylindrical portion 23 opposite to the second cylindrical portion 22. The inlet 24 and the third cylindrical portion 23 are joined, for example, by welding.

A main flow passage 100 is formed inside the housing 20, that is, inside the nozzle portion 10, the first cylindrical portion 21, the second cylindrical portion 22, the third cylindrical portion 23, and the inlet portion 24. The main flow path 100 is connected to the injection hole 13. An inlet 240 is formed on the side of the inlet 24 opposite to the third cylindrical portion 23. Here, the inflow port 240 corresponds to the "inlet". The main flow passage 100 is formed inside the outer wall of the housing 20.
A pipe (not shown) is connected to the inflow port 240. Thereby, the fuel from the fuel supply source flows into the main flow passage 100 through the piping and the inlet 240. The main flow passage 100 leads the fuel to the injection hole 13. The fuel is injected from the injection hole 13.
As described above, the housing 20 has the inlet 240 into which the fuel as fluid flows, the injection hole 13 from which the fuel flows out, and the main flow path 100 connecting the inlet 240 and the injection hole 13 and through which the fuel flows. There is.
A filter 25 is provided inside the inlet portion 24. The filter 25 collects foreign matter in the fuel flowing into the main flow passage 100.

The needle 30 is formed of, for example, a metal such as stainless steel. The needle 30 is subjected to hardening treatment so as to have a predetermined hardness.
The needle 30 is accommodated in the housing 20 so as to be capable of reciprocating in the main flow path 100 in the direction of the axis Ax 1 of the housing 20. The needle 30 has a needle body 31, a seal portion 32, a collar portion 33, and the like.

  The needle body 31 is formed in a rod-like shape, more specifically, in a long cylindrical shape. The seal portion 32 is annularly formed at one end of the needle main body 31, that is, the end on the valve seat 14 side, and can abut on the valve seat 14. The collar portion 33 is annularly formed, and is provided radially outward of the other end of the needle main body 31, that is, the end opposite to the valve seat 14. In the present embodiment, the hook portion 33 is integrally formed with the needle main body 31.

  A large diameter portion 311 is formed in the vicinity of one end of the needle main body 31. The outer diameter of the large diameter portion 311 is larger than the outer diameter of one end side of the needle body 31. The large diameter portion 311 is formed such that the outer wall slides with the inner wall of the nozzle cylinder portion 11 of the nozzle portion 10. Thus, the needle 30 is guided to reciprocate in the direction of the axis Ax1 of the end on the valve seat 14 side. A chamfered portion 312 is formed on the large diameter portion 311 such that a plurality of circumferential portions of the outer wall are chamfered. Thus, the fuel can flow between the chamfered portion 312 and the inner wall of the nozzle cylinder portion 11 of the nozzle portion 10.

  At the other end of the needle body 31, an axial hole 313 extending along the axis Ax2 of the needle body 31 is formed. That is, the other end of the needle main body 31 is formed in a hollow cylindrical shape. Further, in the needle main body 31, a radial direction hole 314 extending in the radial direction of the needle main body 31 is formed so as to connect the end of the axial hole 313 on the valve seat 14 side and the space outside the needle main 31. ing. Thus, the fuel in the main flow passage 100 can flow through the axial holes 313 and the radial holes 314. Thus, the needle body 31 has an axial hole 313 communicating with the space on the outside of the needle body 31 extending in the direction of the axis Ax 2 from the end face opposite to the valve seat 14 via the radial hole 314. doing.

  The needle 30 opens and closes the injection hole 13 by the seal portion 32 moving away from the valve seat 14 (lifting) or abutting (seating) on the valve seat 14. Hereinafter, as appropriate, the direction in which the needle 30 separates from the valve seat 14 is referred to as a valve opening direction, and the direction in which the needle 30 abuts on the valve seat 14 is referred to as a valve closing direction.

  The movable core 40 is formed in a substantially cylindrical shape, for example, by a magnetic material such as ferritic stainless steel. The movable core 40 is subjected to magnetic stabilization processing.

  The movable core 40 is accommodated in the housing 20 in a state in which the needle main body 31 of the needle 30 is inserted inside. The movable core 40 is movable relative to the needle 30 while the inner peripheral wall slides on the outer peripheral wall of the needle main body 31 of the needle 30. Further, the movable core 40 is accommodated in the housing 20 so as to be able to reciprocate in the main flow path 100 in the direction of the axis Ax1 of the housing 20, similarly to the needle 30. The inner peripheral wall of the movable core 40 is subjected to hard processing such as Ni-P plating and a sliding resistance reduction processing, for example.

  In the present embodiment, the surface of the movable core 40 opposite to the valve seat 14 is subjected to hard processing such as hard chromium plating and abrasion resistance.

  The flange 33 of the needle 30 can contact the surface on the valve seat 14 side with the surface of the movable core 40 opposite to the valve seat 14. That is, the needle 30 has an abutment surface 34 that can abut on the surface of the movable core 40 opposite to the valve seat 14. The movable core 40 is provided so as to be movable relative to the needle 30 so as to be able to abut on the abutment surface 34 or to be separated from the abutment surface 34.

  The fixed core 50 is provided on the opposite side to the valve seat 14 with respect to the movable core 40 inside the housing 20. The stationary core 50 has a stationary core body 51 and a bush 52. The fixed core main body 51 is formed in a substantially cylindrical shape, for example, by a magnetic material such as ferritic stainless steel. The stationary core body 51 is subjected to magnetic stabilization processing. The fixed core main body 51 is provided so as to be fixed to the inside of the third cylindrical portion 23 of the housing 20. The fixed core body 51 and the third cylindrical portion 23 of the housing 20 are welded.

  The bush 52 is formed in a substantially cylindrical shape, for example, of a material having a relatively high hardness such as stainless steel. The bush 52 is provided in a recessed portion 511 formed so as to be recessed radially outward from the inner peripheral wall of the end portion on the valve seat 14 side of the fixed core main body 51. Here, the inner diameter of the bush 52 and the inner diameter of the fixed core body 51 are approximately equal. The end face of the bush 52 on the valve seat 14 side is located closer to the valve seat 14 than the end face of the fixed core main body 51 on the valve seat 14 side. Therefore, the surface of the movable core 40 opposite to the valve seat 14 can abut on the end face of the bush 52 on the valve seat 14 side.

The fixed core body 51 is formed with a groove 512. The groove portion 512 is formed so as to be recessed radially outward from the inner peripheral wall of the fixed core main body 51 and to extend from the vicinity of the bush 52 of the fixed core main body 51 to the vicinity of the end portion on the inlet portion 24 side. The four groove portions 512 are formed at equal intervals in the circumferential direction of the fixed core main body 51 (see FIG. 2). Here, the groove portion 512 forms a part of the main flow path 100.
The fixed core 50 is provided such that the collar 33 of the needle 30 with the seal 32 in contact with the valve seat 14 is located inside the bush 52.

The adjusting pipe 53 is formed in a substantially cylindrical shape, for example, by a metal such as stainless steel. In the present embodiment, the adjusting pipe 53 corresponds to the “tubular portion”.
The adjusting pipe 53 is provided inside the fixed core main body 51 so that the outer peripheral wall is fitted to the inner peripheral wall of the fixed core main body 51. Here, the adjusting pipe 53 is located between one end and the other end of the groove 512. One end of the adjusting pipe 53 is connected to the injection hole 13 side of the main flow passage 100, and the other end is connected to the inlet 240 side of the main flow passage 100. The other end of the adjusting pipe 53 is also connected to the injection hole 13 side of the main flow passage 100 via the groove portion 512, the axial direction hole portion 313, and the radial direction hole portion 314.

  A gap forming member 60 is provided on the opposite side of the needle 30 and the movable core 40 from the valve seat 14. The gap forming member 60 is formed of, for example, a nonmagnetic material. The hardness of the gap forming member 60 is set to be substantially equal to the hardness of the needle 30 and the bush 52.

The gap forming member 60 is formed in a bottomed cylindrical shape. The bottom of the gap forming member 60 can contact the needle 30, that is, the end face of the needle body 31 opposite to the valve seat 14 and the end face of the flange 33 opposite to the valve seat 14.
The gap forming member 60 is provided such that the collar 33 of the needle 30 is located inside the cylindrical portion extending from the bottom to the valve seat 14 side. Further, the end face of the cylindrical portion of the gap forming member 60 on the valve seat 14 side can abut on the end face of the movable core 40 on the fixed core 50 side.

  In the present embodiment, the cylindrical portion of the gap forming member 60 is formed such that the axial length thereof is longer than the axial length of the collar portion 33. Therefore, when the bottom portion of the clearance forming member 60 is in contact with the needle 30, and the cylindrical portion is in contact with the movable core 40, an axial clearance that is a clearance in the direction of the axis Ax2 between the collar 33 and the movable core 40 It is possible to form CL1.

  Here, the inner diameter of the cylindrical portion of the gap forming member 60 is set to be equal to the outer diameter of the collar portion 33 or slightly larger than the outer diameter of the collar portion 33. Therefore, in the gap forming member 60, the inner peripheral wall of the cylindrical portion can slide on the outer peripheral wall of the collar portion 33, and can move relative to the needle 30.

  Further, the outer diameter of the gap forming member 60 is set to be equal to the inner diameter of the fixed core 50 or slightly smaller than the inner diameter of the fixed core 50. Therefore, the outer peripheral wall of the gap forming member 60 can slide on the inner peripheral wall of the bush 52.

  In the present embodiment, the needle 30 is supported so that the end on the valve seat 14 side can be reciprocated by the inner wall of the nozzle cylinder 11 of the nozzle unit 10, and the end on the fixed core 50 is the gap forming member 60 and the fixed core 50 is supported so as to be capable of reciprocating. In this manner, the needle 30 is guided in axial reciprocation by the two portions in the direction of the axis Ax1 of the housing 20.

  The gap forming member 60 further has a hole 601. The hole 601 connects one end face of the bottom of the gap forming member 60 and the other end face, and can communicate with the axial hole 313 of the needle 30. As a result, the fuel on the opposite side of the valve seat 14 of the gap forming member 60 in the main flow passage 100 passes through the hole portion 601, the axial direction hole portion 313 of the needle 30 and the radial direction hole portion 314 of the movable core 40. It can be distributed to the valve seat 14 side.

The spring 61 is, for example, a coil spring, and is provided on the opposite side of the gap forming member 60 to the valve seat 14. Here, the spring 61 corresponds to the "biasing member". One end of the spring 61 is in contact with the bottom of the gap forming member 60. The other end of the spring 61 is in contact with one end of the adjusting pipe 53, that is, the end on the valve seat 14 side.
The spring 61 biases the gap forming member 60 toward the valve seat 14, that is, toward the injection hole 13. The spring 61 can bias the needle 30 to the injection hole 13 and the valve seat 14 side, that is, the valve closing direction via the gap forming member 60 when the bottom of the gap forming member 60 is in contact with the needle 30 . Further, when the cylindrical portion of the gap forming member 60 is in contact with the movable core 40, the spring 61 can bias the movable core 40 toward the injection hole 13 and the valve seat 14 via the gap forming member 60. That is, the spring 61 can bias the needle 30 and the movable core 40 toward the injection hole 13 and the valve seat 14 via the gap forming member 60. The biasing force of the spring 61 can be adjusted by the position of the adjusting pipe 53 with respect to the fixed core 50.

  The coil 62 is formed in a substantially cylindrical shape, and is provided so as to surround particularly the radially outer side of the second cylindrical portion 22 and the third cylindrical portion 23 of the housing 20. The coil 62 generates a magnetic force when power is supplied (energized). When a magnetic force is generated in the coil 62, a magnetic circuit is formed in the fixed core body 51, the movable core 40, the first cylindrical portion 21 and the third cylindrical portion 23. As a result, a magnetic attraction force is generated between the fixed core body 51 and the movable core 40, and the movable core 40 is attracted to the fixed core 50 side. At this time, the movable core 40 moves in the valve opening direction while accelerating the axial gap CL1, and collides with the contact surface 34 of the collar portion 33 of the needle 30. As a result, the needle 30 moves in the valve opening direction, the seal portion 32 separates from the valve seat 14, and the valve opens. As a result, the injection hole 13 is opened and fuel is injected from the injection hole 13. Thus, when energized, the coil 62 can cause the movable core 40 to be attracted to the fixed core 50 side and abut against the flange 33 to move the needle 30 to the opposite side to the valve seat 14 .

  As described above, in the present embodiment, when the gap forming member 60 forms the axial gap CL1 between the collar 33 and the movable core 40 in the valve closed state, the movable core 40 is energized when the coil 62 is energized. Can be accelerated by the axial clearance CL1 to collide with the collar portion 33. Thereby, even when the pressure in the main flow passage 100 is relatively high, the valve can be opened without increasing the power supplied to the coil 62. Therefore, high-pressure fuel can be injected with low power consumption.

  When the movable core 40 is attracted toward the fixed core 50 (the valve opening direction) by the magnetic attraction force, the end face of the movable core 40 on the fixed core 50 side collides with the end face of the bush 52 on the valve seat 14 side. Thereby, the movement of the movable core 40 in the valve opening direction is restricted.

  As shown in FIG. 1, the radially outer side of the inlet portion 24 and the third cylindrical portion 23 is molded with resin. A connector 27 is formed on the mold portion. A terminal 271 for supplying power to the coil 62 is insert-molded in the connector 27. Further, a cylindrical holder 26 is provided on the radially outer side of the coil 62 so as to cover the coil 62.

  The spring seat 63 is formed in a tubular shape, for example, by a metal such as stainless steel. The spring seat portion 63 is provided radially outside the needle main body 31 on the valve seat 14 side with respect to the movable core 40. The spring seat portion 63 is fixed to the needle main body 31 so that the inner peripheral wall is fitted to the outer peripheral wall of the needle main body 31. Thus, the spring seat portion 63 is fixed to the radially outer side of the needle main body 31 on the valve seat 14 side with respect to the movable core 40.

  The spring 64 is, for example, a coil spring, and one end thereof is in contact with the spring seat 63 and the other end is in contact with the surface of the movable core 40 on the valve seat 14 side. The spring 64 can bias the movable core 40 toward the fixed core 50. The biasing force of the spring 64 is smaller than the biasing force of the spring 61.

  The spring 61 urges the gap forming member 60 toward the valve seat 14, whereby the bottom of the gap forming member 60 abuts on the needle 30, and the needle 30 presses the seal portion 32 against the valve seat 14. At this time, the spring 64 biases the movable core 40 toward the fixed core 50, whereby the cylindrical portion of the gap forming member 60 abuts on the movable core 40. In this state, an axial gap CL1 is formed between the contact surface 34 of the collar 33 of the needle 30 and the movable core 40.

  The movable core 40 is provided so as to be axially reciprocally movable between the collar 33 and the spring seat 63 of the needle 30. That is, the movable core 40 is provided so as to be movable relative to the needle 30 so as to be able to abut on the abutment surface 34 or to be separated from the abutment surface 34.

  An annular gap is formed between the outer edge portion of the spring seat portion 63 and the inner peripheral wall of the first cylindrical portion 21 of the housing 20. Therefore, the fuel in the axial hole 313 is passed through the radial hole 314 and the gap between the outer edge of the spring seat 63 and the inner peripheral wall of the first cylindrical portion 21 to form the spring seat 63. It can be distributed to the valve seat 14 side.

  In the present embodiment, when energization of the coil 62 is stopped in a state where the movable core 40 is attracted to the fixed core 50 side, the needle 30 and the movable core 40 receive the biasing force of the spring 61 via the gap forming member 60. , Is biased toward the valve seat 14 side. As a result, the needle 30 moves in the valve closing direction, and the seal portion 32 abuts on the valve seat 14 to close the valve. As a result, the injection hole 13 is closed.

The strain generating body 70 is formed in a plate shape of the same material as the adjusting pipe 53, that is, a metal such as stainless steel. The strain generating body 70 is integrally formed with the adjusting pipe 53 so as to close the end on the inlet 240 side of the adjusting pipe 53. That is, the strain generating body 70 is provided inside the end on the inlet 240 side of the adjusting pipe 53 (see FIGS. 1 and 2). Here, the strain generating body 70 is provided such that one surface 71 faces the injection hole 13 side and the other surface 72 faces the inflow port 240 side.
In the inside of the adjusting pipe 53, there is formed a sub flow passage 101 whose one end is connected to the injection hole 13 side of the main flow passage 100 and the other end is connected to the inflow port 240 side of the main flow passage 100. Therefore, it can be said that the strain generating body 70 is provided in the sub flow passage 101.
The other end of the sub flow passage 101 is also connected to the injection hole 13 side of the main flow passage 100 via the groove portion 512, the axial direction hole portion 313, and the radial direction hole portion 314.

  As shown in FIGS. 1 and 4, the first space S <b> 1, which is a space in contact with one surface 71 of the strain generating body 70, communicates with the main flow passage 100. Further, a second space S2 which is a space in contact with the other surface 72 of the strain generating body 70 is in communication with the main flow passage 100. The strain generating body 70 can be elastically deformed by the pressure difference between the first space S1 and the second space S2. Here, the strain generating body 70 is formed to have a relatively low rigidity.

The differential pressure sensor 80 is provided in contact with the center of the other surface 72 of the strain generating body 70. The differential pressure sensor 80 has a sensor element 81.
The sensor element 81 is formed of, for example, a semiconductor such as single crystal silicon. As shown in FIG. 3, the sensor element 81 has a bridge circuit 82. In the bridge circuit 82, resistors 821 to 824 are formed. The differential pressure sensor 80 has terminals 831 to 834.

  One end of the resistor 821 and one end of the resistor 822 are connected. One end of the resistor 823 and one end of the resistor 824 are connected. The other end of the resistor 821 and the other end of the resistor 823 are connected. The other end of the resistor 822 and the other end of the resistor 824 are connected.

The connection point between the other end of the resistor 821 and the other end of the resistor 823 is connected to the terminal 831. The connection point between the other end of the resistor 822 and the other end of the resistor 824 is connected to the terminal 832. A connection point between one end of the resistor 821 and one end of the resistor 822 is connected to the terminal 833. A connection point between one end of the resistor 823 and one end of the resistor 824 is connected to the terminal 834.
The positive terminal of a battery (not shown) is connected to the terminal 831. Terminal 832 is connected to the ground of the vehicle.

When strain is generated in the strain generating body 70 due to the pressure difference between the first space S1 and the second space S2, stress is applied to the sensor element 81, and the resistance value of the resistors 821 to 824 changes due to the piezoresistance effect. As a result, an electrical signal corresponding to the magnitude of strain generated in the strain generating body 70, that is, the pressure difference between the first space S1 and the second space S2, is output from the terminals 833 and 834.
In the present embodiment, the differential pressure sensor 80 is covered by the protective film 2. The protective film 2 is formed of, for example, a resin or the like, and the thermal conductivity is set to a predetermined value or less. That is, the thermal conductivity of the protective film 2 is relatively low. Therefore, the differential pressure sensor 80 can be insulated from the fuel, and the influence of the temperature on the differential pressure sensor 80 can be reduced. In addition, the protective film 2 can prevent a short circuit of the differential pressure sensor 80 due to the adhesion of foreign matter.

As shown in FIG. 4, in the main flow passage 100 and the sub flow passage 101, a first path R 1 which is a path connecting the first space S 1 and the injection hole 13, and a second space S 2 and the injection hole 13. A second route R2 which is a route to be connected is set. The pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 by opening the needle 30 and injecting the fuel from the injection hole 13 propagates the first route R1 and reaches the first space S1, and the second The route R2 is propagated to reach the second space S2.
In the present embodiment, the length of the first path R1 is shorter than the length of the second path R2. Therefore, the time for the pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 to propagate through the first route R1 to reach the first space S1, and the time to propagate the second route R2 to reach the second space S2 And there is a difference between

Therefore, as shown in FIG. 5A, in the second space S2, a pressure change (broken line) occurs behind the pressure change (solid line) in the first space S1. At this time, distortion corresponding to the pressure difference between the first space S1 and the second space S2 (see FIG. 5B) is generated in the strain generating body 70. The differential pressure sensor 80 can output an electrical signal corresponding to the magnitude of the distortion from the terminals 833 and 834.
It should be noted that, due to the damping of friction between the members forming the main flow passage 100 and the sub flow passage 101 and the fuel, the time difference between the pressure change propagating through the first path R1 and the pressure change propagating through the second path R2 becomes large. In addition, even when the injection amount of fuel from the injection hole 13 is small, the time difference between the pressure change propagating in the first route R1 and the pressure change propagating in the second route R2 makes the first space S1 and the second space S1 The differential pressure with the space S2 increases.

The vehicle includes an electronic control unit (hereinafter referred to as "ECU") 90.
The ECU 90 is a small computer having a CPU as an operation means, a ROM as a storage means, a RAM, an EEPROM, an I / O as an input / output means, and the like. The ECU 90 executes an operation according to a program stored in the ROM or the like based on information such as signals from various sensors provided in each part of the vehicle, and controls the operation of various devices and devices of the vehicle. Thus, the ECU 90 executes the program stored in the non-transitional tangible storage medium. By executing this program, a method corresponding to the program is executed.

The ECU 90 can control the operation of the throttle valve of the vehicle, the fuel injection device 1 and the like based on information such as signals from various sensors.
The ECU 90 can control the amount of intake air supplied to the engine by controlling the operation of the throttle valve. Further, the ECU 90 can control the amount of fuel injected and supplied to the combustion chamber of the engine by controlling the operation of the fuel injection device 1.
As shown in FIG. 1, the control unit 91, the pressure change detection unit 92, the flow rate estimation unit 93, and the flow rate correction unit 94 are provided in the ECU 90 as a functional unit. Here, part or all (functional parts) of the functions executed by the ECU 90 may be configured as hardware by one or a plurality of ICs or the like. That is, the functions provided by the ECU 90 can be provided by software recorded in a substantial memory device and a computer that executes the software, only software, only hardware, or a combination thereof.

Terminals 833 and 834 of the differential pressure sensor 80 are connected to the ECU 90. Therefore, the electrical signal output from the differential pressure sensor 80 is input to the ECU 90.
The control unit 91 can control the flow rate of the fuel flowing out of the injection hole 13, that is, the injection amount of the fuel, by controlling the energization timing, the energization time, and the like of the coil 62.

The pressure change detection unit 92 detects a pressure difference between the first space S1 and the second space S2 based on the electrical signal from the differential pressure sensor 80, and detects a change in pressure of the main flow passage 100 based on the detected pressure difference. It is possible.
The flow rate estimation unit 93 can estimate the flow rate of the fuel flowing out of the injection hole 13, that is, the injection amount of the fuel, based on the change in pressure detected by the pressure change detection unit 92.
The flow rate correction unit 94 can correct the injection amount of fuel controlled by the control unit 91 based on the flow rate estimated by the flow rate estimation unit 93.

Next, a process related to the correction of the fuel injection amount by the ECU 90 will be described based on FIG.
A series of processes S100 shown in FIG. 6 are executed, for example, when the ignition key of the vehicle is turned on and the ECU 90 is activated.
In S101, the ECU 90 functions as a pressure change detection unit 92, and detects a change in pressure of the main flow passage 100. Specifically, the ECU 90 detects the pressure difference between the first space S1 and the second space S2 based on the electrical signal from the differential pressure sensor 80, and changes the pressure of the main flow passage 100 based on the detected pressure difference. To detect. After S101, the process proceeds to S102.

  In S102, the ECU 90 functions as the flow rate estimation unit 93, and estimates the flow rate of the fuel flowing out of the injection hole 13. Specifically, the ECU 90 estimates the flow rate of the fuel flowing out of the injection hole 13, that is, the injection amount of the fuel, based on the change in pressure detected in S101. More specifically, the ECU 90 calculates the injection start timing, the injection end timing, and the pressure change amount from the injection start timing to the injection end timing based on the change in pressure detected in S101 to estimate the fuel injection amount. Do. After S102, the process proceeds to S103.

In S103, the ECU 90 functions as a flow rate correction unit 94, and corrects the injection amount of fuel controlled by the control unit 91. Specifically, the ECU 90 corrects the injection amount of fuel controlled by the control unit 91 based on the injection amount of fuel estimated in S102. More specifically, the ECU 90 determines the current supply timing, current supply time, and the like for the coil 62 based on the fuel injection amount estimated in S102 so that the injection amount for each injection condition is the same as immediately after the start of use of the fuel injection device 1. And adjust the injection amount of the fuel controlled by the control unit 91. After S103, the ECU 90 ends the series of processing S100.
After finishing the process S100, the ECU 90 starts the process S100 again. That is, the process S100 is a process that is repeatedly executed while the ECU 90 is activated.

  The control unit 91 controls the energization timing, the energization time, and the like of the coil 62 based on the injection amount corrected in the process S100. Thus, the injection amount for each injection condition of the fuel injected from the fuel injection device 1 is maintained to be the same as that immediately after the start of use of the fuel injection device 1.

As described above, (1) the fuel injection device 1 according to the present embodiment includes the housing 20, the strain generating body 70, and the differential pressure sensor 80.
The housing 20 has an inlet 240 into which fuel as fluid flows, a nozzle through which fuel flows out, that is, the injection holes 13 to be injected, and a main flow path 100 which connects the inlet 240 and the injection holes 13 and through which the fuel flows. doing.
In the strain generating body 70, a first space S1 which is a space in contact with one surface 71 communicates with the main flow channel 100, and a second space S2 which is a space in contact with the other surface 72 communicates with the main flow channel 100. It can be elastically deformed by the pressure difference between the space S1 and the second space S2.
The differential pressure sensor 80 is provided on the strain generating body 70, and can detect a pressure difference between the first space S1 and the second space S2.

  When the fuel flows through the main flow passage 100, the first space S1 in contact with the one surface 71 of the strain generating body 70 and the second space S2 in contact with the other surface 72 of the strain generating body 70 are filled with the fuel. Therefore, even when the pressure in the main flow passage 100 is high, generation of an excessive pressure difference on both surfaces of the strain generating body 70 can be suppressed, and the rigidity of the strain generating body 70 can be set low. Thus, the amount of strain of the strain generating body 70 can be increased, and the range of pressure that can be detected by the differential pressure sensor 80 can be increased. Therefore, regardless of the pressure of the fuel flowing through the main flow passage 100, the change in pressure of the main flow passage 100 can be detected with high accuracy.

  (2) In the present embodiment, the length of the first path R1, which is the path connecting the first space S1 and the injection hole 13, is the path connecting the second space S2 and the injection hole 13 2 shorter than the length of route R2. Therefore, the time for the pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 to propagate through the first route R1 to reach the first space S1, and the time to propagate the second route R2 to reach the second space S2 And there is a difference between Thereby, the differential pressure between the first space S1 and the second space S2 when the fuel is injected from the injection hole 13 can be increased. Therefore, the change in pressure of the main flow passage 100 can be detected more accurately.

  (3) The present embodiment further includes the auxiliary flow passage 101. One end of the sub flow channel 101 is connected to the injection hole 13 side of the main flow channel 100, and the other end is connected to the inlet 240 side of the main flow channel 100. The strain generating body 70 is provided in the sub flow passage 101. Therefore, the strain generating body 70 does not prevent the flow of the fuel flowing through the main flow passage 100, and the pressure loss of the injected fuel can be suppressed.

Further, in the present embodiment, the differential pressure sensor 80 has a sensor element 81 capable of outputting an electrical signal corresponding to the magnitude of distortion generated in the strain generating body 70. Therefore, the sensor element 81 can be manufactured by semiconductor technology, and is excellent in mass productivity and low cost.
Further, in the present embodiment, the sensor element 81 has a bridge circuit 82. Therefore, the influence of the temperature on the electrical signal output from the differential pressure sensor 80 can be suppressed. Thereby, the detection error due to the temperature can be reduced, and the detection accuracy of the pressure difference by the differential pressure sensor 80 can be improved.

  Further, in the present embodiment, the strain generating body 70 is provided inside the outer wall of the housing 20. Therefore, as compared with the case where the strain generating body 70 and the differential pressure sensor 80 are provided on the outside of the outer wall of the housing 20, the mountability of the fuel injection device 1 can be improved.

  (5) The present embodiment further includes an adjusting pipe 53 as a cylindrical portion. The adjusting pipe 53 is provided such that one end is connected to the injection hole 13 side of the main flow passage 100 and the other end is connected to the inlet 240 side of the main flow passage 100. The strain generating body 70 is provided inside the cylindrical portion 751. Therefore, the adjusting pipe 53, the strain generating body 70 and the differential pressure sensor 80 can be integrated. Thereby, the assemblability of the fuel injection device 1 is improved.

(6) The present embodiment further includes the needle 30 and the spring 61 as a biasing member.
The needle 30 is provided so as to be capable of reciprocating in the main flow passage 100, and can control the flow rate of the fuel flowing out of the injection hole 13 by opening and closing the injection hole 13.
The spring 61 biases the needle 30 to the injection hole 13 side.
The adjusting pipe 53 is provided such that one end locks the end of the spring 61 opposite to the needle 30.
As described above, the strain generating body 70 is provided on the adjusting pipe 53 that locks the spring 61 and can adjust the biasing force of the spring 61. Therefore, it is not necessary to separately provide a member or the like for installing the strain generating body 70, and the number of members can be reduced.

(12) The present embodiment further includes a control unit 91, a pressure change detection unit 92, a flow rate estimation unit 93, and a flow rate correction unit 94.
The control unit 91 can control the flow rate of the fuel flowing out of the injection hole 13, that is, the injection amount of the fuel.
The pressure change detection unit 92 can detect a change in pressure of the main flow passage 100 based on the pressure difference detected by the differential pressure sensor 80.
The flow rate estimation unit 93 can estimate the flow rate of the fuel flowing out of the injection hole 13, that is, the injection amount of the fuel, based on the change in pressure detected by the pressure change detection unit 92.
The flow rate correction unit 94 can correct the flow rate of the fuel controlled by the control unit 91, that is, the injection amount of the fuel, based on the flow rate estimated by the flow rate estimation unit 93.
Therefore, the injection amount for each injection condition of the fuel injected from the fuel injection device 1 can be maintained to be the same as that immediately after the start of use of the fuel injection device 1. Thus, for example, even if the injection amount of fuel from the fuel injection device 1 in response to the command signal changes due to age or the like compared to immediately after the start of use of the fuel injection device 1, the control unit 91 starts using the fuel injection device 1 As in the case immediately after, it is possible to control the fuel injection amount with high accuracy, and to control the operation of the engine with high accuracy.

Further, in the present embodiment, the fluid flowing through the main flow passage 100 is fuel. The fluid control device according to the present embodiment is a fuel injection device 1 that injects fuel from the injection holes 13.
Gasoline as fuel is a compressible fluid. Here, "compressible fluid" refers to a fluid whose density can be changed inside fluid particles, and which is affected by compression and expansion. However, although liquid fuel such as gasoline is a compressible fluid, the change in density of fluid particles under the influence of compression and expansion is smaller than that of gas such as air.
When the fuel injection device 1 is used, the main flow path 100 and the sub flow path 101 are filled with the liquid fuel. Therefore, the pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 by the opening of the needle 30 and the injection of the fuel from the injection hole 13 propagates the first path R1 in the fuel to the first space S1. The second route R2 is propagated to reach the second space S2.

  Further, when the fuel injection device 1 is used, the first space S1 in contact with one surface 71 of the strain generating body 70 and the second space S2 in contact with the other surface 72 of the strain generating body 70 are filled with liquid fuel. . Therefore, even when the pressure in the main flow passage 100 is high, generation of an excessive pressure difference on both surfaces of the strain generating body 70 can be suppressed, and the rigidity of the strain generating body 70 can be set low. Thus, the amount of strain of the strain generating body 70 can be increased, and the range of pressure that can be detected by the differential pressure sensor 80 can be increased. Therefore, regardless of the pressure of the fuel flowing through the main flow passage 100, the change in pressure of the main flow passage 100 can be detected with high accuracy. Therefore, the injection amount of the fuel from the fuel injection device 1 can be accurately controlled, and the fuel consumption can be improved.

Second Embodiment
A fuel injection system according to a second embodiment is shown in FIG. The second embodiment is different from the first embodiment in the arrangement of the strain generating body 70 and the like.

  In the second embodiment, the needle 30 further includes a needle cylinder 35. In the present embodiment, the needle cylinder portion 35 corresponds to a “cylinder portion”. The needle cylinder portion 35 is formed in a cylindrical shape on the injection hole 13 side with respect to the axial direction hole portion 313 of the needle main body 31. The inner space of the needle cylinder 35 is connected to the axial hole 313. A hole 351 is formed in the needle cylinder 35. The hole 351 is formed to connect the inner circumferential wall and the outer circumferential wall of the needle cylinder 35. Accordingly, one end of the needle cylinder 35 is connected to the injection hole 13 side of the main flow passage 100 via the hole 351, and the other end is connected to the inlet 240 side of the main flow passage 100 via the axial direction hole 313. Connected to The other end of the needle cylinder 35 is also connected to the injection hole 13 side of the main flow passage 100 via the axial hole 313 and the radial hole 314.

  In the present embodiment, the sub flow passage 101 is formed between the hole 351 and the radial hole 314 inside the needle cylinder 35. The strain generating body 70 is provided in the sub flow passage 101 formed in the needle 30. Therefore, the main flow passage 100 is formed inside the adjusting pipe 53, and the fuel on the inlet 240 side of the main flow passage 100 can flow to the injection hole 13 side via the inside of the adjusting pipe 53.

  The strain generating body 70 is provided closer to one end side of the sub flow passage 101 than the center of the sub flow passage 101, that is, on the injection hole 13 side. Here, the strain generating body 70 is provided such that one surface 71 faces the injection hole 13 side and the other surface 72 faces the inflow port 240 side. As in the first embodiment, the differential pressure sensor 80 is provided in contact with the center of the other surface 72 of the strain-generating body 70. The differential pressure sensor 80 is covered by a protective film 2.

As shown in FIG. 8, in the main flow passage 100 and the sub flow passage 101, a first route R 1 which is a route connecting the first space S 1 and the injection hole 13, and a second space S 2 and the injection hole 13. A second route R2 which is a route to be connected is set. Here, the first path R 1 is a path passing through the hole 351, and the second path R 2 is a path passing through the radial hole 314.
The pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 by opening the needle 30 and injecting the fuel from the injection hole 13 propagates the first route R1 and reaches the first space S1, and the second The route R2 is propagated to reach the second space S2.
In the present embodiment, the length of the first path R1 is shorter than the length of the second path R2. Therefore, as in the first embodiment, the time during which the pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 propagates through the first route R1 and reaches the first space S1, and propagates through the second route R2 There is a difference in time to reach the two spaces S2.
The configuration of the second embodiment is the same as that of the first embodiment except for the points described above.

  As described above, (4) in the present embodiment, the strain generating body 70 is provided closer to one end side of the sub flow passage 101 than the center of the sub flow passage 101, that is, the injection hole 13 side. Therefore, the length of the first route R1 can be made shorter than the length of the second route R2. Thereby, the differential pressure between the first space S1 and the second space S2 when fuel is injected from the injection hole 13 can be further increased. Therefore, the change in pressure of the main flow passage 100 can be detected with higher accuracy.

Further, in the present embodiment, the needle 30 further includes a needle cylinder 35 as a cylinder. One end of the needle cylinder 35 is connected to the injection hole 13 side of the main flow passage 100, and the other end is connected to the inlet 240 side of the main flow passage 100.
The strain generating body 70 is provided inside the needle cylinder 35. Therefore, the needle 30, the strain generating body 70, and the differential pressure sensor 80 can be integrated, and the assemblability of the fuel injection device 1 is improved, and it is not necessary to separately provide a member etc. for installing the strain generating body 70. It can be reduced.

Third Embodiment
A fuel injection system according to a third embodiment is shown in FIG. The third embodiment is different from the first embodiment in the configuration of the fixed core 50, the arrangement of the strain generating body 70, and the like.

In the third embodiment, in the fixed core main body 51, the sub flow passage 101 is formed instead of the groove portion 512.
In the sub flow passage 101, one end is connected to the injection hole 13 side with respect to the adjusting pipe 53 in the space inside the fixed core main body 51, and the other end is connected to the adjusting pipe 53 in the space inside the fixed core main body 51. It is formed within the thickness of the fixed core main body 51 so as to be connected to the opposite inlet 240 side. That is, the sub flow passage 101 is formed to bypass the adjusting pipe 53 and connect the injection hole 13 side of the main flow passage 100 and the inflow port 240 side.
Here, one end of the sub flow passage 101 is connected to the injection hole 13 side of the main flow passage 100, and the other end is connected to the inflow port 240 side of the main flow passage 100.

In the present embodiment, the strain generating body 70 is provided in the sub flow passage 101 formed in the fixed core main body 51. Therefore, the main flow passage 100 is formed inside the adjusting pipe 53, and the fuel on the inlet 240 side of the main flow passage 100 can flow to the injection hole 13 side via the inside of the adjusting pipe 53.
The other end of the sub flow passage 101 is also connected to the injection hole 13 side of the main flow passage 100 via the inside of the adjusting pipe 53.

  The strain generating body 70 is provided closer to one end side of the sub flow passage 101 than the center of the sub flow passage 101, that is, on the injection hole 13 side. Here, the strain generating body 70 is provided such that one surface 71 faces the injection hole 13 side and the other surface 72 faces the inflow port 240 side. As in the first embodiment, the differential pressure sensor 80 is provided in contact with the center of the other surface 72 of the strain-generating body 70. The differential pressure sensor 80 is covered by a protective film 2.

As shown in FIG. 10, in the main flow path 100 and the sub flow path 101, a first path R1 which is a path connecting the first space S1 and the injection hole 13 and a second space S2 and the injection hole 13 are provided. A second route R2 which is a route to be connected is set.
The pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 by opening the needle 30 and injecting the fuel from the injection hole 13 propagates the first route R1 and reaches the first space S1, and the second The route R2 is propagated to reach the second space S2.
In the present embodiment, the length of the first path R1 is shorter than the length of the second path R2. Therefore, as in the first embodiment, the time during which the pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 propagates through the first route R1 and reaches the first space S1, and propagates through the second route R2 There is a difference in time to reach the two spaces S2.
The third embodiment is the same as the first embodiment except for the points described above.

Fourth Embodiment
A fuel injection system according to a fourth embodiment is shown in FIG. The fourth embodiment is different from the third embodiment in the arrangement of the strain generating body 70 and the like.

In the fourth embodiment, the auxiliary flow passage 101 is not formed in the fixed core main body 51.
The fourth embodiment further includes a cylindrical member 75. The cylindrical member 75 has a cylindrical portion 751 and a communication passage 752.
The cylindrical portion 751 is formed, for example, of a resin or the like in a substantially cylindrical shape. The communication passage 752 is formed within the thickness of the cylindrical portion 751 so as to connect one end surface of the cylindrical portion 751 and the other end surface. Four communicating passages 752 are formed at equal intervals in the circumferential direction of the cylindrical portion 751 (see FIG. 12A).

  In the present embodiment, the sub flow passage 101 is formed inside the cylindrical portion 751. The strain generating body 70 is provided in the sub flow passage 101 formed in the cylindrical member 75. The strain generating body 70 is provided on the cylindrical member 75 by insert molding, for example. The main flow passage 100 is formed in the communication passage 752 of the cylindrical member 75. Therefore, the fuel on the inlet 240 side of the main flow passage 100 can flow to the injection hole 13 side via the communication passage 752 and the inside of the adjusting pipe 53.

  The strain generating body 70 is provided such that one surface 71 faces the injection hole 13 and the other surface 72 faces the inflow port 240. The differential pressure sensor 80 is provided to abut on the center of the other surface 72 of the strain generating body 70, as in the third embodiment. The differential pressure sensor 80 is covered by a protective film 2.

As shown in FIG. 12B, in the main flow path 100 and the sub flow path 101, a first path R1 which is a path connecting the first space S1 and the injection hole 13 and a second space S2 and the injection hole A second route R2 which is a route connecting the line 13 and the line 13 is set. Here, the second path R2 is a path passing through the communication path 752.
The pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 by opening the needle 30 and injecting the fuel from the injection hole 13 propagates the first route R1 and reaches the first space S1, and the second The route R2 is propagated to reach the second space S2.
In the present embodiment, the length of the first path R1 is shorter than the length of the second path R2. Therefore, as in the third embodiment, the time during which the pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 propagates through the first route R1 and reaches the first space S1, and propagates through the second route R2 There is a difference in time to reach the two spaces S2.
The configuration of the fourth embodiment is the same as that of the third embodiment except for the points described above.

As described above, (7) the present embodiment further includes the cylindrical member 75.
The cylindrical member 75 has one end connected to the injection hole 13 side of the main flow passage 100 and the other end connected to the inflow port 240 side of the main flow passage 100, and one end surface and the other end surface of the cylindrical portion 751. And a communication passage 752 for connecting the The strain generating body 70 is provided inside the cylindrical portion 751.
Thus, in the present embodiment, the cylindrical member 75, the strain generating body 70, and the differential pressure sensor 80 can be integrated. Therefore, the assemblability of the fuel injection device 1 is improved.

Fifth Embodiment
A part of the fuel injection device according to the fifth embodiment is shown in FIG. The fifth embodiment differs from the third embodiment in the arrangement of the differential pressure sensor 80 and the like.

In the third embodiment, the differential pressure sensor 80 is provided to abut on the center of one surface 71 of the strain generating body 70.
The fuel injection device 1 of the third embodiment further includes a diaphragm 77 and an incompressible fluid 78.
The diaphragm 77 is formed in a plate shape by a metal such as stainless steel as in the case of the strain generating body 70. The diaphragm 77 is provided on the side of the differential pressure sensor 80 of the strain generating body 70 in the sub flow passage 101. Here, the diaphragm 77 forms a sealed space S3 between one surface 71 of the strain generating body 70 and the differential pressure sensor 80. The space S3 partially overlaps the first space S1.
The diaphragm 77 can be elastically deformed by the pressure difference between the space on one side and the space on the other side. The elastic modulus of the diaphragm 77 is set to be equal to that of the strain generating body 70.

The incompressible fluid 78 is, for example, an incompressible fluid such as silicone oil. Here, "incompressible fluid" refers to a fluid whose density is constant inside fluid particles and in which the effects of compression and expansion can be ignored. Therefore, the incompressible fluid 78 can be treated as having a constant volume and a constant density. The incompressible fluid 78 is provided in a space S3 between the strain generating body 70 and the diaphragm 77. Here, the space S3 is filled with the incompressible fluid 78. The thermal conductivity of the incompressible fluid 78 is set to a predetermined value or less. That is, the thermal conductivity of the incompressible fluid 78 is relatively low.
The present embodiment does not include the protective film 2, and the differential pressure sensor 80 is covered with the incompressible fluid 78.

In the present embodiment, the pressure change propagating through the first path R1 propagates to the one surface 71 of the strain generating body 70 via the diaphragm 77 and the incompressible fluid 78.
The configuration of the fifth embodiment is the same as that of the third embodiment except for the points described above.

As described above, (8) the embodiment further includes the diaphragm 77 and the incompressible fluid 78.
The diaphragm 77 is provided on the differential pressure sensor 80 side of the strain generating body 70, and can be elastically deformed.
An incompressible fluid 78 is provided between the strain generating body 70 and the diaphragm 77. Therefore, the differential pressure sensor 80 can be covered with the incompressible fluid 78. Thus, the differential pressure sensor 80 can be insulated from the fuel, and the influence of the temperature on the differential pressure sensor 80 can be reduced. Therefore, the variation of the sensor output of the differential pressure sensor 80 due to the temperature change of the fuel can be reduced.

  Further, in the present embodiment, since the incompressible fluid 78 is provided in the space S3 between the strain generating body 70 and the diaphragm 77, it is possible to suppress a delay in pressure detection by the differential pressure sensor 80.

Sixth Embodiment
A fuel injection system according to a sixth embodiment is shown in FIG. The sixth embodiment differs from the fourth embodiment in the disposition of the strain generating body 70 and the like.

The fuel injection device 1 of the sixth embodiment further includes a flow path forming portion 3 in place of the cylindrical member 75.
The flow path forming portion 3 is formed in a tubular shape, for example, by a metal such as stainless steel. The flow path forming portion 3 is provided such that one end is connected to the space inside the fixed core main body 51 and the other end is connected to the space inside the inlet portion 24. The flow path forming portion 3 is located outside the outer wall of the housing 20 except for one end and the other end.

  In the present embodiment, the sub flow passage 101 is formed inside the flow passage forming portion 3. Here, one end of the sub flow passage 101 is connected to the injection hole 13 side of the main flow passage 100 via the inside of the adjusting pipe 53, and the other end is connected to the inflow port 240 side of the main flow passage 100. The other end of the sub flow passage 101 is also connected to the injection hole 13 side of the main flow passage 100 via the inside of the adjusting pipe 53.

  In the present embodiment, the strain generating body 70 is provided in the sub flow passage 101 formed in the flow passage forming portion 3. The strain generating body 70 is provided outside the outer wall of the housing 20 on one end side of the sub flow passage 101, that is, on the injection hole 13 side than the center of the sub flow passage 101. Here, the strain generating body 70 is provided such that one surface 71 faces the injection hole 13 side and the other surface 72 faces the inflow port 240 side. The differential pressure sensor 80 is provided in contact with the center of the other surface 72 of the strain generating body 70. The differential pressure sensor 80 is covered by a protective film 2.

As shown in FIG. 15, in the main flow passage 100 and the sub flow passage 101, a first route R1 which is a route connecting the first space S1 and the injection hole 13 and a second space S2 and the injection hole 13 are provided. A second route R2 which is a route to be connected is set.
The pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 by opening the needle 30 and injecting the fuel from the injection hole 13 propagates the first route R1 and reaches the first space S1, and the second The route R2 is propagated to reach the second space S2.
In the present embodiment, the length of the first path R1 is shorter than the length of the second path R2. Therefore, as in the first embodiment, the time during which the pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 propagates through the first route R1 and reaches the first space S1, and propagates through the second route R2 There is a difference in time to reach the two spaces S2.
The configuration of the sixth embodiment is the same as that of the fourth embodiment except for the points described above.

  As described above, in the present embodiment, the strain generating body 70 is provided outside the outer wall of the housing 20. Therefore, the assemblability of the fuel injection device 1 is improved, and the manufacture of the fuel injection device 1 becomes easy.

Seventh Embodiment
A fuel injection system according to a seventh embodiment is shown in FIG. The seventh embodiment is different from the sixth embodiment in the arrangement of the strain generating body 70 and the like.

The fuel injection device 1 of the seventh embodiment further includes a fluid storage unit 4 and an incompressible fluid 78.
One end of the flow path forming portion 3 is located outside the outer wall of the housing 20.
The fluid storage unit 4 is formed of, for example, a metal such as stainless steel. A storage space S4 is formed inside the fluid storage portion 4. The fluid storage portion 4 is integrally formed with the flow path forming portion 3 so as to be connected to one end of the flow path forming portion 3.

Inside the flow passage forming portion 3, a sub flow passage 101 is formed. One end of the sub flow passage 101 is connected to the accommodation space S4.
In the present embodiment, the strain generating body 70 is provided in the sub flow passage 101 formed in the flow passage forming portion 3. The strain generating body 70 is located outside the outer wall of the housing 20. Here, the strain generating body 70 is provided in such a manner that one surface 71 faces the inlet portion 24 and the other surface 72 faces the fluid storage portion 4 side. The differential pressure sensor 80 is provided in contact with the center of the other surface 72 of the strain generating body 70. The differential pressure sensor 80 is not covered by the protective film 2.

The incompressible fluid 78 is an incompressible fluid such as silicone oil, as in the fifth embodiment. The incompressible fluid 78 is a space which is a space in contact with the fluid containing portion 4 side with respect to the strain generating body 70 of the containing space S 4 and the sub flow path 101, that is, the other surface 72 of the strain generating body 70. It is provided in S2. Here, the second space S2 is filled with the incompressible fluid 78. The thermal conductivity of the incompressible fluid 78 is set to a predetermined value or less. That is, the thermal conductivity of the incompressible fluid 78 is relatively low.
The present embodiment does not include the protective film 2, and the differential pressure sensor 80 is covered with the incompressible fluid 78.

As shown in FIG. 17, in the main flow path 100 and the sub flow path 101, a first path R1 which is a path connecting the first space S1 and the injection hole 13 is set. The second space S2 is filled with the incompressible fluid 78.
The pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 by opening the needle 30 and injecting the fuel from the injection hole 13 propagates the first path R1 and reaches the first space S1.

When the pressure change generated in the vicinity of the injection hole 13 of the main flow passage 100 reaches the first space S1, a pressure difference is generated between the first space S1 and the second space S2. As a result, distortion occurs in the strain generating body 70, and the differential pressure sensor 80 outputs an electric signal corresponding to the magnitude of strain of the strain generating body 70.
Also in the seventh embodiment, a change in pressure in the main flow passage 100 can be detected based on the electrical signal from the differential pressure sensor 80.
The configuration of the seventh embodiment is the same as that of the sixth embodiment except the points described above.

As described above, (9) the fuel injection device 1 according to the present embodiment includes the housing 20, the strain generating body 70, the incompressible fluid 78, and the differential pressure sensor 80.
The housing 20 has an inlet 240 into which fuel as fluid flows, a nozzle through which fuel flows out, that is, the injection holes 13 to be injected, and a main flow path 100 which connects the inlet 240 and the injection holes 13 and through which the fuel flows. doing.
The strain generating body 70 has a pressure difference between the first space S1 and the second space S2 which is a space in which the first space S1 which is a space in contact with one surface 71 communicates with the main flow path 100 and the other space 72 is in contact. It is elastically deformable.
The incompressible fluid 78 is provided in the second space S2.
The differential pressure sensor 80 is provided on the strain generating body 70, and can detect a pressure difference between the first space S1 and the second space S2.

  When the fuel flows through the main flow passage 100, the first space S1 in contact with the one surface 71 of the strain generating body 70 is filled with the liquid fuel. Here, the second space S <b> 2 in contact with the other surface 72 of the strain generating body 70 is filled with the incompressible fluid 78. Therefore, even when the pressure in the main flow passage 100 is high, generation of an excessive pressure difference on both surfaces of the strain generating body 70 can be suppressed, and the rigidity of the strain generating body 70 can be set low. Thus, the amount of strain of the strain generating body 70 can be increased, and the range of pressure that can be detected by the differential pressure sensor 80 can be increased. Therefore, regardless of the pressure of the fuel flowing through the main flow passage 100, the change in pressure of the main flow passage 100 can be detected with high accuracy.

Eighth Embodiment
The fuel injection device according to the eighth embodiment and a part thereof are shown in FIGS. The eighth embodiment differs from the fourth embodiment in the basic configuration of the fuel injection device, the arrangement of the strain generating body 70, and the like.

  In the eighth embodiment, the first cylindrical portion 21 and the second cylindrical portion 22 of the housing 20 are integrally formed. Further, the third cylindrical portion 23, the fixed core main body 51, and the inlet portion 24 are integrally formed. Further, the filter 25 is not provided in the inlet portion 24. The inlet portion 24 forms a part of the main flow passage 100 by the inner peripheral wall. That is, the inner peripheral wall of the inlet portion 24 corresponds to the flow path forming wall surface 241.

  In the eighth embodiment, a support member 55 is provided. The support member 55 is made of, for example, metal, and has a fitting portion 551 and a gap forming cylindrical portion 552. The fitting portion 551 is formed in a substantially cylindrical shape. The outer diameter of the fitting portion 551 is slightly larger than the inner diameter of the inlet portion 24, that is, the inner diameter of the flow path forming wall surface 241.

  The clearance forming cylindrical portion 552 is formed in a cylindrical shape, and includes a tapered portion 553 and a cylindrical portion 554. The tapered portion 553 is integrally formed with the fitting portion 551 so that one end is connected to the end portion of the fitting portion 551. The tapered portion 553 is formed in a tapered shape so that the inner circumferential wall and the outer circumferential wall approach the axis as it goes from the fitting portion 551 to the opposite side to the fitting portion 551. The cylindrical portion 554 is integrally formed with the tapered portion 553 such that one end is connected to the other end of the tapered portion 553. The fitting portion 551, the taper portion 553 and the cylindrical portion 554 are integrally formed to be coaxial. The outer diameter of the gap forming cylindrical portion 552, that is, the tapered portion 553 and the cylindrical portion 554 is smaller than the inner diameter of the inlet portion 24, that is, the inner diameter of the flow path forming wall 241.

  The support member 55 is provided inside the inlet portion 24 so that the fitting portion 551 is fitted to the flow path forming wall surface 241 and the gap forming cylindrical portion 552 side is opposite to the inflow port 240. In this state, the gap forming cylindrical portion 552 forms a cylindrical gap CL2 which is a cylindrical gap between the outer peripheral wall and the flow path forming wall surface 241.

  An auxiliary flow passage 101 is formed inside the support member 55. In the vicinity of the tapered portion 553 of the cylindrical portion 554, a communication passage 550 connecting the inner peripheral wall and the outer peripheral wall is formed. The communication passage 550 is in communication with a space on the inflow port 240 side of the main flow path 100 with respect to the support member 55 and a space on the injection hole 13 side with respect to the support member 55. The fuel flowing from the inflow port 240 into the inlet portion 24 flows toward the injection hole 13 through the inside of the fitting portion 551, the inside of the tapered portion 553, the inside of the cylindrical portion 554, the communication passage 550, and the cylindrical clearance CL2. be able to. In the present embodiment, the communication passage 550 is formed, for example, in a circular shape. Two communication paths 550 are formed at equal intervals in the circumferential direction of the cylindrical portion 554 of the support member 55.

  In the present embodiment, the strain generating body 70 is formed of, for example, metal in a bottomed cylindrical shape. The strain generating body 70 is formed separately from the support member 55, and the end of the gap forming cylindrical portion 552 of the support member 55 opposite to the fitting portion 551 is closed by the other surface 72 of the bottom portion. The inner circumferential wall of the portion is provided at the end of the gap forming cylindrical portion 552 so as to be joined to the outer peripheral wall of the end of the gap forming cylindrical portion 552. Here, the inner peripheral wall of the cylindrical portion of the strain generating body 70 and the outer peripheral wall of the gap forming cylindrical portion 552 are held in a liquid tight manner. One surface 71 of the bottom of the strain generating body 70 faces the injection hole 13 side. The other surface 72 of the bottom of the strain generating body 70 faces the inflow port 240 side. The differential pressure sensor 80 and the protective film 2 are provided on one surface 71 of the strain generating body 70. That is, in the present embodiment, the differential pressure sensor 80 is provided on the outer side of the support member 55. The bottom of the strain generating body 70 can be elastically deformed by the pressure difference between the first space S1 and the second space S2.

  In the present embodiment, a terminal hole 280 is formed in the inlet 24 (see FIG. 19). The terminal hole 280 is formed to connect the outer peripheral wall and the inner peripheral wall of the inlet 24. The terminal hole 280 has a large diameter hole 281 and a small diameter hole 282. The large diameter hole portion 281 is formed in a substantially cylindrical shape so as to extend radially inward from the outer peripheral wall of the inlet portion 24. The small diameter hole 282 extends radially outward from the inner circumferential wall of the inlet 24 and is formed to be connected to the large diameter hole 281. The large diameter hole 281 and the small diameter hole 282 are formed coaxially. The inner diameter of the small diameter hole 282 is smaller than the inner diameter of the large diameter hole 281. Therefore, between the large diameter hole portion 281 and the small diameter hole portion 282, a substantially annular flat step surface 283 facing the radial direction outer side of the inlet portion 24 is formed. The support member 55 is provided inside the inlet 24 so that the end of the gap forming cylindrical portion 552 opposite to the fitting portion 551 is positioned in the vicinity of the small diameter hole 282 of the terminal hole 280.

  The present embodiment further includes a terminal cylinder member 85, a sensor terminal 861, and a sealing material 87. The terminal cylinder member 85 is formed, for example, of metal in a substantially cylindrical shape. The outer diameter of the terminal cylindrical member 85 is slightly larger than the inner diameter of the large diameter hole 281 of the terminal hole 280. The terminal cylindrical member 85 is provided in the terminal hole 280 so as to fit in the large diameter hole 281. Here, one end face of the terminal cylindrical member 85 is in contact with the step surface 283 of the terminal hole 280. The other end of the terminal cylindrical member 85 protrudes outward in the radial direction of the terminal hole 280. Furthermore, the inner diameter of the terminal cylindrical member 85 is substantially the same as the inner diameter of the small diameter hole 282.

  A plurality of sensor terminals 861 are provided inside the terminal cylindrical member 85. The sealing material 87 is made of, for example, glass, and is provided inside the terminal cylindrical member 85. The sealing material 87 seals the space between the sensor terminal 861 and the inner peripheral wall of the terminal cylinder member 85 inside the terminal cylinder member 85. Thus, the fuel inside the inlet 24 can be prevented from leaking to the outside through the terminal hole 280.

  The sensor terminal 861 has one end located radially outward of the end of the gap forming cylindrical portion 552 on the side of the strain generating body 70 and is connected to the terminals 831 to 834 of the differential pressure sensor 80, and the other end is a terminal cylindrical member It is exposed to the outside of 85 and connected to the ECU 90 or the battery. Thus, power is supplied from the battery to the differential pressure sensor 80 via the sensor terminal 861, and an electrical signal is output from the differential pressure sensor 80 to the ECU 90 via the sensor terminal 861. In the present embodiment, the communication passage 550 is formed at a position away from one end of the sensor terminal 861 in the circumferential direction of the gap forming cylindrical portion 552.

  As described above, (10) the present embodiment further includes the support member 55. The support member 55 has a fitting portion 551 fitted to the flow path forming wall surface 241 which is a wall surface forming the main flow path 100, and an outer diameter smaller than the inner diameter of the flow path forming wall surface 241 A cylindrical gap CL2 is formed between the wall surface 241 and the cylindrical gap. The strain generating body 70 is provided at an end of the gap forming cylindrical portion 552. In the present embodiment, when the support member 55 is assembled to the inside of the inlet portion 24 and in a state in which the support member 55 is assembled to the inside of the inlet portion 24, the flow path forming wall surface 241 is formed on the fitting portion 551. An external force in the inward radial direction is applied from the inside, causing internal stress. On the other hand, since a cylindrical clearance CL2 is formed between the outer peripheral wall of the clearance forming cylindrical portion 552 and the flow path forming wall surface 241, an external force in the radial inward direction from the flow path forming wall 241 is formed in the clearance forming cylindrical portion 552. Does not participate. Therefore, no stress is generated in the gap forming cylindrical portion 552, and the deformation of the strain generating body 70 provided in the gap forming cylindrical portion 552 can be suppressed. Therefore, the differential pressure sensor 80 can be installed without causing a decrease in pressure resistance and a decrease in detection accuracy due to assembly stress.

  (11) In the present embodiment, the support member 55 communicates with the space on the side of the inlet 240 with respect to the support member 55 in the main flow passage 100 and the space on the side of the injection hole 13 with respect to the support member 55. have. A plurality of communication paths 550 are formed at equal intervals in the circumferential direction of the support member 55. Therefore, by suppressing the uneven flow of fuel before and after the communication passage 550, it is possible to suppress the generation of the pressure distribution and to suppress the decrease in the detection accuracy of the pressure detection by the differential pressure sensor 80.

  Furthermore, in the present embodiment, the communication passage 550 is formed at a position avoiding one end of the sensor terminal 861 in the circumferential direction of the gap forming cylindrical portion 552. Therefore, it is possible to suppress the flow of fuel flowing from the inlet 240 side of the support member 55 to the injection hole 13 side of the support member 55 via the communication passage 550 from being hindered by the sensor terminal 861. Thereby, generation | occurrence | production of pressure distribution can be suppressed and the fall of the detection accuracy of the pressure detection by the differential pressure sensor 80 can be suppressed.

The ninth embodiment
A portion of a fuel injection system according to the ninth embodiment is shown in FIG. The ninth embodiment is different from the eighth embodiment in the arrangement and the like of the support member 55 and the strain generating body 70.

  In the ninth embodiment, the support member 55 is provided inside the inlet portion 24 so that the fitting portion 551 is fitted to the flow path forming wall surface 241 and the gap forming cylindrical portion 552 side faces the inflow port 240 side. The strain generating body 70 closes the end portion of the gap forming cylindrical portion 552 of the support member 55 opposite to the fitting portion 551 with one surface 71 of the bottom portion, and the inner peripheral wall of the cylindrical portion forms the gap forming cylindrical portion 552 It is provided at the end of the gap forming cylindrical portion 552 so as to be joined to the outer peripheral wall of the end. Here, one surface 71 of the bottom of the strain generating body 70 faces the injection hole 13 side. The other surface 72 of the bottom of the strain generating body 70 faces the inflow port 240 side. The differential pressure sensor 80 and the protective film 2 are provided on one surface 71 of the strain generating body 70. That is, in the present embodiment, the differential pressure sensor 80 is provided inside the support member 55. The fuel flowing from the inflow port 240 into the inlet portion 24 flows toward the injection hole 13 via the cylindrical gap CL2, the communication passage 550, the inner side of the cylindrical portion 554, the inner side of the tapered portion 553 and the inner side of the fitting portion 551. be able to. The configuration of the ninth embodiment is similar to that of the eighth embodiment except for the points described above.

Tenth Embodiment
A portion of a fuel injection system according to the tenth embodiment is shown in FIG. The tenth embodiment differs from the eighth embodiment in the configuration and the like of the support member 55 and the strain generating body 70.

  In the tenth embodiment, the support member 55 includes a fitting portion 551, a gap forming cylindrical portion 552, and a taper portion 555. The fitting portion 551 is formed in a substantially cylindrical shape as in the eighth embodiment. The outer diameter of the fitting portion 551 is slightly larger than the inner diameter of the inlet portion 24, that is, the inner diameter of the flow path forming wall surface 241.

  The gap forming cylindrical portion 552 is formed in a cylindrical shape and has a tapered portion 553. Similar to the eighth embodiment, the tapered portion 553 is integrally formed with the fitting portion 551 so that one end thereof is connected to the end portion of the fitting portion 551. The tapered portion 553 is formed in a tapered shape so that the inner circumferential wall and the outer circumferential wall approach the axis as it goes from the fitting portion 551 to the opposite side to the fitting portion 551. The outer diameter of the gap forming cylindrical portion 552, that is, the tapered portion 553 is smaller than the inner diameter of the inlet portion 24, that is, the inner diameter of the flow path forming wall surface 241.

  The tapered portion 555 is integrally formed with the fitting portion 551 so that one end is connected to the end of the fitting portion 551 opposite to the gap forming cylindrical portion 552. The tapered portion 555 is formed in a tapered shape so that the inner circumferential wall and the outer circumferential wall approach the axis as it goes from the fitting portion 551 to the opposite side to the fitting portion 551. The fitting portion 551, the tapered portion 553 and the tapered portion 555 are integrally formed to be coaxial.

  The support member 55 is provided inside the inlet portion 24 so that the fitting portion 551 is fitted to the flow path forming wall surface 241 and the gap forming cylindrical portion 552 side is opposite to the inflow port 240. In this state, the gap forming cylindrical portion 552 forms a cylindrical gap CL2 which is a cylindrical gap between the outer peripheral wall and the flow path forming wall surface 241.

  In the present embodiment, the communication passage 550 is formed in the gap forming cylindrical portion 552 so as to connect the inner peripheral wall and the outer peripheral wall of the tapered portion 553. The communication passage 550 is in communication with a space on the inflow port 240 side of the main flow path 100 with respect to the support member 55 and a space on the injection hole 13 side with respect to the support member 55. The fuel flowing from the inflow port 240 into the inlet portion 24 flows to the injection hole 13 side through the inside of the taper portion 555, the inside of the fitting portion 551, the inside of the taper portion 553, the communication passage 550, and the cylindrical clearance CL2. be able to. In the present embodiment, two communication paths 550 are formed at equal intervals in the circumferential direction of the tapered portion 553 of the support member 55.

  In the present embodiment, the strain generating body 70 is integrally formed with the support member 55 so as to close an end of the gap forming cylindrical portion 552 of the support member 55 opposite to the fitting portion 551. That is, the strain generating body 70 is provided inside the end of the gap forming cylindrical portion 552. Here, one surface 71 of the strain generating body 70 faces the injection hole 13 side. The other surface 72 of the strain generating body 70 faces the inflow port 240 side. The differential pressure sensor 80 and the protective film 2 are provided on one surface 71 of the strain generating body 70. That is, in the present embodiment, the differential pressure sensor 80 is provided on the outer side of the support member 55. The strain generating body 70 can be elastically deformed by the pressure difference between the first space S1 and the second space S2.

  In the present embodiment, one end of the sensor terminal 861 is located radially outside the fitting portion 551 and is connected to the terminals 831 to 834 of the differential pressure sensor 80. The configuration of the tenth embodiment is the same as that of the eighth embodiment except for the points described above.

Eleventh Embodiment
22 and 23 show a part of a fuel injection system according to an eleventh embodiment. The eleventh embodiment differs from the eighth embodiment in the configuration and the like of the support member 55.

  In the eleventh embodiment, the support member 55 has a fitting portion 551 and a gap forming cylindrical portion 552. The gap forming cylindrical portion 552 has a cylindrical portion 554. The cylindrical portion 554 is formed in a substantially cylindrical shape. The outer diameter of the gap forming cylindrical portion 552, that is, the cylindrical portion 554 is smaller than the inner diameter of the inlet portion 24, that is, the inner diameter of the flow path forming wall surface 241.

  The fitting portion 551 is provided radially outside the end of the gap forming cylindrical portion 552. A plurality of fitting portions 551 are provided at equal intervals in the circumferential direction of the gap forming cylindrical portion 552. For example, four fitting portions 551 are provided (see FIG. 23).

  The support member 55 is provided inside the inlet portion 24 so that the fitting portion 551 fits on the flow path forming wall surface 241 and the end portion of the gap forming cylindrical portion 552 on the fitting portion 551 side faces the inflow port 240 side. ing. In this state, the gap forming cylindrical portion 552 forms a cylindrical gap CL2 which is a cylindrical gap between the outer peripheral wall and the flow path forming wall surface 241.

  In the present embodiment, the communication passage 550 is formed between the plurality of fitting portions 551 on the radially outer side of the gap forming cylindrical portion 552. The communication passage 550 is in communication with a space on the inflow port 240 side of the main flow path 100 with respect to the support member 55 and a space on the injection hole 13 side with respect to the support member 55. The fuel that has flowed into the inlet portion 24 from the inflow port 240 can flow to the injection hole 13 side via the communication passage 550 and the cylindrical gap CL2. In the present embodiment, four communication paths 550 are formed at equal intervals in the circumferential direction of the gap forming cylindrical portion 552 of the support member 55 (see FIG. 23).

  In the present embodiment, the strain generating body 70 is formed in a bottomed cylindrical shape, for example, of metal, as in the eighth embodiment. The strain generating body 70 is formed separately from the support member 55, and the end of the gap forming cylindrical portion 552 of the support member 55 opposite to the fitting portion 551 is closed by the other surface 72 of the bottom portion. The inner circumferential wall of the portion is provided at the end of the gap forming cylindrical portion 552 so as to be joined to the outer peripheral wall of the end of the gap forming cylindrical portion 552. The differential pressure sensor 80 and the protective film 2 are provided on one surface 71 of the strain generating body 70. That is, in the present embodiment, the differential pressure sensor 80 is provided on the outer side of the support member 55.

  In the present embodiment, one end of the sensor terminal 861 is located radially outside the end of the gap forming cylindrical portion 552 on the side of the strain generating body 70 and is connected to the terminals 831 to 834 of the differential pressure sensor 80. In the present embodiment, the communication passage 550 is formed at a position away from one end of the sensor terminal 861 in the circumferential direction of the gap forming cylindrical portion 552. That is, one of the plurality of fitting portions 551 is provided at a position overlapping one end of the sensor terminal 861 in the circumferential direction of the gap forming cylindrical portion 552 (see FIG. 23). The eleventh embodiment is the same as the eighth embodiment except for the above-described points.

(Twelfth embodiment)
A part of the fuel injection device according to the twelfth embodiment is shown in FIG. The twelfth embodiment differs from the eighth embodiment in the configuration of the support member 55.

  In the twelfth embodiment, the communication passage 550 is formed in a circular shape so as to connect the inner peripheral wall and the outer peripheral wall of the cylindrical portion 554 of the support member 55. A plurality of communication paths 550 are formed at equal intervals in the circumferential direction of the cylindrical portion 554. The inner diameter of the communication passage 550 of the present embodiment is smaller than the inner diameter of the communication passage 550 of the eighth embodiment. Further, a plurality of communication paths 550 aligned in the circumferential direction are also formed in the axial direction of the cylindrical portion 554. The total flow passage area of the communication passage 550 of the present embodiment is approximately the same as the total flow passage area of the communication passage 550 of the eighth embodiment. The twelfth embodiment is the same as the eighth embodiment except for the points described above.

(13th Embodiment)
A part of the fuel injection device according to the thirteenth embodiment is shown in FIG. The thirteenth embodiment differs from the twelfth embodiment in the configuration of the support member 55.

  In the thirteenth embodiment, the communication passage 550 is formed in a hexagonal shape so as to connect the inner peripheral wall and the outer peripheral wall of the cylindrical portion 554 of the support member 55. The thirteenth embodiment is the same as the twelfth embodiment except for the points described above.

(Other embodiments)
In the first embodiment described above, an example in which the strain generating body 70 is provided inside the end portion on the inlet 240 side of the adjusting pipe 53 has been shown. On the other hand, in the other embodiment of the present invention, the strain generating body 70 may be provided inside the portion on the injection hole 13 side of the adjusting pipe 53. Also, the strain generating body 70 may be formed separately from the adjusting pipe 53.

  Moreover, in the above-mentioned embodiment, the differential pressure sensor 80 showed the example which is a so-called distortion type sensor which has the sensor element 81 which outputs the electric signal corresponding to the magnitude | size of the distortion produced in the strain generating body 70 . On the other hand, in another embodiment of the present invention, the differential pressure sensor 80 may be a transducer type sensor, a capacitance type sensor, a piezoelectric type sensor or the like. The sensor element 81 may not have the bridge circuit 82.

Moreover, in the above-mentioned 5th, 7th embodiment, the example which uses a silicone oil as the incompressible fluid 78 was shown. On the other hand, in another embodiment of the present invention, an alcohol such as ethylene may be used as the incompressible fluid 78. In this case, even if the incompressible fluid 78 leaks into the main flow passage 100, the influence on combustion due to the injection and supply of the incompressible fluid 78 to the engine can be suppressed.
Further, as the incompressible fluid 78, a fluid having a thermal conductivity higher than a predetermined value may be used. Further, the protective film 2 covering the differential pressure sensor 80 may be formed of a material having a thermal conductivity higher than a predetermined value. In this case, the value detected by the differential pressure sensor 80 can be corrected according to the temperature of the fuel.

  Moreover, in the above-mentioned embodiment, the example which forms the strain generating body 70 by metals, such as stainless steel, was shown. On the other hand, in the other embodiment of the present invention, the strain generating body 70 may be formed of any material that can be elastically deformed. For example, in the fourth embodiment, the strain generating body 70 may be integrally formed with the cylindrical portion 751 by a resin. Moreover, the cylinder part 751 may be formed not only with resin but with metals, such as stainless steel.

  In the above eighth to thirteenth embodiments, an example in which the shape of the cross section perpendicular to the axis of the fitting portion 551 of the support member 55 or the gap forming cylindrical portion 552 is a perfect circle is shown. On the other hand, in the other embodiment of the present invention, the fitting portion 551 of the support member 55 or the gap forming cylindrical portion 552 has a cross section perpendicular to the axis that has a polygonal shape such as an ellipse, triangle or square. It may be formed. Further, in the case where the cross-sectional shape is a polygon, a point at which two sides of the polygon intersect, that is, the apex of the polygon may be formed in a curved shape. Further, the shape of the strain generating body 70 provided in the gap forming cylindrical portion 552 may also be formed into a shape other than a perfect circle, such as an ellipse or a polygon, in accordance with the shape of the gap forming cylindrical portion 552.

  Moreover, in the above-mentioned 1st, 4th embodiment, the example which provides the distortion body 70 inside the adjusting pipe 53 or the cylinder part 751 as a cylinder part was shown. On the other hand, in the other embodiment of the present invention, the strain generating body 70 may be provided at the end of the adjusting pipe 53 or the cylindrical portion 751.

Further, in another embodiment of the present invention, the differential pressure sensor 80 may be provided on either of the other surface 72 or one surface 71 of the strain generating body 70.
The present invention is not limited to a direct injection gasoline engine, and may be applied to, for example, a port injection gasoline engine or a diesel engine. The present invention may be applied to a hydraulically driven diesel engine fuel injection device.

In addition, in another embodiment of the present invention, fluids other than fuel may be controlled. In this case, members other than the housing 20, the strain generating body 70, and the differential pressure sensor 80 described in the above embodiment can be omitted, and the configuration can be simplified.
Thus, this invention is not limited to the said embodiment, It can implement with various forms in the range which does not deviate from the summary.

DESCRIPTION OF SYMBOLS 1 Fluid control device 240 inlet (inlet), 13 main hole (outlet), 100 main channel, 20 housing, 70 strain generating body, 71 one surface, S1 first space, 72 other surface, S2 second space, 80 differential pressure sensor, 78 incompressible fluid

Claims (12)

A housing (20) having a fluid inlet (240), a fluid outlet (13), and a main flow passage (100) connecting the inlet and the outlet for fluid flow;
A first space (S1) which is a space in contact with one surface (71) communicates with the main flow channel, and a second space (S2) which is a space in contact with the other surface (72) communicates with the main flow channel A deformable body (70) elastically deformable by a pressure difference between the first space and the second space;
A differential pressure sensor (80) provided on the strain generating body and capable of detecting a pressure difference between the first space and the second space;
A fluid control device (1) comprising:   The length of a first path (R1) which is a path connecting the first space and the outlet is shorter than the length of a second path (R2) which is a path connecting the second space and the outlet The fluid control device according to Item 1. The secondary flow path (101) is further provided, one end of which is connected to the outlet side of the main flow path and the other end of which is connected to the inlet side of the main flow path,
The fluid control device according to claim 1, wherein the strain generating body is provided in the sub flow path.   The fluid control device according to claim 3, wherein the strain generating body is provided closer to one end of the sub flow path than a center of the sub flow path. It further comprises a cylindrical portion (53) provided such that one end is connected to the outlet side of the main flow channel, and the other end is connected to the inlet side of the main flow channel,
The fluid control device according to any one of claims 1 to 4, wherein the strain generating body is provided inside the cylindrical portion or at an end portion of the cylindrical portion. A needle (30) provided so as to be capable of reciprocating in the main flow path, capable of opening and closing the outlet, and controlling the flow rate of fluid flowing out of the outlet;
And a biasing member (61) for biasing the needle toward the outlet.
The fluid control device according to claim 5, wherein the cylindrical portion is provided such that one end thereof locks an end portion of the biasing member opposite to the needle. A cylindrical portion (751) whose one end is connected to the outlet side of the main flow path and the other end is connected to the inlet side of the main flow path, and a communication path connecting one end face and the other end face of the cylindrical portion Further comprising a tubular member (75) having (752),
The fluid control device according to any one of claims 1 to 4, wherein the strain generating body is provided inside the cylindrical portion or at an end portion of the cylindrical portion. An elastically deformable diaphragm (77) provided on the differential pressure sensor side of the strain generating body;
An incompressible fluid (78) provided between the strain generating body and the diaphragm;
The fluid control device according to any one of claims 1 to 7, further comprising: A housing (20) having a fluid inlet (240), a fluid outlet (13), and a main flow passage (100) connecting the inlet and the outlet for fluid flow;
A first space (S1) which is a space in contact with one surface (71) communicates with the main flow path, and a pressure between a second space (S2) which is a space in contact with the other surface (72) and the first space An elastic deformable body (70) which can be elastically deformed by a difference;
An incompressible fluid (78) provided in the second space;
A differential pressure sensor (80) provided on the strain generating body and capable of detecting a pressure difference between the first space and the second space;
A fluid control device (1) comprising: A fitting portion (551) fitted to a flow path forming wall surface (241) which is a wall surface forming the main flow path, and an outer peripheral wall having the outer diameter smaller than the inner diameter of the flow path forming wall surface It further comprises a support member (55) having a gap forming tubular portion (552) forming a tubular gap (CL2) which is a tubular gap with the wall surface,
The fluid control device according to any one of claims 1 to 4, wherein the strain generating body is provided inside the gap forming cylindrical portion or at an end of the gap forming cylindrical portion. The support member has a communication passage (550) communicating with a space on the inlet side with respect to the support member and a space with respect to the support member in the main flow path,
The fluid control device according to claim 10, wherein a plurality of the communication paths are formed in the circumferential direction of the support member. A control unit (91) capable of controlling the flow rate of fluid flowing out of the outlet;
A pressure change detection unit (92) capable of detecting a change in pressure in the main flow passage based on the pressure difference detected by the differential pressure sensor;
A flow rate estimation unit (93) capable of estimating the flow rate of the fluid flowing out from the outlet based on the change in pressure detected by the pressure change detection unit;
A flow rate correction unit (94) capable of correcting the flow rate of the fluid controlled by the control unit based on the flow rate estimated by the flow rate estimation unit;
The fluid control device according to any one of claims 1 to 11, further comprising:

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