Fuel supply system

Abstract

In a fuel supply system that supplies gaseous fuel to the engine of a vehicle, the fluid pressure of the discharged gaseous fuel can be adjusted by electronic control, and the fluid pressure of the gaseous fuel can be safely released in the event of a malfunction such as a power supply failure. [Solution] In a fuel supply system 100 that supplies gas fuel to an engine 6, the system includes an electronically controlled regulator 3 that reduces the introduced gas fuel to a set pressure and discharges it, a pressure sensor 7 that detects the fluid pressure of the gas fuel after reduction, and a normally open electromagnetic relief valve 8 provided downstream of the pressure regulating valve of the electronically controlled regulator 3. The electromagnetic relief valve 8 opens when the fluid pressure detected by the pressure sensor 7 reaches a pressure threshold or when the system is not energized, releasing the gas fuel outside the system.

Description

Technical Field

[0001] The present invention relates to a fuel supply system for supplying gas fuel to an engine.

Background Art

[0002] Since vehicle gas fuel is stored in a tank in a high-pressure liquid state, it is necessary to reduce the pressure to a predetermined pressure and supply it to the engine in a gaseous state. As a pressure regulator for pressure reduction and adjustment, an electronically controlled pressure control device using a solenoid valve such as the device described in Patent Document 1 is known.

[0003] According to the pressure control device described in this Patent Document 1, it has two solenoids, one for the main stop valve and one for the pressure reducing valve, and the pressure of the gaseous fuel discharged can be controlled by continuously changing the current value.

Prior Art Documents

Patent Documents

[0007] The present invention, made to solve the above problems, is a fuel supply system for supplying gaseous fuel to an engine, comprising: an electronically controlled regulator that reduces the introduced gaseous fuel to a set pressure and discharges it; a pressure sensor that detects the fluid pressure of the gaseous fuel after reduction; and a normally open electromagnetic relief valve provided downstream of the pressure regulating valve of the electronically controlled regulator, wherein the electromagnetic relief valve opens when the fluid pressure detected by the pressure sensor reaches a pressure threshold or when the system is not energized, releasing the gaseous fuel outside the system. [Effects of the Invention]

[0008] According to the present invention, fluid pressure can be safely released by an electromagnetic relief valve. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic diagram showing an example of the fuel supply system of the present invention. [Figure 2] A longitudinal cross-sectional view showing the closed valve state of the first embodiment of the electronically controlled regulator according to the present invention. [Figure 3] A longitudinal cross-sectional view showing the valve open state of the first embodiment of the electronically controlled regulator according to the present invention. [Figure 4] A functional block diagram of a fuel supply system to which the first or second embodiment of the electronically controlled regulator of the present invention is applied. [Figure 5] A longitudinal cross-sectional view showing the closed valve state of the second embodiment of the electronically controlled regulator according to the present invention. [Figure 6] A longitudinal cross-sectional view showing the valve open state of the second embodiment of the electronically controlled regulator according to the present invention. [Figure 7] Cross-sectional view along line AA in Figure 6. [Modes for carrying out the invention]

[0010] The embodiments for carrying out the present invention will be described below with reference to the drawings.

[0011] <System Configuration> Figure 1 is a schematic diagram showing an example of the fuel supply system 100 of the present invention. In Figure 1, the solid lines indicate the fuel supply system for gaseous fuel, and the dotted lines indicate the signal communication lines. In the following description, "outside the system" means outside the fuel supply system for gaseous fuel, and for example, release into the atmosphere outside the vehicle.

[0012] This fuel supply system 100 is a system for supplying gaseous fuel to the engine of a vehicle or the like, and includes a fuel tank 1 for storing gaseous fuel such as CNG, LNG, LPG, or hydrogen gas, an electromagnetic shut-off valve 2, an electronically controlled regulator 3, an oil filter 4, an injector 5, a pressure sensor 7, an electromagnetic relief valve 8, and an ECU 9.

[0013] The gaseous fuel delivered from the fuel tank 1 passes in order through the electromagnetic shut-off valve 2, the electronically controlled regulator 3, the oil filter 4, and the injector 5 before being supplied to the engine 6. Further pressure reduction means may be provided between the fuel tank 1 and the electronically controlled regulator 3, or between the electronically controlled regulator 3 and the injector 5 (not shown).

[0014] The electromagnetic shut-off valve 2 is a normally closed solenoid valve located upstream of the electronically controlled regulator 3. Under normal conditions when the engine is running, power is supplied to maintain the valve in the open state.

[0015] The electronically controlled regulator 3 is driven by an electronically controlled electric motor and discharges the introduced gas fuel after reducing its pressure to a set pressure.

[0016] The oil filter 4 is a filter for removing the precipitated oil component.

[0017] The injector 5 is connected to the fuel supply pipe to the engine 6 and the cylinders of the engine 6, and injects the gas fuel after pressure reduction.

[0018] The pressure sensor 7 is arranged downstream of the pressure regulating valve of the electronically controlled regulator 3 and detects the fluid pressure of the gas fuel after pressure reduction.

[0019] The electromagnetic relief valve 8 is a normally open (NO) solenoid valve provided downstream of the electronically controlled regulator 3. In the normal state during engine operation, power is supplied to maintain the valve closed state. The electromagnetic relief valve 8 opens when the fluid pressure detected by the pressure sensor 7 exceeds a predetermined pressure threshold or when the engine stops (when not energized), and releases the gas fuel to the outside of the system to relieve the pressure. The pressure threshold is set in a higher pressure range than the set pressure of the gas fuel.

[0020] In one example shown in FIG. 1, the electromagnetic relief valve 8 is arranged in the branch pipe Bp provided downstream of the electronically controlled regulator 3 and uses a 2-position, 2-port control valve for switching between opening and closing. However, for example, a 3-port control valve may be used. When using a 3-port control valve, since there is no need to branch in advance by a branch pipe, space can be saved.

[0021] The ECU 9 is an electronic control unit (Electronic Control Unit), which is a device connected to the electronically controlled regulator 3, the injector 5 and other devices to perform control and the like.

[0022] <Description of the operation> Hereinafter, the operation of the present invention will be described.

[0023] First, as Comparative Example 1, problems in the case of using a normally closed (NC) mechanical safety valve using, for example, a spring or a diaphragm will be described below.

[0024] In the case of a normally closed mechanical safety valve, this mechanical safety valve automatically operates and opens when the fluid pressure reaches a predetermined pressure threshold, releasing the gaseous fuel outside the system and relieving the fluid pressure. Then, when the fluid pressure falls below a certain value, it automatically returns to the closed state by a biasing means such as a spring or diaphragm.

[0025] Such mechanical safety valves are designed to operate only in emergencies and do not operate or open during normal operation when the fluid pressure does not reach the pressure threshold. Therefore, they cannot perform actions such as opening when the engine is stopped (when the system is not energized) to release the fluid pressure of residual gaseous fuel.

[0026] Next, as Comparative Example 2, the problems when using a normally closed electromagnetic relief valve are described below.

[0027] In the case of a normally closed electromagnetic safety valve, when the fluid pressure reaches a predetermined pressure threshold, the electromagnetic safety valve is energized, the solenoid is energized, and the valve opens, releasing the gaseous fuel to the outside of the system and relieving the fluid pressure. Then, when the fluid pressure falls below a certain value, the valve is de-energized and returns to the closed state. In addition, when the engine is stopped (when the valve is not energized), the electromagnetic relief valve can be opened to release the fluid pressure of the remaining gaseous fuel.

[0028] However, if an electrical malfunction such as a broken wire occurs, the electromagnetic relief valve will not be able to operate and will remain closed. When the electromagnetic relief valve is closed, it cannot function as a relief valve and it becomes impossible to release the fluid pressure of the gas fuel. Therefore, if malfunctions such as a faulty pressure regulation or valve leak in the electronically controlled regulator occur in combination, excessive fluid pressure may be applied, potentially causing serious problems such as damage or failure of the electronically controlled regulator or downstream equipment. In addition, normally closed electromagnetic relief valves require a relay circuit or external power supply to open the electromagnetic relief valve when the engine is stopped (when power is not supplied).

[0029] In contrast, the operation of a normally open electromagnetic relief valve, as in the present invention, will be explained below.

[0030] In the case of a normally open electromagnetic safety valve, this electromagnetic safety valve operates by becoming de-energized and opening when the fluid pressure reaches a predetermined pressure threshold, releasing the gaseous fuel to the outside of the system and relieving the fluid pressure. Then, when the fluid pressure falls below a certain value, it is energized, the solenoid is energized, and it returns to the closed state. In addition, when the engine is stopped (de-energized), the electromagnetic relief valve can be opened to release the fluid pressure of the remaining gaseous fuel.

[0031] By using a normally open electromagnetic relief valve, the valve will automatically activate and open even if an electrical malfunction such as a broken wire occurs. The gas fuel is safely and quickly released out of the system by passing through the opened electromagnetic relief valve.

[0032] In this way, a normally open electromagnetic relief valve can reliably perform its function as a relief valve. Therefore, even if the electronically controlled regulator experiences multiple malfunctions such as pressure regulation failure or valve leakage, it can release the fluid pressure of the gas fuel, thus preventing damage or failure to the electronically controlled regulator or downstream equipment.

[0033] Furthermore, by using a normally open electromagnetic relief valve, unlike a normally closed electromagnetic relief valve, there is no need to configure a relay circuit or external power supply, thus simplifying the configuration and reducing costs.

[0034] Furthermore, the fuel supply system 100 shown in Figure 1 is equipped with a normally closed electromagnetic shut-off valve upstream of the electronically controlled regulator. This electromagnetic shut-off valve operates by becoming de-energized and closing when the fluid pressure reaches a predetermined pressure threshold or when the engine is stopped (not energized).

[0035] By using a normally closed electromagnetic shut-off valve, the valve will automatically operate and close even if an electrical malfunction such as a broken wire occurs. When the electromagnetic shut-off valve is closed, the fluid supply to the electronically controlled regulator is cut off, and the release of gas fuel from the electromagnetic relief valve also stops.

[0036] <Electronically controlled regulator> The electronically controlled regulator in this invention will be described below.

[0037] ≪First Embodiment of Electronically Controlled Regulator≫ Figures 2 and 3 show a first embodiment of an electronically controlled regulator. Figure 2 shows the closed state of the electronically controlled regulator 3A, and Figure 3 shows the open state of the electronically controlled regulator 3A.

[0038] The electronically controlled regulator 3A is a pressure reducing device used in a gas fuel supply system to reduce the pressure of gas fuel, which is a high-pressure fluid, to a predetermined pressure.

[0039] The electronically controlled regulator 3A comprises a body 10A forming a fluid passage 11 through which fluid passes, a pressure regulating valve 20A provided on the fluid passage 11, and an electronically controlled electric motor 30. A pressure sensor 7, an electromagnetic shut-off valve 2, and an electromagnetic relief valve 8 are also connected to it.

[0040] The body 10A is cylindrical in shape, with one end of the fluid passage 11 serving as a fluid inlet 12 and the other end serving as a fluid outlet 13. An inlet cover 14 is fitted to the fluid inlet 12 side, and an outlet cover 15 is fitted to the fluid outlet 13 side.

[0041] The pressure regulating valve 20A is installed on the fluid passage 11 and divides the primary pressure chamber C1 on the fluid inlet 12 side and the secondary pressure chamber C2 on the fluid outlet 13 side. A pressure control chamber C3 is also provided between the primary pressure chamber C1 and the secondary pressure chamber C2 for operating the pressure regulating valve 20A to reduce and adjust the pressure of the discharged fluid to a set pressure.

[0042] The pressure regulating valve 20A consists of a cylindrical valve body 21A that can reciprocate in the axial direction, an annular valve seat 22A having a seat surface 23A that can make close contact with the valve body 21A, and a discharge pressure adjustment mechanism that adjusts the discharge pressure by changing the distance between the valve body 21A and the valve seat 22A by reciprocating the valve body 21A.

[0043] The discharge pressure adjustment mechanism consists of an electric motor 30 equipped with a rotor 31, a motor driver 35 that drives and controls the electric motor 30, and a valve body movement structure 50. Using the electronically controlled electric motor 30 as the drive source, the valve body 21A is moved axially back and forth between a closed position (Figure 2) where the valve body 21A and the seat surface 23A of the valve seat 22A are in close contact and an open position (Figure 3) where the valve body 21A and the seat surface 23A are separated, thereby changing the opening area and automatically adjusting the pressure of the discharged fluid to be equal to the set pressure.

[0044] The valve body 21A is a cylindrical member with a passage 24A through which fluid can pass. The end of the valve body 21A that sits on the valve seat 22A is the tip 211A, and the opposite end is the rear end 212A.

[0045] When the valve is open and separated from the seat surface 23A of the valve seat 22A, the valve body 21A connects the primary pressure chamber C1 on the fluid inlet 12 side and the secondary pressure chamber C2 on the fluid outlet 13 side via the communication passage 24A inside the valve body 21A, thereby moving the gaseous fuel from the primary pressure chamber C1 to the secondary pressure chamber C2.

[0046] Conversely, when the valve is closed, with the valve body 21A seated on the seat surface 23A of the valve seat 22A, the movement of fluid from the primary pressure chamber C1 to the secondary pressure chamber C2 is restricted.

[0047] A valve body retaining portion 16 for holding the valve body 21A is formed at an intermediate position in the fluid passage 11. The valve body retaining portion 16 is fitted with an annular collar 17 and a seal ring 18 located on the primary pressure chamber 1 side of the collar 17.

[0048] The collar 17 has an inner diameter slightly larger than the outer diameter of the valve body 21A, and serves to guide the axial reciprocating motion of the valve body 21A while preventing the valve body 21A from directly contacting the body 10A. The material of the collar 17 can be made of, for example, synthetic resin, and a material with good lubricity such as PTFE is particularly preferred.

[0049] The seal ring 18 serves to airtightly seal the valve body holder 16 and the valve body 21A. The collar 17 and the seal ring 18 are held in place by a retaining member 19 attached to the primary pressure chamber C1 side, preventing them from falling off the valve body holder 16.

[0050] The valve seat 22A is fixed to a disc-shaped valve seat retaining member 25A by means of adhesive or insert molding. The valve seat retaining member 25A is fitted between the inlet cover 14 and the body 10A, and gas fuel can pass through through holes formed around the valve seat 22A.

[0051] A piston 26A, which receives the fluid pressure in the secondary pressure chamber C2, is fixed near the rear end 212A of the valve body 21A, and a seal ring 27A is fitted around the outer circumference of the piston 26A. When the pressure regulating valve 20A is closed, the piston 26A comes into contact with a stepped portion 28A formed on the inside of the body 10A, thereby restricting further movement in the closing direction.

[0052] When the electric motor 30 stops and the valve is closed, the fluid pressure in the secondary pressure chamber C3 received by the piston 26A is converted into a pressure load that presses the valve body 21A against the seat surface 23A. This reduces the pressing force of the valve seat 22A against the seat surface 23A, thus preventing the occurrence of slow leaks via the pressure regulating valve 20A.

[0053] The electric motor 30 consists of a rotor 31 on which magnets 32 are arranged, and a stator 33 that supports the windings 34, and is controlled by a motor driver 35. As the electric motor, for example, an AC servo motor or a DC brushless motor can be used.

[0054] The electric motor 30 is housed in the pressure control chamber 3, which is airtightly isolated from the primary pressure chamber C1 and the secondary pressure chamber C2. The electric motor 30 has a substantially cylindrical rotor 31 with multiple magnets 32 arranged on its outer circumference so as to face each stator 33, and its central axis is aligned with that of the valve body 21A so as to be rotatable.

[0055] The rotor 31 is supported by two sliding bearings 36 located at its upper and lower ends, and rotates due to the magnetic force generated by energizing the winding 34 opposite the magnet 32, thereby driving the electric motor 30. Furthermore, by using a self-lubricating resin with excellent surface lubrication performance as the material for the sliding bearings 36, the smooth rotation of the rotor 31 can be ensured over a long period of time without the need for periodic lubrication of the friction parts.

[0056] A cover 38 for aligning the rotor 31 and mounting the magnetic pole position sensor 37 is provided above the stator 33, and a magnet 39 is provided above the rotor 31. The magnetic pole position sensor 37 can detect the rotational position of the rotor 31 by combining the magnet 39 and the magnetic poles generated by the current flowing through the stator 33.

[0057] The valve body movement structure 40 consists of a male screw portion 41 formed on the outer circumferential surface of the valve body 21A, a female screw portion 42 formed on the inner circumferential surface of the rotor 31 that engages with the male screw portion 41, and a rotation stopper 50 provided on the rear end 212A side of the valve body 21A, and is a feed screw structure that converts the rotational motion of the electric motor 30 into the linear motion of the valve body 21A.

[0058] The anti-rotation device 50 consists of an anti-rotation projection 51 that protrudes circumferentially outward from the rear end 212A of the valve body 21A, and an anti-rotation guide 52 that protrudes axially (towards the fluid discharge port 13) from the piston 26A so as to sandwich the anti-rotation projection 51.

[0059] When the electric motor 30 is driven, the rotational motion of the rotor 31 is transmitted to the valve body 21A via the female screw portion 42 and the male screw portion 41. However, the rotation-restricting projection 51 on the valve body 21A side and the rotation-restricting guide 52 on the piston 26A side come into contact, restricting the rotational motion of the valve body 21A and converting it into linear motion in the axial direction.

[0060] In this case, the tension of the seal ring 27A mounted on the outer circumference of the piston 26A is greater than the motor torque, and furthermore, when pressure is applied, a load is also added that presses the valve body 21A against the seat surface 23A of the valve seat 22A, so the piston 26A and the valve body 21A do not rotate simultaneously.

[0061] The pressure sensor 7 detects the fluid pressure on the secondary pressure chamber C2 side. The pressure sensor is not limited to being installed within the secondary pressure chamber C2; for example, it may be installed at another location, such as downstream of the fluid outlet 13, and the fluid pressure value input to the vehicle's ECU may be used.

[0062] In this embodiment, the pressure regulating structure operates the pressure regulating valve 20A by controlling the electric motor 30 based on the fluid pressure in the secondary pressure chamber C2 detected by the pressure sensor 7, thereby activating the valve body movement structure 50. By changing the lift amount of the valve body 21A, the flow rate of the fluid passing through the communication passage 25A from the primary pressure chamber 1 to the secondary pressure chamber 2 is changed, thereby automatically adjusting the fluid pressure of the discharged gas fuel to be equal to the set pressure.

[0063] As described above, the electronically controlled regulator 3A according to this embodiment employs a method of adjusting the discharge pressure by driving and controlling the electric motor 30 based on the discharge pressure detected by the pressure sensor 7, thereby causing the valve body 21A to reciprocate in the axial direction using the valve body movement structure 50 to open and close the pressure regulating valve 20A (changing the opening area). Therefore, it is possible to handle various required discharge pressures and flow rates with a single product without requiring the replacement of parts.

[0064] Next, while referring to the cross-sectional views of FIGS. 2 to 3 and the functional block diagram of FIG. 4, the operation according to this embodiment will be described.

[0065] During normal operation of the electronically controlled regulator 3A, as shown in FIG. 4, a drive command is input from the ECU 9, which is an electronic control means, to the motor driver 35.

[0066] At this time, when the relationship between the target pressure (Pref) and the discharge pressure (Pout) detected by the pressure sensor 7 is such that Pref > Pout, a current is applied to the winding 34 of the stator 33 so that the rotor 31 rotates in the direction of opening the valve body 22A. When the rotor 31 rotates in the direction of opening the valve body 21A, the valve body 21A moves in the opening direction by the valve body movement structure 50, and the valve body 21A moves away from the seat surface 23A of the valve seat 22A, resulting in an open valve state as shown in FIG. 3.

[0067] Conversely, when the relationship between the target pressure (Pref) and the discharge pressure (Pout) is such that Pref < Pout, a current is applied to the winding 34 of the stator 33 so that the rotor 31 rotates in the direction of closing the valve body 22A. When the rotor 31 rotates in the direction of closing the valve body 21A, the valve body 21A moves in the closing direction by the valve body movement structure 50, and the valve body 21A moves in the closing direction and comes into close contact with the seat surface 23A of the valve seat 22A, resulting in a closed valve state as shown in FIG. 2.

[0068] By performing the above control to open and close (change the opening area) the pressure regulating valve 20A, the pressure of the discharged fluid can be maintained at a predetermined set pressure. The set pressure can be arbitrarily changed according to the usage conditions of the regulator.

[0069] And, for example, when the fluid pressure detected by the pressure sensor 7 exceeds the pressure threshold value or when the engine stops (when not energized), the electromagnetic relief valve 8 is opened to release the gas fuel discharged from the fluid discharge port 13 to the outside and relieve the fluid pressure.

[0070] Furthermore, for example, when the fluid pressure detected by the pressure sensor 7 exceeds the pressure threshold, or when the engine is stopped (not energized), the electromagnetic shut-off valve 2 is also closed to shut off the introduction of gas fuel from the fluid inlet 12.

[0071] When the electromagnetic shut-off valve 2 is closed, the fluid supply to the electronically controlled regulator 3A is cut off, and therefore the release of gas fuel from the electromagnetic relief valve 8 also stops.

[0072] ≪Second Embodiment of Electronically Controlled Regulator≫ A second embodiment of the electronically controlled regulator is described below. Components similar to those in the first embodiment of the electronically controlled regulator are denoted by the same reference numerals and their descriptions are omitted.

[0073] Figure 5 shows the closed state of the second electronically controlled regulator 3B of the present invention, and Figure 6 shows the open state of the electronically controlled regulator 3B.

[0074] This electronically controlled regulator 3B, like the electronically controlled regulator 3A, is a pressure reducing device in a gas fuel supply system that reduces the pressure of a high-pressure fluid, such as gas fuel, to a predetermined pressure.

[0075] The electronically controlled regulator 3B comprises a body 10B forming a fluid passage 11 through which gas fuel passes, a pressure regulating valve 20B provided on the fluid passage 11, and an electronically controlled electric motor 30. The electronically controlled regulator 3B is also connected to a pressure sensor 7, an electromagnetic shut-off valve 2, and an electromagnetic relief valve 8.

[0076] The body 10B is cylindrical in shape, with one end of the fluid passage 11 serving as the fluid inlet 12 and the other end of the fluid passage 11 serving as the fluid outlet 13.

[0077] The pressure regulating valve 20B is installed on the fluid passage 11 and separates the primary pressure chamber C1 on the fluid inlet 12 side from the secondary pressure chamber C2 on the fluid outlet 13 side. In addition, a pressure control chamber C3 is provided within the body 10B, isolated from the primary pressure chamber C1 and the secondary pressure chamber C2, for operating the pressure regulating valve 20B to reduce and adjust the fluid pressure of the discharged gas fuel to a set pressure.

[0078] The pressure regulating valve 20B consists of a rod-shaped valve body 21B that can reciprocate in the axial direction, an annular valve seat 22B having a valve hole 23B that can be closed by the valve body 21B at its center, and a discharge pressure regulating mechanism that adjusts the discharge pressure by changing the distance between the valve body 21B and the valve seat 22B by reciprocating the valve body 21B.

[0079] The discharge pressure adjustment mechanism consists of an electric motor 30 equipped with a rotor 31, a motor driver 35 that drives and controls the electric motor 30, and a valve body movement structure 40.

[0080] Then, using an electronically controlled electric motor 30 as the driving source, the valve seat 22B is moved axially back and forth between a closed position (Figure 5) where the valve body 21B closes the valve hole 23B of the valve seat 22B and an open position (Figure 6) where the valve body 21B is separated from the valve hole 23B of the valve seat 22B, thereby changing the opening area and automatically adjusting so that the pressure of the discharged fluid becomes equal to the set pressure.

[0081] A valve body retaining portion 16 for holding the valve body 21B is formed at an intermediate position in the fluid passage 11. A seal ring 18 is fitted to the valve body retaining portion 16.

[0082] The seal ring 18, through engagement with the valve body 21B, hermetically isolates the pressure control chamber C3 from the primary pressure chamber C1 and the secondary pressure chamber C2.

[0083] When the valve is open and the valve body 21B is separated from the valve hole 23B of the valve seat 22B, the primary pressure chamber C1 on the fluid inlet 12 side and the secondary pressure chamber C2 on the fluid outlet 13 side are connected via the valve hole 23B, and the gaseous fuel is moved from the primary pressure chamber C1 to the secondary pressure chamber C2.

[0084] Conversely, when the valve is closed, with the valve body 21B blocking the valve hole 23B of the valve seat 22B, the movement of fluid from the primary pressure chamber C1 to the secondary pressure chamber C2 is restricted.

[0085] The valve body 21B is pushed up by spring 29a so as to close the valve hole 23B of the valve seat 22B. The valve seat 22B is also pressed and held in place by spring 29b.

[0086] The valve body movement structure 40 consists of a male screw portion 41 formed on the outer circumferential surface of the motion shaft 60B, a female screw portion 42 formed on the inner circumferential surface of the rotor 31 that meshes with the male screw portion 41, and a rotation stopper 50 using a rotation stopper shaft 70B that is slidably inserted into the motion shaft 60B, and is a feed screw structure that converts the rotational motion of the electric motor 30 into the linear motion of the valve body 21B.

[0087] The motion shaft 60B is coaxially connected to the valve body 21B by inserting one end of the valve body 21B into a connecting hole 61B formed at one end of the shaft 60B. The valve body 21B and the motion shaft 60B can be fixed to each other, for example, by screw fitting.

[0088] The motion shaft 60B has an insertion hole 62B formed on its inner circumferential surface at the end opposite to the connecting hole 61B, with a flat portion 63B formed thereon. The anti-rotation shaft 70B, with its base end 72B fixed to the body 10B and a flat portion 73B formed on the outer circumferential surface of its tip 71B, is slidably inserted into the insertion hole 62B in the axial direction, thereby forming the anti-rotation mechanism 50 (see Figure 7).

[0089] In other words, the rotational motion of the motion shaft 60 is restricted by the contact of the planar portions of the motion shaft 60B and the anti-rotation shaft 70B, and converted into linear motion in the axial direction, thereby moving the valve body 21B connected to the motion shaft 60.

[0090] Next, the operation of this embodiment will be explained with reference to the cross-sectional views in Figures 5 and 6, and the functional block diagram in Figure 4.

[0091] During normal operation of the electronic control regulator 3B, as shown in Fig. 4, a drive command is input from the ECU 9, which is an electronic control means, to the motor driver 35.

[0092] At this time, when the relationship between the target pressure (Pref) and the discharge pressure (Pout) detected by the pressure sensor 40 is such that Pref > Pout, a current is applied to the winding 34 of the stator 33 so that the rotor 31 rotates in the direction of opening the valve body 21B. When the rotor 31 rotates in the direction of opening the valve body 21B, the valve body 21B moves in the opening direction by the valve body movement structure 40, and the closing of the valve hole 23B of the valve seat 22B by the valve body 21B is released, resulting in an open valve state as shown in Fig. 6.

[0093] Conversely, when the relationship between the target pressure (Pref) and the discharge pressure (Pout) is such that Pref < Pout, a current is applied to the winding 34 of the stator 33 so that the rotor 31 rotates in the direction of closing the valve body 21B. When the rotor 31 rotates in the direction of closing the valve body 21B, the valve body 21B moves in the closing direction by the valve body movement structure 40, the valve body 21A moves in the closing direction, the valve body 21B closes the valve hole 23B of the valve seat 22B, resulting in a closed valve state as shown in Fig. 5.

[0094] By performing the above control to open and close (change the opening area) the pressure regulating valve 20B, the pressure of the discharged fluid can be maintained at a predetermined set pressure. The set pressure can be arbitrarily changed according to the usage conditions of the regulator.

[0095] Thus, according to the electronic control regulators 3A and 3B, based on the discharge pressure detected by the pressure sensor 7, the electric motor 30 is driven and controlled to reciprocate the valve bodies 21A and 21B in the axial direction to open and close (change the opening area) the pressure regulating valves 20A and 20B, thereby adopting a method of adjusting the discharge pressure. This enables one product to cope with various required discharge pressures and required flow rates without the need for component replacement.

[0096] Although the electronically controlled regulator 3A of the first embodiment and the electronically controlled regulator 3B of the second embodiment have a relationship where the structure of the valve body and valve seat are inversely related, the present invention can be applied to both embodiments.

[0097] As described above, the present invention provides a fuel supply system that can automatically maintain various specified discharge pressures while responding to fluctuations in the required flow rate by using an electronically controlled regulator, and that can safely switch to an open state in the event of a malfunction such as a power supply failure, thereby releasing fluid pressure and preventing damage or failure of the equipment by using a normally open electromagnetic relief valve. [Explanation of Symbols]

[0098] 100 Fuel supply system 1 Fuel tank 2. Electromagnetic shutoff valve 3,3A,3B Electronically Controlled Regulator 4. Oil filter 5 Injectors 6 engines 7. Pressure Sensor 8. Electromagnetic relief valve 9 ECU 10A, 10B Body 11 Fluid passage 12 Fluid inlet 13 Fluid outlet 14 Entrance cover 15. Outlet cover 16 Valve body retaining part 17 colors 18 sealing rings 19 Retaining member 20A, 20B pressure regulating valve 21A, 21B valve body 22A,22B Valve seat 23A Seat surface 23B Valve hole 24A communication path 25A Valve seat retaining member 26A Piston 27A Seal Ring 28A Step 29a, 29b Spring 30 Electric motors 31 Rotors 32 magnets 33 Status 34 windings 35 Motor Driver 36 Bearings 37 Magnetic pole position sensor 38 Cover 39 Magnets 40 Valve body movement structure 41 Male screw part 42 Female thread section 50 Rotation stopper 51 Anti-rotation projection 52 Anti-rotation guide 60B motion axis 61B connection hole 62B Insertion hole 63B Plane part 70B Anti-rotation shaft 71B Tip 72B Proximal end 73B Plane part 211A Tip 212A rear end C1 Primary pressure chamber C2 Secondary pressure chamber C3 Pressure Control Room Bp branch pipe

Claims

1. In a fuel supply system that supplies gaseous fuel to an engine, An electronically controlled regulator that reduces the introduced gas fuel to a set pressure and discharges it, A pressure sensor that detects the fluid pressure of gaseous fuel after depressurization, The electronically controlled regulator is equipped with a normally open electromagnetic relief valve located downstream of the pressure regulating valve, The electromagnetic relief valve opens when the fluid pressure detected by the pressure sensor reaches a pressure threshold or when the system is de-energized, releasing the gaseous fuel outside the system. A fuel supply system characterized by the following features.

2. The aforementioned electronically controlled regulator is A body having a fluid passage formed inside, with each end of the fluid passage serving as a fluid inlet and a fluid outlet, A pressure regulating valve is provided in the fluid passage and divides the primary pressure chamber on the fluid inlet side and the secondary pressure chamber on the fluid outlet side. Equipped with an electronically controlled electric motor, The pressure regulating valve is A valve body capable of reciprocating motion in the axial direction, A valve seat positioned opposite the valve body, The discharge pressure adjustment mechanism uses the aforementioned electric motor as a driving source to reciprocate the valve body in the axial direction, thereby changing the distance between the valve body and the valve seat and adjusting the pressure of the gas fuel to the set pressure, The fuel supply system according to claim 1, characterized in that it is the same as described in claim 1.

3. The aforementioned discharge pressure adjustment mechanism is It consists of a male screw portion, a female screw portion, and a rotation stopper, and has a valve body movement structure that converts the rotational motion of the electric motor into the linear motion of the valve body. The male screw portion is formed on the outer circumferential surface of the valve body or on the outer circumferential surface of the motion shaft connected to the valve body. The female screw portion is formed on the inner circumferential surface of the rotor that constitutes the electric motor. The fuel supply system according to claim 2, characterized in that it is as described above.

4. The valve seat is an annular or disc-shaped member, The valve body is a cylindrical member having a communication passage that connects the primary pressure chamber and the secondary pressure chamber when the valve is open. The fuel supply system according to claim 2, characterized in that it is as described above.

5. The valve seat is an annular member having a valve hole, The valve body is a rod-shaped member that closes the valve hole when the valve is closed. The fuel supply system according to claim 2, characterized in that it is as described above.

6. Upstream from the aforementioned electronically controlled regulator, a normally closed electromagnetic shutoff valve is provided. The electromagnetic shut-off valve closes when the fluid pressure detected by the pressure sensor reaches the pressure threshold or when the valve is not energized. A fuel supply system according to claim 1, 2, 3, 4, or 5, characterized in that it is the same as described above.

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