Fuel supply system

Abstract

Provided is a fuel supply system that supplies a gaseous fuel to an engine of a vehicle or the like, that can adjust the fluid pressure of the discharged gaseous fuel by electronic control, and that can safely release the fluid pressure of the gaseous fuel when a malfunction such as an energization failure occurs. A fuel supply system (100) for supplying a gaseous fuel to an engine (6) is provided with: an electronically controlled regulator (3) for reducing the pressure of an introduced gaseous fuel to a set pressure and discharging the gaseous fuel; a pressure sensor (7) that detects the fluid pressure of the decompressed gas fuel; and a normally open electromagnetic relief valve (8) which is provided downstream of the pressure regulating valve of the electronically controlled regulator (3), and which opens and releases the gaseous fuel to the outside of the system when the fluid pressure detected by the pressure sensor (7) reaches a pressure threshold value or when the pressure sensor (7) is not energized.

Description

TECHNICAL FIELD

[0001] The present application relates to a fuel supply system that supplies gaseous fuel to an engine. BACKGROUND

[0002] Gaseous fuel for vehicles is stored in a tank in a high-pressure liquid state, and therefore needs to be reduced in pressure to a predetermined pressure and supplied to an engine in a gaseous state. As a regulator for pressure reduction adjustment, for example, an electronic control type pressure control device using a solenoid valve, such as that described in Patent Document 1, is known.

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

[0004] PRIOR ART DOCUMENTS

[0005] PATENT DOCUMENTS

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-005729 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] However, the pressure control device of Patent Document 1 is a structure that closes the valve at the time of engine stop (non-energization), and the fuel tank valve provided at the fuel tank has the function as a safety device. Therefore, in the case where a failure occurs in the fuel tank valve, high-pressure gaseous fuel will flow into the pressure control device, and the excess fluid pressure can cause damage, failure of the pressure control device and the equipment further downstream, and thus a serious problem can occur.

[0009] The present application is made to solve the above problems, and aims to, in a fuel supply system that supplies gaseous fuel to an engine of a vehicle or the like, be able to adjust the fluid pressure of the discharged gaseous fuel by electronic control, and be able to safely release the fluid pressure of the gaseous fuel at the time of a failure such as poor energization.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] To solve the above problems, the present application provides a fuel supply system that supplies gaseous fuel to an engine, characterized by comprising: an electronically controlled regulator that depressurizes introduced gaseous fuel to a set pressure and discharges it; a pressure sensor that detects the fluid pressure of the depressurized gaseous fuel; and a normally open electromagnetic dump valve provided downstream of a pressure regulating valve of the electronically controlled regulator, which opens to release gaseous fuel to the outside of the system when the fluid pressure detected by the pressure sensor reaches a pressure threshold or when it is not energized.

[0012] Effects of the Invention

[0013] According to the present application, the fluid pressure can be safely dumped by the electromagnetic dump valve. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic configuration view showing an example of the fuel supply system of the present application;

[0015] Figure 2 is a longitudinal sectional view showing a closed valve state of the first embodiment of the electronically controlled regulator of the present application;

[0016] Figure 3 is a longitudinal sectional view showing an open valve state of the first embodiment of the electronically controlled regulator of the present application;

[0017] Figure 4 is a functional block diagram of the fuel supply system to which the first or second embodiment of the electronically controlled regulator of the present application is applied;

[0018] Figure 5 is a longitudinal sectional view showing a closed valve state of the second embodiment of the electronically controlled regulator of the present application;

[0019] Figure 6 is a longitudinal sectional view showing an open valve state of the second embodiment of the electronically controlled regulator of the present application;

[0020] Figure 7 is Figure 6 an A-A line sectional view of

[0021] Explanation of Symbols

[0022] 100 fuel supply system;

[0023] 1 fuel tank;

[0024] 2 electromagnetic shutoff valve;

[0025] 3, 3A, 3B electronically controlled regulator;

[0026] 4 oil filter;

[0027] 5 injector;

[0028] 6 engine;

[0029] 7 pressure sensor;

[0030] 8 electromagnetic unloading valve;

[0031] 9 ECU;

[0032] 10A, 10B main body;

[0033] 11 fluid passage;

[0034] 12 fluid introduction port;

[0035] 13 fluid discharge port;

[0036] 14 inlet cover;

[0037] 15 outlet cover;

[0038] 16 valve core holding portion;

[0039] 17 collar;

[0040] 18 seal ring;

[0041] 19 restriction member;

[0042] 20A, 20B pressure regulating valve;

[0043] 21A, 21B valve core;

[0044] 22A, 22B valve seat;

[0045] 23A valve seat seating surface;

[0046] 23B valve hole;

[0047] 24A communication path;

[0048] 25A valve seat holding member;

[0049] 26A piston;

[0050] 27A seal ring;

[0051] 28A stepped portion;

[0052] 29a, 29b spring;

[0053] 30 electric motor;

[0054] 31 rotor;

[0055] 32 magnet;

[0056] 33 stator;

[0057] 34 winding;

[0058] 35 motor driver;

[0059] 36 bearing;

[0060] 37 magnetic pole position sensor;

[0061] 38 cover;

[0062] 39 magnet;

[0063] 40 valve core moving structure;

[0064] 41 male screw portion;

[0065] 42 female screw portion;

[0066] 50 stopper;

[0067] 51 stopper protrusion;

[0068] 52 stopper guide;

[0069] 60B movement shaft;

[0070] 61B connecting hole;

[0071] 62B insertion hole;

[0072] 63B flat portion;

[0073] 70B stopper shaft;

[0074] 71B front end;

[0075] 72B base end;

[0076] 73B flat portion;

[0077] 211A front end;

[0078] 212A rear end;

[0079] C1 primary pressure chamber;

[0080] C2 secondary pressure chamber;

[0081] C3 pressure control chamber;

[0082] Bp bifurcated pipe. DETAILED DESCRIPTION

[0083] Hereinafter, a mode for carrying out the present application will be described with reference to the accompanying drawings.

[0084] <system configuration>

[0085] Figure 1 is a schematic configuration diagram showing an example of a fuel supply system 100 of the present application. Figure 1 The path shown in a solid line in the figure shows a fuel supply system of gaseous fuel, and the path shown in a broken line shows a communication line of signals. In the following description, the so-called "outside of the system" means the outside of the fuel supply system of gaseous fuel, such as the atmosphere released to the outside of the vehicle.

[0086] The fuel supply system 100 is a system that supplies gaseous fuel to an engine of a vehicle or the like, and has a fuel tank 1 that stores gaseous fuel such as CNG, LNG, LPG, hydrogen, an electromagnetic shutoff valve 2, an electronically controlled regulator 3, an oil filter 4, an injector 5, a pressure sensor 7, an electromagnetic dump valve 8, and an ECU 9.

[0087] Gaseous fuel sent out from the fuel tank 1 is supplied to the engine 6 in turn through the electromagnetic shutoff valve 2, the electronically controlled regulator 3, the oil filter 4, and the injector 5. Further, a further pressure reducing unit (not shown) can be provided between the fuel tank 1 and the electronically controlled regulator 3, or between the electronically controlled regulator 3 and the injector 5.

[0088] The electromagnetic shutoff valve 2 is a normally closed electromagnetic valve provided upstream of the electronically controlled regulator 3, and is maintained in an open state by being supplied with a power source in a normal state during engine driving.

[0089] The electronically controlled regulator 3 is driven by an electric motor controlled electronically, and reduces and discharges the introduced gaseous fuel to a set pressure.

[0090] The oil separator 4 is a filter for removing separated oil.

[0091] The injector 5 is connected to a fuel supply pipe of the engine 6 and a cylinder of the engine 6, and injects the reduced gaseous fuel.

[0092] The pressure sensor 7 is disposed at a downstream side of a pressure regulating valve of the electronically controlled regulator 3, and detects the fluid pressure of the reduced gaseous fuel.

[0093] The electromagnetic dump valve 8 is a normally open electromagnetic valve provided downstream of the electronically controlled regulator 3, and is maintained in a closed state by being supplied with a power source in a normal state during engine driving. When the fluid pressure detected by the pressure sensor 7 exceeds a predetermined pressure threshold, or when the engine is stopped (non-energized), the electromagnetic dump valve 8 is opened to release gaseous fuel to the outside of the system and to dump the pressure. The pressure threshold is set to a high pressure region higher than the set pressure of the gaseous fuel.

[0094] In Figure 1 In the example shown, the electromagnetic relief valve 8 is disposed at the branch pipe Bp provided downstream of the electronic control regulator 3, and a two-position two-port type control valve that switches between open and closed is used, but a three-port type control valve can also be used. In the case of using a three-port type control valve, there is no need to branch in advance through the branch pipe, and thus space saving can be achieved.

[0095] The ECU 9 is an electronic control unit that is connected to the electronic control regulator 3, the injector 5, and other devices, and performs control and the like.

[0096] <Explanation of Effects>

[0097] The effects of the present application will be described below.

[0098] First, as Comparative Example 1, the problems in the case of using a mechanical safety valve in a normally closed (normally closed) manner, for example, using a spring, diaphragm, or the like, will be described below.

[0099] In the case of using a mechanical safety valve in a normally closed manner, the mechanical safety valve operates automatically under the action of fluid pressure when the fluid pressure reaches a predetermined pressure threshold, opens the valve, and releases the gaseous fuel to the outside of the system to relieve the fluid pressure. Also, it automatically returns to the closed valve state by a spring, diaphragm, or the like force application unit when the fluid pressure is below a certain value.

[0100] The mechanical safety valve is premised on operating in an abnormal situation, and does not operate and does not open the valve during normal operation when the fluid pressure does not reach the pressure threshold. Therefore, it is not possible to perform an action such as opening the valve at the time of engine stop (non-energized time) in order to relieve the fluid pressure of the remaining gaseous fuel.

[0101] Next, as Comparative Example 2, the problems in the case of using an electromagnetic relief valve in a normally closed (normally closed) manner will be described below.

[0102] In the case of using an electromagnetic safety valve in a normally closed manner, the electromagnetic safety valve is energized when the fluid pressure reaches a predetermined pressure threshold, the solenoid is energized to open the valve, and the gaseous fuel is released to the outside of the system to relieve the fluid pressure. Also, it becomes non-energized and returns to the closed valve state when the fluid pressure is below a certain value. In addition to this, it is possible to open the electromagnetic relief valve at the time of engine stop (non-energized time) to relieve the fluid pressure of the remaining gaseous fuel.

[0103] However, assuming an electrical fault such as a broken wire occurs, the solenoid relief valve will fail to operate and remain closed. If the solenoid relief valve is closed, it cannot function as a relief valve and cannot release the fluid pressure of the gaseous fuel. Therefore, under conditions of poor pressure regulation by the electronically controlled regulator, valve leakage, etc., the excessive fluid pressure may lead to serious problems such as damage or malfunction of the electronically controlled regulator or downstream equipment. Furthermore, normally closed solenoid relief valves require a relay circuit and an external power supply to open the valve when the engine is stopped (not energized).

[0104] In contrast, the following describes the operation of an electromagnetic discharge valve that is normally open (normally open) as described in this invention.

[0105] When using a normally open electromagnetic safety valve, the valve becomes de-energized and opens when the fluid pressure reaches a predetermined pressure threshold, releasing the gaseous fuel outside the system to relieve fluid pressure. Furthermore, when the fluid pressure falls below a certain value, it is energized, activating the helical tube and returning it to the closed state. In addition, the electromagnetic relief valve can be opened when the engine is stopped (when de-energized) to release the residual fluid pressure of the gaseous fuel.

[0106] By using a normally open electromagnetic discharge valve, the valve can automatically operate and open even in the event of an electrical fault such as a broken wire. The gaseous fuel is then safely and quickly released outside the system through the opened electromagnetic discharge valve.

[0107] In this way, the normally open electromagnetic relief valve can reliably perform its function as a relief valve. Therefore, even if there are multiple adverse conditions such as poor pressure regulation of the electronic control regulator or valve leakage, the fluid pressure of the gaseous fuel can be relieved, thereby avoiding damage or failure of the electronic control regulator or downstream equipment.

[0108] Moreover, by using a normally open electromagnetic discharge valve, unlike a normally closed electromagnetic discharge valve, there is no need to construct a relay circuit or external power supply. Therefore, the structure can be simplified and the cost can be reduced.

[0109] In addition, Figure 1 In the fuel supply system 100 shown, a normally closed (usually shut-off) electromagnetic shut-off valve is installed upstream of the electronically controlled regulator. The electromagnetic shut-off valve becomes de-energized and closes when the fluid pressure reaches a predetermined pressure threshold or when the engine is stopped (not energized).

[0110] By using the electromagnetic shutoff valve of the normally closed type, even in the event of an electrical failure such as a broken wire, the electromagnetic shutoff valve automatically operates to close the valve. At the time when the electromagnetic shutoff valve is closed, the supply of fluid to the electronically controlled regulator is cut off, and therefore the release of gaseous fuel from the electromagnetic release valve is also stopped.

[0111]

[0112] Next, the electronically controlled regulator of the present application will be described.

[0113] First Embodiment of Electronically Controlled Regulator

[0114] Figure 2 and Figure 3 are diagrams showing the first embodiment of the electronically controlled regulator. Figure 2 shows a closed valve state of the electronically controlled regulator 3A, Figure 3 shows an open valve state of the electronically controlled regulator 3A.

[0115] The electronically controlled regulator 3A is a pressure reducing device that reduces the pressure of gaseous fuel, which is a high-pressure fluid, to a predetermined pressure in a gaseous fuel supply system.

[0116] The electronically controlled regulator 3A includes a main body 10A that forms a fluid passage 11 through which fluid passes, a pressure regulating valve 20A that is provided on the fluid passage 11, and an electronically controlled electric motor 30. In addition, a pressure sensor 7, an electromagnetic shutoff valve 2, and an electromagnetic release valve 8 are connected.

[0117] The main body 10A is cylindrical, has one end of the fluid passage 11 as a fluid inlet 12 and the other end of the fluid passage 11 as a fluid outlet 13. An inlet cover 14 is attached to the fluid inlet 12 side, and an outlet cover 15 is attached to the fluid outlet 13 side.

[0118] The pressure regulating valve 20A is provided on the fluid passage 11 and divides a primary pressure chamber Cl on the fluid inlet 12 side and a secondary pressure chamber C2 on the fluid outlet 13 side. In addition, a pressure control chamber C3 for operating the pressure regulating valve 20A is provided between the primary pressure chamber Cl and the secondary pressure chamber C2, and reduces and regulates the pressure of the discharged fluid to a set pressure.

[0119] The pressure regulating valve 20A is composed of a cylindrical valve element 21A that can reciprocate in the axial direction, a ring-shaped valve seat 22A that has a valve seat seating surface 23A against which the valve element 21A abuts, and an outlet pressure regulating mechanism that regulates the outlet pressure by causing the valve element 21A to reciprocate so as to change the distance between the valve element 21A and the valve seat 22A. ​

[0120] The discharge pressure regulating mechanism is constituted by an electric motor 30 including a rotor 31, a motor driver 35 which drives and controls the electric motor 30, and a spool moving mechanism 40. Further, the electric motor 30 is driven as a drive source to be electronically controlled, and the spool 21A is reciprocated along the axial direction between a closed valve position (X1) in which the spool 21A is in close contact with the valve seat surface 23A of the valve seat 22A and an open valve position (X2) in which the spool 21A is separated from the valve seat surface 23A of the valve seat 22A, so as to change the opening area, while the pressure of the discharged fluid is automatically regulated to be equal to the set pressure. Figure 2 )and the open valve position ( Figure 3 )in which the spool 21A is separated from the valve seat surface 23A of the valve seat 22A, so as to change the opening area, while the pressure of the discharged fluid is automatically regulated to be equal to the set pressure.

[0121] The spool 21A is a cylindrical member in which a communication passage 24A through which fluid passes is formed in the inside. The end portion of the spool 21A seated on the side of the valve seat 22A is provided as a front end 211A, and the end portion on the opposite side thereof is provided as a rear end 212A.

[0122] In the open valve in which the spool 21A is separated from the valve seat surface 23A of the valve seat 22A, the primary pressure chamber Cl side of the fluid introduction port 12 and the secondary pressure chamber C2 side of the fluid discharge port 13 are communicated via the communication passage 24A in the inside of the spool 21A, so as to move the gaseous fuel from the primary pressure chamber Cl to the secondary pressure chamber C2.

[0123] On the contrary, in the closed valve in which the spool 21A is seated on the valve seat surface 23A of the valve seat 22A, the movement of the fluid from the primary pressure chamber Cl to the secondary pressure chamber C2 is restricted.

[0124] The valve spool holding portion 16 for holding the spool 21A is formed at the intermediate position of the fluid passage 11. The annular collar 17 and the seal ring 18 located on the primary pressure chamber Cl side than the collar 17 are installed in the valve spool holding portion 16.

[0125] The collar 17 has an inner diameter slightly larger than the outer diameter of the spool 21A, and has a function of preventing the spool 21A from directly contacting the main body 10A while guiding the reciprocating movement of the spool 21A in the axial direction. The material of the collar 17 can be formed of synthetic resin, and is particularly preferably PTFE or the like having good sliding properties.

[0126] The seal ring 18 has a function of hermetically sealing the valve spool holding portion 16 and the spool 21A. The collar 17 and the seal ring 18 are held by the restriction member 19 on the primary pressure chamber Cl side so as not to be detached from the valve spool holding portion 16.

[0127] The valve seat 22A is fixed to the disc-shaped valve seat holding member 25A by adhesion, insert molding, or the like. The valve seat holding member 25A is fitted between the inlet cover 14 and the main body 10A, and allows the gaseous fuel to pass through the through hole formed around the valve seat 22A.

[0128] A piston 26A that receives the fluid pressure in the secondary pressure chamber C2 is fixed near the rear end 212A of the valve element 21A, and a seal ring 27A is fitted to the outer periphery of the piston 26A. When the pressure regulating valve 20A is closed, the piston 26A is brought into contact with a stepped portion 28A formed on the inner side of the main body 10A, so as to restrict further movement thereof in the closing direction.

[0129] At the time of closing when the electric motor 30 is stopped, the fluid pressure in the secondary pressure chamber C2 received by the piston 26A is converted into a pressure load in the direction in which the valve element 21A is pressed against the valve seat surface 23A, and thus, slow leakage through the pressure regulating valve 20A due to a decrease in the pressing force against the valve seat surface 23A of the valve seat 22A can be prevented.

[0130] The electric motor 30 is composed of a rotor 31 to which a magnet 32 is attached and a stator 33 that supports the rotor 31 in a state in which a winding 34 is wound therearound, and is controlled by a motor driver 35. As the electric motor, for example, an AC servo motor or a DC brushless motor, or the like can be used.

[0131] The electric motor 30 is housed in a pressure control chamber C3 that is hermetically separated from the primary pressure chamber Cl and the secondary pressure chamber C2. In the electric motor 30, a substantially cylindrical rotor 31 is attached so as to have the same center axis as the valve element 21A and be rotatable, and a plurality of magnets 32 are attached to the outer periphery side of the rotor in opposition to the respective stators 33.

[0132] The rotor 31 is axially supported by two sliding bearings 36 attached to the upper and lower end sides thereof, is rotated by the magnetic force generated by energizing the winding 34 opposite to the magnet 32, and drives the electric motor 30. In addition, a self-lubricating resin having excellent surface lubrication properties is used as the raw material of the sliding bearing 36, and thus, smooth rotation of the rotor 31 can be ensured for a long period of time without the need for periodic oiling of the frictional portion.

[0133] A cover 38 for centering the shaft of the rotor 31 and mounting of a magnetic pole position sensor 37 is attached to the upper side of the stator 33, and a magnet 39 is attached to the upper side of the rotor 31. The rotational position of the rotor 31 is detected by the magnetic pole position sensor 37 in combination with the magnetic poles generated by the magnet 39 and the current flowing through the stator 33.

[0134] The valve core moving structure 40 is constituted of a male screw portion 41, a female screw portion 42, and a rotation stopper 50, which is a feed screw structure that converts the rotational motion of the electric motor 30 into the linear motion of the valve core 21A, wherein the male screw portion is formed on the outer peripheral surface of the valve core 21A, the female screw portion is formed on the inner peripheral surface of the rotor 31 and engages with the male screw portion 41, and the rotation stopper is provided on the rear end 212A side of the valve core 21A.

[0135] The rotation stopper 50 is constituted of a rotation stopper protrusion 51, which is provided to protrude outward in the circumferential direction at the rear end 212A of the valve core 21A, and a rotation stopper guide 52, which is provided to protrude from the piston 26A toward the axial direction (the fluid discharge port 13 direction) in a manner of sandwiching the rotation stopper protrusion 51.

[0136] When the electric motor 30 is driven, the rotational motion of the rotor 31 is transmitted to the valve core 21A via the female screw portion 42 and the male screw portion 41, but is restricted from rotating by the rotation stopper protrusion 51 on the valve core 21A side contacting the rotation stopper guide 52 on the piston 26A side, and is converted into the linear motion in the axial direction.

[0137] At this time, the pressing force of the seal ring 27A, which is mounted on the outer periphery of the piston 26A, is greater than the motor torque, and in addition to the pressing force, a load in the direction of pushing the valve core 21A toward the valve seat seating surface 23A of the valve seat 22A is also applied, so the piston 26A and the valve core 21A do not rotate at the same time.

[0138] The pressure sensor 7 detects the fluid pressure on the secondary pressure chamber C2 side. The setting position of the pressure sensor is not limited to the inside of the secondary pressure chamber C2, and for example, can be set at other positions such as the downstream of the fluid discharge port 13, and the value of the fluid pressure input to the ECU of the vehicle is used.

[0139] The pressure regulating structure of the present embodiment controls the electric motor 30 based on the fluid pressure on the secondary pressure chamber C2 side detected by the pressure sensor 7, whereby the valve core moving structure 40 is operated to operate the pressure regulating valve 20A. Thereafter, the flow rate of the fluid flowing from the primary pressure chamber Cl to the secondary pressure chamber C2 through the communication path 24A is changed by changing the lift amount of the valve core 21A, whereby the fluid pressure of the discharged gaseous fuel is automatically regulated to be equal to the set pressure.

[0140] The electronic control type regulator 3A of the present embodiment, as follows, adopts a manner in which the electric motor 30 is driven and controlled based on the discharge pressure detected by the pressure sensor 7, and the valve element 21A is reciprocated along the axial direction by the valve element moving structure 40 to open and close (change the opening area) the pressure regulating valve 20A, thereby regulating the discharge pressure. Thus, without replacing parts, various required discharge pressures and required flow rates can be dealt with by one product.

[0141] Next, the operation of the present embodiment will be described with reference to Figure 2 to Figure 3 a cross-sectional view and Figure 4 a functional block diagram.

[0142] As shown in Figure 4 , during normal operation of the electronic control type regulator 3A, a drive command is input from the ECU 9 as an electronic control unit to the motor driver 35.

[0143] At this time, in a case where the relationship between the target pressure (Pref) and the discharge pressure (Pout) detected by the pressure sensor 7 is Pref > Pout, current is applied to the winding 34 of the stator 33 in a manner such that the rotor 31 rotates in a direction in which the valve element 21A is opened. When the rotor 31 rotates in the direction in which the valve element 21A is opened, the valve element 21A is moved in the opening direction by the valve element moving structure 40, the valve element 21A separates from the valve seat seating surface 23A of the valve seat 22A, and becomes an open valve state as shown in Figure 3 .

[0144] On the contrary, in a case where the relationship between the target pressure (Pref) and the discharge pressure (Pout) is Pref < Pout, current is applied to the winding 34 of the stator 33 in a manner such that the rotor 31 rotates in a direction in which the valve element 21A is closed. When the rotor 31 rotates in the direction in which the valve element 21A is closed, the valve element 21A is moved in the closing direction by the valve element moving structure 40, the valve element 21A comes into close contact with the valve seat seating surface 23A of the valve seat 22A, and becomes a closed valve state as shown in Figure 2 .

[0145] 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 use conditions of the regulator.

[0146] Furthermore, for example, when the fluid pressure detected by the pressure sensor 7 exceeds a pressure threshold, at the time of engine stop (non-energization), the electromagnetic dump valve 8 is opened to release the gaseous fuel discharged from the fluid discharge port 13 to the outside to dump the fluid pressure.

[0147] Further, when the fluid pressure detected by the pressure sensor 7 exceeds the pressure threshold value, when the engine is stopped (non-energized), and at the same time the electromagnetic shutoff valve 2 is closed, the introduction of the gaseous fuel from the fluid introduction port 12 is cut off.

[0148] At the time when the electromagnetic shutoff valve 2 is closed, the supply of the fluid to the electronically controlled regulator 3A is cut off, and therefore the release of the gaseous fuel from the electromagnetic dump valve 8 is also stopped.

[0149] Second Embodiment of Electronically Controlled Regulator

[0150] Next, the second embodiment of the electronically controlled regulator will be described. The same reference numerals are assigned to the same structural elements as those of the first embodiment of the electronically controlled regulator, and the description thereof will be omitted.

[0151] Figure 5 A closed state of the second electronically controlled regulator 3B of the present application is shown, Figure 6 An open state of the electronically controlled regulator 3B is shown.

[0152] The electronically controlled regulator 3B is, like the electronically controlled regulator 3A, a pressure-reducing device that reduces the gaseous fuel as a high-pressure fluid to a predetermined pressure in a gaseous fuel supply system.

[0153] The electronically controlled regulator 3B includes a main body 10B that forms a fluid passage 11 through which the gaseous fuel passes, a pressure regulating valve 20B that is provided on the fluid passage 11, and an electronically controlled electric motor 30. Further, the electronically controlled regulator 3B is connected to the pressure sensor 7, the electromagnetic shutoff valve 2, and the electromagnetic dump valve 8.

[0154] The main body 10B is cylindrical, and one end of the fluid passage 11 is a fluid introduction port 12, and the other end of the fluid passage 11 is a fluid discharge port 13.

[0155] The pressure regulating valve 20B is provided on the fluid passage 11 and divides a primary pressure chamber Cl on the fluid introduction port 12 side and a secondary pressure chamber C2 on the fluid discharge port 13 side. Further, in the main body 10B, a pressure control chamber C3 for operating the pressure regulating valve 20B to reduce and regulate the fluid pressure of the discharged gaseous fuel to a set pressure is provided separately from the primary pressure chamber Cl and the secondary pressure chamber C2.

[0156] The pressure regulating valve 20B consists of a rod-shaped valve core 21B, an annular valve seat 22B, and a discharge pressure regulating mechanism. The valve core can reciprocate along the axial direction, and the valve seat has a valve hole 23B at the center that can be blocked by the valve core 21B. The discharge pressure regulating mechanism adjusts the discharge pressure by causing the valve core 21B to reciprocate, thereby changing the distance between it and the valve seat 22B.

[0157] The discharge pressure regulating mechanism consists of an electric motor 30, a motor driver 35, and a valve core moving structure 40. The electric motor includes a rotor 31, and the motor driver drives and controls the electric motor 30.

[0158] Furthermore, using an electronically controlled electric motor 30 as the driving source, the valve core 21B is positioned along the axial direction at the valve-closed position where the valve core 21B blocks the valve hole 23B of the valve seat 22B. Figure 5 The valve opening position is when the valve core 21B is separated from the valve hole 23B of the valve seat 22B. Figure 6 The reciprocating motion between the two causes the opening area to change, and at the same time, the pressure of the discharged fluid is automatically adjusted to be equal to the set pressure.

[0159] A valve core retaining portion 16 for retaining the valve core 21B is formed at the middle position of the fluid passage 11. A sealing ring 18 is installed in the valve core retaining portion 16.

[0160] The sealing ring 18 engages with the valve core 21B to airtightly isolate the pressure control chamber C3 from the primary pressure chamber C1 and the secondary pressure chamber C2.

[0161] When the valve is opened and the valve core 21B and the valve seat 22B are separated by the valve hole 23B, the primary pressure chamber C1 on the fluid inlet 12 side is connected to the secondary pressure chamber C2 on the fluid outlet 13 side through the valve hole 23B, so that the gaseous fuel moves from the primary pressure chamber C1 to the secondary pressure chamber C2.

[0162] Conversely, when the valve core 21B closes the valve by blocking the valve orifice 23B of the valve seat 22B, the movement of fluid from the primary pressure chamber C1 to the secondary pressure chamber C2 is restricted.

[0163] The valve core 21B is pushed upward by the spring 29a so that the valve core 21B blocks the valve hole 23B of the valve seat 22B. In addition, the valve seat 22B is pressed and held in place by the spring 29b.

[0164] The valve core moving structure 40 consists of a male threaded portion 41, a female threaded portion 42, and an anti-rotation member 50. It is a feed screw structure that converts the rotational motion of the electric motor 30 into the linear motion of the valve core 21B. The male threaded portion is formed on the outer peripheral surface of the motion shaft 60B, the female threaded portion is formed on the inner peripheral surface of the rotor 31 and meshes with the male threaded portion 41, and the anti-rotation member can be slidably inserted into the motion shaft 60B and uses an anti-rotation shaft 70B.

[0165] One end of the valve core 21B is inserted into the connecting hole 61B formed at one end of the motion shaft 60B, so that the motion shaft 60B and the valve core 21B are coaxially connected. The valve core 21B and the motion shaft 60B can be fixed to each other, for example, by threaded engagement.

[0166] The motion shaft 60B has an insertion hole 62B at its end opposite to the connecting hole 61B. The insertion hole 62B has a flat portion 63B on its inner circumferential surface. The anti-rotation shaft 70, whose base end 72B is fixed to the main body 10B and whose front end 71B has a flat portion 73B on its outer circumferential surface, is freely slidably inserted into the insertion hole 62B along the axial direction to form an anti-rotation member 50 (see reference). Figure 7 ).

[0167] That is, the structure is as follows: by the planar portions of the motion shaft 60B and the anti-rotation shaft 70B being in close contact with each other, the rotational motion in the motion shaft 60 is restricted and transformed into a linear motion in the axial direction, thereby causing the valve core 21B connected to the motion shaft 60 to move.

[0168] Next, refer to Figure 5 to Figure 6 sectional view and Figure 4 The functional block diagram illustrates the function of this embodiment.

[0169] like Figure 4 As shown, during normal operation of the electronically controlled regulator 3B, drive commands are input from the ECU9, which is an electronic control unit, to the motor driver 35.

[0170] At this time, when the relationship between the target pressure (Pref) and the discharge pressure (Pout) detected by the pressure sensor 7 is Pref > Pout, current is applied to the winding 34 of the stator 33 by rotating the rotor 31 in the direction that opens the valve core 21B. When the rotor 31 rotates in the direction that opens the valve core 21B, the valve core 21B moves in the opening direction through the valve core moving structure 40, and the blockage of the valve core 21B on the valve hole 23B of the valve seat 22B is released, becoming... Figure 6 The valve is open as shown.

[0171] On the contrary, in a case where the relationship between the target pressure (Pref) and the discharge pressure (Pout) is Pref < Pout, the current is applied to the winding 34 of the stator 33 in such a manner that the rotor 31 is rotated toward the direction in which the valve element 21B closes the valve. When the rotor 31 is rotated toward the direction in which the valve element 21B closes the valve, the valve element 21B is moved toward the closing direction by the valve element moving structure 40, and the valve element 21B closes the valve hole 23B of the valve seat 22B, becoming Figure 5 the closing state of the kind shown in the drawing.

[0172] 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 use conditions of the regulator.

[0173] Thus, according to the electronic control type regulator 3A, 3B, based on the discharge pressure detected by the pressure sensor 7, the electric motor 30 is driven and controlled, and the valve element 21A, 21B is reciprocally moved in the axial direction to open and close (change the opening area) the pressure regulating valve 20A, 20B to regulate the discharge pressure, and in this way, without replacement of parts, various required discharge pressures and required flow rates can be dealt with by one product.

[0174] The electronic control type regulator 3A of the first embodiment and the electronic control type regulator 3B of the second embodiment have a relationship in which the structures of the valve elements and the valve seats of the two are opposite to each other, but the present application can be applied to either of the embodiments.

[0175] As described above, the present application can provide a fuel supply system that can deal with variations in required flow rates by using an electronic control type regulator, while automatically maintaining various specified discharge pressures, and by using a normally open type electromagnetic relief valve, even in the case of occurrence of a poor condition such as poor energization, can safely switch to an open valve state, relieve the fluid pressure, and can avoid damage and malfunction of the equipment.

Claims

1. A fuel supply system for supplying gaseous fuel to an engine, Its features are, include: An electronically controlled regulator that reduces the pressure of the introduced gaseous fuel to a set pressure and then discharges it; A pressure sensor, wherein the pressure sensor detects the fluid pressure of the depressurized gaseous fuel; and A normally open electromagnetic discharge valve, wherein the electromagnetic discharge valve is located downstream of the pressure regulating valve of the electronically controlled regulator. When the fluid pressure detected by the pressure sensor reaches the pressure threshold or when the system is not energized, the electromagnetic discharge valve opens to release the gaseous fuel outside the system.

2. The fuel supply system as claimed in claim 1, characterized in that, The electronically controlled regulator includes: The main body forms a fluid passage inside, and each end of the fluid passage serves as a fluid inlet and a fluid outlet; A pressure regulating valve, wherein the pressure regulating valve is disposed 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; and Electronically controlled electric motor The pressure regulating valve includes: A valve core, which is capable of reciprocating along an axial direction; Valve seat, the valve seat being configured opposite to the valve core; and The discharge pressure regulating mechanism uses the electric motor as a drive source and causes the valve core to reciprocate along the axial direction to change the distance between the valve core and the valve seat, thereby regulating the pressure of the gaseous fuel to the set pressure.

3. The fuel supply system as described in claim 2, characterized in that, The discharge pressure regulating mechanism consists of a male threaded portion, a female threaded portion, and an anti-rotation component. It has a valve core moving structure that converts the rotational motion of the electric motor into the linear motion of the valve core. The male threaded portion is formed on the outer peripheral surface of the valve core or on the outer peripheral surface of the moving shaft connected to the valve core. The female thread is formed on the inner circumferential surface of the rotor constituting the electric motor.

4. The fuel supply system as described in claim 2, characterized in that, The valve seat is a ring-shaped or disc-shaped component. The valve core is a cylindrical component having a communication path that connects the primary pressure chamber and the secondary pressure chamber when the valve is opened.

5. The fuel supply system as described in claim 2, characterized in that, The valve seat is an annular component with a valve hole. The valve core is a rod-shaped component that seals the valve orifice when the valve is closed.

6. The fuel supply system as claimed in any one of claims 1 to 5, characterized in that, A normally closed electromagnetic shut-off valve is installed upstream of the electronically controlled regulator. When the fluid pressure detected by the pressure sensor reaches the pressure threshold or when no power is applied, the electromagnetic shut-off valve closes.

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