Actuator valve for regulating a gas and supply system for a consumer such as a heat engine

Abstract

An actuator valve for regulating the flow rate of a gas, the valve comprising - a body (12) comprising an inlet (10) and an outlet for the gas and a seat (120) between the inlet (10) and the outlet (11), the seat (120) being flared; - a needle (13, 13') of which a first end (131) comes into contact with the seat (120) in a closed position by the support of a spring (14); - an actuator (15) tending to detach the needle (13, 13') from the seat (120) towards an open position against the spring (14).The needle comprises at its first end (131) a stud (133, 133') which is inserted in a fitted manner into a tunnel (101) of the inlet in the closed position, the tunnel (101) having a cylindrical shape, the stud (133, 133') being disengaged from the tunnel (101) in the open position, the stud (133, 133') comprising at least one lumen (17) opening onto a cylindrical face (1330) of the stud (133, 133') opposite the tunnel (101) and being in fluid communication with the inlet (10). Figure for the abstract: Fig. 1.

Description

Title of the invention: Actuator valve for regulating a gas and system for supplying a consumer such as a heat engine Technical field

[0001] The present invention generally relates to an actuator valve for regulating the pressure of a gas for a consumer, in particular for a fuel supply system of a consumer such as a combustion engine or a fuel cell. Prior art

[0002] Many stationary and mobile internal combustion engines use a compressed gas as gaseous fuel which, when mixed with air, provides the energy necessary to operate the engine. The gaseous fuel, for example compressed or liquefied natural gas (CNG) or hydrogen, is generally stored in a tank under high pressure, which may be, for example, of the order of about 700 bar. Such a pressure is generally not compatible with the operation of an internal combustion engine. Therefore, the pressure of the gas must be reduced to an acceptable level to be introduced into the internal combustion engine. The pressure level of the natural gas to be introduced into the internal combustion engine may be of the order of 2 to 10 bar and up to 40 bar for an internal combustion engine running on hydrogen.A pressure regulator is therefore installed between the fuel tank and the fuel rail / injectors to ensure the desired reduction in gaseous fuel pressure.

[0003] Many pressure regulator applications have so far used a mechanical pressure regulator to provide gas pressure reduction using a combination of valves, diaphragms and / or pistons, springs and other mechanical devices to provide gas pressure reduction. These regulators are not sufficient in the case where the requirement is a pressure level that must be matched, for example between idle operation and nominal speed.

[0004] Electronically controlled gas pressure regulators are also known. However, most known electronic gas pressure regulators for CNG applications can only operate at a pressure of up to 16 bar, making them unsuitable for hydrogen engines that operate at higher pressures, typically between 20 and 40 bar.

[0005] Another disadvantage of conventional pressure regulators for gaseous fuels is related to the interface design. The valve element usually has a conical shape that cooperates with a conical valve seat, and pressure regulation is achieved by controlling the axial position of the valve element relative to the valve seat. Depending on the configuration, it may be difficult to maintain a reduced flow area.

[0006] Finally, it is desirable to be able to use an actuator requiring little power and taking up little space. Statement of the invention

[0007] The invention aims to provide an actuator valve for regulating a gas flow by controlling the actuator, allowing fine adjustment of the flow rate while limiting the size and power of the actuator.

[0008] With these objectives in view, the invention relates to an actuator valve for regulating the flow rate of a gas, the valve comprising - a body comprising an inlet and an outlet for the gas and a seat between the inlet and the outlet, the seat being flared; - a needle, a first end of which comes into contact with the seat in a closed position by the support of a spring; - an actuator tending to detach the needle from the seat towards an open position against the spring, characterized in that the needle comprises at its first end a stud which is inserted in a fitted manner into a tunnel of the inlet in the closed position, the tunnel having a cylindrical shape, the stud being released from the tunnel in the open position, the stud comprising at least one lumen opening onto a cylindrical face of the stud opposite the tunnel and being in fluid communication with the inlet.

[0009] The movement imposed by the actuator on the needle allows the nipple to be moved inside the tunnel. Depending on the position reached, a more or less significant passage section is released between the inlet and the outlet, which allows a gas flow to be modulated in the direction from the inlet to the outlet. The passage section is initially between the cylindrical surface of the nipple and the tunnel, then, as the light passes beyond the tunnel, through the part of the light released from the tunnel. The more light is released from the tunnel, the greater the passage section. The flow rate can thus be finely regulated using the valve. The variation of the flow modulation as a function of the stroke can be adjusted by choosing the geometry of the light.

[0010] According to a constructive arrangement, the nipple has two axially symmetrical slots. This arrangement is a good compromise between the available passage section and the quality of the guidance of the nipple in the tunnel.

[0011] According to an improvement, the nipple comprises an axial bore opening at the first end to provide fluid communication between the inlet and the light. This provides a maximum cross-section for the passage of a gas between the inlet and the outlet.

[0012] According to a first embodiment, a radially extending slot forms the two openings, the slot opening at the first end. This ensures a large passage section with ease of production by a simple slot, for example by machining.

[0013] According to a second embodiment, the nipple is terminated by a ring at the first end. This embodiment allows good guidance of the nipple thanks to the ring, as well as better mechanical resistance by connecting the end parts of the nipple together with the ring.

[0014] According to an improvement, the light has a width, measured over a diameter of the nipple, which increases in the direction towards the first end. Thus, when the needle, and therefore the nipple, is moved, only a small width of the light is initially uncovered, which allows a very gradual opening of the valve. The increase in section is, on the other hand, more significant towards the end of the needle's travel.

[0015] According to a constructive arrangement, the light has a V-shaped profile whose tip is opposite the first end, the angle of the V being between 30° and 60°, preferably between 40° and 50°.

[0016] According to an improvement, the light has a rounding in the part furthest from the first end, with a radius between 15% and 25% of the diameter of the nipple.

[0017] According to a constructive arrangement, the lumen extends up to a distance of 90% to 130% of the diameter of the nipple, measured from the first end.

[0018] According to an improvement, the needle comprises a circular groove containing a flexible seal bearing against the seat in the closed position. In the closed position, sealing is thus easily ensured with contact between the seat and the seal, with a low bearing force.

[0019] According to a constructive arrangement, the radial clearance between the nipple and the tunnel is between 1 and 10 μm. This provides, at the start of the needle lifting phase, a calibration of the flow rate, determined by the radial clearance, before the ports are uncovered. This flow rate is, for example, calibrated for an idling speed of a thermal engine.

[0020] According to a constructive arrangement, the needle comprises a stop face to limit the travel of the needle in the closed position while being in contact with the seat. This limits the compression of the seal, which preserves its service life.

[0021] According to a constructive arrangement, the spring is dimensioned to provide a pressing force of the needle against the seat of between 35 and 50 N. Such a force is sufficient to hold the needle in the closed position when gas is supplied at a pressure of 35 bar up to 50 bar.

[0022] The invention also relates to a gas supply system for a consumer such as a heat engine or a fuel cell, the system comprising a fuel tank connected to a regulating device comprising a valve according to one of the preceding claims, the inlet of the valve being connected on the tank side, the outlet being connected on the consumer side.

[0023] According to one application, the fuel is hydrogen stored under pressure in the tank, the system further comprising a pressure reducer at the outlet of the tank to expand the gas to a targeted pressure of 25 to 50 bars, the valve making it possible to deliver the gas to the outlet at a regulated pressure between 5 and 40 bars. Brief description of the figures

[0024] The invention will be better understood and other features and advantages will appear on reading the description which follows, the description making reference to the appended drawings among which: • [Fig.l] is a schematic view of a gas supply system; • [Fig.2] is a sectional view of a valve conforming to a first mode of realization of the invention; • [Fig.3] is a perspective view of the end of a needle of the valve of [Fig.2]; • [Fig.4] is a view of detail IV of [Fig.2]; • [Fig.5] is a graph showing the evolution of the flow rate and section of passage depending on the needle lift; • [Fig.6] is a view of the end of the needle according to a second embodiment; • [Fig.7] is a perspective view of the end of the needle of [Fig.6]. Detailed description

[0025] An actuator valve 1 is provided for a gas supply system for a consumer 2 such as a heat engine or a fuel cell, shown schematically in [Fig.l]. The system comprises a pressurized gas reservoir 3, connected via a mechanical pressure reducer 30 to a regulating device 4 incorporating said valve 1 and making it possible to deliver on command the quantity of gas useful to the consumer 2.

[0026] The regulating device may integrate relief valve functions, not shown, to limit the pressure in the network, a closing valve, not shown, and / or a controllable purge to put the installation at rest, not shown. The regulator 30 reduces the gas pressure to a substantially constant level and, in the case of a liquefied gas, allows it to be gasified. In the case of hydrogen supplying an internal combustion engine, this pressure level is, for example, 25 to 50 bars. Valve 1 is, for example, configured to deliver the gas to the outlet at a regulated pressure between 5 and 40 bars. In direct injection applications, the supply pressure can be around 50 bars and the regulation is between 20 and 40 bars, depending on the engine load. In indirect injection applications, the supply pressure is lower, around 25 bars and more, and the regulation is made from 5 bars.

[0027] The valve according to a first embodiment of the invention is shown in Figures 2 to 4.

[0028] The valve 1 comprises an inlet 10 connected to the side of the regulator 30 and an outlet 11 connected to the side of the consumer 2. The connections are made by pipes and fittings in a manner not detailed here. The valve 1 comprises a body 12 comprising the inlet 10 and the outlet 11 for the gas and a seat 120 between the inlet 10 and the outlet 11, the seat 120 being flared. The valve further comprises a needle 13, a first end 131 of which comes into contact with the seat 120 in a closed position by the support of a spring 14 and an actuator 15 tending to detach the needle 13 from the seat 120 towards an open position against the spring 14. The body 12 has a generally cylindrical shape extending in a main direction. The inlet 10 comprises a tunnel 101 in the form of a cylindrical bore at one end of the body 12 and having an axis parallel to the main direction.The outlet 11 is formed by a plurality of radial holes 110 in the body 12, with an axis perpendicular to the main direction, and opening downstream of the seat 120.

[0029] Opposite the seat 120, the needle 13 is force-fitted onto a hollow armature 150. The armature 150 is part of the actuator 15 and is designed to be actuated by a coil / solenoid, not shown. When the coil is energized, it creates a magnetic field which acts on the armature 150 to move it to the left, and lift it from the seat 120. The spring 14 is housed in the hollow of the armature 150 and acts on it, and therefore on the needle 13, to bring the needle 13 into contact against the seat 120.

[0030] The needle 13 further comprises a circular groove 130 containing a flexible seal 16 bearing against the seat 120 in the closed position, as shown in [Fig.4]. The needle 13 further comprises a stop face 132 beyond the groove 130 to limit the travel of the needle 13 in the closed position by being in contact with the seat 120.

[0031] The needle 13 has at its first end 131 a stud 133 which is inserted in a fitted manner into the tunnel 101 in the closed position. The radial clearance between the stud 133 and the tunnel 101 is between 1 μm and 10 μm.

[0032] In this first embodiment, as shown in Figures 3 and 4, the stud 133 comprises an axial bore 1331 opening at the first end to provide fluid communication between the inlet and the ports, two axially symmetrical ports 17 opening onto a cylindrical face 1330 of the stud 133 opposite the tunnel 101 and being in fluid communication with the inlet 10. For this, a slot 170 extends radially to provide the two ports 17, the slot 170 opening at the first end 131 of the needle. The slot 170, and therefore each light 17, has a width, measured over a diameter of the stud 133, which increases in the direction towards the first end 131. At the furthest point from the end, the slot 170 has a rounded portion 1701 with a radius between 15% and 25% of the diameter of the stud 133. The slot 170 is extended by a V-shaped profile 1702 whose tip is opposite the first end 131 while being connected to the rounded portion 1701.The angle of the vee 1702 being for example 55°. The part of the slot 170 closest to the end 131 comprises two parallel faces 1703 between them and to the axis of the needle 13. The depth of the slot 170 is 120% of the diameter of the nipple 133.

[0033] In use, the spring 14 keeps the needle 13 pressed against the seat 120, as shown in [Fig. 2], contact being established between the abutment face 132 and the seat 120. The inlet 10 receives the pressurized gas, for example hydrogen at a pressure of 50 bars. The seal 16 is sufficiently compressed to obtain a gas seal between the inlet 10 and the outlet 11.

[0034] When opening begins, the coil 151 is actuated to move the armature 150 and the needle 13 against the spring 14, to the left of [Fig.2]. The gas can then pass between the nipple 133 and the tunnel 101 in the clearance provided between the two and then head towards the outlet 11. The flow rate is quite low and calibrated by the clearance between the nipple 133 and the tunnel 101.

[0035] By continuing the stroke of the needle 13, the nipple 133 gradually disengages from the tunnel 101, so that the openings 17 are uncovered from the tunnel 101, first at the level of the rounded portion 1701, then during the stroke of the needle 13 at the level of the V-shape 1702, and finally at the level of the parallel faces 1703. The gas can then pass between the parallel faces 1703 from the inlet, into the slot 170 and towards the outlet via the openings 17. Thus, the passage section for the gas changes more and more strongly as a function of the stroke of the needle. This makes it possible to control the gas flow rate more precisely, in particular low flow rates.

[0036] By releasing the action of the coil, the needle 13 returns to the closed position as shown in [Fig.2], under the effect of the spring 14, which induces the complete closure of the gas passage.

[0037] [Fig.5] shows a diagram with the lift of needle 13 on the abscissa. A first curve A represents the evolution of the flow rate in grams per second, a second curve B represents the evolution of the passage section. We see that the flow rate evolves in a substantially linear fashion up to a lift of 1000 pm, which allows good control of this flow rate.

[0038] The nipple 133 has for example a diameter of 2.5 mm and the seal 16 a diameter of 3.5 mm. The total stroke of the needle 13 is for example 3 mm. The pressing force provided by the spring 14 of the needle 13 against the seat 120 is between 35 and 50 N.

[0039] In a second embodiment, shown in Figures 6 and 7, the stud 133' of the needle 13' has an axial bore 1331' opening at the first end 131 to provide fluid communication between the inlet 10 and the two ports 17', the stud 133 being terminated by a ring 1332 at the first end 131. Thus the ports 17' are interrupted at the first end 131 by the ring 1332. The operating mode of this embodiment remains identical to that of the first embodiment.

Claims

Claims

1. Actuator valve for regulating the flow of a gas, the valve comprising - a body (12) comprising an inlet (10) and an outlet for the gas and a seat (120) between the inlet (10) and the outlet (11), the seat (120) being flared; - a needle (13, 13') of which a first end (131) comes into contact with the seat (120) in a closed position by the support of a spring (14);- an actuator (15) tending to detach the needle (13, 13') from the seat (120) towards an open position against the spring (14), characterized in that the needle comprises at its first end (131) a stud (133, 133') which is inserted in a fitted manner into a tunnel (101) of the inlet in the closed position, the tunnel (101) having a cylindrical shape, the stud (133, 133') being released from the tunnel (101) in the open position, the stud (133, 133') comprising at least one lumen (17) opening onto a cylindrical face (1330) of the stud (133, 133') opposite the tunnel (101) and being in fluid communication with the inlet (10).;

2. Valve according to one of the preceding claims, in which the nipple (133, 133') comprises two axially symmetrical ports (17).

3. Valve according to one of claims 1 or 2, in which the nipple (133') comprises an axial bore (1331, 1331') opening at the first end (131) to provide fluid communication between the inlet (10) and the port (17').

4. A valve according to claim 2 or 3, wherein a radially extending slot (170) forms the two ports (17), the slot (170) opening at the first end (131).

5. A valve according to claim 3, wherein the nipple (133') is terminated by a ring (1332) at the first end (131).

6. A valve according to any preceding claim, wherein the lumen (17) has a width, measured over a diameter of the nipple (133, 133'), which increases in the direction towards the first end (131).

7. Valve according to claim 6, in which the light (17) has a V-shaped profile (1702) whose tip is opposite the first end (131), the angle of the V-shaped profile (1702) being between 30° and 60°, preferably between 40° and 50°.

8. Valve according to claim 6 or 7, in which the light (17) has a rounding (1701) in the part furthest from the first end (131), with a radius between 15% and 25% of the diameter of the nipple (133, 133').

9. A valve according to any preceding claim, wherein the lumen (17) extends to a distance of 90% to 130% of the diameter of the nipple (133, 133'), measured from the first end (131).

10. Valve according to one of the preceding claims, in which the needle comprises a circular groove (130) containing a flexible seal (16) bearing against the seat (120) in the closed position.

11. Valve according to one of the preceding claims, in which the radial clearance between the nipple (133, 133') and the tunnel (101) is between 1 pm and 10 pm.

12. Valve according to one of the preceding claims, in which the needle comprises a stop face (132) for limiting the travel of the needle (13, 13') in the closed position by being in contact with the seat (120).

13. Valve according to one of the preceding claims, in which the spring (14) is dimensioned to provide a pressing force of the needle against the seat (120) of between 35 and 50 N.

14. Gas supply system for a consumer (2) such as a heat engine or a fuel cell, the system comprising a fuel tank (3) connected to a regulating device (4) comprising a valve (1) according to one of the preceding claims, the inlet of the valve (10) being connected on the side of the tank (3), the outlet (11) being connected on the side of the consumer (2).

15. A system according to claim 14, wherein the fuel is hydrogen stored under pressure in the tank (3), the system further comprising a pressure reducer (30) at the outlet of the tank (3) for reducing the gas to a target pressure of 25 to 50 bars, the valve (1) making it possible to deliver the gas to the outlet at a regulated pressure of between 5 and 40 bars.

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