control valve with integrated motor

Abstract

The invention provides a control valve (16) for regulating the quantity of hydrogen supplied to at least one cell of a fuel cell. The control valve (16) has a main axis A and includes, in particular, a valve (18) for supplying hydrogen and an actuator (20) that drives the valve (18) to selectively and precisely open and / or close the valve (18). The valve (18) and the actuator (20) are stacked axially on top of each other. The actuator (20) is a stepper motor comprising two coils (38) stacked along the main axis of the control valve (16) and a core (40) consisting of a permanent magnet. The core (40) is connected to a moving component (34) of the valve (18) by a motion transformation device. (See Figure 2 for abbreviations.)

Description

Title of the invention: Control valve with integrated motor Technical field

[0001] The invention relates to a regulating valve intended to supply fuel cells, themselves intended for transport in their general design.

[0002] The main function of the control valve is to regulate the pressure and flow rate of hydrogen supplying the fuel cell to ensure operation of the system in accordance with demand, both in terms of performance and efficiency. STATE OF THE PRIOR ART

[0003] A control valve is intended to supply hydrogen to fuel cell cells with precise pressure and flow rate criteria, in order to meet the performance demands of the fuel cells.

[0004] A control valve consists mainly of an electronically controlled actuator and a valve which is driven by the actuator and which allows, depending on its degree of opening, to supply the quantity of fluid, here pressurized hydrogen, corresponding to the demand.

[0005] According to a known embodiment, the actuator of a control valve is a solenoid. Such an actuator has the advantage of having a reduced response time but its precision is particularly low. Indeed, for the same control instruction that it can receive, the solenoid can have several positions of its output axis. In addition, a control valve comprising a solenoid type actuator has a particularly marked hysteresis.

[0006] [Fig.l] is a graph representing, for different types of control valves, the hydrogen flow rate at the valve outlet (ordinates) as a function of the pulse width modulation (PMW) (abscises).

[0007] The first three curves 10, 12 and 14 show the measurements for three different solenoid-actuated control valves.

[0008] It can be seen in these curves that the hysteresis is relatively significant, which is detrimental to the efficiency and repeatability of the operating points of the fuel cell. This also reduces the operating range of the fuel cell power. Indeed, an imprecise flow rate interval implies that the corresponding power interval of the fuel cell is prohibited.

[0009] The aim of the invention is to propose a control valve having improved performance compared to control valves according to the state of the art. Presentation of the invention

[0010] The invention provides a regulating valve intended to regulate the quantity hydrogen supplying at least one cell of a fuel cell,

[0011] the control valve having a main axis A and comprising in particular a valve which is intended to be supplied with hydrogen and an actuator which drives the valve, to open and / or close the valve in a selective and controlled manner,

[0012] the valve and the actuator being stacked axially on top of each other,

[0013] characterized in that the actuator is a stepper type motor comprising two coils stacked along the main axis of the control valve and a core consisting of a permanent magnet, the core being connected to a mobile component of the valve by a motion transformation device.

[0014] The use of a stepper motor type actuator makes it possible to operate with a precise angular position of the actuator shaft.

[0015] This shaft being connected to the valve by a suitable device, the position of the valve, in opening / closing, can consequently be controlled with precision.

[0016] Preferably, the valve comprises a hydrogen inlet opening, a hydrogen outlet opening and a valve which is movable in the valve to open or close the outlet opening and a valve stem mounted movable in translation in the valve, in which the valve stem carries the valve and is connected to the core by the motion transformation device.

[0017] Preferably, the valve comprises a valve stem mounted to move in translation in the valve, which carries the valve and which is connected to the core by the movement transformation device.

[0018] Preferably, the valve stem extends partially within the actuator.

[0019] Preferably, the movement transformation device consists of a screw and nut system comprising a rotary member, a member movable in translation and a member for locking the translational member in rotation.

[0020] Preferably, the motion transformation device comprises a thread formed in the core, a thread formed on the valve stem and which is complementary to the thread of the core and a rotation locking ring which is fixed in the valve and which cooperates with the valve stem to prevent the valve stem from rotating about the main axis A. Brief description of the drawings

[0021] [Fig. 1] is a graph showing a comparison between the response curve of a control valve according to the invention and the response curves of solenoid control valves according to the invention.

[0022] [Fig. 2] is a schematic representation in axial section of a control valve according to the invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] [Fig. 2] shows a regulating valve 16 intended to regulate the quantity of hydrogen supplying an electrochemical accumulator battery (not shown).

[0024] In the following description, a main axis A of the regulating valve 16 is defined as being its main axis of symmetry.

[0025] The regulating valve 16 comprises a valve 18 which is intended to be installed in a hydrogen circulation circuit supplying the accumulator battery and an actuator 20 for driving the valve 18.

[0026] The valve 18 comprises a body 22 delimiting an internal volume 24.

[0027] The body 22 has an inlet opening 28 through which the internal volume 24 is connected to a source of pressurized hydrogen and an outlet opening 26 connecting the internal volume 24 to the storage battery.

[0028] Preferably, the inlet opening 28 is coaxial with the main axis A of the control valve 16 and the outlet opening 26 is oriented mainly radially with respect to the main axis A, as can be seen in [Fig.2].

[0029] It will be understood that the invention is not limited to this embodiment and that the inlet opening may be oriented mainly radially relative to the main axis A and the outlet opening may be coaxial with the main axis A of the control valve 16 without departing from the scope of the invention.

[0030] the valve 18 also comprises a valve 30 which is movable in the body 22 in the direction of the main axis A. The valve 30 is intended to close or open the outlet opening 26 of the body 22 to a greater or lesser extent.

[0031] For this, the outlet opening 26 comprises, at its end opening into the internal volume 24, a seat 32 against which the valve 30 bears when the valve 18 is closed. The profile of the seat 32 is identical to the profile of a face opposite the valve 30 allowing, when the valve 30 bears against the seat 32, to completely close the outlet opening 26, blocking the passage of hydrogen present in the internal volume 24.

[0032] The valve 30 is thus mounted axially movable in the internal volume 24 of the body 22 between a closed position of the valve 18 in which the valve 30 is in abutment against the seat 32 and several open positions of the valve 18. The variation of the distance between the valve 30 and the seat 32 varies, making it possible to regulate the flow rate and / or the pressure of hydrogen leaving the valve 18.

[0033] The valve 18 also comprises a valve stem 34 which is coaxial with the main axis A and which is movable in the body 22 along the main axis A. The valve stem 34 carries the valve 30 and it is connected to the actuator 20, as will be seen in more detail later.

[0034] The body 22 of the valve 18 has for this purpose a control opening 36 which is coaxial with the main axis A and is located at an axial end of the body 22. This control opening 36 is crossed by the valve stem 34 to allow the connection between the valve stem 34 and the actuator 20.

[0035] The actuator 20 is a stepper motor type actuator. It comprises a member which is mounted to rotate around the main axis A of the control valve 16.

[0036] The actuator 20 comprises two coils 38 which are coaxial with the main axis A and which are axially offset from each other. The coils 38 are arranged and designed to give the actuator 20 a number of steps which is generally 24 or 48 steps. The actuator 20 also comprises a core 40 consisting of a permanent magnet which is rotatable about the main axis A and which is arranged coaxial with the main axis A, in a volume delimited by the coils 38.

[0037] The core 40 is of annular main shape and is coaxial with the main axis A of the control valve 16. It delimits a cylindrical volume in which an end portion of the valve stem 34 is received.

[0038] The axial movement of the valve 30 is obtained by a system for transforming the rotational movement of the core 40 into a translational movement of the valve stem 34.

[0039] According to a preferred embodiment, the movement transformation system is of the screw and nut type. It comprises a thread formed in a rotating member, a thread complementary to the thread formed in a translationally mobile member and a member blocking the rotation of the translationally mobile member.

[0040] Preferably, according to the embodiment shown in the figures, the tapping is formed in the core 40 and the thread is formed on the end portion of the valve stem 34 which is located in the volume delimited by the core 40.

[0041] The member blocking the rotation of the valve stem 34 consists of a ring 42 which is fixed in an immobile manner to the body 22, in the internal volume 24.

[0042] Thus, when the regulating valve 16 is controlled, the coils 38 are supplied with electricity in a controlled manner, which produces a rotation of the core 40 in one direction around the main axis A and according to a predefined degree.

[0043] This rotation of the core 40 is converted into a translation of the valve stem 34 by the cooperation of the valve stem 34 with the core 40 and with the ring 42. Consequently, the valve 30 translates axially and moves closer to or further away from the seat 32 according to an amplitude corresponding to the rotation of the core 40.

[0044] According to an alternative embodiment, the valve 18 and the actuator are mounted in the same external housing 46. This external housing 46 makes it possible to secure together the valve 18 and the actuator 20, as well as their components which cooperate with each other. This makes it possible to have a complete sub-assembly ready to be installed. This makes it possible to limit the operations during the assembly of the system in which the valve regulation 16 is installed.

[0045] As can be seen in [Fig. 1], in which a curve 44 representative of the hydrogen flow rate at the outlet of the regulating valve 16 according to the invention is also shown, the variation in the hydrogen flow rate is more progressive compared to the embodiments of the prior art.

[0046] Also, the hysteresis is less important for the control valve according to the invention.

[0047] These results show that the control valve 16 according to the invention makes it possible to achieve more precise regulation of the pressure and / or the flow rate of hydrogen. The use of the control valve according to the invention then makes it possible to have improved performance of the system with which the control valve 16 is used.

[0048] Another advantage of the control valve 16 according to the invention concerns its compactness compared to the control valves according to the prior art.

[0049] Indeed, a solenoid is larger than a stepper motor for the same axial travel of the valve and the same axial pressure force on the valve.

[0050] NOMENCLATURE:

[0051] 10 curve

[0052] 12 curve

[0053] 14 curve

[0054] 16 control valve

[0055] 18 valve

[0056] 20 actuator

[0057] 22 bodies

[0058] 24 internal volume

[0059] 26 outlet opening

[0060] 28 inlet opening

[0061] 30 valve

[0062] 32 seat

[0063] 34 valve stem

[0064] 36 order opening

[0065] 38 reels

[0066] 40 core

[0067] 42 ring

[0068] 44 curve

[0069] 46 outer casing

Claims

Claims

1. A control valve (16) for controlling the quantity of hydrogen supplied to at least one cell of a fuel cell, the control valve (16) having a main axis A and comprising in particular a valve (18) which is intended to be supplied with hydrogen and an actuator (20) which drives the valve (18), to selectively and controlledly open and / or close the valve (18), the valve (18) and the actuator (20) being axially stacked on top of each other, characterized in that the actuator (20) is a stepper motor comprising two coils (38) stacked along the main axis of the control valve (16) and a core (40) consisting of a permanent magnet, the core (40) being connected to a moving component (34) of the valve (18) by a motion transformation device.

2. Control valve (16) according to the preceding claim, characterized in that the valve (18) comprises a hydrogen inlet opening (28), a hydrogen outlet opening (26) and a valve (30) which is movable in the valve to open or close the outlet opening (26) and a valve stem (34) mounted movable in translation in the valve (18), in which the valve stem (34) carries the valve (30) and is connected to the core (40) by the movement transformation device.

3. Control valve (16) according to the preceding claim, characterized in that the valve comprises a valve stem (34) mounted movable in translation in the valve (18), which carries the valve (30) and which is connected to the core (40) by the movement transformation device.

4. Control valve (16) according to the preceding claim, characterized in that the valve stem (34) extends partly inside the actuator (20).

5. Regulating valve (16) according to the preceding claim, characterized in that the movement transformation device consists of a screw and nut system comprising a rotary member (40), a member (34) movable in translation and a member for locking the rotation of the member (34) movable in translation.

6. Regulating valve (16) according to the preceding claim, characterized in that the movement transformation device comprises a tapping formed in the core (40), a thread formed on the stem of valve (34) and which is complementary to the tapping of the core (40) and a rotation locking ring (42) which is fixed in the valve and which cooperates with the valve stem (34) to prevent the valve stem (34) from rotating around the main axis A.

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