DESCRIPTION

[0001]The present invention is in the field of components for hydrogen fuel cell automotive systems; in particular, the present invention refers to an anode valve, i.e., a valve that intercepts the low-pressure branch of the system that feeds hydrogen to the fuel cells.

[0002]In a fuel cell system for automotive transport, hydrogen is forced at high pressure into a tank and fed through a high-pressure line to a pressure regulator, downstream of which a low-pressure line starts that feeds the fuel cells. As products of the chemical reactions that lead to the production of electricity, which is used to drive an electric motor, fuel cells discharge a mixture consisting of hydrogen, nitrogen, water vapor, and liquid water. The mixture is treated with an Anode Water Separator (AWS), which separates the hydrogen, which is intended to be recirculated, from the other components. The mixture formed by nitrogen, water vapor, and liquid water is directed to one or more anode valves, which assume different names according to the mixture treated. Usually, a valve that treats a mixture with a prevalent liquid component is called an Anode Drain Valve (ADV); a valve that treats a mixture with a prevalent gaseous component is called an Anode Purge Valve (APV); a valve that treats a mixture with a prevalent gaseous component, placed upstream of the ADV valve, is called an Anode Drain Valve Header (ADVH).

[0003]Anode valves need to ensure high reliability, which is severely tested by the required service life and the time spent in contact with the gas and liquid mixture being treated. The object of the present invention is to provide an anode valve with high reliability.

[0004]Said object is achieved by an anode valve according to claim 1. The claims dependent thereon identify additional advantageous embodiments of the invention.

[0005]The features and advantages of the anode valve according to the present invention will become apparent from the following description, given by way of non- limiting example in accordance with the figures in the accompanying drawings, wherein:

Fig. 1 depicts an anode valve according to an embodiment of the present invention, in separate parts;

- Fig. 2 depicts a cross section of the anode valve from Fig. 1;

- Fig. 3 shows an armature of a solenoid device of the anode valve according to the present invention; and

- Fig. 4 illustrates an assembly comprising the armature and winding of the solenoid device of the anode valve according to the present invention. [0006]With reference to the figure in the attached drawing, the reference 1 has been used to indicate an anode valve operating along a line downstream of fuel cells, supplied with a fluid which, depending on the uses of the valve, is primarily composed of gaseous components, such as hydrogen, nitrogen, and water vapor, or water.

[0007]The anode valve 1 comprises a valve body 2, which is usually made in a single piece from aluminum, for example obtained from a bar by tooling. The valve body 2 has an inlet duct 4 for a fluid entering in the anode valve 1 and an outlet duct 6 for draining the fluid, which is connectable to the inlet duct 4.

[0008]The valve body 2 also has a compartment 5 for containing some components; said compartment 5 has on its bottom, at the passage between the inlet duct 4 and the outlet duct 6, a support surface 16, which will be described hereinafter.

[0009]An at least partially elastically deformable shutter 8 is operational between the inlet duct 4 and the outlet duct 6; in a closed configuration, the shutter 8 sealingly closes the passage of the fluid from the inlet duct 4 to the outlet duct 6, while in an open configuration, the shutter 8 at least partially clears the passage allowing the fluid to pass from the inlet duct 4 to the outlet duct 6.

[0010]The shutter 8 comprises a shutter body 10, which has at least one contact surface with a sealing surface of the valve body 2 for closing the passage between the inlet duct 4 and the outlet duct 6, and an elastically deformable shutter diaphragm 12 joined to the shutter body 10. The shutter body and shutter diaphragm are preferably made in one piece, for example of synthetic rubber, such as EPDM (Ethylene-Propylene Diene Monomer). [0011]For example, the shutter body 10 is cylindrical in shape and the shutter diaphragm 12 extends in a ring radially from the shutter body 10.

[0012]Preferably, the shutter diaphragm 12 has peripherally an annular enlargement 14 to improve its sealing characteristics.

[0013]The shutter diaphragm 12 rests on the support surface 16.

[0014]The anode valve 1 further comprises a pressure element 18, for example annular, usually made of a metal material, accommodated in the body compartment 5 of the valve body 2 and suitable for pressing on the shutter diaphragm 12 so as to achieve a fluid seal between the pressure element 18 and the shutter diaphragm 12 and between the shutter diaphragm 12 and the support surface 16 of the valve body 2. [0015]Consequently, the body compartment 5 is hermetically sealed off from the inlet duct 4 and the outlet duct 6. [0016]The anode valve 1 further comprises an inner casing 20, for example tubular, accommodated at least partially in the body compartment 5.

[0017]In particular, the inner casing 20 comprises a first portion 22, accommodated in the body compartment 5, in contact with the pressure element 18, comprising a first tubular wall 24 surrounding a first chamber 26. [0018]On the first portion 22, externally, a nut 28 operates, which, screwed to the valve body 2 at the mouth of the body compartment 5, operates with thrust on the first portion 22, whereby the thrust action is transmitted to the pressure element 18. [0019]The inner casing 20 further comprises a second portion 30, which extends axially from the first portion 22 to exit the body compartment 5 through the nut 28; the second portion 30 comprises a second tubular wall 32 surrounding a second chamber 34. The second wall 32, terminating in a wall end 32a, is made of a ferromagnetic metal material, for example carbon steel, such as llSMn37.

[0020]Lastly, the inner casing 20 comprises a third portion 36 joined to the second portion 30 outside of the body compartment 5, which closes the second chamber 34. According to an embodiment, said third portion 36 further comprises a fixed core 36' of a solenoid device suitable for moving the shutter body 10 of the shutter 8 by electromagnetic actuation. [0021]The third portion 36 is made of a ferromagnetic metal material, for example carbon steel, such as H SMn37 steel.

[0022]The inner casing 20 further comprises an annular band 38, made of a non-magnetic material, for example a copper alloy such as CuA18 or generically of bronze, applied to the wall end 32a, interrupting the magnetic continuity with the third portion 36 or fixed core 36'. For example, the band 38 comprises the remaining portion of a weld made between the second wall 32 and the third portion 36 or fixed core 36'.

[0023]The anode valve 1 further comprises a fixed guide 40 accommodated in the second chamber 34; the guide 40 comprises a foot 42 fixed to the third portion 36, a stem 44 extending along a major axis X from the foot 42, and a head 46 joined to the end of the stem 44 opposite the foot 42.

[0024]The anode valve 1 further comprises a movable core 48 of the solenoid device, made of a ferromagnetic metal material, accommodated in the second chamber 34 and slidably mounted on the stem 44 of the guide 40. The movable core 48 extends along the main axis X between a first end 50, facing the third portion 36 (fixed core), and a second end 52, facing the head 46, which forms an abutment. [0025]The anode valve 1 further comprises a socket 54 integral with the movable core 48, for example applied to said movable core 48 at the second end 52; the socket 54 comprises an annular socket wall 56 and a socket base 58 which delimit, together with the movable core 48, a socket compartment 60, in the head 46 of which the guide 40 is located.

[0026]The anode valve 1 further comprises elastic return means suitable for operating permanently on the socket 54 to bring it toward the closed configuration. For example, said return means comprise a spring 62 accommodated in the socket compartment 60, in compression between the guide 40, and in particular applied to the head 46, and the socket base 58.

[0027]The socket 54 is connected to the shutter 8, whereby translation of the socket 54 results in a displacement of the shutter body 10 between the closed configuration and the open configuration.

[0028]For example, the shutter 8 comprises a peg 64 integral with the shutter body 10, e.g., made by co- molding or co-injection with the shutter body 10; the peg 64, extending along said main axis X, is engaged, e.g., screwed, to the socket base 58.

[0029]The anode valve 1 further comprises guiding means accommodated in the inner casing 20, and in particular in the first chamber 26, integral with the movable core 48, and in particular applied to the socket 54, and suitable for guiding said socket 54 translationally on the inner casing 20.

[0030]Preferably, said guiding means comprise at least one skid 65 supported by the socket 54 and slidable on the inner side surface 24a of the first wall 24 to guide the translation of said socket 54. For example, the skid 65 is made of PTFE (Polytetrafluoroethylene) or PUR (Polyurethane). [0031]The solenoid device further comprises a fixed armature 68 that supports an electrically powerable winding 70 to generate a magnetic field; within the winding 70 is contained at least partially the fixed core 36' and, within the fixed core, at least partially the movable core 48. The band 38 made of non-magnetic metal material is arranged between the winding 70 and the second chamber 34, to deflect the magnetic field and convey it into the movable core 48.

[0032]The armature 68, preferably made of steel, is C- shaped and comprises a main wall 69, facing the side surface 70a of the winding 70, and a pair of base walls 71, projecting from the main wall 69, between which the winding 70 is held.

[0033]Lastly, the solenoid device preferably comprises an outer casing 72, which encloses the armature 68 with the winding 70 and the fixed core 36'.

[0034]According to one embodiment, moreover, the anode valve 1 comprises at least one heater 74, electrically powerable, to heat the valve body 2 and melt any ice deposits formed at low temperatures.

[0035]In the normal operation of the anode valve 1, said anode valve is initially in the closed configuration wherein the solenoid device is in a deactivated state in which the winding 70 is not electrically powered; consequently, there are no magnetic actions of attraction between the fixed core 36' and the movable core 48, and the action of the return means, particularly the spring 62, causes the shutter body to obstruct the passage of fluid from the inlet duct 4 to the outlet duct 6. In said configuration, the movable core 48 is in a closed position wherein the first end 50 forms a gap G with the fixed core 36'.

[0036]When the anode valve 1 is in the closed configuration, the fluid accumulates in the inlet duct 4 and exerts a pressure on the shutter that tends to lift it, bringing it into the open configuration. The action of the return means must therefore be particularly energetic in order to keep the shutter in the closed configuration . [0037]When the system requires the fluid to be discharged, the winding 70 is electrically powered so that the solenoid device goes into an activated state. The action of attraction between the movable and fixed cores generated by the magnetic field attracts the movable core 48 toward the fixed core 36'; the movable core 48 then moves to an open position wherein the gap G is reduced to the minimum. Accordingly, the shutter body 10 clears the passage between the inlet duct 4 and the outlet duct 6. The valve 1 thus assumes the open configuration and the fluid may be discharged downstream. [0038]Since the action of the spring 62, as discussed above, must be very energetic to ensure closure in the closed configuration, the action of attraction between the movable and fixed cores must be equally energetic to pass into the open configuration. To this end, the band 38 allows the magnetic flux from the winding to the movable core to be properly channeled, preventing it from being channeled into the inner casing and thereby increasing the attractive action between the fixed core and the movable core. [0039]Advantageously, the shutter provided with a diaphragm allows the body compartment 5 to be isolated from the inlet duct 4, whereby hydrogen or other components of the pressurized fluid in the inlet duct may not travel up the inner casing to the band 38, the material of which is particularly deteriorable when in contact with such gases. In effect, by virtue of the shutter diaphragm, the inlet duct 4 and the outlet duct 6 are hermetically separated from the body compartment and from the second chamber which faces the band 38 made of non-magnetic material.

[0040]Moreover, the presence of the C-shaped armature causes an asymmetry of the actions acting on the movable core, which therefore pushes on the stem 44 with off-axis actions that, in the long run, would cause wear to the stem and the jamming of the movable core. Advantageously, however, the anode valve provides for the guiding means to guide the movable core during translation.

[0041]Moreover, the skid, and in particular the material and the special geometry, advantageously prevents the sliding of the movable core, made of steel, on the surface of the inner casing wall, also made of steel, thus reducing friction and limiting force dissipation; consequently, with the same size of the solenoid device, it is possible to pass the valve into the open configuration under more critical temperature or power supply conditions.

[0042]Innovatively, therefore, the anode valve according to the present invention enables the aforementioned reliability requirements to be met.

[0043]It is understood that a person skilled in the art, in order to meet contingent needs, may make modifications to the anode valve described above, all of which are contained within the scope of protection as defined by the following claims.