Hydrogen purging system and control method thereof

Abstract

The present invention provides a hydrogen purge system and a control method thereof, by allowing the degree of opening of a purge valve to a hydrogen purge flow path to be adjusted by current control or PWM control according to a mapping of a pressure difference between an anode and a cathode of a fuel cell stack, regardless of the size of the hydrogen purge flow path of the purge valve, the degree of opening of the purge valve to the hydrogen purge flow path can be adjusted. And the hydrogen purging amount can be kept constant based on the pressure difference between the anode and the cathode.

Description

Technical Field

[0001] The present invention relates to a hydrogen purge system for a fuel cell system. Background Art

[0002] The fuel cell system installed on a fuel cell vehicle may include a fuel cell stack (in which a plurality of unit cells are stacked to generate electricity by an electrochemical reaction of hydrogen and oxygen), a hydrogen supply system for supplying hydrogen (fuel) to the fuel cell stack, an air supply system for supplying oxygen in the air (which is an oxidant required for the electrochemical reaction) to the fuel cell stack, and a heat and water management system that removes electrochemical reaction heat from the fuel cell stack while controlling operating temperature, etc.

[0003] During the operation of such a fuel cell system, hydrogen from a hydrogen tank through a regulator and a hydrogen supply valve is supplied to the anode of the fuel cell stack through an injector, and then the above reaction is completed to generate electricity. A portion of the hydrogen is recycled to the anode, and the remaining hydrogen is discharged to the outside through a purge valve to form a hydrogen purge.

[0004] Hydrogen purge (through hydrogen purge, hydrogen is discharged to the outside through a purge valve) may be performed periodically to control the hydrogen concentration of the anode at a certain level and to discharge condensed water remaining in the anode.

[0005] A conventional purge valve may include a body portion having a hydrogen purge flow path, a membrane that opens and closes the hydrogen purge flow path, and a driving unit that drives the membrane to open or close according to power on / off.

[0006] Accordingly, when the power of the driving unit is turned on, the hydrogen purge flow path may be opened by the opening operation of the membrane member, and when the power of the driving unit is turned off, the hydrogen purge flow path may be closed by the closing operation of the membrane member.

[0007] In the open state of the hydrogen purge flow path due to energization of the driving unit of the purge valve, the hydrogen purge amount may be determined in proportion to the size of the hydrogen purge flow path and the pressure difference between the anode and cathode of the fuel cell stack.

[0008] However, if the pressure difference between the anode and cathode of the fuel cell stack is momentarily over-pressured, the amount of hydrogen purge discharged from the anode will excessively increase, making it difficult to control the hydrogen concentration of the anode at a certain level.

[0009] In addition, when the pressure difference between the anode and the cathode is greater than the appropriate range, the hydrogen purge amount increases excessively as the size of the hydrogen purge flow path of the purge valve increases, which may be problematic because the hydrogen consumption may increase and the error in the hydrogen concentration estimation (hydrogen purge amount estimation) within the fuel cell stack may increase significantly.

[0010] In contrast, when the pressure difference between the anode and the cathode is less than the appropriate range, as the size of the hydrogen purge flow path of the purge valve decreases, the amount of water discharged from the anode together with the hydrogen decreases, which may be problematic because flooding may occur due to an increase in the amount of remaining water in the fuel cell stack. Summary of the invention

[0011] The present invention relates to a hydrogen purge system and a control method thereof, and more particularly, to a hydrogen purge system and a control method thereof, which can adjust the opening amount by adjusting the opening and closing strokes of a purge valve, thereby constantly determining the hydrogen purge amount discharged from a fuel cell stack.

[0012] Embodiments of the present invention solve the above-mentioned conventional disadvantages. In an embodiment, by allowing the opening of the purge valve to the hydrogen purge flow path to be adjusted by current control or PWM control according to the pressure difference between the anode and the cathode of the fuel cell stack, the hydrogen purge system and the control method thereof can keep the hydrogen purge amount constant for each pressure difference between the anode and the cathode, regardless of the size of the hydrogen purge flow path of the purge valve.

[0013] An implementation or embodiment of the present invention provides a hydrogen purge system, which includes a fuel cell stack, a purge valve having a hydrogen purge flow path and installed on the hydrogen outlet of the anode of the fuel cell stack, and a controller, which is configured to perform current control or PWM control on the purge valve to adjust the opening of the hydrogen purge flow path of the purge valve according to the pressure difference between the anode and the cathode of the fuel cell stack.

[0014] In an embodiment, the purge valve may include a valve housing (in which a hydrogen purge flow path is formed and configured to be connected to the hydrogen outlet of the anode), a drive unit housing mounted on the outside of the valve housing, a coil mounted on the inner diameter of the drive unit housing and to which current is applied by current control or PWM control of a controller, and a plunger configured to be movable back and forth in the center of the drive unit housing, and a diaphragm mounted on the front end of the plunger to adjust the opening of the hydrogen purge flow path according to the amount of current applied to the coil through the back and forth stroke of the plunger, wherein a vent hole passes through the valve housing and the drive unit housing to maintain the internal space of the drive unit housing at atmospheric pressure.

[0015] The controller may be configured to perform current control or PWM control on the coil of the purge valve using current-hydrogen purge amount map data for each pressure difference between the anode and the cathode after checking the pressure difference between the anode and the cathode.

[0016] The vent hole in the valve housing may pass through an area between a first O-ring for sealing an interior space of the valve housing and a second O-ring for sealing a hydrogen purge flow path.

[0017] Additionally, a vent hole may be in the valve housing to allow the vent hole to communicate with the atmosphere.

[0018] Furthermore, the ventilation holes can be equipped with membrane filters to prevent reverse penetration of moisture.

[0019] In an implementation or embodiment of the present invention, a method for controlling a hydrogen purge system includes checking the pressure difference between the anode and the cathode of a fuel cell stack by a controller, determining the amount of current to be applied to a purge valve based on current-hydrogen purge amount mapping data for each pressure difference between the anode and the cathode by the controller, applying the determined amount of current to the coil of the purge valve through current control or PWM control of the controller, and adjusting the opening of the hydrogen purge flow path of the purge valve through the forward and backward stroke of the plunger according to the amount of current applied to the coil of the purge valve.

[0020] The opening degree of the hydrogen purge flow path can be adjusted according to the amount of current applied to the coil through the membrane mounted on the front end of the plunger and through the forward and backward stroke of the plunger.

[0021] If the hydrogen concentration of the fuel cell stack is lower than the lower limit reference value, the controller can check the pressure difference between the anode and the cathode, and if the hydrogen concentration of the fuel cell stack is greater than the upper limit reference value after the opening of the hydrogen purge flow path is adjusted, the controller can perform shutdown control for closing the purge valve.

[0022] In an embodiment, the purge valve may include a valve housing having a hydrogen purge flow path and a drive unit housing in which a coil and a plunger are installed, and the internal space of the drive unit housing can be maintained at atmospheric pressure through a vent and an air vent, which are located in the valve housing and the drive unit housing, and the air vent is located in the valve housing to communicate with the vent.

[0023] In an embodiment, if a phenomenon in which the amount of fluid including hydrogen and water discharged to the outside through the hydrogen purge flow path does not exceed a reference amount occurs more than five times in a row after the opening of the hydrogen purge flow path is adjusted by current control or PWM control for the purge valve, the controller may determine that the purge valve is faulty.

[0024] In an embodiment, if a phenomenon in which the amount of fluid including hydrogen and water discharged to the outside through the hydrogen purge flow path exceeds a reference amount occurs more than five times in a row after the opening of the hydrogen purge flow path is adjusted by current control or PWM control for the purge valve, the controller may determine that the purge valve is faulty.

[0025] In an embodiment, the controller may determine that the purge valve is faulty if a phenomenon that fluid including hydrogen and water is not discharged through the hydrogen purge flow path occurs more than five times in a row after adjusting the opening of the hydrogen purge flow path by current control or PWM control for the purge valve.

[0026] In an embodiment, the controller may determine that the purge valve is faulty if a phenomenon in which the fluid including hydrogen and water is discharged through the hydrogen purge flow path occurs more than five times in succession after shutoff control for closing the purge valve.

[0027] By solving the above-mentioned problems, the embodiments of the present invention can provide the following effects.

[0028] First, in an embodiment, for each pressure difference between the anode and the cathode, by allowing the opening of the purge valve to the hydrogen purge flow path to be adjusted by current control or PWM control according to the pressure difference between the anode and the cathode of the fuel cell stack, the amount of hydrogen purge discharged from the fuel cell stack can be kept constant.

[0029] Second, in an embodiment, by having ventilation holes and air vents in the valve housing and the drive unit housing of the purge valve to maintain the internal space of the drive unit housing at atmospheric pressure, the forward and backward stroke movement of the plunger and the opening and closing operations of the membrane member for the hydrogen purge flow path can be performed consistently and smoothly according to the amount of current applied to the coil of the purge valve.

[0030] Third, in an embodiment, regardless of the size of the hydrogen purge flow path of the purge valve, the amount of hydrogen purge discharged from the fuel cell stack can be consistently adjusted for each pressure difference between the anode and the cathode, thereby preventing an increase in hydrogen consumption due to the conventional excessive increase in the hydrogen purge amount and at the same time minimizing the error in estimating the hydrogen concentration in the fuel cell stack (estimated hydrogen purge amount).

[0031] Fourth, in an embodiment, regardless of the size of the hydrogen purge flow path of the purge valve, the amount of hydrogen purge discharged from the fuel cell stack can be consistently adjusted for each pressure difference between the anode and the cathode, so that water can be smoothly discharged from the anode together with the hydrogen and thus flooding within the fuel cell stack can be prevented. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other features and advantages of the present invention will now be described in detail with reference to certain examples of the present invention shown in the accompanying drawings, which are given hereinafter by way of illustration and thus are not intended to limit the present invention, in which:

[0033] Figure 1 is a graph comparing a conventional hydrogen purging method with a hydrogen purging method according to an embodiment of the present invention;

[0034] Figure 2 is a front view showing a purge valve of a hydrogen purge system according to an embodiment of the present invention;

[0035] Figure 3 is a side cross-sectional view showing a purge valve of a hydrogen purge system according to an embodiment of the present invention;

[0036] Figure 4 is a side cross-sectional view showing an example purge valve of a hydrogen purge system according to an embodiment of the present invention mounted on a hydrogen outlet of an anode of a fuel cell stack;

[0037] Figure 5 is a graph showing current-hydrogen purge amount mapping data for various pressures between an anode and a cathode used in a method for controlling a hydrogen purge system according to an embodiment of the present invention; and

[0038] Figure 6 is a flowchart illustrating a control method of a hydrogen purge system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] For the purpose of describing the embodiments according to the present invention, the specific structural or functional descriptions described in the embodiments of the present invention are provided in an exemplary manner, and the embodiments may be implemented in various forms. In addition, the present invention should not be interpreted as being limited to the embodiments described herein, but should be understood to include all changes, equivalents and alternatives included in the technical concept and scope of the present invention.

[0040] As used herein, terms such as "first", "second", etc. may be used to explain various components, but the components are not necessarily limited by these terms. The above terms may be used for the purpose of distinguishing one component from other components. For example, a first component may be designated as a second component, and similarly, a second component may be designated as a first component without departing from the scope of the present invention.

[0041] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0042] refer to Figure 1 , when the conventional purge valve is energized and the hydrogen purge flow path is open, the hydrogen purge amount can be determined in proportion to the pressure difference between the anode and the cathode of the fuel cell stack, so that the hydrogen purge amount (cc) increases with the increase of the pressure difference (kPa) between the anode and the cathode.

[0043] The embodiment of the present invention is characterized in that, by allowing the opening of the purge valve relative to the hydrogen purge flow path to be adjusted by current control or PWM control according to the pressure difference between the anode and the cathode of the fuel cell stack, the amount of hydrogen purge discharged from the fuel cell stack can be kept constant for each pressure difference between the anode and the cathode, such as Figure 1 shown.

[0044] Figure 2 and Figure 3 1 and 2 are a front view and a side cross-sectional view respectively showing a purge valve of a hydrogen purge system according to an embodiment of the present invention. Figure 4 is a side sectional view showing an example in which a purge valve of a hydrogen purge system according to an embodiment of the present invention is installed on a hydrogen outlet of an anode of a fuel cell stack.

[0045] refer to Figure 4 , a purge valve 100 having a hydrogen purge flow path 113 is installed on the hydrogen outlet 12 of the anode of the fuel cell stack 10 .

[0046] like Figures 2 to 4 As shown, the purge valve 100 may include a valve housing 110 as a frame thereof and a driving unit housing 120 installed on the outer side of the valve housing 110 , and a hydrogen purge flow path 113 communicating with the hydrogen outlet 12 of the anode is formed in the valve housing 110 .

[0047] A front end of the hydrogen purge flow path 113 may communicate with the hydrogen outlet 12 of the anode, and a rear end of the hydrogen purge flow path 113 may be connected to an external exhaust pipe 114 .

[0048] The driving unit housing 120 may be a solenoid housing, and the coil 122 may be mounted on an inner diameter portion thereof, and current may be applied to this coil 122 by current control or pulse width modulation (PWM) control of the controller 200, for example.

[0049] In addition, the plunger 124 may be surrounded by the coil 122 and configured to be movable forward and backward in the center of the driving unit housing 120 .

[0050] Accordingly, when current is applied to the coil 122 through current control or PWM control of the controller 200 , the plunger 124 may move forward and backward at a set or predetermined stroke based on a known solenoid principle.

[0051] The forward and backward stroke length of the plunger 124 may be determined according to the amount of current applied to the coil 122 by, for example, current control or PWM control of a controller.

[0052] Furthermore, a membrane 126 may be installed on the front end of the plunger 124 for adjusting the opening degree (opening amount) of the hydrogen purge flow path 113 or closing the hydrogen purge flow path.

[0053] Accordingly, the membrane 126 can move forward and backward together with the plunger 124 according to the forward and backward stroke of the plunger 124 according to the amount of current applied to the coil 122. The opening (opening amount) of the hydrogen purge flow path 113 can be adjusted, or when the current applied to the coil 122 is disconnected, the plunger 124 can be pulled and moved forward to the maximum extent due to the elastic restoring force in the expansion direction of the membrane 126, so that the membrane 126 closes the hydrogen purge flow path 113.

[0054] The ventilation hole 130 may penetrate the valve housing 110 and the driving unit housing 120 to maintain the inner space 125 of the driving unit housing 120 at atmospheric pressure, and the vent hole 132 may be located in the valve housing 110 to communicate the ventilation hole 130 with the atmosphere.

[0055] The ventilation hole 130 may be communicatively formed in the outer wall of the valve housing 110 and the inner wall of the driving unit case 120 , and they may be in close contact with each other.

[0056] The interior space 125 of the drive unit housing 120 located behind the plunger 124 may be fluidly connected to the atmosphere through the ventilation hole 130 and the vent hole 132 and may be maintained at atmospheric pressure.

[0057] Bringing the internal space 125 of the drive unit housing 120 to atmospheric pressure may enable the plunger 124 to smoothly move forward and backward strokes according to the amount of current applied to the coil 122 .

[0058] If the internal space 125 of the drive unit housing 120 is not close to or equal to atmospheric pressure, pressure changes may occur in the internal space 125 of the drive unit housing 120 due to temperature changes caused by various factors (for example, the current applied to the coil, external temperature, etc.), thereby preventing or reducing the smooth forward and backward movement of the plunger 124, and as a result, the forward and backward stroke movement of the plunger 124 according to the amount of current applied to the coil 122 cannot be carried out smoothly.

[0059] For example, the volume V of the internal space 125 of the drive unit housing may be fixed, but the temperature T of the internal space 125 may change depending on the current applied to the coil according to the solenoid operating principle and the ambient temperature, and if the temperature within the internal space 125 becomes higher after a certain period of time, then since the temperature T of the internal space 125 increases and the volume V of the internal space 125 is fixed, according to the formula "PV=nRT", the pressure P of the internal space 125 may eventually increase.

[0060] When the pressure in the internal space 125 of the drive unit housing increases, force can be applied to the plunger 124 in the forward direction (closing direction), resulting in inconsistent forward and backward stroke movement of the plunger 124 according to the amount of current applied to the coil 122, and thus causing the membrane 126 installed on the plunger 124 to open and close the hydrogen purge flow path 113. The response speed is also inconsistent, ultimately resulting in an unbalanced amount of hydrogen purge discharged through the hydrogen purge flow path 113.

[0061] Accordingly, by enabling the internal space 125 of the drive unit housing 120 located behind the plunger 124 to be connected to the atmosphere through the ventilation hole 130 and the air vent 132 and maintained at atmospheric pressure, the forward and backward stroke movement of the plunger 124 and the opening and closing operation of the membrane 126 on the hydrogen purge flow path can be performed consistently and smoothly according to the amount of current applied to the coil 122.

[0062] like Figure 4 As shown, the ventilation hole 130 formed in the valve housing 110 can pass through the outer wall of the valve housing 110 in close contact with the drive unit housing 120 in the area between the first O-ring 111 for sealing the internal space of the valve housing 110 and the second O-ring 112 for sealing the hydrogen purge flow path 113. The reason is that such a construction can prevent moisture and the like from penetrating into the drive unit housing 120 through the ventilation hole 130.

[0063] More specifically, if the ventilation hole 130 does not maintain water tightness, the coil 122 and the plunger 124 may be corroded due to moisture penetrating into the drive unit housing 120 through the ventilation hole 130, but the first O-ring 111 can block moisture and the like from penetrating into the ventilation hole 130 from the outside, and the second O-ring 112 can block hydrogen and condensed water from the hydrogen purge flow path 113 from penetrating into the ventilation hole 130. By blocking moisture from penetrating into the drive unit housing 120 through the ventilation hole 130, the parts within the drive unit housing 120 can be easily protected from corrosion.

[0064] In addition, a membrane filter 134 may be installed inside the vent 132 to prevent reverse penetration of moisture, so that moisture, foreign matter, etc. that penetrate into the vent 132 from the outside are filtered out by the membrane filter 134. Therefore, moisture, foreign matter, etc. that penetrate into the vent 130 and the drive unit housing 120 from the outside can be blocked or hindered.

[0065] The controller 200 may be configured to perform current control or PWM control on the coil 122 of the purge valve 100 to adjust the opening of the hydrogen purge flow path of the purge valve according to the pressure difference between the anode and the cathode of the fuel cell stack.

[0066] The controller 200 may be configured to perform current control or PWM control on the coil 122 of the purge valve 100 using current-hydrogen purge amount mapping data for each pressure difference between the anode and the cathode after checking (determining) the pressure difference between the anode and the cathode.

[0067] The controller 200 may be configured to perform a fail-safe control to determine a failure of the purge valve 100 .

[0068] The following is a description of a hydrogen purge system control method according to an embodiment of the present invention based on the above configuration. Figure 6 is a flowchart illustrating a control method of a hydrogen purge system according to an embodiment of the present invention.

[0069] In operation S101 , the hydrogen concentration of the fuel cell stack may be monitored.

[0070] For example, the controller 200 may monitor the hydrogen concentration of the fuel cell stack by receiving a signal indicative of a measurement result obtained by a concentration measurement sensor (not shown) of the fuel cell stack.

[0071] In operation S102 , the hydrogen concentration monitored in the above-described operation S101 may be compared with a lower limit management reference value.

[0072] For example, the controller 200 may compare the current hydrogen concentration of the fuel cell stack with a lower limit management reference value.

[0073] If the current hydrogen concentration of the fuel cell stack is lower than the lower limit management reference value, in order to increase the hydrogen concentration in the anode of the fuel cell stack, the condensed water, nitrogen, etc. remaining in the anode of the fuel cell stack can be purged to the outside together with the hydrogen remaining in the anode of the fuel cell stack while hydrogen is supplied to the anode of the fuel cell stack. The reason is that the condensed water, nitrogen, etc. remaining in the anode of the fuel cell stack may cause the hydrogen concentration to decrease.

[0074] If the hydrogen concentration of the fuel cell stack is lower than the lower limit reference value as a result of the comparison in the above-described operation S102 , the controller 200 may check a pressure difference between an anode and a cathode of the fuel cell stack (operation S103 ).

[0075] For example, the controller 200 may receive a signal indicative of measurements taken by a pressure sensor (not shown) of the fuel cell stack to check the pressure differential between the anode and cathode of the stack.

[0076] In operation S104 , the controller 200 may determine the amount of current to be applied to the purge valve based on the current-hydrogen purge amount mapping data for each pressure difference between the anode and the cathode.

[0077] For example, the current-hydrogen purge amount mapping data may be pre-constructed in a table format, where Figure 5 As shown, the pressure difference between the anode and the cathode, the amount of current applied to the coil by current control or PWM control of the controller, and the amount of hydrogen purge are set as X-axis, Y-axis and Z-axis respectively, and can be stored for use by the controller 200.

[0078] In operation S105, the amount of current determined in the above operation S104 may be applied to the coil 122 of the purge valve 100, for example, by current control of the controller 200, or the amount of current determined in the above step S104 may be applied to the coil 122 of the purge valve 100 in a duty cycle manner by PWM control of the controller 200.

[0079] Accordingly, when current is applied to the coil 122 through current control or PWM control of the controller 200, the plunger 124 can move back and forth at a set or predetermined stroke, and at the same time, the membrane member 126 installed on the front end of the plunger 124 can move back and forth, and the opening (opening amount) of the hydrogen purge flow path 113 can be adjusted by the back and forth movement of the membrane member 126.

[0080] The purge valve 100 may include a valve housing 110 having a hydrogen purge flow path 113, and a drive unit housing 120 in which a coil 122 and a plunger 124 are installed, and as described above, the internal space of the drive unit housing 120 can be maintained at atmospheric pressure without pressure changes through a vent hole 130 formed in the valve housing 110 and the drive unit housing 120 and through a vent hole 132 in the valve housing 110 that is connected to the vent hole fluid.

[0081] Accordingly, according to the amount of current applied to the coil 122 , the forward and backward stroke movement of the plunger 124 and the opening adjustment movement of the membrane 126 to the hydrogen purge flow path 113 may be performed uniformly and smoothly.

[0082] By realizing the amount of current applied to the coil 122 according to the pressure difference between the anode and the cathode, and by being able to adjust the opening (opening amount) of the hydrogen purge flow path 113 based on the amount of current for each pressure difference applied to the coil 122 through the forward and backward movement of the membrane 126 and the forward and backward stroke of the plunger 124, condensed water, nitrogen, etc. remaining in the anode of the stack can be purged to the outside through the hydrogen purge flow path 113 together with the residual hydrogen, and the hydrogen purge amount including condensed water, nitrogen, residual hydrogen, etc. can be kept constant for each pressure difference between the anode and the cathode of the fuel cell stack.

[0083] After the opening of the hydrogen purge flow path 113 has been adjusted and the condensed water, nitrogen, etc. remaining in the anode have been purged to the outside through the hydrogen purge flow path 113 together with the residual hydrogen, the controller 200 can compare the hydrogen concentration of the fuel cell stack with the upper limit reference value (operation S106).

[0084] As a result of the comparison in operation S106 , if the hydrogen concentration of the fuel cell stack is greater than the upper limit reference value, the controller 200 may perform shutoff control for closing the purge valve 100 (operation S107 ) because hydrogen purge is no longer required.

[0085] When the current of the coil 122 is disconnected, the plunger 124 may be pulled to the maximum extent and moved forward due to the elastic restoring force in the expansion direction of the membrane 126 , so that the membrane 126 closes the hydrogen purge flow path 113 .

[0086] The controller 200 may be configured to perform a fail-safe function on the purge valve 100 , and the fail-safe function may be intended to determine whether the purge valve 100 functions properly and direct maintenance and replacement in response to a failure of the purge valve 100 .

[0087] If the opening of the hydrogen purge flow path 113 has been adjusted by current control or PWM control of the purge valve 100, and the phenomenon that the amount of fluid including hydrogen, water, etc. discharged to the outside through the hydrogen purge flow path 113 (hydrogen purge amount) does not exceed the reference amount occurs more than five times in a row, the controller 200 can determine that the purge valve 100 is faulty.

[0088] For example, when, based on a signal from a flow sensor (not shown) for measuring the flow rate through the hydrogen purge flow path 113, it is confirmed that the amount of fluid including hydrogen, water, etc. discharged to the outside through the hydrogen purge flow path 113 (hydrogen purge amount) does not exceed a reference amount for more than five consecutive times, the controller 200 may deem that the plunger 124, the membrane 126, etc., which are fixed in the hydrogen purge flow path 113, can be adjusted to a state where the opening is less than the expected level, and may determine that the purge valve 100 is faulty, and may control the operation of known visual and auditory alarm devices.

[0089] In addition, if the amount of fluid including hydrogen, water, etc. discharged to the outside through the hydrogen purge flow path 113 (hydrogen purge amount) exceeds the reference amount for more than five consecutive times after the opening of the hydrogen purge flow path 113 has been adjusted by current control or PWM control of the purge valve 100, the controller 200 can determine that the purge valve 100 is faulty.

[0090] For example, when it is confirmed based on the signal of a flow sensor (not shown) for measuring the flow rate through the hydrogen purge flow path 113 that the amount of fluid including hydrogen, water, etc. discharged to the outside through the hydrogen purge flow path 113 (hydrogen purge amount) exceeds the reference amount for more than five consecutive times, the controller 200 can consider that the plunger 124, the membrane 126, etc. are fixed in the state where the opening of the hydrogen purge flow path 113 can be adjusted to be greater than the expected level, and can determine that the purge valve 100 is faulty, and can control the operation of known visual and auditory alarm devices.

[0091] If the phenomenon that the fluid including hydrogen and water is not discharged from the fuel cell stack through the hydrogen purge flow path 113 occurs more than five times in a row after the opening of the hydrogen purge flow path 113 has been adjusted by current control or PWM control of the purge valve 100, the controller 200 can determine that the purge valve 100 is faulty.

[0092] For example, when, based on the signal of a flow sensor (not shown) for measuring the flow through the hydrogen purge flow path 113, it is confirmed that the fluid including hydrogen and water is not discharged from the fuel cell stack through the hydrogen purge flow path 113 for more than five consecutive times, the controller 200 can deem that the plunger 124, the membrane 126, etc. are fixed in the closed position, and can determine that the purge valve 100 is faulty, and can control the operation of known visual and auditory alarm devices.

[0093] If the phenomenon that fluid including hydrogen and water is discharged from the fuel cell stack through the hydrogen purge flow path 113 occurs five or more times in succession after off control for closing the purge valve 100 has been performed, the controller 200 may determine that the purge valve 100 is faulty.

[0094] For example, when it is confirmed based on the signal of a flow sensor (not shown) for measuring the flow through the hydrogen purge flow path 113 that after the shut-off control for closing the purge valve 100, the phenomenon of fluid including hydrogen and water (hydrogen purge amount) being discharged from the fuel cell stack through the hydrogen purge flow path 113 occurs continuously for more than five times, the controller 200 can consider that the plunger 124, the membrane 126, etc. are fixed in the open position, and can determine that the purge valve 100 is faulty, and can control the operation of known visual and auditory alarm devices.

[0095] By enabling the controller 200 to perform fail-safe functions of the purge valve 100 , maintenance, replacement, etc. may be directed in response to a failure of the purge valve 100 .

[0096] Although the present invention describes the implementation mode, the patent scope of the present invention is not limited thereto, and various modifications and improvements that can be made by those skilled in the art using the concept of the present invention defined in the appended claims may also fall within the patent scope of the present invention.

Claims

1. A hydrogen purge system, comprising: a purge valve having a hydrogen purge flow path and configured to be mounted on a hydrogen outlet of an anode of a fuel cell stack; and A controller is configured to perform current control or PWM control on the purge valve to adjust an opening degree of the hydrogen purge flow path of the purge valve according to a pressure difference between an anode and a cathode of the fuel cell stack.

2. The system according to claim 1, wherein: The purge valve comprises: a valve housing, the hydrogen purge flow path being formed in the valve housing and being configured to be in fluid communication with a hydrogen outlet of the anode; a drive unit housing mounted on the valve housing; a coil located in an inner space of the drive unit housing, the coil being configured to receive a current based on the current control or the PWM control of the controller; a plunger configured to be movable back and forth within the drive unit housing; and a diaphragm member coupled to the front end of the plunger and configured to adjust the opening of the hydrogen purge flow path based on the forward and backward stroke of the plunger according to the amount of current applied to the coil, The ventilation hole passes through the valve housing and the drive unit housing, and the ventilation hole is configured to keep the inner space of the drive unit housing at atmospheric pressure.

3. The system according to claim 2, wherein: The controller is configured to perform the current control or the PWM control on the coil of the purge valve using current-hydrogen purge amount mapping data for each pressure difference between the anode and the cathode after checking the measured pressure difference between the anode and the cathode.

4. The system according to claim 2, wherein: The vent hole in the valve housing penetrates a first area between a first O-ring and a second O-ring, wherein the first O-ring is configured to seal the first area of ​​the valve housing relative to the outside, and wherein the second O-ring is configured to seal the first area of ​​the valve housing relative to the hydrogen purge flow path.

5. The system according to claim 2, wherein: A vent in the drive unit housing places the vent in fluid communication with the atmosphere.

6. The system according to claim 5, wherein: The vent includes a membrane filter disposed therein that is configured to prevent reverse permeation of moisture.

7. A method for controlling a hydrogen purge system, the method comprising the steps of: Check the pressure difference between the anode and cathode of the fuel cell stack; determining an amount of current to be applied to a coil of a purge valve based on current-hydrogen purge amount mapping data for each pressure difference between the anode and the cathode; applying the determined amount of current to the coil of the purge valve by current control or PWM control; as well as The opening degree of the hydrogen purge flow path of the purge valve is adjusted by the forward and backward stroke of the plunger according to the amount of current applied to the coil of the purge valve.

8. The method according to claim 7, further comprising the steps of: The opening degree of the hydrogen purge flow path is adjusted by a membrane member mounted on a front end of the plunger according to the amount of current applied to the coil.

9. The method according to claim 7, wherein: If the hydrogen concentration of the fuel cell stack is lower than the lower limit reference value, checking the measured pressure difference between the anode and the cathode, and If the hydrogen concentration of the fuel cell stack is greater than an upper limit reference value after the opening degree of the hydrogen purge flow path is adjusted, shutoff control for closing the purge valve is performed.

10. The method according to claim 7, wherein: The purge valve includes a valve housing having the hydrogen purge flow path therethrough, and the valve housing has a drive unit housing, wherein the coil and the plunger are mounted in an inner space of the drive unit housing, and The method further includes: maintaining the internal space of the drive unit housing at atmospheric pressure via a ventilation hole and via a vent in the drive unit housing, the ventilation hole being located in the valve housing and the drive unit housing and passing through the valve housing and the drive unit housing to be fluidically connected, the vent being fluidically connected to the ventilation hole.

11. The method according to claim 7, further comprising: If, after the opening of the hydrogen purge flow path is adjusted by the current control or the PWM control for the purge valve, the phenomenon that the amount of fluid including hydrogen and water discharged to the outside through the hydrogen purge flow path does not exceed a reference amount occurs continuously for more than five times, it is determined that the purge valve is faulty.

12. The method according to claim 7, further comprising: If, after the opening of the hydrogen purge flow path is adjusted by the current control or the PWM control for the purge valve, the amount of fluid including hydrogen and water discharged to the outside through the hydrogen purge flow path exceeds a reference amount for more than five consecutive times, it is determined that the purge valve is faulty.

13. The method according to claim 7, further comprising: If the phenomenon that the fluid including hydrogen and water is not discharged through the hydrogen purge flow path occurs five or more times in succession after the opening of the hydrogen purge flow path is adjusted by the current control or the PWM control for the purge valve, it is determined that the purge valve is faulty.

14. The method according to claim 7, further comprising: If the phenomenon that the fluid including hydrogen and water is discharged through the hydrogen purge flow path occurs five or more times in succession after the shutoff control for closing the purge valve, it is determined that the purge valve is faulty.

15. A fuel cell vehicle, comprising: a fuel cell stack in which a plurality of unit cells are stacked to generate electricity using an electrochemical reaction of hydrogen and oxygen; a purge valve having a hydrogen purge flow path and configured to be mounted on a hydrogen outlet of an anode of a fuel cell stack; and A controller is configured to perform current control or PWM control on the purge valve to adjust an opening degree of the hydrogen purge flow path of the purge valve according to a pressure difference between an anode and a cathode of the fuel cell stack.

16. The fuel cell vehicle according to claim 15, wherein: The purge valve comprises: a valve housing, the hydrogen purge flow path being formed in the valve housing and being configured to be in fluid communication with a hydrogen outlet of the anode; a drive unit housing mounted on the valve housing; a coil located in an inner space of the drive unit housing, the coil being configured to receive a current based on the current control or the PWM control of the controller; a plunger configured to be movable back and forth within the drive unit housing; and a diaphragm member coupled to the front end of the plunger and configured to adjust the opening of the hydrogen purge flow path based on the forward and backward stroke of the plunger according to the amount of current applied to the coil, The ventilation hole passes through the valve housing and the drive unit housing, and the ventilation hole is configured to keep the inner space of the drive unit housing at atmospheric pressure.

17. The fuel cell vehicle according to claim 16, wherein: The controller is configured to perform the current control or the PWM control on the coil of the purge valve using current-hydrogen purge amount mapping data for each pressure difference between the anode and the cathode after checking the measured pressure difference between the anode and the cathode.

18. The fuel cell vehicle according to claim 16, wherein: The vent hole in the valve housing penetrates a first area between a first O-ring and a second O-ring, wherein the first O-ring is configured to seal the first area of ​​the valve housing relative to the outside, and wherein the second O-ring is configured to seal the first area of ​​the valve housing relative to the hydrogen purge flow path.

19. The fuel cell vehicle according to claim 16, wherein: A vent in the drive unit housing places the vent in fluid communication with the atmosphere.

20. The fuel cell vehicle according to claim 19, wherein: The vent includes a membrane filter disposed therein that is configured to prevent reverse permeation of moisture.

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