Abstract:
The present invention provides a fuel cell vehicle, particularly a fuel cell vehicle equipped with a moisture remover that removes moisture from an air conditioner evaporator. The fuel cell vehicle includes: a fuel cell stack as a power supplier; an electric heater operated by power from the fuel cell stack; a blower fan for providing air to the electric heater; an air channel configured to supply the air passing through the electric heater to an air conditioner evaporator; and a controller for controlling the operations of the electric heater and the blower fan, whereby moisture is removed from the air conditioner evaporator by supplying air heated by the electric heater to the air conditioner evaporator. The fuel cell vehicle effectively removes moisture from an air conditioner evaporator, solves the problem of a bad smell in the related art, and further removes the oxygen and the stack voltage which remain in the cathode, such that it is possible to avoid cathode oxygen depletion of the related art.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims under 35 U.S.C. §119(a) the benefit of Korean Patent Application No. 10-2010-0123149 filed Dec. 6, 2010, the entire contents of which are incorporated herein by reference. 
     BACKGROUND 
     (a) Technical Field 
     The present invention relates to a fuel cell vehicle. More particularly, it relates to a fuel cell vehicle equipped with a moisture remover that can remove moisture from an air conditioner evaporator. 
     (b) Background Art 
     A fuel cell is a type of electric generator which directly converts chemical energy of fuel into electric energy. 
     PEMFCs (Polymer Electrolyte Membrane Fuel Cell) are fuel cells that demonstrate high efficiency, large current density and output density, short start time, and rapid response to a change against a load, and, thus, are widely used for vehicles. 
     In order to use a fuel cell for the power unit of a vehicle, a stack is formed by stacking unit cells of fuel cells to achieve desired power. Various operation devices are then added to form the power unit, and the unit is mounted in the vehicle. 
     The operation devices of the fuel cell include a hydrogen supply device, an air supply device, and a heat and water management system. The hydrogen supply device supplies hydrogen as fuel to the stack. The air supply device supplies air containing oxygen as an oxidizer to the stack. The heat and water management system optimally manages the operation temperature of the stack by externally discharging heat, which is a byproduct of electrochemical reaction in the stack, and manages water. 
     The hydrogen supply device includes a hydrogen tank, a hydrogen supply valve, a compressor adjuster, and a hydrogen recirculator (recirculating blower and ejector). The air supplier includes an air supplier (air blower), an air valve, and a humidifier. The heat and water management system includes a cooling water pump, a radiator, a 3-way valve, and a water discharger for discharging water from the stack. 
     Further, a hydrogen purge valve is provided in a hydrogen exhaust line for removing impurities from an anode, and a cathode oxygen depletion is provided for removing stack voltage. 
     The cathode oxygen depletion is described in more detail as follows. When a fuel cell vehicle is stopped and the system is shutdown by Key-off/IG-off, hydrogen and oxygen are exchanged through the electrolyte membrane and deterioration of the catalyst layer is accelerated. Further, when the stack voltage is higher than the predetermined voltage, hydrogen and oxygen remain at the anode and the cathode, respectively. 
     Therefore, when shutting down the system, it is essential to reduce the stack voltage so as to remove the hydrogen and oxygen from the anode and the cathode. One conventional method is to reduce the stack voltage while reducing the oxygen remaining in the cathode by connecting a COD (Cathode Oxygen Depletion) to the stack. 
     The COD removes the oxygen and voltage remaining in the cathode of the stack by reacting the oxygen remaining in the stack with the hydrogen for each shutdown, thereby discharging the electricity into heat 
     Similar to conventional engine vehicles, a fuel cell vehicle is equipped with an air-conditioning system to control the interior temperature. Unlike conventional engine vehicles which use hot cooling water of the engine to heat the vehicle interior, fuel cells use an electric heater to heat the interior. A PTC (Positive Temperature Coefficient) heater is commonly used as the electric heater. 
     A fuel cell vehicle is further equipped with a liquid coolant type of air conditioner, which comprises an evaporator, a compressor, a condenser, and a throttle valve, similar to conventional engine vehicles. However, unlike conventional engine vehicles, fuel cell vehicles cannot utilize driving force from the engine to operate a compressor. Instead, an electric compressor using torque of a motor is used. 
     However, during operation of the air conditioner, a large amount of water condenses on the core surface of the evaporator. Further, even when the air conditioner is turned off, water condenses from the cold air on or around the core surface of the evaporator, which is in contacts with the external hot air. Therefore, although water is discharged through a drain hose of an air-conditioning duct, water that condenses on the core of the evaporator is not completely discharged through the drain hose and, thus, remains therein. As a result, when external dust and pollen enters the interior while water remains in the evaporator, molds form and proliferate, which results in the generation of a bad and unpleasant odor during the early operation of an air conditioner. 
       FIG. 1  shows an example of the configuration of an air-conditioning system provided in a common fuel cell vehicle. As shown, the system includes which an air-conditioning heater (PTC heater)  30 , a blower fan  31 , an air-conditioning duct  33 , an air conditioner (evaporator)  51 , a compressor  52 , a condenser  53 , a throttle valve  54 , a stack  10  that is the main power supplier of the fuel cell vehicle, and a COD  20  that removes oxygen remaining in the cathode of the stack  10  in shutdown. 
     Looking to  FIG. 1 , when a switch  32  is turned on, the electric heater  30  is operated by power from the stack  10 . As external air or internal air pass through the electric heater  30  by means of the blower fan  31 , it becomes heated. The heated air is then supplied to the inside of the vehicle through the air-conditioning duct  33 . 
     Further, when the fuel cell system is shut down, the COD  20  is connected to the stack  10  by turning on the switch  21 , such that oxygen in the cathode of the stack and the remaining voltage are removed. 
     However, the electric heater  30  of the fuel cell vehicle is used only as a heater for heating the interior, such as in the winter, and the air conditioner evaporator  51  is not equipped with any device for removing moisture. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY OF THE DISCLOSURE 
     The present invention relates to a fuel cell vehicle equipped with a moisture remover that can remove moisture from an air conditioner evaporator. 
     The present invention provides a fuel cell vehicle including: a fuel cell stack as a power supplier; an electric heater operated by power from the fuel cell stack; a blower fan for sucking air into the electric heater; an air channel for allowing the air passing through the electric heater to be supplied to an air conditioner evaporator; and a controller for controlling the operations of the electric heater and the blower fan, in order to remove moisture from the air conditioner evaporator, particularly by supplying air heated by the electric heater to the air conditioner evaporator. 
     In a preferred embodiment, the controller is set to operate the electric heater by using power from the fuel cell stack, wherein when a fuel cell system is shut down, the electric heater removes oxygen remaining in a cathode and removes moisture from the air conditioner evaporator. 
     In another preferred embodiment, an electric heater and a blower fan configured for heating an interior are disposed in an air-conditioning duct connected to the interior of the vehicle. An air channel, which is a diverging channel that diverges from an air-conditioning duct and extends to the air conditioner evaporator, is further provided. The fuel cell vehicle further includes an opening/closing device that is disposed to selectively open/close the diverging channel, and which opens the diverging channel in response to a control signal from the controller to remove moisture. 
     In still another preferred embodiment, the opening/closing device for opening/closing the air channel is a damper door device that switches an air flow passage between the diverging channel and the air-conditioning duct connected to the interior of the vehicle. 
     In yet another preferred embodiment, an electric heater and a blower fan configured for heating the interior are disposed in an air-conditioning duct connected to the interior of the vehicle. An air channel extends from the interior of the vehicle to the air conditioner evaporator. The fuel cell vehicle further comprises a blower fan for an evaporator that is controlled by the controller, and which blows interior air heated by the electric heater to heat the air conditioner evaporator. 
     In another aspect, the present invention provides a fuel cell vehicle including: a fuel cell stack as a power supplier; an electric heater attached to an air conditioner evaporator and operated by power from the fuel cell stack; and a controller for controlling operation of the electric heater, whereby the electric heater is operated by power from the fuel cell stack to heat the air conditioner evaporator and to remove moisture. 
     In a preferred embodiment, the controller is configured to operate the electric heater, which uses power from the fuel cell stack. In particular, when a fuel cell system is shut down, the electric heater is operated to remove oxygen remaining in a cathode and removes moisture from the air conditioner evaporator. 
     Therefore, according to an embodiment of the present invention, the electric heater and blower fan operate to supply hot dry air, that is heated by the electric heater, to the air conditioner evaporator through the diverging channel. It is, thus, possible to effectively remove moisture from the air conditioner evaporator and solve the problem of bad odor in the related art. 
     In particular, by using the electric heater as a cathode oxygen depletion, stack power is consumed in the process of removing moisture during fuel cell system shut down. Thus, it is possible to remove moisture from the evaporator and oxygen remaining in the cathode (remove stack voltage) during shutdown, such that it is possible to remove the COD. 
     It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles. 
     The above and other features of the invention are discussed infra. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other features of the present invention will now be described in detail with reference to certain exemplary embodiments thereof illustrated the accompanying drawings which are given hereinafter by way of illustration only, and thus are not limitative of the present invention, and wherein: 
         FIG. 1  is a diagram showing the configuration of an air-conditioning system that is used for a common fuel cell vehicle; 
         FIG. 2  is a diagram when an air-conditioning moisture remover is provided in a fuel cell vehicle according to an embodiment of the present invention; 
         FIG. 3  is a flowchart illustrating a process of removing moisture which is performed by the air-conditioning moisture remover in a fuel cell vehicle according to an embodiment of the present invention; 
         FIG. 4  is a diagram illustrating an air-conditioning moisture remover provided in a fuel cell vehicle according to another embodiment of the present invention; and 
         FIG. 5  is a diagram illustrating an air-con moisture remover provided in a fuel cell vehicle according to another embodiment of the present invention. 
     
    
    
     It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
     In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
     DETAILED DESCRIPTION 
     Hereinafter reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention to those exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings so that they can be easily carried out by those skilled in the art. 
       FIG. 2  is a diagram illustrating an air-conditioning moisture remover provided in a fuel cell vehicle according to an embodiment of the present invention. 
     In this embodiment, a fuel cell vehicle is equipped with a moisture remover that removes moisture from an air conditioner evaporator  51 . As shown, using power from the stack  10 , an electric heater  30  supplies air with increased temperature to the evaporator  51  such that moisture is removed. In particular, in order to consume stack power and remove oxygen remaining in a cathode when a fuel cell system is shut down, the electric heater  30  is connected to the stack  10  in shutdown. 
     According to conventional systems, the voltage of the stack remains at 400V or higher in Key-off and a COD is connected to the fuel cell stack  10  to remove the remaining voltage. However, according to the present invention, instead of using the COD, the electric heater  30  mounted in the vehicle to heat the interior is used as a load for removing the remaining voltage in shutdown. In other words, according to the present invention, the electric heater  30  that is mainly used to heat the interior when needed (e.g. in winter), is connected to the fuel cell stack  10  to be used as a load that consumes the stack power and removes the oxygen in the cathode. 
     Therefore, as shown in  FIG. 2 , an evaporator moisture remover in a fuel cell vehicle according to the present invention includes a fuel cell stack  10  which functions as a power supplier, an electric heater  30  operated by power from the fuel cell stack  10 , a blower fan  31  for providing air to the electric heater  30 , an air channel  34  for supplying the air passing through the electric heater  30  to the air conditioner evaporator  51 , and a controller  40  for controlling the electric heater  30  and the blower fan  31 . 
     In this configuration, the electric heater  30  can be any type of electric heater and may, for example, be a PTC heater that is commonly used as a heater for heating the interior of a fuel cell vehicle. 
     As further shown in  FIG. 2 , a heater switch  32  can be disposed between the fuel cell stack  10  and the electric heater  30  such that the stack power may be selectively applied to the electric heater  30 . For example, the heater switch  32  may be a relay that is opened/closed by an electric signal from the controller  50 . 
     As further shown, the heater  30  and the blower fan  31  can be disposed in the air-conditioning duct  33  connected to the interior of the vehicle to heat the interior of the fuel cell vehicle, in which the air channel  34  is a diverging channel that diverges from the air-conditioning duct  33  and extends to the air conditioner evaporator  51 . 
     The electric heater  30  and the blower fan  31  operate such that air heated by the electric heater  30  is supplied to the interior of the vehicle through the air-conditioning duct  33 , in order to heat the interior. When the heated air does not need to heat the interior (such as in shutdown), it can be supplied to the evaporator  51  through the diverging channel  34 , thereby removing moisture. 
     As shown in this embodiment, an opening/closing unit  35  that selectively opens/closes the air-conditioning duct  33  connected to the interior of the vehicle and the diverging channel  34  is provided. For example, as shown, the opening/closing unit  35  may be disposed at the diverging point where the diverging channel  34  diverges. 
     The opening/closing unit  35  may be, for example, a damper door device that switches the air flow passage between the diverging channel  34  and the air-conditioning duct  33  connected to the interior of the vehicle, such as in response to a control signal from the controller  40 . 
     The damper door device  35  can be configured such that an actuator  36  operates in response to a control signal from the controller  40  to rotate a damper door  37 . As such, the air flow passage is switched in accordance with the positions of the damper door  37 , which is determined by the actuator  36 . 
     A process of removing moisture from the air conditioner evaporator by means of the air-conditioning moisture remover in a fuel cell vehicle according to an embodiment of the present invention is described below. 
     First, as the opening/closing device  35  operates in response to a control signal from the controller  40 , the air-conditioning duct  33  is opened to heat the interior, while the diverging channel  34  is opened to shut down the fuel cell system. In other words, the opening/closing device  35  closes the diverging channel  34  and opens the air-conditioning duct  33  to heat the interior (e.g. in winter). As shown, when the heater switch  32  is turned on, the electric heater  30  is in connection with the stack  10 , such that the electric heater  30  is operated by the stack power. 
     Further, the controller  40  operates the blower fan  31 , such that the air heated by the electric heater  30  is supplied to the interior of the vehicle through the air-conditioning duct  33 , thereby heating the interior. 
     When the driver stops the vehicle and turns the key to the OFF-position, common shutdown of the fuel cell system is performed, in which moisture is removed from the evaporator by using the remaining voltage in the stack, as described below with respect to  FIG. 3 . 
     As the controller  40  detects a key-off signal, the process of removing moisture is performed. First, when the key-off signal is detected, the heater switch  32  is turned on such that the electric heater  30  is connected to the fuel cell stack  10  and the electric heater  30  is operated. 
     The diverging channel  34  is opened and the air-conditioning duct  33  is closed by controlling the opening/closing unit  35 , together with the operation of the electric heater  30  by means of the stack power, and operation of the blower fan  31 . 
     As a result, the air provided by the blower fan  31  is heated by the electric heater  30  and is supplied to the diverging channel  34 , and the hot dry air heated by the electric heater  30  is supplied to the evaporator  51  through the diverging channel  34 , such that moisture can be removed. 
     In the process of removing moisture from the evaporator  51 , as the electric heater  30  consumes the stack power, the oxygen remaining in the cathode is removed, such that the electric heater  30  functions as the COD of the related art. 
     When the oxygen has been removed from the cathode and the moisture has been removed from the evaporator  51 , the stack voltage (e.g. as detected by a voltage detector) drops below a predetermined voltage (e.g., 20V). In response, the controller  40  stops the operation of the electric heater  30  by turning off the heater switch  32 , and also stops the operation of the blower fan  31 . 
     According to the described configuration and operation of the air-conditioning moisture remover in a fuel cell vehicle, the process of removing moisture and oxygen can always be performed in shutdown, regardless of whether the air conditioner operates while the vehicle is in use. 
     Further, according to the present invention, the actuator  36  and the blower fan  41  of the opening/closing device  35  may be operated by the stack power or by power from an individual battery in the vehicle. 
     Meanwhile,  FIG. 4  shows a diagram in accordance with another embodiment of the present invention. 
     In particular, according to the embodiment shown in  FIG. 2 , air heated by the electric heater  30  is provided to the air conditioner evaporator  51  through an the air channel diverging from the air-conditioning duct, that is, the diverging channel  34 . According to the embodiment shown in  FIG. 4 , air heated by the electric heater (e.g., PTC heater)  30  is first supplied to the interior, and is subsequently supplied to the air conditioner evaporator  51  through an air channel  38 . For example, as shown, the air channel  38  extends to the air conditioner evaporator  51  from the interior of the vehicle. 
     In this case, for example, the air that has circulated in the interior of the vehicle may then be supplied to the air conditioner evaporator  51  through an air-conditioner filter, which is not shown. 
     Further, in this embodiment, a blower fan  55  can be further disposed near the air conditioner evaporator  51  such that the interior air (i.e. the air heated by the electric heater that has been supplied to the interior) is sucked through the air channel  38  and supplied to the air conditioner evaporator  51  by the blower fan  55 . 
     For this configuration, the controller  40  can be configured to operate the blower fan  55  for the evaporator  51 , together with the blower fan  31  for the electric heater  30 , such as in shutting down the fuel cell system. 
     In this embodiment shown in  FIG. 4 , since the hot dry air that has been heated by the electric heater  30  is supplied first to the interior and also to the air conditioner evaporator  51  through the air channel  38 , it is possible to effectively remove moisture from the air conditioner evaporator  51 . 
     The embodiment shown in  FIG. 4  is the same or similar to the operational process, state and effect as that of  FIG. 2 , except that the air channel is not a diverging channel that diverges from the air-conditioning duct, but rather is an air channel  38  connected between the interior of the vehicle and the air conditioner evaporator  51  via a blower fan  55 . 
       FIG. 5  is a diagram illustrating another embodiment of air-conditioning moisture remover of the present invention, in which an electric heater (e.g., PTC heater)  56  is directly attached to the air conditioner evaporator  51 . 
     In particular, the air conditioner evaporator  51  is directly heated by operating the electric heater  56  attached thereto such that moisture can be removed. 
     In this configuration, the electric heater  56  attached to the air conditioner evaporator  51  is a heater separate from the electric heater  30  which is configured for heating the interior. The electric heater  56  can be configured such that it is turned on/off by a switch  57 . 
     Thus, for example, the electric heater  30  in the embodiments of  FIGS. 2 and 4  is configured for both heating the interior of the vehicle and for heating the air for removing moisture from the evaporator while consuming the stack power (removing the oxygen remaining in the cathode) in shutting down the fuel cell system. On the other hand, in the embodiment shown in  FIG. 5 , the electric heater  56  attached to the air conditioner evaporator  51  directly heats the air conditioner evaporator  51  by means of the stack power to remove the moisture and remove the remaining oxygen and voltage of the stack in shutting down the fuel cell system. 
     According to the embodiment shown in  FIG. 5 , also referred to as the direct-heating type, a specific air channel and a blower fan are not required. 
     The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.