Abstract:
A method for refueling hydrogen fuel cell powered vehicles is disclosed, that is capable of automatically disabling the vehicle systems, resetting the vehicle systems to allow for normal vehicle operation after the refueling event is complete, and determining if a faulty refueling event has been detected and allows normal vehicle operation.

Description:
FIELD OF THE INVENTION 
     This invention relates to a method of operation of a hydrogen fuel cell powered vehicle. More particularly, this invention is directed to a method of refueling a hydrogen fuel cell powered vehicle. 
     BACKGROUND OF THE INVENTION 
     Vehicle fueling stations typically require that vehicles be turned off during refueling to minimize the risks of vehicle damage associated with vehicle operation during the refueling process. Ensuring vehicles are not operated during refueling is primarily accomplished through enforcement by fueling station attendants, or is a voluntary process depending upon the cooperation of the vehicle operator. 
     As hydrogen fuel cell power plants are increasingly being integrated into vehicles, preventing operators from driving away during refueling is becoming increasingly important in order to prevent damage to both the vehicle and fuel station equipment. 
     It would be desirable to have a hydrogen refueling system that automatically disables vehicle systems in order to militate against damage to the vehicle when refueling is occurring. It would be further desirable to have a hydrogen vehicle refueling system that resets the vehicle systems after the refueling event is complete. Also, it would further be desirable to have a hydrogen refueling system that determines if a faulty refueling event has been detected and maintains typical vehicle operation. 
     SUMMARY OF THE INVENTION 
     According to the present invention, a hydrogen fueling system that automatically disables vehicle systems when refueling is occurring, resets the vehicle systems after the refueling is complete, and determines if a faulty refueling event has been detected has surprisingly been discovered. 
     In one embodiment, the method of refueling a hydrogen fuel cell powered vehicle, includes the steps of providing a traction drive system, a control system in electrical communication with the traction drive system, and at least one refueling sensor in electrical communication with the control system; determining the vehicle is refueling using the refueling sensors; communicating a vehicle refueling signal from the refueling sensors to the control system; and disabling the traction drive system using the control system when a vehicle refueling signal is received. 
     In another embodiment, the method of refueling a hydrogen fuel cell powered vehicle, includes the steps of providing a traction drive system, a control system in electrical communication with the traction drive system, at least one fuel inlet sensor in electrical communication with the control system, and at least one fuel tank sensor in electrical communication with the control system; determining vehicle refueling using the fuel inlet sensor; determining vehicle refueling using the fuel tank sensor; communicating a first vehicle refueling signal from the fuel inlet sensor and a second refueling signal from the fuel tank sensor to the control system; disabling the traction drive system using the control system when a vehicle refueling signal is received; and re-enabling the traction drive system using the control system when the refueling is complete. 
     In another embodiment, the method of refueling a hydrogen fuel cell powered vehicle, includes the steps of providing a traction drive system, a control system in electrical communication with the traction drive system, at least one fuel inlet sensor in electrical communication with the control system, and at least one fuel tank sensor in electrical communication with the control system; determining vehicle refueling using the fuel inlet sensor; determining vehicle refueling using the fuel tank sensor; communicating a first vehicle refueling signal from the fuel inlet sensor and a second refueling signal from the fuel tank sensor to the control system; determining a faulty refueling signal when the first refueling signal and the second refueling signal do not both communicate a refueling signal to the control system within, a predetermined time period; disabling the traction drive system using the control system when the vehicle refueling signal received is not faulty; and re-enabling the traction drive system using the control system when the refueling is complete. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which: 
         FIG. 1  is a schematic illustration of a hydrogen powered vehicle with refueling system components of the present invention; 
         FIG. 2  shows a fragmentary perspective view of a fuel door in the open position and showing the control systems schematically according to the embodiment of the invention shown in  FIG. 1 ; and 
         FIG. 3  is a flow diagram illustrating a method of operation of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following detailed description and appended drawings describe and illustrate various exemplary embodiments of the invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. In respect of the methods disclosed, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical. 
     In the exemplary embodiment described herein, the hydrogen powered vehicle refueling strategy is provided in a vehicle  2 , as shown in  FIG. 1 . The vehicle  2  includes a traction drive system or vehicle system  10 . It is understood that other vehicle systems can be used as desired. A plurality of wheels  4  are mechanically coupled to the traction drive system  10 . The traction drive system  10  is electrically linked to a control system  16  via a connection  12 . The connection  12  may be any conventional means of electrical communication. 
     A fuel inlet  24  is formed in the vehicle  2  and is in fluid communication with a fuel tank  20 . The fuel inlet  24  includes at least one fuel inlet sensor, such as a fuel door switch  40 , and a fuel nozzle sensor  42 , for example, as clearly shown in  FIG. 2 . The fuel inlet sensor is in electrical communication with the control system  16  via an electrical connection  14 . The fuel tank  20  includes at least one fuel tank sensor, such as a temperature sensor  26 , and a pressure sensor  27 . The fuel tank sensor is in electrical communication with the control system  16  via an electrical connection  18 . Additionally, the vehicle  2  may include other sensors without departing from the scope of this invention. 
     Referring now to  FIG. 2 , a fuel inlet door  34  is pivotally connected to the fuel inlet  24  via a hinge  32 . An aperture  30  is formed in the fuel inlet  24 . The aperture  30  is adapted to receive a hydrogen fuel pump nozzle (not shown). The fuel door switch  40  is disposed adjacent the fuel inlet  24  to sense when the fuel door  34  is in an open or closed position. The fuel inlet sensor  42  is disposed near the aperture  30  to sense when a hydrogen fuel pump nozzle is inserted in the aperture  30 . The fuel door switch  40  and the fuel nozzle sensor  42  generate and transmit a refueling signal to the control system  16  via the connection  14 . Other sensors may be used without departing from the scope of this invention. 
     In operation, the traction drive system  10  controls whether power generated by a fuel cell is sent to the vehicles wheels  4  and/or whether the traction drive system converts the available power to mechanical work. The control system  16  selectively controls the traction drive system  10  via the communication  12 . 
     The control system  16  disables the traction drive system  10  when vehicle refueling occurs (Y at  52 ), shown in  FIG. 3 . Disabling the traction drive system  10  prevents a user from driving away while the vehicle  2  is being refueled. The control system  16  enables the traction drive system  10  when refueling is not occurring (N at  52 ). Additionally, it may be desirable for the control system  16  to disable other vehicle  2  systems, such as the fuel cell power system (not shown), when refueling is detected. 
     In the embodiment shown and described herein, refueling is communicated to the control system  16  in several methods. A first refueling signal is communicated to the control system  16  from the at least one fuel inlet sensor via the connection  14 . It may be desirable to communicate the first refueling signal from the fuel nozzle sensor  42 . When a hydrogen fuel pump nozzle is detected in the aperture  30  the fuel nozzle sensor  42  generates and transmits a signal that refueling is occurring (Y at  52 ) to the control system  16 . Alternatively, it may be desirable to communicate the first refueling signal from the fuel door switch  40 . When the fuel door  34  is an open position the fuel door switch  40  generates and transmits a signal that refueling is occurring (Y at  52 ) to the control system  16 . It may desirable for the fuel door switch  40 , and the fuel inlet sensor  42  to be contact sensors such as micro-switches, or non-contact sensors such as proximity sensors. Additionally, other types of sensors or combinations of sensors may be used without departing from the scope of this invention. 
     A second refueling signal is sent to the control system  16  from the at least one fuel tank sensor via the connection  18 . It may be desirable to send the second refueling signal from the temperature sensor  26 . When a sudden drop in fuel tank  20  temperature is detected the temperature sensor  26  generates and transmits a signal to the control system  16 . It may be further desirable to communicate the second refueling signal from the pressure sensor  27 . When rapidly rising fuel tank  20  pressure is detected, the pressure sensor  27  generates and transmits a signal to the control system  16 . Additionally, other types of sensors may be used without departing from the scope of this invention. 
     Additionally, it may be desirable to use both the first refueling signal and the second refueling signal together in order to determine whether a faulty refueling signal has been communicated to the control system  16 . For example, if the control system  16  receives the first refueling signal from the fuel door switch  40 , and does not receive a second refueling signal from the pressure sensor  27  within a predetermined time period, the control system  16  could determine that the fuel door switch  40  sent a faulty signal and the system may be re-enabled because refueling is not taking place. 
     When the control system  16  determines that refueling is complete or not occurring (N at  52 ) the traction drive system  10  is re-enabled. It may be desirable to implement a time delay before re-enabling the traction drive system  10  in order to ensure that the refueling process is complete. 
     From the foregoing description, one ordinarily skilled in the a can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, make various changes and modifications to the invention to adapt it to various usages and conditions.