Abstract: A hybrid fuel cell system that employs a fuel cell stack and an ultracapacitor. A diode is provided on a high voltage electrical bus between the fuel cell stack and the ultracapacitor so that high voltage from the ultracapacitor does not affect the operation of the fuel cell stack. During system start-up, a by-pass switch is closed to by-pass the ultracapacitor so that power from the ultracapacitor can be used to start various system loads, such as a cathode side air compressor that provides air to the fuel cell stack. A 12 volt-to-high voltage converter is employed to provide a low power, high voltage supply from a low voltage battery to the system loads at start-up when the by-pass switch is opened, but before a fuel cell stack switch is closed.

Abstract: A system and method for operating a cooling fluid pump and cooling fluid heater in a vehicle when the vehicle is not being used so that the temperature of the cooling fluid does not drop to low in a cold environment. The system includes an AC connector for plugging the system into an AC power outlet. The system also includes AC/DC converter that converts the AC power to a DC signal suitable to operate the pump. The system also includes a temperature switch that closes if the ambient temperature falls below a predetermined temperature, which electrically connects the AC connector to the AC/DC converter. When the AC/DC converter is powered, a switch is closed to connect the pump to a pulse width modulation (PWM) generator to operate the pump. Further, when the temperature switch is closed, power is provided to the heater.

Abstract: A hybrid fuel cell system that employs a fuel cell stack and an ultracapacitor. A diode is provided on a high voltage electrical bus between the fuel cell stack and the ultracapacitor so that high voltage from the ultracapacitor does not affect the operation of the fuel cell stack. During system start-up, a by-pass switch is closed to by-pass the ultracapacitor so that power from the ultracapacitor can be used to start various system loads, such as a cathode side air compressor that provides air to the fuel cell stack. A 12 volt-to-high voltage converter is employed to provide a low power, high voltage supply from a low voltage battery to the system loads at start-up when the by-pass switch is opened, but before a fuel cell stack switch is closed.

Abstract: A system and method for operating a cooling fluid pump and cooling fluid heater in a vehicle when the vehicle is not being used so that the temperature of the cooling fluid does not drop to low in a cold environment. The system includes an AC connector for plugging the system into an AC power outlet. The system also includes AC/DC converter that converts the AC power to a DC signal suitable to operate the pump. The system also includes a temperature switch that closes if the ambient temperature falls below a predetermined temperature, which electrically connects the AC connector to the AC/DC converter. When the AC/DC converter is powered, a switch is closed to connect the pump to a pulse width modulation (PWM) generator to operate the pump. Further, when the temperature switch is closed, power is provided to the heater.