Abstract: Improvements in startup time for an electrochemical fuel cell system from freezing and sub-freezing temperatures are obtained by utilizing an insulated fuel cell stack in combination with an thermal control subsystem. Temperature of the insulated electrochemical fuel cell stack, as well as temperature of the ambient environment, are monitored and a heating fluid is heated by thermal transfer with the environment under appropriate thermal conditions. The heated fluid is then passed to the insulated fuel cell in order to increase the temperature of the same, typically to a temperature at or near the temperature of the ambient environment. In this manner, ambient heat from the environment is utilized to increase the temperature of the insulated fuel cell stack, thus improving conditions for subsequent cold start of the insulated fuel cell stack.
Abstract: A HVAC system for reducing the level of air rush and blower noise escaping into the interior of the vehicle when the HVAC system is operating in the recirculation mode. The HVAC system includes a recirculation door having an acoustically transparent portion that enables a component of the air rush and blower noise to pass through the recirculation door to the vehicle exterior instead of entering the vehicle cabin or interior through the recirculation air inlet.