Pulsed coolant control for improved stack cold starting

A fuel cell system comprising:

• a fuel cell stack including an inlet cooling fluid manifold, an outlet cooling fluid manifold and cooling fluid flow channels therebetween;
• a pump for pumping a cooling fluid through a coolant loop outside of the fuel cell stack and through the inlet manifold, the outlet manifold and the cooling fluid flow channels;
• a temperature sensor positioned within or proximate to the inlet manifold, said temperature sensor providing a temperature signal indicative of the temperature of the cooling fluid;
• a heater positioned within the inlet manifold;
• and
• a controller for controlling the operation of the pump and the heater based on predetermined variables, said controller being responsive to the temperature signal, said controller intermittently turning the pump on and off to pump the cooling fluid through the fuel cell stack and turning the heater on during a cold stack start-up operation.

A fuel cell system comprising:

• a fuel cell stack including an inlet cooling fluid manifold, an outlet cooling fluid manifold and cooling fluid flow channels therebetween;
• a pump for pumping a cooling fluid through a coolant loop outside of the fuel cell stack and through the inlet manifold, the outlet manifold and the cooling fluid flow channels;
• a heater positioned within the inlet manifold;
• and
• a controller for controlling the operation of the pump, said controller turning the heater on during a cold stack start-up operation.