Patent ID: 7063138

Claim:
A method for cooling a passenger compartment in a hybrid vehicle that operates an engine intermittently during vehicle operation, the hybrid vehicle having an HVAC system including an HVAC duct, a blower adapted to direct a flow of air through the HVAC duct, an evaporator located within the HVAC duct, and a heater core, which has a coolant inlet and a coolant outlet and is located downstream of the evaporator in the HVAC duct, the method comprising the steps of: a) cooling a refrigerant; b) inducing a flow of said cooled refrigerant through said evaporator; c) blocking a flow of coolant through at least one of said coolant inlet and said coolant outlet to thereby trap a predetermined amount of coolant in said heater core; d) activating said blower to move air through said evaporator and heater core; e) turning off the vehicle engine; f) measuring a temperature indicative of a cooling function of said HVAC system; g) starting the engine when the measured temperature is above a predetermined temperature; and h) measuring an evaporator air outlet temperature; i) measuring a heater core surface temperature; j) blocking the flow of air through the heater core when the evaporator air outlet temperature is less than the heater core surface temperature and the vehicle engine is off; and k) continuing the flow of air through the heater core when the evaporator air outlet temperature is not less than the heater core surface temperature and the vehicle engine is off.