Patent ID: 6913067

Claim:
A vehicle air conditioning system utilizing a gaseous refrigerant and capable of operating in a heating or cooling mode comprising: a compressor ( 6 ) for compressing and raising the temperature of the refrigerant, an auxiliary heat exchanger ( 10 ) downstream of said compressor ( 6 ) to remove heat from the refrigerant and provide heat to the vehicle passenger compartment when the system is operating in the heating mode, a refrigerant cooler ( 7 ) downstream of said auxiliary heat exchanger to lower the temperature of the refrigerant, a first valve ( 11 ) between said auxiliary heat exchanger ( 10 ) and said refrigerant cooler ( 7 ) and movable between an open position wherein the system operates in a cooling mode and a closed position wherein the system operates in a heating mode, a first expansion valve ( 14 ) between said auxiliary heat exchanger ( 10 ) and said refrigerant cooler ( 7 ) and disposed in parallel with said first valve ( 11 ) whereby when first valve ( 11 ) is in a closed position, first expansion valve ( 14 ) is operable to reduce the pressure of the refrigerant, a primary heat exchanger ( 8 ) downstream of said refrigerant cooler ( 7 ), an evaporator ( 5 ) downstream of said primary heat exchanger ( 8 ), a second valve ( 12 ) between said primary heat exchanger ( 8 ) and said evaporator ( 5 ) and movable between an open position wherein the system operates in a heating mode and a closed position wherein the system operates in a cooling mode, and a second expansion valve ( 9 ) between said primary heat exchanger ( 8 ) and said evaporator ( 5 ) and disposed in parallel with said second valve ( 12 ) wherein when second valve ( 12 ) is in a closed position second expansion valve ( 9 ) is operable to restore vaporization pressure.