Air conditioner for vehicles

An air conditioner for vehicles comprising:

• a refrigerant circuit having a compressor with means for varying an output of the compressor, a refrigerant evaporator provided at an upstream location in an air duct, a refrigerant condenser provided at a downstream location in said air duct, and an external heat exchanger positioned on the vehicle separate from said air duct;
• means for controlling said refrigerant circuit for performing a cooling operation by supplying refrigerant from said compressor through said external heat exchanger and then through said evaporator, a heating operation by supplying refrigerant from said compressor through said condenser and then through said external heat exchanger, and a dehumidifying operation by supplying refrigerant from said compressor through said condenser and then through said evaporator;
• means for detecting an air temperature downstream of said condenser;
• and
• means for controlling the output of said compressor in response to the air temperature detected at the output-side position of said condenser.

An air conditioner for vehicles comprising:

• a refrigerant circuit having a compressor with means for varying the compressor output, a heat sink provided at an upstream position in an air duct for performing a heat absorbing action, and a radiator provided at a downstream position in said air duct for performing a heat radiating action, said refrigerant circuit serving to provide a cooling operation utilizing said heat absorbing action, a heating operation utilizing mainly said heat radiating action, and a dehumidifying operation utilizing both said heat absorbing action and said heat radiating action;
• means for detecting air temperatures at output-side positions of said heat sink and said radiator, respectively;
• means for controlling the output of said compressor in response to at least one of either the air temperature detected at an output-side position of said heat sink or the air temperature detected at an output-side position of said radiator;
• and
• means for controlling the volume of air passing through said radiator;
• said air volume control means being controlled during said dehumidifying operation so that said volume of air passing through said radiator is controlled to an air volume based on a ratio of said air temperature detected at said output-side position of said radiator to a target discharge air temperature, and said compressor output control means is controlled so that said air temperature detected at said output-side position of said heat sink is controlled to a target dehumidification temperature.