Abstract: An energy-efficient air conditioning control method regulates the capacity of a variable capacity refrigerant compressor based on the compressor suction and discharge pressures and a measure of the ambient temperature. A target suction pressure is selected based on the ambient temperature and the sensed discharge pressure, and the capacity of the compressor is adjusted as required to attain the target suction pressure. In a first embodiment of the control method, the ambient temperature is used to select a target evaporator outlet air temperature, which is used along with the sensed discharge pressure to select the target suction pressure, while in a second embodiment of the control method, the target suction pressure is selected directly on the basis of the ambient temperature and the sensed discharge pressure.

Abstract: An energy-efficient vehicle air conditioning system includes a variable capacity refrigerant compressor having a capacity control valve with integral refrigerant sensors and control circuitry, and a driver interface panel for selecting the discharge air temperature and inlet air source, and for selecting either a normal control mode or an energy-efficient control mode. When the energy-efficient control mode is selected, control setting indicators prompt the driver to request full-cold discharge air temperature and recirculated cabin air, and the control circuitry initiates a compressor capacity control based on the refrigerant sensor information and a measure of the outside air temperature to produce a suitable discharge air temperature at a reduced power consumption level.