US 2008/0289347 A1 · Control method for a variable displacement refrigerant compressor in a high-efficiency AC system

Abstract

A high efficiency air conditioning system includes a pneumatically-controlled variable displacement compressor and a compressor clutch that is selectively cycled on and off to minimize series re-heating of conditioned air. Conditioned air is discharged after passing through an evaporator core, and a target value for the evaporator outlet air temperature is determined based on the desired air discharge temperature. The compressor clutch is cycled off when the evaporator outlet air temperature falls below the target value by at least a calibrated amount, and is thereafter cycled on again when the evaporator outlet air temperature rises above the target value. The target value is preferably biased to prevent compressor operation when the desired air discharge temperature exceeds outside air temperature by at least a calibrated amount and to prevent the relative humidity in the air-conditioned space from rising above a desired level.

Claims10

Dependent claims

A method of operation for an air conditioning system including a variable displacement refrigerant compressor having a clutch that is selectively activated and deactivated for turning the compressor on and off and a pneumatic control valve for adjusting a pumping capacity of the compressor in relation to its suction pressure, and an evaporator that conditions inlet air for discharge into a conditioned space, the method comprising the step of:

determining a target temperature for air exiting the evaporator;
determining an actual temperature of air exiting the evaporator;
and
deactivating the clutch to turn off the compressor when the actual temperature falls below the target temperature by at least a calibrated amount, and then activating the clutch to turn on the compressor when the actual temperature rises above the target temperature.

1 more element

A method of operation for a motor vehicle air conditioning system including a variable displacement refrigerant compressor having a clutch that is selectively activated and deactivated for turning the compressor on and off and a pneumatic control valve for adjusting a pumping capacity of the compressor in relation to its suction pressure, an evaporator that chills inlet air passing therethrough, and a heater core for selectively re-heating air exiting the evaporator to satisfy a desired air discharge temperature of the system, the method comprising the steps of:

detecting an over-capacity condition of the system for which the pumping capacity of the compressor is such that series re-heating of the air exiting the evaporator is required to satisfy the desired air discharge temperature;
and
cyclically activating and deactivating the clutch to cycle the compressor on and off while the over-capacity condition is detected so as to satisfy the desired air discharge temperature with a reduced compressor pumping capacity.

Dependencies are inferred from the claim text.

Control method for a variable displacement refrigerant compressor in a high-efficiency AC system

Life of this patent

Control method for a variable displacement refrigerant compressor in a high-efficiency AC system

Life of this patent

Abstract

Claims10