Automatic air conditioner system with variable displacement compressor

Abstract

An automatic air conditioning system for automotive vehicles with a variable displacement compressor comprises a sensor for detecting an intake air temperature of air flowing through an evaporator placed just behind the evaporator, a control valve for essentially changing the discharge volume of the compressor on the basis of the difference between the intake air temperature and its target value, and a CPU for deriving the different target values in response to two modes, namely a BI-LEVEL mode wherein conditioned air is simultaneously discharged from both upper and lower discharge outlets, and a MONO-LEVEL mode wherein conditioned air is discharged from either the upper or lower discharge outlets. The control valve operates in such a manner that, when the difference is plus, that is, the intake air temperature is higher than the target value, the discharge volume is essentially increased, and when the difference is minus, that is, the intake air temperature is lower than the target value, the discharge volume is essentially decreased. Thus, in the BI-LEVEL mode the amount of air reheated by a heater unit becomes larger than the amount of reheated air in the MONO-LEVEL mode. According to the invention, the BI-LEVEL mode effect can be sufficiently satisfied, particalarly, in a fuel-saving mode wherein the difference between the intake air temperature and the temperature of air to be discharged from the discharge outlets is very small.