Nissan Motor Company Limited

Ikuo Kiminami

Toshimitsu Nose

Hideyuki Sakamoto

Masaki Kaiju

In an automotive automatic air conditioning system having at least a variable displacement compressor, a condenser, an expansion valve, and an evaporator; an improvement comprising a refrigerant temperature sensor disposed between the outlet of the expansion valve and the inlet of the evaporator for detecting a refrigerant temperature, and a controller for setting a target refrigerant temperature are disclosed. The controller controls the discharge of refrigerant from the compressor such that the refrigerant temperature reaches the target refrigerant temperature. Thus, the system provides optimum dehumidification under conditions of high humidity and relatively low ambient temperature, such as a rainy spell in autumn.

Automotive automatic air conditioning system with variable displacement

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.

Automatic air conditioner system with variable displacement compressor

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 the evaporator placed just behind the evaporator, a control valve for the compressor essentially changing the discharge of said compressor on the basis of the difference between the intake air temperature and its target value, and a CPU for changing the target value of the intake air temperature. When the CPU does not receive a signal indicative of a requirement for quick-cooling, the target value is set to a freezing start possible temperature defined by an intake air temperature such that the freezing of the evaporator starts, and when the CPU receives the signal indicative of a requirement for quick-cooling, the target value is set to a predetermined temperature lower than the freezing start possible temperature. Thus, the automatic air conditioning system is capable of maintaining a high displacement of refrigerant in spite of the lowering of suction pressure of the compressor, related to the dropping of the intake air temperature, when the quick-cooling is required.

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Kanagawa, Japan

Ikuo Kiminami