Vehicle air conditioning apparatus
A vehicle air conditioning apparatus is provided that can prevent temperature variations of the air after the heat exchange in a radiator to reliably control the temperature of the air supplied to the vehicle interior. During the heating operation and the heating and dehumidifying operation, target degree of supercooling SCt when target air-blowing temperature TAO is a predetermined temperature or higher is set to SCt 1 that is greater than SCt 2 when the target air-blowing temperature TAO is lower than the predetermined temperature. When amount of air Ga supplied from indoor fan 12 is lower than a predetermined value, the target degree of supercooling SCt is corrected, which is set such that the degree of supercooling is lower than target degree of supercooling corrected when the amount of air Ga supplied from the indoor fan 12 is a predetermined value or higher.
1. A vehicle air conditioning apparatus comprising:
a compressor configured to compress and discharge a refrigerant;
a radiator provided in a vehicle interior and configured to release heat from the refrigerant;
a heat exchanger provided in the vehicle interior and configured to absorb the heat into the refrigerant; and
an outdoor heat exchanger provided outside the vehicle interior and configured to release the heat from or absorb the heat into the refrigerant,
the vehicle air conditioning apparatus performing:
a heating operation to release the heat from the refrigerant discharged from the compressor in the radiator, and to absorb the heat into the refrigerant in the outdoor heat exchanger; and
a cooling and dehumidifying operation to release the heat from the refrigerant discharged from the compressor in the radiator, and additionally to release the heat from the refrigerant in the outdoor heat exchanger, and then to absorb the heat into the refrigerant in the heat exchanger,
the vehicle air conditioning apparatus further comprising:
a flow regulating valve provided in a refrigerant flow passage that allows the refrigerant flowing out of the radiator to flow into the outdoor heat exchanger, an opening of the flow regulating valve being regulated within following two ranges: a decompression range that allows the refrigerant flowing through the refrigerant flow passage to be decompressed during the heating operation; and a condensing pressure regulating range that allows an opening area of the flow regulating valve to be a same as an opening area of an upstream or downstream refrigerant flow channel when the opening of the flow regulating valve is maximized, and that can regulate the condensing pressure of the refrigerant in the radiator by regulating an amount of the refrigerant flowing through the refrigerant flow channel during the cooling and dehumidifying operation; and
a valve opening control part configured to control the opening of the flow regulating valve within the decompression range during the heating operation, and to control the opening of the flow regulating valve within the condensing pressure regulating range during the cooling and dehumidifying operation.
2. The vehicle air conditioning apparatus according to claim 1 , further comprising:
a target condensing pressure calculation part configured to calculate a target value of the condensing pressure of the refrigerant in the radiator;
a condensing pressure detection part configured to detect the condensing pressure of the refrigerant in the radiator;
an evaporating temperature detection part configured to detect an evaporating temperature of the refrigerant in the heat exchanger; and
a cooling and dehumidifying performance control part configured to control the opening of the flow regulating valve within the condensing pressure regulating range based on the target condensing pressure calculated by the target condensing pressure calculation part and the pressure detected by the condensing pressure detection part, and to control a number of rotations of the compressor based on the evaporating temperature detected by the evaporating temperature detection part.
3. The vehicle air conditioning apparatus according to claim 1 , wherein the valve opening control part sets the opening of the flow regulating valve in the condensing pressure regulating range to one of two different openings.
4. The vehicle air conditioning apparatus according to claim 1 , wherein the valve opening control part switches the opening of the flow regulating valve in the condensing pressure regulating range between a fully open state and a state to regulate a pressure difference between the refrigerant flowing into the radiator and the refrigerant flowing out of the radiator.