Air conditioner for vehicle

Abstract

Provided is an air conditioner for a vehicle which can prevent the controls over cooling cycle and heating cycle from interfering with each other and thereby prevent hunting between the cooling and heating cycles even when a compressor is operated to perform the heating cycle in an overlapping temperature range where air cooling and air heating are both required. An air conditioner (4) for a vehicle includes a refrigerant circulation circuit (9b) for air heating to circulate a refrigerant, and a control unit (29) to selectively perform a normal air conditioning mode in which a normal cooling operation is feasible by circulating the refrigerant through a refrigerant circulation circuit (9a) for air cooling and an auxiliary heating mode in which an auxiliary heating operation is performed by circulating the refrigerant through the refrigerant circulating circuit (9b) for air heating.

Description

TECHNICAL FIELD[0001]The present invention relates to an air conditioner for a vehicle to heat the air in a vehicle interior using the heat from a cooling water.BACKGROUND ART[0002]A conventional vehicle air conditioner is generally comprised of an air heating unit using the heat from an engine cooling water and an air cooling unit using a refrigeration cycle.[0003]In the air heating unit, a high-temperature engine cooling water having absorbed heat from the engine is circulated inside a heater core in an instrument panel to heat the air by the heat from the heater core and blow the heated air from an outlet of the instrument panel for heating the air in the vehicle interior.[0004]However, since the air heating unit uses the engine cooling water, the temperature of the cooling water remains low for a while after an engine start so that the air temperature blown to the vehicle interior is also low.[0005]Thus, it may take a certain length of time for the air temperature of the vehicle...

AI Technical Summary

Benefits of technology

[0022]According to claim 1 of the present invention as thus configured, the vehicle air conditioner can operate in the auxiliary air heating mode in which refrigerant is circulated through the refrigerant circulation circuit for air heating. Because of this, it can introduce warm air into the vehicle interior even immediately after the start of the vehicle drive unit by supplying to the heater core the cooling water heated by the heat exchanger means for heating cooling water while the vehicle drive unit's cooling water temperature is rising enough for the air heating after the vehicle drive unit starts.

[0023]According to claim 2 of the present invention, the vehicle air conditioner can selectively execute the normal airconditioning mode and the auxiliary air heating mode on the basis of the condition of not only the outside and inside air temperatures but also the cooling water temperature. Because of this, it can introduce warm air into the vehicle interior even immediately after the start of the vehicle drive unit by supplying to the heater core the cooling water heated by the heat exchanger means for heating cooling water while the vehicle drive unit's cooling water temperature is rising enough for the air heating after the vehicle drive unit starts.

[0024]Further, according to claim 3 of the present invention, the vehicle air conditioner is configured to be switched to the auxiliary air heating mode only when the auxiliary air heating switch is turned on in the normal airconditioning mode but not in the air cooling operation. This can prevent hunting between the air cooling and air heating cycles since the normal airconditioning mode is performed with priority when the compressor is driven for the air heating in an overlapping temperature range in which air heating and air cooling are both required.

[0025]According to claim 4 of the present invention, the vehicle air conditioner can selectively execute the normal airconditioning mode and the auxiliary air heating mode on the basis of the condition of not only the outside and inside air temperatures but also the cooling water temperature. Because of this, it can introduce warm air into the vehicle interior even immediately after the start of the vehicle drive unit by supplying to the heater core the cooling water heated by the heat exchanger means for heating cooling water while the vehicle drive unit's cooling water temperature is rising enough for the air heating after the vehicle drive unit starts.

[0026]Further, according to claim 5 of the present invention, in switching to the auxiliary air heating mode after the air cooling operation, the vehicle air conditioner can operate in the refrigerant recovery mode in which the remnant refrigerant in the condenser and evaporator is recovered in the accumulator. Therefore, it can efficiently use the refrigerant in the auxiliary air heating and efficiently perform air heating. Besides, the compressor can be free from a shortage of lubricant.

[0027]Further, according to claim 6 of the present invention, the vehicle air conditioner includes the memory to store the airconditioning control state of the vehicle air conditioner at stop of the vehicle drive unit. Accordingly, it can determine whether or not to need to operate in the refrigerant recovery mode when the vehicle drive unit is restarted to resume the air heating operation or whether or not to restart the air heating control of the vehicle air conditioner from the beginning or from the stop point of the vehicle drive unit on the basis of the cooling water temperature.

Problems solved by technology

However, since the air heating unit uses the engine cooling water, the temperature of the cooling water remains low for a while after an engine start so that the air temperature blown to the vehicle interior is also low.

Thus, it may take a certain length of time for the air temperature of the vehicle interior to reach a temperature at which occupants can feel comfortable.

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