Air-conditioning system for vehicle

Abstract

An air-conditioning system for a vehicle according to the present invention has an ECU which executes a control routine for controlling the cooling performance of a refrigeration circuit during vehicle acceleration. The control routine includes the steps of detecting demanded vehicle-acceleration degree, detecting evaporator exit air temperature at the time vehicle acceleration starts, selecting acceleration-period cooling performance on the basis of the demanded acceleration degree and the exit air temperature, and outputting a capacity control signal to a compressor on the basis of the acceleration-period cooling performance selected.

1 . An air-conditioning system for a vehicle, comprising:
 a refrigeration circuit including a circulation path along which a refrigerant circulates, said refrigeration circuit having a variable capacity compressor, a condenser, an expansion mechanism and an evaporator disposed in the circulation path in this order;   a degree detection device for detecting demanded vehicle-acceleration degree;   a temperature detection device for detecting temperature of the evaporator or temperature correlating with the temperature of the evaporator, at vehicle-acceleration start time;   a selection device for selecting acceleration-period cooling performance of the refrigeration circuit, on the basis of the demanded acceleration degree and the temperature detected; and   an output device for generating a capacity control signal for determining an amount of the refrigerant discharged from the compressor, on the basis of the acceleration-period cooling performance selected, and outputting the capacity control signal to the compressor.   
   
   
       2 . The system according to  claim 1 , wherein
 said selection device have control modes for controlling the acceleration-period cooling performance of the refrigeration circuit, where selection from the control modes is performed on the basis of a difference between pre-acceleration cooling performance of the refrigeration circuit at the acceleration start time and post-acceleration cooling performance of the refrigeration circuit estimated in consideration of vehicle acceleration.   
   
   
       3 . The system according to  claim 2 , wherein
 the control modes include a HOLD mode to be selected when said difference is within a specified range, for maintaining the acceleration-period cooling performance at the same level as the pre-acceleration cooling performance.   
   
   
       4 . The system according to  claim 2 , wherein
 the control modes include at least one of an UP mode and a DOWN mode to be selected when said difference is out of a specified range; wherein   the UP mode maintains the acceleration-period cooling performance at a higher level compared with the pre-acceleration cooling performance, and the DOWN mode maintains the acceleration-period cooling performance at a lower level compared with the pre-acceleration cooling performance.   
   
   
       5 . The system according to  claim 4 , wherein
 the UP mode is provided to cause the acceleration-period cooling performance to increase with an increase in the temperature detected.   
   
   
       6 . The system according to  claim 4 , wherein
 the DOWN mode is provided to cause the acceleration-period cooling performance to decrease with an increase in the demanded acceleration degree.   
   
   
       7 . The system according to  claim 1 , wherein
 said selection device calculates an acceleration-period target temperature for the evaporator, on the basis of the demanded acceleration degree and the temperature detected, and set the acceleration-period cooling performance on the basis of the acceleration-period target temperature.   
   
   
       8 . The system according to  claim 7 , wherein
 the acceleration-period target temperature is a target temperature for exit air having passed through the evaporator.   
   
   
       9 . The system according to  claim 1 , wherein
 said selection device calculates an acceleration-period target pressure for the compressor, on the basis of the demanded acceleration degree and the temperature detected, and sets the acceleration-period cooling performance on the basis of the acceleration-period target pressure.   
   
   
       10 . The system according to  claim 9 , wherein
 the acceleration-period target pressure is a target intake pressure at which the compressor should suck in the refrigerant.