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.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates to an air-conditioning system for a vehicle, specifically, an air-conditioning system comprising a variable capacity compressor.[0003]2. Description of the Related Art[0004]A variable capacity compressor provided in an air-conditioning system for a vehicle can regulate the cooling performance of the air-conditioning system, or in other words, the cooling performance of the refrigeration circuit thereof by its refrigerant discharge capacity being varied. Specifically, under the conditions such that the thermal load in a passenger compartment of the vehicle is high, as in summer, the compressor is driven to operate with a maximum refrigerant discharge capacity. This causes a drop in the temperature of conditioned air blown out into the compartment so that the compartment temperature is regulated to a level comfortable to the vehicle occupant.[0005]When the compressor is driven to operate with the ma...

AI Technical Summary

Benefits of technology

[0017]According to the air-conditioning system described above, in selecting the cooling performance of the refrigeration circuit to decrease the drive power supplied to the compressor during vehicle acceleration, the demanded acceleration degree and the temperature are taken into consideration. Thus, during the vehicle acceleration, the cooling performance selected does not arbitrarily decreased. This makes it possible to ensure the vehicle acceleration performance and at the same time maintain the comfortable compartment temperature of the vehicle.

[0026]Whether the acceleration-period cooling performance is calculated on the basis of the target temperature for the evaporator or the target pressure for the compressor as mentioned above, the acceleration-period cooling performance calculated is such that makes it possible to ensure the vehicle acceleration performance and at the same time maintain the comfortable compartment temperature.

Problems solved by technology

When the compressor is driven to operate with the maximum refrigerant discharge capacity during acceleration of the vehicle, however, the drive power consumed by the compressor greatly increases with an increase in rotation speed of an engine equipped with the vehicle, which causes a great decrease in the acceleration performance of the vehicle.

When the drive power supplied to the compressor is unconditionally decreased during vehicle acceleration, the conditioned-air temperature however rises so that the compartment temperature cannot be maintained at a level comfortable to the vehicle occupant.

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