Air conditioning systems for vehicles

Abstract

An air conditioning system for vehicles includes a refrigeration cycle having a variable displacement compressor with a displacement control valve, for controlling a discharge amount of the compressor, so that a pressure difference (Pd-Ps) between a discharged refrigerant pressure (Pd) and a drawn-refrigerant pressure (Ps) equals a set value, an acceleration state detecting device, and an engine rotational speed detecting device. The system further includes a device for determining a condition in which the acceleration state is detected or a condition in which the engine rotational speed equals or is greater than a set value as an elevated compressor load condition, and during the elevated compressor load condition, controlling the discharge amount of the compressor, so that the pressure difference (Pd-Ps) equals or is less than a pressure difference (Pd-Ps) immediately before elevated the compressor load condition. Both superior acceleration performance of a vehicle and driver comfort due to air conditioning may be achieved.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to air conditioning systems for vehicles, and more specifically, to air conditioning systems for vehicles which improve the acceleration performance of a vehicle by appropriately reducing the displacement of a compressor during acceleration, without adversely affecting operation of air conditioning or performance of the vehicle, or both. [0003] 2. Description of Related Art [0004] In a known technology, a refrigeration cycle has a variable displacement compressor, and the power consumed by driving the compressor is reduced by reducing the displacement of the compressor during vehicle acceleration. An amount of power made available to the vehicle by reducing power consumption by the compressor is utilized to improve the acceleration performance of the vehicle. An example of the known technology is described in Japanese Published Patent Application No. JP-A-57-175422. [0005] Nevertheless,...

AI Technical Summary

Benefits of technology

[0006] Accordingly, a need has arisen to provide air conditioning systems for vehicles, which prevent a compressor from being driven at a maximum displacement during acceleration, avoid excessive power consumption by the compressor during acceleration, and realize improved acceleration performance of the vehicle and reduced fuel consumption.

[0007] Further, a need has arisen to provide air conditioning systems for vehicles, which appropriately reduce the displacement of the compressor during acceleration to improve the acceleration performance of the vehicle, and, at the same time, which prevent the degradation of the driver's comfort, by suppressing the excessive elevation of the temperature of the air blown into a vehicle interior.

[0014] Thus, in air conditioning systems for vehicles according to the present invention, the compressor is not always driven at a maximum displacement during acceleration, excessive power consumption of the compressor during acceleration may be avoided, and improved acceleration performance of the vehicle and reduced fuel consumption may be achieved.

[0015] Further, because the displacement of the compressor is controlled, so that the pressure difference between the discharged refrigerant pressure and the drawn-refrigerant pressure is a target value both before acceleration and during acceleration, the cooling ability is not reduced during acceleration, and the comfort level in the vehicle interior may be maintained.

Problems solved by technology

Nevertheless, there are problems with this known technology for reducing a displacement of a compressor during acceleration.

Therefore, the driver's comfort may be adversely affected.

On the other hand, if the above-described compressor control is not performed during acceleration, the power consumption of the compressor increases along with the increase in engine rotational speed.

The acceleration performance of the vehicle may be degraded, and fuel consumption may increase.

Therefore, the power consumption of the compressor increases along with the elevation of the engine rotational speed, and the acceleration performance of the vehicle may deteriorate significantly.

Images