Vehicle air conditioner in which shaft seal is protected

Abstract

An object of the present invention is to protect a shaft seal of a variable displacement compressor of an air conditioner for a vehicle by the control thereof. The air conditioner for a vehicle comprises a variable displacement swash plate type compressor for compressing a refrigerant and a control unit for controlling the compressor. The compressor is driven by an engine of a vehicle and is normally connected to the engine at all times. The control unit controls the compressor such that when the compressor is in an off state the compressor turns on and operates at predetermined time intervals of 10 minutes and for one minute, and the revolution speed of the compressor is equal to or higher than predetermined 6,000 rpm.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an air conditioner for a vehicle and, particularly, to a compressor of an air conditioner for a vehicle and, more particularly, to control of a variable displacement compressor of an air conditioner. [0003] 2. Description of the Related Art [0004] Some vehicle air conditioners comprise a variable displacement compressor. A variable displacement compressor is capable of properly changing its displacement in accordance with the load of an air conditioner, the operating state of a vehicle, etc., and has various advantages such as in temperature control, energy saving effect, etc. Further, a variable displacement compressor may be directly connected to an engine, which is the drive unit of a compressor and there is no need for it to be connected via a clutch etc. and, therefore, the number of parts can be reduced and is more advantageous in cost compared to the case where a fixed displac...

AI Technical Summary

Benefits of technology

[0011] Another object of the present invention is to provide a control method capable of protecting a shaft seal of a compressor and, more particularly, of a variable displacement compressor for an air conditioner of a vehicle.

[0019] According to the present aspect, the revolution speed of the compressor, which is a control parameter of the compressor of an air conditioner for a vehicle according to the present invention, is made more concrete.

Problems solved by technology

In the prior art, when a vehicle is in operation and the compressor is off, the flow of the oil shown in FIG. 1 and FIG. 2 becomes unsmooth and then, in particular, when the revolution speed of the engine becomes high, the pressure around the shaft seal becomes high, resulting in severe conditions to the shaft seal.

Such conditions adversely affect the durability of the shaft seal and as a result, increase the possibility that a problem of seal defect at the shaft etc. arises.

As describe above, when the compressor is in the off state and the revolution speed of the engine is high, the shaft seal is adversely affected because the temperature and the pressure around the shaft seal rise.

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