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.

1 . An air conditioner for a vehicle, comprising: 
 a variable displacement compressor for compressing a refrigerant; and    a control unit for controlling the compressor, wherein:    the compressor is driven by an engine of a vehicle and is normally connected to the engine at all times; and    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 T 1  and intermittently during time T 2  and a revolution speed of the compressor is equal to or higher than a predetermined revolution speed N.    
   
   
       2 . The air conditioner as set forth in  claim 1 , wherein the compressor is a swash plate type.  
   
   
       3 . The air conditioner as set forth in  claim 1 , wherein it is preferable for the control unit to control the compressor such that the compressor turns on and operates at the time intervals T 1  substantially equal to or longer than one minute and for the time T 2  substantially equal to or longer than one minute when the compressor is in the off state and the revolution speed of the compressor is equal to or higher than a predetermined revolution speed N, and it is more preferable to control the compressor such that the compressor turns on and operates at the time intervals T 1  substantially equal to or longer than ten minutes and for the time T 2  of substantially one minute.  
   
   
       4 . The air conditioner as set forth in  claim 1 , wherein preferably the predetermined revolution speed N of the compressor is substantially 6,000 rpm.  
   
   
       5 . A method for controlling an air conditioner for a vehicle comprising a variable displacement compressor for compressing a refrigerant and a control unit for controlling the compressor, wherein 
 the control method is carried out by the control unit, the compressor being driven by an engine of a vehicle and normally connected to the engine at all times, and wherein    the control method comprises:    a step for checking whether the revolution speed of the compressor is equal to or higher than a predetermined revolution speed N;    a step for checking whether the compressor is off; and    a step for turning on and operating the compressor at predetermined time intervals T 1  and intermittently during time T 2  when the compressor is in an off state, and revolution speed of the compressor is equal to or higher than a predetermined revolution speed N.    
   
   
       6 . The control method as set forth in  claim 5 , wherein the compressor is a swash plate type.  
   
   
       7 . The control method as set forth in  claim 5 , wherein it is preferable for the control unit to control the compressor such that the compressor turns on and operates at the time intervals T 1  substantially equal to or longer than one minute and for the time T 2  substantially equal to or longer than one minute when the compressor is in an off state and the revolution speed of the compressor is equal to or higher than the predetermined revolution speed N, and it is more preferable to control the compressor such that the compressor turns on and operates at the time intervals T 1  substantially equal to or longer than ten minutes and for the time T 2  of substantially one minute.  
   
   
       8 . The control method as set forth in  claim 5 , wherein preferably the predetermined revolution speed N of the compressor is substantially 6,000 rpm.