| 摘要 |
A control unit for a clutchless variable displacement compressor with a solenoid is used in an air conditioning system for vehicles. The control unit includes a solenoid drive for adjusting a current flowing in the solenoid, a voltmeter for detecting a voltage applied to the solenoid, an ammeter for detecting the current of the solenoid, and a control for supplying current to the solenoid drive during a first predetermined time period when the air conditioning system is not in operation, and current has been prevented from flowing to the solenoid during a second predetermined time period. A resistance of a coil of the solenoid is calculated from the detected voltage and the detected current. A temperature of the compressor is determined from the calculated resistance based on a predetermined relationship between the resistance and the temperature of the coil of the solenoid when the air conditioning system is not in operation; the compressor is operated by supplying current to the solenoid when the calculated temperature exceeds a set value. Thus, the temperature of the compressor may be detected by a control mechanism, and the compressor may be protected against an excessive increase of temperature.
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