| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent oil from staying in an evaporator, to provide an excellent coefficient of performance, and to secure sufficient oil circulation. <P>SOLUTION: An electronic expansion valve 3 is controlled to bring a refrigerant in an outlet of the evaporator 4 into a superheat condition all the time in a usual operation, and is controlled to forcibly have a negative super heat degree periodically by a prescribed period, using a superheat controller 6. A refrigeration cycle is thereby operated under the condition of the excellent result coefficient because the refrigerant sucked into the variable displacement compressor 1 has the super heat degree all the time in the usual operation, and an engine for driving the compressor 1 is allowed to be operated under a fuel consumption saving condition. The lubricating oil staying in the evaporator 4 is able to flow out to a variable displacement compressor 1 side by conducting the control to have the negative superheat degree temporarily, and the compressor 1 is thereby prevented from seizing caused by drying-up of the lubricating oil. <P>COPYRIGHT: (C)2004,JPO |
