摘要 |
In an ejector cycle having an ejector for decompressing refrigerant, a check valve is disposed in an oil return passage through which refrigerant including a lubrication oil is introduced from a refrigerant outlet side of an evaporator to a refrigerant suction side of a compressor while bypassing the ejector. When the lubrication oil amount staying in the evaporator reduces, the check valve is automatically closed, and a normal operation mode of the ejector cycle is automatically set. On the contrary, when a large amount of lubrication oil stays in the evaporator, the check valve is automatically opened, and an oil return mode is automatically set. Therefore, the lubrication oil staying in the evaporator can be controlled equal to or lower than a predetermined amount, thereby effectively returning the lubrication oil to the compressor.
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