High Efficiency Compact Rotary Compressor Using the New Refrigerant HFC-134a for Automotive Air Conditioners

In accordance with worldwide consensus, the use of chlorofluorocarbons, which play an important role in damaging the ozone layer, should be completely abolished by the end of 1995. This provided the impetus for developing the three vane rotary compressor. Formerly CFC-12 was used as the refrigerant in automotive air conditioners, until HFC-134a was substituted for CFC-12. In response to the change to HFC-134a, we developed the vane rotary compressor, which is smaller in size than, but superior in effectiveness to, the previous rotary compressor. We eliminated the problems caused by changing the refrigerant to HFC-134a by examining the materials for seals, choosing lubricating oil specifically for this compressor, and lightening lubricating conditions in the compressor, as well as reconsidering the materials for the rubbing parts. Moreover, by measuring the fluctuating pressure in the compression process and by performing a quantitative analysis of the compression losses, we reduced the gas leakage, which was a fundamental component of the loss. We redeveloped the seal ring, and reduced gas leakage by optimizing the oil supplying passages. These developments made it possible to improve the compression efficiency by 15% over that of the previous rotary compressors. In this report we explain why the three vane rotary compressor is so efficient, concentrating on the aforementioned developments.