Study on a variable wall thickness profile of electric scroll compressor used for automobile air conditioner

Profile design plays an important role in improving the performance and reliability of scroll compressors. To expand design ideas of variable wall thickness profile (VWTP) of electric scroll compressor used for automobile air conditioner, a method to generate and modify VWTP is developed in this paper. The VWTP is generated according to the generalized profile theory and modified with symmetrical arc modification (SAM) and symmetrical arc plus line modification (SAPLM) at the central part. To make sure that the generated VWTP can form scroll profile, the generation conditions for coefficients of swing radius are discussed in detail. For the VWTP modified with SAM and SAPLM at the central part, a new way to classify scroll chambers and analyze the evolution of scroll chambers is proposed. Geometry analyses such as conjugate points on involute curves and arc segments, volume and its derivative with respect to orbiting angle are conducted as well. The generation and geometry analysis method of VWTP is validated through a design example of VWTP for electric scroll compressor with a displacement of 34 mL. The performance of the electric scroll compressor was tested through experiment and the results show that the cooling capacity can reach 7.5 kW and the COP can reach 3.0.