油循环率对电动汽车空调压缩机性能的影响

Effect of Oil Circulation Rate on the Performance of Compressor in Electric Vehicle Air-conditioning

为研究油循环率对电动汽车用变频空调涡旋式压缩机(R134a)性能的影响,本文通过应用第二制冷剂法压缩机性能测试台及油分离式油循环率测量装置,实验对比了压缩机转速分别为3000、4500、6000 r/min在两个高负荷工况下的性能,实验结果表明:油循环率对电动汽车空调涡旋式压缩机性能有显著影响。油循环率在1%~10%范围内,同一工况、不同转速时,压缩机容积效率和电效率均随油循环率的降低而减小0.02~0.05,而压缩机排气温度和壳体温度均随油循环率的降低而升高5~15℃,且低转速时油循环率的影响更大;总体而言,油循环率<5%时,油循环率对压缩机性能的影响比油循环率>5%时更显著,因此5%是适度的油循环率。

To investigate the effect of the oil circulation rate(OCR)on the performance of a variable-speed scroll compressor(R134a)for electric vehicle air-conditioning,elaborate experiments were conducted to obtain the performance and OCR in a test bench using a secondary fluid calorimeter and OCR measurement by a separator.The results show that the OCR significantly influences the scroll compressor performance when speeds of 3000 r/min,4500 r/min,and 6000 r/min are compared under two heavy-load conditions.More specifically,when the OCR is between 1%and 10%under the same condition,the volume efficiency and electrical efficiency decline by 0.02-0.05,whereas both the discharge temperature and shell temperature rise by 5-15℃as the OCR decreases from 10%to 1%.This occurs at every speed,and it is especially evident at low speed.Generally,a moderate OCR should be near 5%because an OCR that is less than 5%has a higher impact than that greater than 5%.