Test study on the effect of lubricants on E-axle power loss

LIU Hongwei; KONG Zhuo; YAN Shufa; HAO Lina; WEI Jianglong; SHI Qian

doi:10.16578/j.issn.1004.2539.2025.02.014

Abstract：[Objective]The typical input speed of the electric drive axle is 12 000-22 000 r/min,but the existing research work basically focuses on the gearbox,drive axle and other gear transmission devices used in traditional internal combustion en-gines.The difference in operating conditions will lead to the difference in the impact law of power loss.At the same time,the ex-isting research has not classified and analyzed the oil mixing loss and the loss of different transmission levels.Based on the above issues,power loss tests were conducted on a high-speed electric drive axle for a certain light commercial vehicle under dif-ferent oil types,oil temperatures,oil levels,and other conditions.[Methods]Based on bench tests,this article studied the influ-ence of lubricating oil on the power loss of a certain electric drive bridge,and analyzed the influence of lubricating oil formula,oil temperature,and oil quantity factors on the transmission efficiency of the drive system.[Results]The test results show that the E-axle power loss is significantly influenced byoperating conditions,oil formulations,oil temperatures,and oil levels.Under nominal operating conditions of the E-axle,the no-load power loss accounts for more than 80%of the total power loss,of which the first stage component accounts for more than 80%of the no-load power loss.Selecting appropriate lubricant formulas,reduc-ing the oil level,and adjusting the oil temperature are effective measures for power loss reduction,with a potential efficiency im-provement of more than 1.04%,3.90%,and 1.60%,respectively.The achieved results can be utilized to improve the E-axle.