Impact of Water Contamination and Iron Particles on the Performance Loss of e-Drive Transmission Fluids in Wet Clutches

The present study delves into the connection between the driving comfort and safety of electric vehicles and the e-drive transmission fluid (ETF), examining how water influx arising from environmental factors and iron particles resulting from wear of various transmission components can leadto Performance degradation in the lubricant. The Performance loss is evaluated based on the changes in the friction behavior of wet multi-plate clutches. Previous studies on automatic transmission fluids (ATF) have shown that water and iron contamination contribute to the earlier failure of transmission components and tend to lead to NVH behavior (noise, Vibration, harshness), particularly in wet clutch Systems [1,2]. Hence, it is essential to expand this knowledge on e-drive lubricants to prevent premature damage to various transmission components by exchanging the lubricant. This paper provides insights into component test rigs and associated test methods to determine the Performance loss of the e-drive transmission fluid in an application-related test environment. Exemplary results are shown from investigations with wet clutch parts from a transfer case used in serial automotive applications, considering the influence of water contamination and iron particles as well as their mutual interactions.