Low Temperature Performance of a Magnetorheological Fluid Fan Drive

Magnetorheological fluid (MRF) fan drives have been considered for truck cooling applications due to their excellent controllability, reduced noise, improved fuel economy, and improved diagnostic capability. However, there are several concerns related to their cold weather operation: drag torque may be high, the MR fluid may slump creating a dynamic imbalance and features designed for low temperature operation must work at high temperature.

The impact of MR fluid composition and rotor surface finish on these concerns was evaluated by testing several MRF fan drive and fluid combinations in a cold cell. The best rotor/fluid combinations were then subjected to durability tests and validated at high temperature.