e Vehicle Cooling System Approach for Off-Highway Machines

Traditionally the off-highway vehicles like tractors, construction and road building machinery have been using diesel engine as the power source. In recent times there has been more and more focus to adopt either all electric or hybrid powertrain for off highway vehicles to reduce the carbon footprint. The e machines involve various electrical components like Battery pack, On board Charger, DC/DC converter, Inverters, Traction motors, PTO Motor and e transmission. The cooling requirement and the fluid temperature limits for these electric components is different compared to the conventional engine. In most of the cases the battery cell temperature needs to be around 20 to 30 °C which in most cases would be below the ambient temperature. Whereas the hydraulic oil temperature can be as high as 100 °C. The hydraulic oil temperature can be maintained using a separate air-cooled hydraulic oil cooler or a plate cooler. Therefore, the cooling system for the e components will be unique and different compared to the conventional diesel engines. The cooling system for a Battery electric vehicle (BEV) involves multiple cooling loops due to difference in fluid temperature limit. A typical Battery electric vehicle (BEV) may involve the Water Ethyl glycol loop, Battery loop, HVAC loop & e- transmission loop. This study talks about the approach that has been followed to design the cooling system for the all-electric e machines using 1D KULI simulations.