Air-Cooled vs Liquid-Cooled Transmission Oil Cooler for Heavy-Duty Vehicles

For an automobile equipped with a liquid-cooled engine, the automatic transmission unit can be either air-cooled or liquid-cooled. Theoretical analysis of one liquid-cooled, and two air-cooled transmission cooling schemes were carried out. It was found that the air-cooled scheme, with the transmission oil cooler placed right behind the engine radiator in the cooling air flow path, is the most suitable for heavy duty vehicles when the system size and the fan power requirements are considered as principal evaluation criteria. Computer simulation for the cooling system of a typical heavy duty vehicle confirms this finding.