Abstract: In view of the vital importance of the accuracy of heat balance test to the selection and matching of vehicle cooling system, a measure is proposed to increase the difference between outlet temperatures and inlet temperature for reducing test error based on an analysis on the error mechanism of heat balance test, and a modification design of existing test bench is conducted with good results achieved. On this basis, the effects of key factors such as different coolant temperatures, different inlet air temperatures and with or without test fan etc. on the results of heat balance test are also studied.

Key words: Engine, Heat balance, Test precision, Inlet air temperature, engine, heat balance, test accuracy, inlet air temperature