Abstract
Nowadays, cooling system specifications are usually determined by transient coolant temperature in idling condition, because of demand-orientation of vehicles and higher air-conditioner performance. However, because transient coolant temperature is influenced by various factors that change with time, it is difficult to predict. Therefore, measures for decreasing the temperature have been developed through a trial and error process. This paper describes a method for simulating transient coolant temperature in the idling condition by setting up a differential equation and examining and quantifying each term in it. This simulation method can reduce the vehicle development period and increase the efficiency of the design process. (A)