Optimization of an automotive radiator fan array operation to reduce power consumption

The cooling system for internal combustion engines removes waste heat to ensure a normal in-cylinder combustion process. To accomplish this task, the thermostat valve, radiator, radiator fan(s), and water pump circulate cooling fluid through the engine block and reject heat to the local environment. Since the cooling system consumes a portion of the engine's power, it is important that its operation uses minimal input energy. In this paper, a multiple radiator fan matrix was controlled to minimize energy usage for subsequent efficiency gains. A mathematical model for the radiator fan(s) and the forced convection heat transfer process was developed to establish a mixed integer nonlinear programming problem. An interior points approach was introduced to solve the minimization problem. A series of laboratory tests have been conducted with different fan and speed combinations, with the objective to cool a thermal-loaded engine. Both the mathematical approach and test results indicated similar control strategies. Based on the tests data and accompanying mathematical analysis, an optimization control strategy reduced the fan matrix power consumption by up to 67% for the specified thermal load. An improvement in cooling system performance can offer greater vehicle fuel economy to help meet legislated mobility standards.