A Smart Engine Cooling System - Experimental Study of Integrated Actuator Transient Behavior

Smart thermal management systems can positively impact the performance, fuel economy, and reliability of internal combustion engines. Advanced cooling systems typically feature multiple computer controlled actuators - a three way smart valve, a variable speed pump, and a variable speed electric radiator fan(s). To investigate the contributions of these electro-mechanical devices, a scale multifunction test bench was constructed which integrated these actuators, accompanying system sensors, and a controllable engine thermal load with real time data acquisition and control hardware/software. This paper presents a series of experimental studies that focus on the engine's thermal transient response to various actuators input control combinations. The test results established a basis for several key operating conclusions. First, the smart valve and variable speed pump impact the engine temperature by changing the heat transfer rate between the engine and the radiator through coolant redirection and/or coolant flow rate. On the other hand, the radiator fan(s) operation affects the engine's temperature by changing the heat rejection rate of the radiator which can influence the entire cooling system. Third, the smart valve's operation changes the engine's temperature magnitude the greatest amount (4.0%) followed by the radiator fan(s) (1.6%) and coolant the pump (0.5%). Finally, from a power consumption aspect, the radiator fan(s) consumes the most engine power in comparison to the two other actuators. Overall the experimental results offer insight to the control engineers for creating the frame work for advanced engine cooling system control algorithms.