Internal Combustion Engine Cooling Strategies: Theory and Test

Advanced automotive thermal management systems integrate electro-mechanical components for improved fluid flow and thermodynamic control action. Progressively, the design of ground vehicle heating and cooling management systems require analytical and empirical models to establish a basis for real time control algorithms. One of the key elements in this computer controlled system is the smart thermostat valve which replaces the traditional wax-based unit. The thermostat regulates the coolant flow through the radiator and/or engine bypass to control the heat exchange between the radiator’s coolant fluid and the ambient air. The electric water pump improves upon this concept by prescribing the coolant flow rate based on the engine’s overall operation and the driver commands rather than solely on the crankshaft speed. The traditional radiator fan is belt driven and equipped with a clutch to limit parasitic loads during operating conditions that provide sufficient radiator heat rejection. A DC motor-driven radiator fan offers improved control over the air flow rate to better regulate radiator heat rejection while reducing power consumption. Ideally, the thermal management system will accept multiple engine sensor feedback including, but not limited to, the engine cylinder temperature, oil temperature, coolant temperature, engine block temperature, engine load, and throttle angle. To achieve this concept, these electrically driven system components must be mathematically described, computer controlled, and configured on an internal combustion engine. A unique experimental platform has been developed featuring a 4.6L V8 engine, with extensive block-embedded thermocouples, attached to a water-brake dynamometer.