Modeling and analysis of a thermal management system for engine calibration

Controlling engine coolant and oil temperatures to desired values is critical to effective engine calibration on a dynamometer. Because of the large time constants associated with thermodynamic systems, the slow response of coolant and oil temperature often represents a bottleneck in improving engine mapping and calibration efficiency. Nonlinearities in component characteristics, together with varying operating conditions, render the simple PED controller ineffective, thereby motivating a model-based strategy. In this paper, we present a dynamic model of a thermal management system that involves both beat exchangers and heaters. The model is developed using thermodynamic principles and parameter identification techniques, and has been validated using experimental data. Based on the validated model, we present the system analysis results that have significant implications to system performance and subsequent control strategy development. It is worth noting that the dynamometer based model presented here may also be applied to the modeling of an in-vehicle cooling system.