Model-Based Calibration of an Automotive Climate Control System 2020-01-1253
In modern cars the control of heating, ventilation and air-conditioning (HVAC) systems is oftentimes realized by means of a cascade of gain scheduling controllers. The calibration of this control cascade is a complicated and strenuous, hence expensive process. To establish a model based calibration process, a fast executing and accurate model of the HVAC system is required. This paper describes a novel approach for the modelling of an automotive HVAC system. The model consists of a black box model trained with experimental data from a self-developed measurement setup. It is capable to predict the temperature and mass flow of the air entering the vehicle cabin at the different outlets. The measurement setup is based on a combination of temperature and velocity sensors. A measurement fault analysis is conducted to validate the accuracy of the measurement system. As the data collection is done under fluctuating ambient conditions, an extensive analysis of the impact of different ambient conditions on the HVAC unit is performed and incorporated into correction models that account for the different ambient conditions. Different types of black box models are compared to identify the best suited type of black box model for this approach. Based on this selection, the most suitable model is presented and its accuracy analysed. To quantify the impact of the inaccuracies of the model on the model based calibration process, further studies are recommended.