Validation and Calibration Process of Powertrain Model for Engine Torque Control Development

The growing complexity of engine control systems and its integration with vehicle dynamics controls systems has lead to the use of torque-based engine control. Torque-based control enables flexibility and expandability of the powertrain control system structure. It allows new engine technologies (displacement on demand, cam phasing, supercharger, etc.) to be easily incorporated, to coordinate better engine and transmission controls, and to enable a simpler control structure than current production controls. This paper describes the role of Engine Torque Control in a torque-based control system and it formulates main requirements to a model-based control strategy. Development of this strategy is impossible without an accurate model of powertrain system. There are many publications describing models of powertrain system elements for research purpose, however only few provided us with information about model validation, calibration process and accuracy for production. This paper considers a mean-value powertrain model for Engine Torque Control and it describes model validation and calibration process. This model may be used in different Engine Torque Control design phases such as control structure design, robustness and stability analysis, and DFMEA. It incorporates engine, transmission, and vehicle models with mean-value type of fidelity that is good for Engine Torque Control design. The influence of different powertrain parameters on Engine Torque Control will be discussed. This paper provides substantial experimental results that confirm the model's validity under various operational conditions.