Implementation of Model-Based Calibration for a Gasoline Engine

Abstract

To meet the ever increasing requirements in the areas of performance, fuel economy and emission, more and more subsystems and control functions are being added to modern engines. This leads to a quick increase in the number of control parameters and consequently dramatic time and cost increase for engine calibration. To deal with this problem, the automotive industry has turned to model-based calibration for a solution. Model-based calibration is a method that uses modern Design of Experiments (DoE), statistical modeling and optimization techniques to efficiently produce high quality calibrations for engines. There are two major enablers for carrying out this method - fully automated engine control and measurement system, and advanced mathematical tools for DoE, modeling and optimization. This paper presents a case study of adopting this methodology for the determination of optimum steady state calibrations of ignition timing, air-fuel ratio and intake cam phasing for a gasoline engine. ORION automated engine control and measurement system is used for testing data collection. EasyDoE Toolsuite is used for DoE, engine response modeling and control parameter optimization. Major features of these tools are described. Each step in performing this process, including definition of factors and responses, DoE, automatic measurement on engine test bench, creation of engine models of sufficient accuracy, and generation of control maps using optimization techniques, is covered. The results demonstrate that the model-based approach is a well suited method for engine calibration, and the integrated system provides an effective solution for implementing model-based calibration.