Development and Validation of a Control-Oriented Analytic Engine Simulator

Due to the recent anti-pollution policies, the performance increase in Spark Ignition (SI) engines is currently under the focus of automotive manufacturers. This trend drives control systems designers to investigate accurate solutions and build more sophisticated algorithms to increase the efficiency of this kind of engines. The development of a control strategy is composed of several phases and steps, and the first part of such process is typically spent in defining and investigating the logic of the strategy. During this phase it is often useful to have a light engine simulator, which allows to have robust synthetic combustion data with a low calibration and computational effort. In the first part of this paper, a description of the control-oriented ANalytical Engine SIMulator (ANESIM) is carried out. The latest results about the zero-dimensional knock model presented in a previous paper and some interesting analytical equations which define the main mean-combustion indexes trends (for example maximum in-cylinder pressure, or Pmax, 50 percent fuel mass fraction burned angle, or MFB50, Indicated Mean Effective Pressure, or IMEP) as functions of engine speed and load are analyzed for the entire engine operating range. A detailed sensitivity analysis to the fitting order is presented and the final formulas are showed and used for the calibration. The second part focuses on the model implementation in a Simulink environment and the resulting validation process of the analytic simulator carried out on a Gasoline Direct Injection (GDI) Turbo Charged (TC) engine. ANESIM performance is then tested by comparing the calculated and the experimental data, for both steady state and transient operating conditions.