Development and Software in the Loop Validation of a Model-based Water Injection Combustion Controller for a GDI TC Engine 2019-01-1174
Turbocharged (TC) engines work at high Indicated Mean Effective Pressure (IMEP), resulting in high in-cylinder pressures and temperatures, improving thermal efficiency, but at the same time increasing the possibility of abnormal combustion events like knock and pre-ignition. To mitigate knocking conditions engine control systems typically apply spark retard and/or mixture enrichment, which decrease indicated work and increase specific fuel consumption.
Many recent studies have advocated Water Injection (WI) as an approach to replace or supplement existing knock mitigation techniques. Water reduces temperatures in the end gas zone due to its high latent heat of vaporization. Furthermore, water vapor acts as diluent in the combustion process.
In this paper, the development of a novel closed-loop, model-based WI controller is discussed and critically analyzed. The proposed control strategy is based on experimental data acquired in a focused campaign on a GDI TC engine.
At first the WI setup is described, the main experimental data are presented, and processed for model identification. The algorithm is then explained in detail and implemented in Simulink environment, with a real-time oriented approach. In the last part of this work, the WI control strategy is tested in a real-time (RT) Software in the Loop (SiL) system, coupled with a one-dimensional Fast Running Model (FRM).
Francesco Ranuzzi, Nicolo Cavina, Alessandro Brusa, Matteo De Cesare, Marco Panciroli
University of Bologna, MAGNETI MARELLI SpA - Div. Driveline