Estimation of Cylinder-Wise Combustion Features with Combined Processing of Engine Speed and Cylinder Pressure Regarding Torsional Deflections of the

Rising fuel prices, stricter emission standards, as well as the increasing demands from consumers for driving comfort, all motivate the rapid development and improvement of combustion engine control systems. New concepts, such as variable valve timing systems, downsizing in combination with supercharging systems and new injection systems bring significant advantages for engines, however they result in increased system complexity. In order to provide optimal operating conditions for these concepts, advanced control and diagnosis strategies are necessary. They require feedback information from the combustion chamber. The in-cylinder pressure has a close relationship to the thermodynamics of a combustion and, consequently, is suited to this purpose. In-cylinder pressure sensors are already widely used in today's research engine test beds. However, a fully-equipped engine with pressure sensors is too expensive for series production. This motivates this work to investigate a cost efficient approach using only one in-cylinder pressure sensor in combination with the engine speed sensor. The engine speed signal contains the cylinder-wise combustion information and is measured at the crankshaft. Torsional defections at the crankshaft distort the engine speed signal. This work shows how to compensate this effect in order to provide highly accurate combustion features for engine control and diagnosis.