In-cylinder pressure reconstruction for multicylinder SI-engine by combined processing of engine speed and one cylinder pressure

The paper presents an approach to reconstruct cylinder-individual pressure of each combustion cycle by processing the instantaneous fluctuations of the engine speed and the in-cylinder pressure of one cylinder. A new pressure model with a feasible number of parameters is combined with a model-based torque estimation in order to reconstruct the pressure traces. The performance of the proposed algorithm is demonstrated with measurement data acquired from a vehicle with a four cylinder spark ignition (SI) engine.