SI-Engine Cylinder Pressure Estimation using Torque Sensors

In order to maximise engine efficiency it is of interest to find the peak pressure position (PPP) of the cylinder pressure when controlling combustion engines. Cylinder mounted pressure sensors can be used to measure the pressure, but these are expensive and suffer from limited durability. Alternative pressure estimation methods using cheaper and more durable sensors are needed.

This paper shows the performance when estimating the cylinder pressure of a five cylinder SI-engine using a crankshaft integrated torque sensor. An engine model is constructed to be able to eliminate the torsional resonances in the sensed torque signal and the cylinder pressure is reconstructed using a parameterised pressure model. The performance of the estimator is studied in three different simulation cases. Finally, the performance based on measured torque is presented.