Real-time assessment of in-cylinder pressure for fresh air mass estimation using the example of modern spark-ignited combustion engines

This article describes an approach suitable for real-time application, which enables the estimation of the trapped air mass in the cylinder of a modern spark ignition engine using the information of a combustion pressure sensor. First of all, different criteria are derived and assessed from the in-cylinder pressure signal. Then, an empirical model on the basis of engine test bench measurements is developed. Finally, the results of the methods are compared with cylinder and cycle individually to a reference air mass, which is obtained by the engine measurements and a subsequent zero-dimensional low-pressure-based air mass calculation.