TWO OBSERVERS FOR IN-CYLINDER MASS ESTIMATION USING CYLINDER PRESSURE MEASUREMENTS

To meet future pollutant emissions Standards, it is crucial to be able to estimate the cycle by cycle in-cylinder mass and the composition of the combustion chamber charge. This charge consists of residual gas from the previous cycle, fresh air and fuel. Consequently, the estimation of the fresh air mass based on total in-cylinder mass is a function of the residual gas fraction. This estimation is essential to compute the fuel mass to be injected. This paper proposes two observers, based on a physical approach, that estimate the in-cylinder mass and composition using the cylinder pressure. To test the estimator, several parameters are varied, especially the cylinder pressure offset compensation and the exhaust gases temperature.