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With stricter emission legislations and demands on low fuel consumption, new engine technologies are continuously investigated. At the same time the accuracy in the over all engine control and diagnosis and hence also the required estimation accuracy is tightened. Central for the internal combustion control is the trapped cylinder charge and composition Traditionally cylinder charge is estimated using mean intake manifold pressure and engine speed in a two dimensional lookup table. With the introduction of variable valve timing, two additional degrees of freedom are introduced that makes this approach very time consuming and therefore expensive. Especially if the cam phasers are given large enough authority to offer powerful thermal management possibilities. The paper presents a physical model for estimating in-cylinder trapped mass and residual gas fraction utilizing cylinder pressure measurements, and intake and exhaust valve lift profiles.

The amount of emitted pollutants from an internal combustion engine is regulated by emission legislation. Commonly regulated pollutants for the diesel engine are NOx and PM. Exhaust gas recirculation (EGR) is one efficient way of controlling the NOx emissions, and to control PM emissions an accurate lambda control is used. Both EGR- and lambda control requires good knowledge of the gas flows in the engine. The gas flows of interest are inlet air, EGR, total gas flow through the engine and total amount of exhaust gas. There are several possible concepts to measure and/or model these gas flows, all with their pros and cons. Flow and concentration based measurement concepts for determining the gas flows in a heavy duty diesel engine with EGR are investigated. The flow based concepts measures the amount of gas directly with a flow meter such as a hot-film air meter, ultrasonic flow meter or an orifice plate.