In this project different methods to model two-stroke diesel engines have been investigated. The goal of the project is to obtain a model capable to capture both the steady states and the transients of the engine system. The interest MAN Diesel&Turbo has in this model is to obtain a reliable simulation platform to be used as a tool to evaluate the performance of new control systems for the Exhaust Gas Recirculation (EGR) system. A non-linear model of the engine air-path with EGR is derived and validated against measurements. The specific engine corresponds to a 4T50ME-X located at MAN Diesel&Turbo research center. The model consists of the following components: the turbocharger, the scavenging and exhaust manifolds, the cylinders and the EGR system. The turbocharger model is externalized to an advance simulator software (GT-Power), all other components are modeled in Simulink. A Seiliger cycle capable of handling variable exhaust valve opening and closing is proposed. The polytropic coefficients for the compression and expansion are analytically estimated from in-cylinder pressure measurements. The model derived in this project is capable to fit well the measured data in steady states. The appropriate dynamics are obtained in transient operations, although the model shows a generalized faster response than the measured data.

Outgoing