Quasi-dimensional multizone combustion model for direct injection engines fuelled with dimethyl ether

Abstract

Experimental studies have proved that dimethyl ether (DME) is a promising alternative fuel for compression ignition direct injection (CIDI) engines. To study the mechanisms of DME combustion and the formation of NO x emissions, which becomes the most noticeable pollutant since no soot is produced even under heavy loads for DME operation, a quasi-dimensional multizone combustion model for DI engines fuelled with DME is presented in this paper, together with its application on a DME engine, which is derived by revamping a diesel engine. To validate the model, an extensive experimental investigation has been conducted on the DME engine. By comparing theoretical and experimental results it is revealed that the model predicts with reasonable accuracy NO x emissions and engine performance. Furthermore, the model makes it possible to study the combustion mechanism by visualizing the temperature and fuel distribution at various instances of time from fuel injection. The model also offers a better understanding of the mechanisms of NO x formation by providing information on the areas inside the fuel jet where the pollutants are formed, on the evolution of the jet and on the evolution of the NO x concentration in the jet.