Modelling of Methanol Combustion in a Direct Injection Compression Ignition Engine using an Accelerated Stochastic Fields Method

Methanol combustion in a direct injection compression ignition (DICI) engine is studied using experiments and a novel approach based on Eulerian stochastic fields (ESF) method accelerated by the chemistry coordinate mapping (CCM) technique. This method is capable of handling all modes of combustion from auto-ignition to premixed flames and non-premixed flames in a mixture where they can potentially co-exist. Two operating conditions, namely, a HCCI and a partially premixed charged (PPC) operating modes are studied. It is shown that even in the PPC case, where the start of injection is near the top dead center (TDC), the start of ignition is well after the end of injection. As a result, combustion of methanol under both the HCCI and the PPC conditions involve strong auto-ignition contribution. In the PPC case, however, there are strong evidences of the presence of fuel-lean premixed flames in stratified mixtures. It is conformed the turbulence-chemistry interaction in the PPC case does have significant effects on the prediction of the onset of ignition, as well as on the progress of combustion to the later stages.