Abstract:

In order to make diesel methanol compound combustion (DMCC) engine better applied to the actual and to maximize the methanol replacement rate, the experimental study was conducted to investigate the ignition and combustion characteristics in an electronically controlled unit pump diesel engine with the amount
of diesel fixed. The results showed that, with the amount of diesel fixed, in-cylinder pressure and pressure rise rate in dual fuel engine first increases lightly and then sharply compared with pure diesel mode. As the engine load increases, the combustion process proceeds in two distinguishable phases, where the peak of premixed combustion heat release rate increases with the increase of the amount of methanol and then tended to be the same. Ignition delay period of duel fuel combustion is longer than that of pure diesel mode. As the load increases, dual fuel ignition delay prolongs first and then decrease. It is concluded that dual-fuel combustion duration first increases and then shortens rapidly with increasing engine load, meanwhile the curve center of the heat release rate for dual fuel combustion tends to move towards TDC which is earlier than pure diesel mode.

Key words: diesel engines, mixed combustion, diesel methanol compound combustion (DMCC), ignition delay, methanol