Combustion of Alternative Fuels in a Dual Fuel Diesel Engine for Low Emissions

Abstract

: Fundamental concept for low emission engines in the present study is utilization of alternative fuels such as natural gas and methanol with low evaporation temperature for reducing smoke, and high EGR engine operation for reducing NOx. The final goal is to achieve the extremely low levels of both NOx and smoke without deteriorating high thermal efficiency in a dual fuel diesel engine. Natural gas or methanol was charged into the suction air, and a small amount of gas oil as an ignition source was injected directly into the combustion chamber of a four-cylinder DI diesel engine. The injection amount of gas oil, intake temperature, compression ratio and EGR ratio were changed in the experiments. The effects of these parameters on ignition delay, maximum rate of heat release, knock limit and misfire limit were clarified for the premixture of natural gas or methanol respectively.