Progresses in Dual Fuel Combustion Engines - A Review

摘要

A conventional compression-ignition engine can be used as a dual-fuel engine with relatively simple conversion. Such engines employ gaseous fuel as primary fuel pre-mixed with air, and liquid fuel as pilot fuel for initiating combustion. An attempt has been made in the present study to review the progresses in dual fuel engines and the combustion and emission characteristics. Dual fuel operation allows for lower-cost and lower-carbon fuel substitution, and potential reduction of emissions, especially particulates and oxides of nitrogen. Experimental and numerical studies have shown that dual-fuel operation results in higher ignition delay, lower peak cylinder pressure, and lower initial heat release rate, compared to normal diesel operation at the same load and speed. Dual-fuel operation also showed an increase in specific fuel energy consumption, lower NO emissions, and higher CO and HC emission. But at high engine load, a high level of gaseous fuel substitution results in better utilization of the gaseous fuel and an improvement in engine total specific fuel consumption. Relatively larger pilot fuel quantity may need to be used at light load and it may be reduced substantially at full loads.