Effect of coal to liquid fuel on combustion and emission in a heavy-duty diesel engine

Coal to liquid fuel has the potential to substitute the petroleum fuels due to the huge reserves of coal in the earth, the development of direct coal liquefaction technology and the application of carbon dioxide capture and storage technology. The effect of coal to liquid fuel on the combustion and emission has been investigated experimentally in a heavy-duty diesel engine. The experimental results showed that compared to diesel, the coal to liquid fuel had obviously longer ignition delay but slightly later CA50, and the higher premixed combustion ratio and maximum rate of heat release; it had the benefit in soot reduction but slightly higher HC, CO and NO x emissions. The brake specific fuel consumption of coal to liquid fuel was slightly higher than that of diesel, while the brake fuel conversion efficiency of coal to liquid fuel was slightly lower than that of diesel. Furthermore, the trade-off of NO x –soot emissions in diesel engines has been improved by coal to liquid fuel, due to the predominant evaporation rate, virtually free from sulfur and aromatics, and the longer ignition delay.