Autoignition and Combustion of Fuels In Diesel Engines Under Low Ambient Temperatures

The autoignition and combustion of four fuels having different distillation ranges and cetane numbers have been investigated in a single cylinder, direct injection diesel engine, at ambient temperatures between 30°C and −30°C. The effects of ambient air temperature on the compression pressure, compression temperature, blow-by mass fraction, ignition delay and cycle-to-cycle variation have been determined. The results indicate that the chemical preignition processes rather than the physical processes are the controlling processes in the ignition delay in diesel engines, even at very low ambient temperatures. Low ignition quality fuels produce cycle-to-cycle variations in their autoignition at low ambient temperatures.