The Use of Auxiliary Ignition Devices to Improve Combustion of Low Cetane-High Volatility Fuels in a Diesel Engine

The use of auxiliary ignition devices to improve the combustion of low cetane-high volatility fuels in a Diesel engine is described. Previous combustion with a low cetane-high volatility fuel (with a spark plug located at the periphery of the cylinder) resulted in engine knock at heavy loads and poor engine operation at light loads. In the present investigation, several new ignition devices were used to ignite the fuel in the center of the cylinder, to allow combustion to be controlled by rate of injection. The devices used were an extended spark electrode, a fuel spray deflector, a nozzle glow ring, and a nozzle fuel cage. High speed photography and heat release were used to characterize the ignition and combustion process of the low cetane fuel in conjunction with the ignition devices. Combustion with all of the ignition devices was initiated in the center of the cylinder, significantly reducing engine knock. The use of the auxiliary ignition devices to ignite the fuel in the center of the chamber demonstrated extended operation of the Diesel engine for all of the devices tested.