An Experimental Approach to the Controlled Auto-Ignition

Auto-ignition may be considered as the ultimate combustion process for vehicle engines. Regarding combustion control, ignition timing and heat release are the chief concerns. The former is finding a solution, however the latter has, as yet, several approaches.

As a means to control the heat release, this paper introduces a universal parameter; ΔT, which is the difference between the adiabatic flame temperature and the initial in-cylinder gas temperature before combustion. Firing tests of a four-stroke auto-ignition gasoline engine revealed that the heat release process could be successfully controlled when ΔT was maintained at a proper level. As a result, the auto-ignition zone was greatly enlarged in the tested engine with a moderate compression ratio.