Abstract
The auto-ignition is focused as the ultimate combustion process for the vehicle engines. Regarding the combustion control, ignition timing and heat release would be the chief concerns. The former is finding a solution, however the latter has yet several approaches. As a means to control the heat release, this paper introduces a universal parameter; ΔT, which is a difference between the adiabatic flame temperature and the initial in-cylinder gas temperature before the combustion. Firing tests of a four-stroke auto-ignition gasoline engine revealed that the heat release process could be successfully controlled when ΔT were maintained in a proper level. As a result, the auto-ignition zone was remarkably enlarged in the tested engine with a moderate compression ratio.
