Radical Ignition Combustion Studies with Hydrogen in a Two-Stroke DI-HCRI Diesel Engine 2007-01-0135

This work represents an extension of the homogeneous combustion radical ignition (HCRI) process to a two-stroke direct injection (DI) diesel engine operated at normal diesel compression ratios (CR's). As in four-stroke DI-HCRI diesel engine variants, this engine has periphery mounted secondary radical generation chambers (mini-chambers ) that enable control of the radical generation process. One goal of this study is to see whether the use of HCRI alone can extend the lean burn region of the two-stroke DI engine to enable low NO_x operations with hydrogen at such CR's. To this end, a detailed examination is made of the effects of internally generated “radicals” on the chemical-kinetics of the two-stroke radical ignition (RI) diesel cycle. The starting point for this simulation is a modified variant of the well corroborated formulation used in the earlier hydrogen four-stroke studies. This variant is chemical-kinetics focused while still providing a fairly serious qualitative accounting for the regional effects of heat transfer, mass and momentum transfer and turbulence within the two separate but connected open systems representing the main and mini chambers.