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The paper examines the rapid compression process of methane-air mixtures while using a zero-dimensional simulation and a detailed chemical kinetic scheme involving 137 reaction steps for methane-air combustion with an account made for heat transfer. The results of this simulation are compared with the corresponding values obtained when using multi-dimensional CFD simulation of the temporal and spatial evolution of the physical properties inside the cylinder while using KIVA-3 code both for reactive and non-reactive “methane”-air mixtures. The reaction rate data used in the code were overall rates of varyingly fitted data based on results of the full detailed kinetic scheme under the same local conditions. The effects of the non-uniformity in the charge physical properties due to heat transfer and compression effects on the evolution of the chemical processes leading to autoignition are presented and discussed.

Dual-fuel engines represent a simple and flexible approach to employing gaseous fuels including hydrogen in conventional diesel engines. This paper reports on the investigation into the effects on performance, emissions and combustion characteristics of introducing low volumetric concentrations of hydrogen into the intake air of a multi-cylinder IDI diesel engine. It is shown that increasing the admission of hydrogen up to a certain low concentration increased power output, whereas further increases in hydrogen admission began to decrease power output. For the same total fuel energy input, the engine brake power and thermal efficiency were less with hydrogen admission as compared to the corresponding pure diesel operation. The exhaust gas opacity and the emissions of oxides of nitrogen and carbon monoxide showed correspondingly relatively significant reductions.