CHEMICAL KINETIC MODELING OF HYDROGEN UNDER CONDITIONS FOUND IN INTERNAL-COMBUSTION ENGINES

A chemical kinetic model is used to study the combustion characteristi cs of hydrogen under conditions found in internal combustion engines. Laminar flame speeds are predicted under the high-pressure and high-te mperature conditions found in a spark-ignition engine. The variation o f laminar flame speed with temperature, pressure, and equivalence rati o is examined. The autoignition of hydrogen and hydrogen-natural gas m ixtures is also studied under conditions found in a free-piston compre ssion-ignition engine. This engine is expected to exhibit high efficie ncies operating on hydrogen, The results suggest that adding small amo unts of natural gas to hydrogen will reduce NOx emissions from a free- piston compression-ignition engine. Calculations showed that the predi cted NO concentrations correlated well with the maximum temperature in the cycle and that the NO was mostly produced by Ng + O = NO + N.