NOx formation chemical kinetics in IC engines

NOx and their derivatives have severe environmental and health impacts. Concerning the environment, nitrogen oxide has a higher global warming potential. It reacts with organic compounds to form photochemical smog. Furthermore, NOx is well known for the formation of atmospheric ozone and secondary aerosol, which contribute to particulate matter emissions. Considering the effect of NOx on humanity, NOx is poisonous when humans are exposed to high concentrations. In recent years, research on environmental and health issues caused by nitrogen oxides that are produced by vehicles has become a hot topic of research. In this chapter, the importance of detailed chemical kinetic models with reference to thermochemical properties and reaction mechanisms for nitrogen oxide formation are explored. Various methods of nitrogen oxide formation during the combustion process such as thermal, prompt, and fuel nitrogen oxides are explained. For the formation and calculation of nitrogen oxide emissions exhausted from engines, the Zeldovich, nitrous oxide, Fenimore, and NNH mechanism-based kinetic models are discussed. Uncontrolled nitrogen oxide emissions and the factors responsible for nitrogen oxide formation in IC engines are described in detail. The nitrogen oxide formation mechanisms outlined in this chapter will aid in the investigation of NO formation in IC engines. However, to fully understand nitrogen chemistry, the mechanisms must be applied to modern fuels such as biofuels. Furthermore, the use of oxygenated biofuels decreases particulate matter (PM) emissions substantially. Because of the trade-off nature of these two emissions, the analysis of NOx and PM emissions is the thrust field in IC engines. Prospectively, low-temperature combustion as well as pre- and posttreatment technologies open up new views to alleviate NOx and help us build the next generation of IC engines.