Chapter 14 - NOX reduction through various low temperature combustion technologies

Abstract

Nitrogen oxide (NOx) emissions are known for causing acidification, eutrophication, and destructive environmental effects. Internal combustion engines are prime generating sources for emitting unpleasant nitrogen oxide emissions and the usage of IC engines significantly increased by the industrial revolution. High in-cylinder temperatures, around stoichiometric flame zones, are originating in the formation of NOx emissions. Curtailing NOx emissions with conventional strategies is nonviable to satisfy future NOx standards. Therefore, after-treatment technologies are employed to satisfy the stringent emission norms but implementation of these techniques require high initial and maintenance cost. Consequently, researchers are more fascinated by advanced low-temperature combustion (LTC) strategies. LTC strategies are prominent engine technologies that can reduce NOx and soot emissions simultaneously while maintaining higher thermal efficiency. Among the LTC mode engines, homogeneous charge compression ignition (HCCI) engine, premixed charge compression ignition (PCCI) engine, and reactivity controlled compression ignition (RCCI) engine obtains better low temperature combustion through enhanced performance and emission characteristics can be achieved. Therefore, the improvisation of LTC strategies (HCCI, PCCI, and RCCI) ensures greater prospects in the automobile industry. So, efforts are required to emphasize LTC characteristics by optimization in various aspects. Accordingly, this chapter discusses the significant role of LTC strategies such as HCCI charge preparation techniques and alternative fuels on PCCI and low-high reactive fuel-powered RCCI engines in NOx reduction.