Emission control studies in homogeneous charge compression ignition, premixed charge compression ignition and common rail direct injection engines–a review

Automobiles, as a means of transportation, have great importance in our day-to-day life. The propulsive power for automobiles is derived mainly by subjecting petroleum-based liquid or gaseous fuels to combustion inside the engines. The products of combustion emitted from such internal combustion engines have become a matter of concern due to the increase in global warming, visibility problems arising due to smog formation, respiratory and other illness in human beings, and discolouration of monuments and structures. Emissions such as nitrogen oxides (NO_x)_, carbon dioxide (CO₂), carbon monoxide (CO), hydrocarbons (HC) and smoke are highly harmful to the ecosystem. There is an urgent need to reduce the harmful automobile engine exhaust pollutants. With the application of techniques such as homogeneous charge compression ignition, premixed charge compression ignition and common rail direct injection, and by adapting fuel modifications, such harmful exhaust emissions can be significantly reduced. A review of the work carried out by various researchers using such techniques and systems is presented in this article.