Emission Control Technologies in Spark Ignition Engines

Abstract

This paper extensively discusses a review of the latest technologies considered to control emissions in spark-ignition engines in addition to the background and history of the industry. Moreover, the paper discusses in detail the major pollutants affecting the environment negatively, which are Carbon Monoxide (CO), Hydrocarbons (HC), Oxides of Nitrogen (NOx), Sulfur Oxides (SOx), Carbon Dioxide (CO2), and Particulates. Furthermore, the crankcase emissions, the fuel system, and the exhaust system are discussed which are considered to be the main sources of pollution coming from a conventional spark-ignition engine. Also, the major emission control technologies in spark-ignition engines among numerous methods could be shortlisted in the following factors: modifications in the engine design and operating parameters, treatment of exhaust products of combustion, and modification of the fuels. Each technology has its branches and subcategories. In this paper, mainly the most prominent, up to date, and effective technologies were reviewed and discussed, which are lean combustion, design of a muffler, automatic hot air intake system, engine compression ratio, modification of combustion chamber, modification of the fuels, treatment of exhaust products of combustion, three-way, and four-way catalytic converters, exhaust gas recirculation (EGR), total emissions control packages, pre-combustion control; (Positive Crankcase Ventilation (PCV), and valve gear design. The points covered were related but not limited to the three main categories mentioned above. Finally, a conclusion and recommendations for future work are considered.