Computational Investigation of a Novel Technique to Control NOx Emissions in Spark Ignition Engines

This work aims at evaluating a proposed novel technique for NOx reduction and knock control in spark ignition engines. The proposed technique is based on adding a secondary chamber equipped with a piston to the engine combustion chamber. This variable volume secondary chamber is tuned to the combustion process in the engine to achieve NOx reduction as well as knock control. The phenomenological analysis of the proposed technique showed that the achieved outputs come out as a result of three mechanisms. These mechanisms include; control of the heat release rate inside the engine, combustion staging and enhancing turbulence inside the engine especially during the later stage of combustion. The later ensures complete combustion inside the engine.