Multi-objective optimization of operating parameters for hydrogen-fueled spark-ignition engines

This work deals with the engine performance and emissions of a single cylinder spark-ignition (SI) engine fueled by hydrogen. Advanced simulations of the combustion process were performed using a commercial software package. The extended Zeldovich mechanism with coefficients for carbon-free fuel was utilized to investigate the most accurate formation rate of nitrogen oxide (NOx) emissions within the engine. The first part of this work focuses on simulating the engine performance and emissions at different equivalence ratios. Different techniques that have significant effects on engine performance and emissions such as exhaust gas recirculation and ignition timing, were also were studied. A thorough explanation of the relationship between the performance, emissions, and the operating parameters considered is presented. The second part of this work focuses on optimization of the operating parameters. The best operating conditions for hydrogen engines were obtained by solving the multi-objective problem of maximizing engine power and efficiency while minimizing the NOx.