Effect of adding hydrogen-rich synthesis gas and ethanol on NOx emissions with gasoline at different air/fuel mixtures

Environmental contamination poses a real threat to the environment and all organisms. Air pollution has increased markedly due to an increase in human activities and petroleum use for electricity generation, transportation, and industrial applications. Internal combustion engines play a significant role in society's health and power requirements. However, automobiles are the main source of pollution and NOx emissions. This work presents a study of the performance and exhaust emissions of an internal combustion engine fuelled by gasoline available in the Saudi Arabian market, RON91/RON95, with an admixture of syngas and 5% by volume pure ethanol (E5) in the presence of different ultralean mixture regimes, including lambda=1 for a stoichiometric mixture. The studied ranges were lambda=1.13, lambda=1.26, lambda=1.43, and lambda=1.67. An entirely automated engine and plasma converter system was developed for feeding the same type of fuel. The engine was modified for a more efficient operation by introducing a plasma-based fuel reformer. Syngas was produced through the partial oxidation of gasoline with air in a plasma-assisted fuel reformer in the presence of steam to reduce the amount of soot formed in the plasma reactor. The fuel consumption and related emissions were measured. The experimental results demonstrated a significant total reduction of NOx emissions compared with those from the original engine. The most obvious reduction (approximately 50%) of harmful pollution was observed under lean conditions, and the total gasoline consumption (including the gasoline required for the plasma-assisted converter) slightly increased. Comparing the results for the two used gasoline types, gasoline RON 91 showed more NOx reduction more than gasoline RON 95.