The Influence of Hydrogen Addition on a SI Engine—Theoretical and Experimental Investigations

In a world with severe pollution regulations and restrictions imposed to internal combustion engines, improving efficiency and reducing pollutant emissions and greenhouse gases are important goals for researchers. A highly effective method to achieve the premises written above is to use alternative fuels, which may have a strong influence on combustion processes in spark ignition engines. In order to increase the heat release rate during combustion, the brake thermal efficiency, and to decrease the levels of pollutant emissions and greenhouse gases, the use of sustainable alternative fuels, in parallel with conventional fuels is a great choice. Among alternative fuels, hydrogen is an excellent fuel in terms of its physical-chemical properties, making it an attractive replacement for classic fuels in the combustion process. This article demonstrates AMESim 13.0.0/Rev13 theoretical and experimental investigations conducted on a supercharged spark ignition engine at 55% engine load and 2500 rpm speed, analyzes the effect of 2.15% hydrogen that substitutes gasoline on combustion, implicitly investigates energy and fuel efficiency of the engine and investigates pollutant and greenhouse gas emission levels. These experimental investigations confirm the theoretical study of thermo-gas-dynamic processes of a SI engine fueled with gasoline and hydrogen, and it shows the importance of engine tunings and hydrogen quantity on engine operation. The obtained results indicate the advantages of fueling the engine with both gasoline and hydrogen: the increase of the heat release rate which leads to the increase of maximum pressure and maximum pressure rise rate during combustion, the increase of the brake thermal efficiency, the decrease of the combustion duration, the decrease of the brake specific energetic consumption by 4.8%, the decrease of the levels of pollutant emissions by 11.11% for unburned hydrocarbons HC, by 12.5% for monoxide carbon CO, by 63.23% for nitrogen oxides NOx, and by 33.7% for carbon dioxide CO2 as a greenhouse gas. Further research directions can be developed from this research for other operating regimes and other hydrogen quantities.