Effect of Hydrogen–Oxygen Mixture Addition on Exhaust Emissions and Performance of a Spark Ignition Engine

In the last decade, there has been a major ascending interest in reducing the polluting concentration and fuel consumption of internal combustion engines. The solution proposed in this research project was to integrate a hydrogen and oxygen mixture H2/O2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm H}_{2}/{\rm O}_{2}}$$\end{document}, obtained through an electrolysis process of water, as supplementary fuel, in a 93 cm3\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${^{3}}$$\end{document} gasoline engine. Several experimental tests were carried out under different engine loads (0, 20, 50, 80 and 100 %) in order to investigate the effect of H2/O2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm H}_{2}/{\rm O}_{2}}$$\end{document} addition on the engine performance characteristics and the exhaust gas concentration. At engine loads more than 20 %, tests showed that adding H2/O2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm H}_{2}/{\rm O}_{2}}$$\end{document} reduced the brake-specific fuel consumption by an average of 7.8 %. They also showed that the alternative fuel was very efficient in reducing the concentration of pollutant emissions in the exhaust gases: hydrocarbon (HC) concentration diminished by an average of 18 %, carbon monoxide (CO) concentration decreased by an average of 31.8 %, and CO2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm CO}_{2}}$$\end{document} concentration decreased up to 30 %. However, at low engine loads, NOx\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${{\rm NO}_{x}}$$\end{document} concentration decreased by an average of 26 %, but it increased significantly with the increase in engine loads (exceeding 80 %).