Effect of the addition of hydrogen-containing (H2/O2) gas on indicated and effective parameters of a gasoline engine

Abstract

The article presents experimental research and calculations of spark ignition engine indicators, using hydrogen-containing H2/O2 gas, when the engine is running at low power. The engine throttle was opened 8°, the amount of H2/O2 gas was increased from 0 to 7.9 % of the mass of gasoline, the stoichiometric (λ = 1) air/fuel ratio was maintained. Research shows that the addition of the H2/O2 gas leads a great influence on the energetic and ecologic indicators of the engine and this depends on the change in the combustion process and the change in the composition of the fuel. The calculation methodology of the combustion process when the engine is fuelled with pure gasoline and with additives of hydrogen-containing gas presented. Presented results how addition of H2/O2 leads to a reduction in the duration of the combustion process and also has a significant effect on a faster rise of combustion pressure and temperature. Shorter combustion duration leads to a rise of the indicated efficiency of the engine, the heat utilisation factor and an increase in the indicated power. As a result of bench tests, an increase in the effective power and a decrease in the brake-specific fuel consumption of the engine were found. When assessing the influence of H2/O2 on the concentration of CO2 in the exhaust gas, no decreases was not observed, as hydrogen improves the combustion process. Only the concentration of incomplete combustion process products (e.g., HC) decreases, but the concentration of NOx increases at the same time.