Effect of hydrogen blending on the combustion performance, emission, and cycle-to-cycle variation characteristics of a single-cylinder GDI spark ignition dual-fuel engine

The effect of hydrogen addition on combustion, performance, emission and cyclic variation under different hydrogen flow rates (2, 5, 8, 11, and 14 LPM) were investigated based on a SI engine with hydrogen port induction and gasoline direct injection. The in-cylinder pressure increases by 52.04% with an 8LPM of hydrogen flow rate. The rate of pressure rise and heat release from the hydrogen-gasoline mixture combustion are more concentrated and 95.53% increase in the engine torque. For the specified hydrogen flow rate, brake specific energy consumption was reduced by 92.27% and brake thermal efficiency increased by 25%. Moreover, CO emission was improved after hydrogen addition under all operating conditions. CO₂ and NO_X emissions were continuously increased with hydrogen addition. The cyclic variation was increased with the increase in the hydrogen flow rate and reduced with the increase in gasoline injection quantity.