Impact of Hydrogen Energy Share and Spark Ignition Timing on Combustion Behavior, Performance, and Emissions of a Gasoline Engine

Abstract This study investigates experimentally the impact of hydrogen energy share (HES) and ignition timing (IG) on the combustion, performance, thermal behavior, and emissions of a hydrogen–gasoline dual-fuel spark-ignition engine. Experiments were conducted at a fixed engine speed of 1500 rpm, with hydrogen enrichment varied from 0% to 40% by energy share. Ignition timing was adjusted between 14 deg crank angle (CA) and 18 deg CA before top dead center (BTDC). The results showed that increasing HES to 40% led to an earlier mass fraction burned (MFB), a shorter burn duration, and increases in peak in-cylinder pressure and maximum pressure rate (MPR) by up to 22.6% and 56%, respectively. The peak heat…