Experimental and numerical study on a SI engine fueled with gasohol and dissociated methanol gas blends at lean conditions

Hydrogen-rich dissociated methanol gas (DMG) and ethanol are both promising alternative fuels for engines. The study investigates the performance of a spark ignition engine using various gasohol-DMG blends under lean conditions, aiming to evaluate the influence of fuel composition, excess air ratio, and operational parameters including engine load and speed. The results demonstrate that the introduction of DMG substantially enhances the engine's fuel economy, combustion efficiency, combustion stability, and the HC and CO emissions. The addition of ethanol has a distinct impact on engine performance, including increased peak cylinder pressure at lower DMG ratios and a subsequent decrease at higher DMG ratios. It also leads to substantial reductions in HC and NOx emissions but shows a non-linear effect on CO emissions with an increasing ethanol blending ratio. An increase in excess air ratio results in simultaneous reductions in peak cylinder pressure, HC, CO, and NOx emissions. Moreover, variations in engine load and speed respectively impact the cylinder's thermal environment and gas flow, consequently influencing combustion and emission characteristics.