Research on the Lean Burn Characteristics of Gasoline Engine Blending with Hydrogen-Rich Gas

Methanol has become an important alternative energy source due to its wide availability and renewable properties. Hydrogen, with its fast flame propagation speed and wide combustion limits, can help improve engine efficiency. For further improvement of the overall thermal efficiency, this paper builds an experimental platform to catalytically dissociate methanol using engine exhaust heat, and then mixes the obtained hydrogen-rich gas with gasoline for combustion. The lean burn characteristics of the gasoline engine blended with dissociated methanol gas (GDM) are studied through a combination of experimental and simulation methods. The result shows that under the stoichiometric condition, the brake thermal efficiency (BTE) gradually improves and the brake specific fuel consumption (BSFC) decreases as the methanol substitution ratio (MSR) increases. When the MSR increases from 0 to 80%, the BTE increases by 9.72% at 40 N∙m. At the lean burn condition, the fuel efficiency of the GDM engine is still higher than the original one at the same air–fuel ratio (AFR). Increased λ values can further improve the BTE of GDM engine. Compared to conventional gasoline engine, GDM engine combust faster and the phase of peak cylinder pressure and the phase of maximum heat release rate are (HRR) both closer to the top dead center. The aforementioned phenomenon becomes more prominent as the λ and MSR value increases.