Feasibility of Methanol-Gasoline Blends in a Production Grade Spark Ignited Carbureted Genset Engine—Part 1: Engine Performance, Combustion, and Emission Characteristics

Abstract This study aimed to evaluate the effect of methanol/gasoline blends on performance, combustion, and regulated emissions of spark-ignited Genset engines. The test engine was fueled with M15 (15% (v/v) methanol + 3% (v/v) isopropyl alcohol + 82% (v/v) gasoline), M20 (20% (v/v) methanol + 80% (v/v) gasoline), and baseline gasoline. The test engine was operated at different engine loads at a constant speed of 3500. A comparative analysis was made between engine performance, regulated emissions, and combustion parameters. M15 and M20 exhibited ∼14% and ∼4.9% higher brake thermal efficiency at 2.4 kW load, respectively, while at full load (2.8 kW), it was 7.91% and 3.55% higher, respectively, compared to baseline gasoline. Brake-specific fuel consumption and exhaust gas temperature were higher for methanol blends than for baseline gasoline. Peak in-cylinder pressure and heat release rate of methanol blends were lower than baseline gasoline at higher engine loads but comparable at lower loads. This is possible due to the unmodified carburetor jets, which were calibrated for gasoline only; thus, they eventually did not achieve the stoichiometric air–fuel ratio, leading to a lower heat release rate and cumulative heat release. The start of combustion and the end of combustion were delayed for methanol blends. Methanol blends' combustion duration was higher than that of baseline gasoline at high loads. Engine-out carbon monoxide and hydrocarbon emissions were lower for M15 and M20 than baseline gasoline, but a small increase in nitrogen oxides was detected at a higher loads.