With the boom in Electrical Vehicles due to the benefits that they offer, Spark Ignition (SI) Engines seems to take back seat. However the narrative is not true, and the benefits that biofuels offer are vast. Ethanol is one such fuel, which is widely available, low cost, high purity, and low toxicity. Countries like Brazil have been using it since 1920. Brazil and the USA together contribute to more than 80% of the world's ethanol production. Ethanol contains roughly 34% less energy per unit volume than gasoline, and hence, burning pure ethanol in an engine reduces range per unit volume roughly by 34% viz-a-viz burning pure gasoline. Since, octane rating of ethanol is comparatively higher, the engine can be operated at higher compression ratio efficiently. High octane numbers in ethanol than gasoline reduces engine knocking and performs better than gasoline. Also, Ethanol fuels with lower concentrations can be used in SI engines without any alterations. Some modifications are required for SI engine while using pure ethanol too. But, these modifications are based on blend concentration. Engine performance can be improved while utilizing blends by connecting fuel sensors to an electronic fuel module, which can be modified by placing electronic control modules (ECMs/ECUs) between the electrical connectors and the fuel injector. Also, harnessing the advantage of advance injection timing is easier with these blends.

Keywords: SI engine; Alternative fuels; Ethanol; Gasoline–ethanol blends