Experimental Investigation of Combustion Characteristics, Performance, and Emissions of a Spark Ignition Engine with 2nd Generation Bio-Gasoline and Ethanol Fuels

Abstract

Climate change mitigation is the main challenge for the automotive industry, as the government issues legislation to combat CO2 emissions. In addition to electrification and battery electric vehicles, using low-carbon and zero-carbon fuels in Internal Combustion (IC) engines can also be an effective way to reach net zero-carbon transport. This study investigated and compared the combustion characteristics, performance and emissions of a highly boosted spark ignition (SI) engine fuelled with EU VI 95 RON E10 gasoline and blends of second-generation bio-gasoline with different ethanol contents of 5% (E5), 10% (E10), and 20% (E20). The single-cylinder SI engine was equipped with a centrally mounted high-pressure injector and supplied externally boosted air. Engine experiments were conducted at 2000 RPM and 3000 RPM with low and high load operations. The overall finding indicates that increasing the ethanol content of second-generation biofuels from 5% to 20% improves the indicated thermal efficiency at low load by 2.1% and increases the knock resistance by 16.8% at high load operation as well as a reduction by 0.7% on cycle-to-cycle variation. The engine emissions were primarily affected by the engine operating conditions, and no consistent correlation between the ethanol content and emissions. However, it was noted that the average NOx and THC emissions were increased by 11.02% and 66%, respectively, at the low load operation when the ethanol content was increased from 5% to 20% at the exact fuel injection timing of 350 BTDC.