An Investigation of Potential and Challenges with Higher Ethanol-gasoline Blend on a Single Cylinder Spark Ignition Research Engine

For several years, ethanol is being used in controlled but unmarked fashion (levels less than 5%) in gasoline worldwide. Several problems associated with ethanol have put a restriction in using gasoline-ethanol blends with higher ethanol percentage, as it is in an existing engine. Changed physico-chemical properties of high ethanol percentage gasoline blend needs several challenges to be overcome in order to harness the potential of high ethanol content in the blend.

The present paper highlights the results of investigation carried out with three different ethanol-gasoline blends i.e 10, 30 and 70 % ethanol blended with gasoline (E10, E30 and E70 respectively). An electronically controlled online fuel blending mechanism was designed and developed to ensure correct blending of two fuels in desired percentage. Suitable modifications in the engine operating parameters were carried out to meet the specified performance with improved emission level of the engine with three different blends. Comparison of specific combustion parameters such as, peak cylinder pressure, rate of heat release and mass burn fraction of all the three blends wrt to 100% gasoline operation were carried out to identify the most influential operating parameter. Each operating parameters were further optimized for improved performance and emission with each blend.

The investigation has shown that an improved engine performance and lower emission can be obtained with higher ethanol percentage in the blend by proper optimization of operating parameters without doing any major modification in the existing engine hardware.