Comparison of operational parameters and stability of performance of an automotive SI engine powered by methyl and ethyl alcohols

The article presents research results performed using automotive spark ignition engine run on methyl and ethyl alcohols as well as gasoline as reference fuel. The research was performed on automotive engine of Fiat 1100 MPI type. The subject of the performed analysis was to compare operational parameters of the engine such as: engine power output, overall efficiency, emission of toxic components of exhaust gases, as well as comparison of course of combustion process calculated on the basis of recorded and averaged indicator diagrams, and on the basis of individual combustion cycles. The averaged diagrams were used in analysis of the pressure course during combustion, in analysis of pressure growth rate and heat release rate. Diagrams of individual combustion served for assessment of operational smoothness of the engine when fueled with alcohols. As the reference, parameters measured in case of gasoline fueling were used. The experiments have confirmed stable engine operation on methyl and ethyl alcohols. Increase of engine power output with o 3.8-7.7% was confirmed for methanol and with 1.7-3.3% for ethanol, while increase of the efficiency with 1.5-7.5% was confirmed for methanol and with 1.2-2.5% for ethanol, comparing with gasoline fueling. Obtained results are pointing at possibilities of fueling of modern SI engines with alcohols only, especially including water-logged ethyl alcohol, obtained directly from distillery. This should increase share of alcohols in overall balance of consumed engine fuels.