Emission characterization of petrol, ethanol and spent engine oil blends for two-stroke spark ignition engine

Abstract

Exhaust emission has remained a big global concern in atmospheric change, and has thus, lead to stiffer polices on emission. To achieve the set emission targets different fuel mix and combustion process are continuously been investigated. This work is used to practically model the condition of a two-stroke engine that has run over time whose used lubricating oil finds its way from the sump to the combustion chamber and thus resulting to greater rate of incomplete combustion and higher emission. An exhaust analyser with a deep probe was deployed to access the out-going burnt gasses from a two-stroke spark ignition engine that is fed with multi blends of petrol, ethanol and spent engine oil. The characteristics of the emission constituents were investigated and compared to the global limits set by different organizations such as California Air Resources Board, Environmental Protection Agency in USA, International Council on Clean Transportation, Road Transport Bureau- in Japan, and European Emission Standard Agency, among others. The result shows an increase in CO, HC and NO_x emissions with samples that contain spent oil as against those with new engine oil which is also more effective. It was also found that samples with higher quantity of ethanol show lower emission of CO, HC and NO_x gases. This is likely due to interstation of ethanol molecules with that of the spent oil, thus making it more potent for further combustion. This was also supported with the fact that CO₂ emission was higher in blends with higher quantity of ethanol. Thus, the presence of ethanol in fuel blend used in two-stroke spark ignition engine may be considered to be a source of improvement in combustion and hence a means of reducing emission in two-stroke port operated spark ignition engines.