Integrated Diagnostics for combustion investigation in a DISI engine fueled with butanol and gasoline at different load

Within the context of ever limits on exhaust emisisons and growing concerns regarding the uncertainty of fuel availability, research into alternative energy sources is receiving increased attention. In this work the effect of replacing gasoline with n-butanol on the combustion process in a spark ignition engine was investigated through the combined analysis of in-cylinder pressure measurements and optical data. The trials were performed on an optically accessible engine equipped with the cylinder head of an automitive power unit featuring wall guided direct injection. engine speed, partially - and wide-open throttle conditions were chosen as representative for mid-road load automotive use, with close to stoichiometric air-fuel ratio. Split injection was found to be beneficial when using the alternative fuel. Optical diagnostics based on cycle resolved UV-visible digital imaging and natural emissions spetrocopy were applied in order to study the development of combustion processes from ignition to exhaust valve opening. finally, pollutant emission measurements for the two fuels were correlated with thermodynamic and optical results.