Diesel Emissions from an Emulsified Fuel During Engine Transient Operation

The work has been focused on the measurement and analysis of the main Diesel emissions from an automotive Diesel engine mounted in a test bench prepared for operating in different transient sequences. The engine was fuelled with a conventional fuel and an emulsified fuel. A commercial pure low sulphur diesel fuel and an emulsified fuel (water in oil, w/o) with 5% v/v of water, were used as test fuels. A smoke meter and a gaseous emissions analyser allowed for the study of the effect of these fuels on the Diesel emissions under the different operating transient sequences. The properties of the test fuels and the time-recording of some engine parameters, such as fuel/air ratio or exhaust gas recirculation ratio, were used for the analysis and interpretation of the results. The obtained results suggested that the use of the emulsified fuel with a small water portion is an interesting alternative for a significant reduction in the main Diesel emissions, nitrogen oxides (NOx), smoke opacity and unburned total hydrocarbons (TH), under transient conditions, whose contribution to the total emissions throughout the certification driving cycle is very important.