Carbonyls speciation in a typical European automotive diesel engine using bioethanol/butanol–diesel blends

Carbonyl compounds have been lately measured among researches in diesel exhaust emissions, due to its high atmospheric reactivity. This reactivity is quantified by the Maximum Incremental Reactivity, MIR. However, if comparing different fuels or engine conditions, weighing the emissions generated with their respective MIR is necessary. This weighed parameter is the specific reactivity, SR. The sampling procedure varies from author to author, since it is not normalized. In this paper, exhaust samples were pumped directly through the 2,4-dinitrophenylhydrazine cartridges, without any air dilution ratio. A diesel engine Nissan Euro 5 M1D-Bk, equipped with intercooler, diesel oxidation catalyst and diesel particle filter was used. Four operating modes were chosen from the New European Driving Cycle, two from the urban subcycle and two from the extra-urban one. Samples were collected at three different points along the exhaust pipe, to study the effect of two post-treatment systems. A pure diesel fuel, as reference, and two blends, one with a 10% v/v of bioethanol and another with a 16% v/v of butanol, were used during experiments. For the analysis, a High Performance Liquid Chromatograph, with a C-18 column and ultraviolet–visible detector, was used. Results showed that the emissions of the blends tested were higher than the diesel ones. Besides, in all fuels, urban mode (U10) was the mode with highest emissions. The reduction of emissions due to the post-treatment systems was detected in all fuels too.