Performance and emissions of diesel engine operating on biodiesel and butanol blends

Abstract

The paper presents the experimental test results reflecting the comparative changes in the performance efficiency and emissions of the exhaust of a normally aspirated, four-stroke, single-cylinder, air-cooled diesel engine F1L511 occurring due to its transition from neat rapeseed oil biodiesel to operation on renewable fuel blends prepared by mixing in various proportion (by volume) rapeseed methyl ester (RME) and butanol (B).In contrast to previous works, the undertaken investigation was performed with totally renewable binary liquid fuel blends.The purpose of the research was to reduce the production of both exhaust smoke and NOx emissions with respect to neat biodiesel due to potentially improved homogeneity of combustible mixture and particulate matter emissions benefits suggested by the higher oxygen content (21.62 wt %) and the relatively lower carbonto-hydrogen ratio (4.8) of butanol.The three renewable fuel blends B5, B10 and B15 were prepared by mixing 95 vol.% RME/5 vol.% B, 90 vol.% RME/10 % B and 85vol.% RME/15vol.% B, respectively.It was found that the brake specific fuel consumption for the tested biodiesel-butanol fuel blends was always higher than that measured under the same operating conditions with neat biodiesel.The lowest level of carbon monoxide emissions (CO) was also measured with the same biofuel blend B15 at medium (50 % of full) load.While the production of maximum NO x emissions from combustion of blend B15 was 0.6 % lower than that experienced with neat biodiesel under the same test conditions.It is important to note that the lower NO x emissions have been accompanied by the lower smoke opacity from combustion of the most butanol-oxygenated fuel blend B15.Thus, the most problematic issue related with the reduction of both the NO x emissions and the smoke opacity (PM) can be solved quite easy by using for diesel engine powering totally renewable biodiesel-butanol fuel blends.