A comparison of performance of higher alcohols/diesel fuel blends in a diesel engine

The use of alcohols provides an attractive alternative fuel for internal combustion engines. Moreover, alcohol can be produced by biorefineries, thus reducing the consumption of fossil resources. Heretofore, research related to the use of alcohols as alternative fuels for internal combustion engines has been focused on the employment of short chain alcohols, mainly methanol and ethanol, blended with fossil fuels. Despite their adequate combustion properties, long chain alcohols like butanol or pentanol have been barely investigated. The objective of this work was to compare the short-term performance of a direct injection diesel engine fueled with different 1-butanol/diesel and 1-pentanol/diesel fuel blends, without any modifications of the engine. To gain knowledge about the implications of the use of the proposed blends, results were compared with those achieved with the use of neat diesel fuel. 1-butanol/diesel fuel blends (from 10% to 30% of 1-butanol by volume) and 1-pentanol/diesel fuel blends (from 10% to 25% of 1-pentanol by volume) were tested. Experimental results showed a slight engine power loss and an increase in brake thermal efficiency when the engine was fueled with higher alcohols blends instead of straight diesel fuel. However, some 1-butanol blends depicted a decrease in the brake specific fuel consumption compared to the use of neat diesel fuel. After using 1-butanol blends and 1-pentanol blends, no engine performance problems were visually detected. Moreover, statistical analysis showed no significant differences between tests. It can be concluded from this field trial that a diesel engine, without any modifications, can run successfully on a blend up to 30% 1-butanol/70% diesel fuel or 25% 1-pentanol/75% diesel fuel without externally apparent damage to the engine parts. Nevertheless, to recommend its use as a substitute of straight diesel fuel, long-term durability tests are needed. (C) 2012 Elsevier Ltd. All rights reserved.