Effects of using alcohols on the performance and emissions of a diesel engine

Addition of renewable alcohols to diesel is being investigated extensively to reduce greenhouse gas emissions. The objective of this study was to examine the suitability of such renewable alcohols. In this study, emissions and performance characteristics of alcohol/diesel blends were evaluated for a four stroke single cylinder diesel engine test rig. n-octanol and n-butanol were the alcohols considered. Experiments were conducted at different loads up to 4 kW and for alcohol contents from 10% to 40% by volume. The results indicated that the alcohol/diesel blends exhibited similar performance characteristics to that possessed by diesel. A slight drop in brake power was observed in all the blends compared to pure diesel. The brake thermal efficiency and brake specific fuel consumption increased in all alcohol blends at almost all the loads considered in the study. The emission analysis was also conducted using the AVL DI Test. The results revealed that CO and NO emissions decreased compared to pure diesel. However, HC emissions increased for n-butanol blends but they decreased in case of n-octanol blends. Results are a clear indication that these blends have an excellent potential and detailed investigations in real life conditions can lead to commercial usage. (paper)