Assessment of the Performance and Emission Characteristics of 1-Octanol/Diesel Fuel Blends in a Water Cooled Compression Ignition Engine 2014-01-2830

The interest of using alternative fuels in diesel engines has been accelerated exponentially due to a foreseen scarcity in world petroleum reserves, increase in the prices of the conventional fossil fuels and restrictions on exhaust emissions such as greenhouse gases from internal combustion (IC) engines initiated by environmental concerns. The constant trade-off between efficiency and emissions should be in proper balance with the conventional fuels in a fuel design process for future combustors. Unlike gasoline and diesel, alcohols act as oxygenated fuels. Adding alcohols to petroleum products allows the fuel to combust properly due to the presence of oxygen, which enhances premixed combustion phase, improves the diffusive combustion phase which increases the combustion efficiency and reduces air pollution. The higher activation energy of alcohols leads to better resistance to engine knocking that allows higher compression ratios and greater engine thermal efficiencies. The use of higher alcohols blended with diesel fuel may provide additional advantages compared to short-chain alcohols, i.e. longer molecular un-branched structure of alcohols that means higher calorific value and better cetane number. However, very little work has been reported on higher-alcohols such as 1-octanol, being used as alternative fuel. In the present study, various engine trails have been conducted to analyses the influence of 1-octanol/diesel fuel blends while comparing the performance and emissions characteristics with mineral diesel fuel. The target of current research includes testing a medium capacity unmodified water cooled diesel engine fuelled with different 1-octanol/ diesel fuel blends i.e. OCT10D90 (10% 1-octanol with 90% diesel), OCT20D80, OCT30D70, OCT40D60 which were prepared by volumetric ratio and analyzing brake-specific fuel consumption, brake thermal efficiency on the performance aspects while studying NO_X, CO, HC and smoke opacity on the emission aspects with an objective to find out the optimum alcohol/fuel blend to be run on diesel engine. When compared to higher alcohols, 1-Octanol has the most similar physical properties to diesel; thus, the effect on fuel consumption is insignificant. On increasing the concentration of 1-octanol, the NOx is found to be slightly decreasing while there is an increase in HC level and also, the brake thermal efficiency is marginally decreased with considerably increased in CO, NO_X and smoke opacity. Therefore, 1-octanol can be added to mineral diesel for compensating the ever increasing energy needs.