Simultaneous reduction of NOx and smoke from a direct-injection diesel engine with exhaust gas recirculation and diethyl ether

An experimental investigation was carried out to analyse the simultaneous reduction of oxides of nitrogen (NOx) and smoke emissions. The tests were performed on a single-cylinder direct-injection diesel engine. The engine was made to run on both pure diesel and diethyl ether (DEE)-diesel blends. The DEE-diesel blends were prepared by mixing certain proportions of DEE and diesel fuel. The amount of DEE in the diesel fuel blend was varied up to 30 vol % in steps of 10 vol % by volume. The results obtained from DEE-diesel blends were compared with those from pure diesel and it was found that the 20 vol % DEE-diesel blend resulted in the optimum performance and emission characteristics. The study was further extended by using exhaust gas recirculation (EGR) with 20 per cent DEE-diesel blend and pure diesel. At 5 vol % EGR operated with 20 vol % DEE-diesel blend, there is a simultaneous reduction of NOx and smoke emissions by 54 per cent and 20 per cent respectively. In contrast, in the case of the pure diesel mode, when the EGR rate was increased, NOx emission was reduced at the expense of smoke emissions. The alternative fuel, namely the DEE-diesel blend shows very promising results with respect to emissions, efficiency, and durability.