Influence of EGR on the simultaneous reduction of NOx-smoke emissions trade-off under CNG-biodiesel dual fuel engine

Dwindling fossil fuel resources and deteriorating ambient air quality has mandate the search for suitable alternative fuels for diesel engine. Dual fuel engines show remarkable engine performance characteristics at higher engine loads but suffer from high NOx-smoke opacity emissions trade-off. In the present study, an attempt has been made to introduce exhaust gas recirculation (EGR) under compressed natural gas (CNG) fuelled diesel engine using Jatropha biodiesel (B20) blend as pilot fuel. Experimental investigations were carried out in a single cylinder direct injection compression ignition engine, which was suitably modified to operate under dual fuel mode along with EGR. Comparative analysis was made on the basis of combustion, performance and emissions characteristics at different engine operating loads for fossil diesel, CNG and biodiesel blend (B20) with and without EGR. It was evident from the experimental investigations that dual fuel mode with EGR improved the NOx-smoke emission trade-off at higher engine loads without deteriorating engine combustion and performance characteristics.