Effect of Fuel Reactivity on Engine Performance and Exhaust Gas Emissions in a Diesel Engine

Using a compression engine with dual fuel is the most promising technology to control emissions and for fuel economy, to meet the upcoming legislative norms. This experimental study was conducted to understand the effect of fuel reactivity on engine performance and emission in a compression ignition (CI) engine. The effect of injection timing, gasoline ratio, and exhaust gas recirculation (EGR) rate on emission is compared to the conventional diesel engine. In this study, high-octane fuel (gasoline) is injected manifold the intake of a diesel engine (high-reactivity fuel) to primarily investigate the effects of balance between fuels having low and high reactivity. Fuel reactivity is optimized on different load and speed conditions by varying the diesel and gasoline quantity. Experimental results indicate that dual fuel helps to avoid nitrogen oxides (NO_x) and soot trade-off, mitigating both to near-zero values. The engine was tested at a constant speed of 1520 rpm and showed a reduction in NO_x and soot emissions with an increase in the gasoline content ratio. The fuel consumption was reduced to 249 g/kWhr from 254 g/kWhr of the diesel engine when operated with a gasoline ratio of 70%. Simultaneously, both NO_x and soot emissions were reduced to about 0.42 g/kWhr and 0.06 g/kWhr, respectively. The best operating zone with dual fuel showed a significant reduction of NO_x and soot emission but high HC and CO with the use of EGR and gasoline variation in different loads and speeds. The enhancement in thermal efficiency and lowering of heat and exhaust losses were secured using low-reactivity fuel.