Study on the effects of nitro-based fuel additive on diesel engine performance and emissions

Abstract

Through adding nitro-based fuel additive into diesel fuel,the influences of additive on engine performance, gaseous emission, particle number concentration and exhaust smoke were studied on a test bench. Meanwhile, the functioning mechanism and combustion characteristics were studied through constant volume combustion vessel. The system is composed of high pressure common rail fuel injection system, high pressure constant volume combustion vessel, high speed camera, data synchronization and acquisition system. The maximum diesel injection pressure is 160 MPa, and it can be heated to 1000 K under the back pressure of 3 MPa. According to the research results, adding fuel additive can decrease both exhaust smoke and exhaust temperature of engine for european steady state cycle(ESC). Moreover, The fuel additive improved the engine’s power slightly and expanded the economic fuel consumption working area. The minimum fuel consumption rate was reduced from 204.6g/kWh to 202.2g/kWh, and the highest fuel saving rate was about 2%. After adding MAZ, the mass of the recycled particles can be reduced by about 15%,and the average smoke intensity of most operating points showed a downward trend, with a maximum drop of 55%, the NOx weighted emissions of the whole cycle decreased by more than 2%. After adding nitro-based fuel additive, the ignition delay and flame lift-off length became longer in the combustion process, but the duration of combustion was shorter, which are in accordance with chemical reaction kinetics analysis.