Experimental Study on Urea Dosing Strategy for SCR on an Engine Fuelled with Bio-Diesel

Abstract

Urea dosing strategy for SCR is studied for a diesel engine fuelled with bio-diesel BD20. Bio-diesel BD20 is consisted of biofuels made from waste cooking oil and national V diesel, and biofuels accounts for 20% by volume. The results show that, bio-diesel engine torque decreases by a maximum of 0.55%, brake fuel consumption rate increases by a maximum of 0.53% ,when the urea dosing strategy is adjusted and the engine and SCR are not changed. ESC tests show that, the maximum of NOXconversion ratio is 95%, the minimum is 57%, and the average value is 74% under ESC 12 conditions except idling, the maximum of HC decrease ratio is 74%, the minimum is 35%, and the average value is 55%, when the urea is dosed. NOXemission is 1.55 g/(kW·h) in ESC test, NOXemission is 2 g/(kW·h) in ETC test, and NH3slip is lower than 10×10-6, which proves that the NOXemission from the engine fuelled with BD20 can meet national emission standards V by adjusting the urea dosing strategy.