The effects of Fe2O3 based DOC and SCR catalyst on the combustion and emission characteristics of a diesel engine fueled with biodiesel

Abstract

The Fe2O3 catalyst exhibits excellent activity in the reduction of nitrogen oxides. However, the improvement of its high-temperature stability is a well-known challenge in application of diesel engine fueled with biodiesels. The paper offers an investigation on the effects of Fe2O3 based diesel oxidation catalyst and selective catalytic reduction catalyst on the engine characteristic of diesel engine fueled with biodiesels and diesel in the experimental study. The catalyst of Al2O3-Nb2O5/CeO2/Fe2O3 was produced with the impregnation method. The characteristics of selective catalytic reduction catalyst and diesel oxidation catalyst were investigated in term of CO, smoke, NOx, CO2 and O2 emissions. In addition, the engine combustion characteristic was studied in term of brake specific fuel consumption, exhaust temperature and excessive air factor. The experiments were carried out with a four cylinders electronic control diesel engine under a constant engine speed of 1000 rpm and various engine loads. The results show that the average increases of BSFC are 10.60%, 5.35% and 5.22% for diesel, RME and CSME catalyst, respectively. In addition, applying of biodiesel fuel drops in CO by 35%, HC by 64%, and smoke by 45% in average, whereas NOx growths by 11% at medium and high loads. The NO conversions of diesel engine fueled with diesel, rapeseed methyl ester and cottonseed methyl ester are up to 72.3%, 81.3% and 78.6%, respectively. Similarly, NOx conversions are up to 76.1%, 82.3% and 83.5%, respectively.