The investigation of emission characteristics and carbon deposition over motorcycle monolith catalytic converter using different fuels

The effects of MTBE-blended gasoline and 10% (v/v) ethanol–gasoline blended fuel (E10) on HC, CO and NOx conversions over catalytic converters were investigated. Two 4-stroke motorcycle engines outfitted with typical three-way catalytic converters were used and regulated emissions were measured according to ECE-40 test cycle. The results show that the influence of E10 on the catalytic conversion is less significant at grinding stages, compared with that of MTBE-blended gasoline, the catalytic conversion, however, decreases remarkably for E10 at the point of 10 000 km. The carbon deposition information in the direction of the radius of two used monolith exhaust catalytic converters was studied by SEM, EPMA, XPS, TG–DTA and FTIR after a 10 000 km test program. The results indicate that carbon deposition occurs first at the center of a converter, gradually extending to its edge. The carbonaceous species are in the form of CxHy if the vehicle is fueled with MTBE-blended gasoline, whereas the carbonaceous species are CxHyO for E10. The majority of the carbonaceous species are deposited on the precious metal (PM) sites. Further, aromatic rings, alkyl groups and their partial oxidation products are found in the carbonaceous deposit.