PAH EMISSIONS INFLUENCED BY MN-BASED ADDITIVE AND TURBOCHARGING FROM A HEAVY-DUTY DIESEL-ENGINE

A manganese-based additive was used in this study to investigate the e ffects on the polycyclic aromatic hydrocarbons (PAHs) emission from a natural-aspirated heavy-duty diesel-powered engine. A similar turbocha rged engine was tested and compared with the natural-aspirated one for the PAH emission. The concentrations of 21 individual PAHs (gas + par ticle phases) and the metal element (Mn) of the particulate from the e ngine exhaust and in the diesel fuel, respectively, were determined. E ngine exhaust (PAHs and Mn) was collected over the modified JAMA J-13 mode by a PAH sampling system. By adding 400 mg/kg of Mn-based additiv e in the diesel, the reduction fraction of mean total-PAM (gas plus pa rticle phase) emission was 37.2%, while for the 10 higher molecular we ight (HMW) PAHs, the mean reduction fraction was 64.5%. These results indicate that the Mn-based additive in the diesel engine can act as a catalyst enhancing the oxidation process and reducing a considerable a mount of PAH emission. In addition, the amount of 10 HMW PAH emission from the turbocharged engine averaged 92.4% of magnitude lower than th at of the natural-aspirated engine. This result revealed that the turb ocharged engine has higher pressure and temperature and thus makes a m ore complete combustion of the fuel. (C) 1998 Elsevier Science Ltd.