Search Results

Diesel particulate filters (DPF), in conjunction with fuel borne catalysts (FBC) to facilitate regeneration, are now an accepted technology for passenger car application. Retrofitting of such systems has demonstrated the possibility of applying this technology to heavy-duty vehicles. To demonstrate the efficacy of DPF/FBC systems and to assess their affect on engine durability and economy, five heavy-duty trucks were fitted with DPF/FBC systems. After the completion of over ¼ million kms four trucks underwent a full engine strip-down and rating. This paper briefly reviews the installation of the systems and their effect on the regulated emissions, present details of the mileage accumulation and of the engine strip-downs. The conclusions drawn are that after a ¼ million km of use with the DPF/FBC systems the trucks had not suffered any abnormal deterioration and in fact there was some indication of reduced wear on the engine.

Impending legislation will make it almost inevitable that heavy-duty trucks will have to be fitted with some form of particulate removal after-treatment device. The challenge is to provide a system that is not only environmentally acceptable and cost effective but also durable enough to meet the demands of the trucking industry. Diesel particulate filters (DPF), in conjunction with fuel borne catalysts to facilitate regeneration, are now a recognised technology for meeting future passenger car emissions limits. Retrofitting of such systems to older technology vehicles, where specific environmental concerns exist, has demonstrated the possibility of applying this technology to the heavy-duty vehicle sector. Most of these retrofit applications tend to be to vehicles with a relatively low duty cycle. Whereas this type of duty cycle poses the greatest challenge to the successful regeneration of the filters it is not necessarily the most arduous test of the durability of the system.

Work was carried out on three passenger cars and a light truck. The test vehicles were chosen to cover a range of engine technologies. Different DPF technologies were also employed. The programme showed that an improved fuel additive based on the combination of iron and strontium compounds would allow all four vehicles to be successfully operated under a wide range of conditions. The three passenger cars were driven over the road for considerable distances. Regeneration of the DPF was successfully achieved under normal operating conditions in all the vehicles without recourse to use of additional heaters, fuel injection or other technique to assist regeneration. Fuel additive treat rate was low, suggesting that long-term operation without significant ash accumulation in the DPF could be achieved.