Retrofit program of a EURO 1 and EURO 2 urban bus fleet in La Rochelle, using the ceria-based fuel-borne catalyst for diesel particulate filter regeneration (phase #1)

摘要

In urban areas, particulate emission from diesel engines is one of the pollutants of most concern. As a result, particulate emission control from urban bus diesel engines using particulate filter technology is being introducing in La Rochelle. The Diesel Particulate Filter (DPF) introduction on the existing urban bus fleet has been initiated by the CDA La Rochelle through a voluntary retrofit program. The class of urban bus to be retrofitted is based on EURO 1 and EURO 2 diesel engines, using a standard European diesel fuel with 300 ppm of Sulfur content. In that case, the appropriated technology for DPF regeneration requires a very flexible strategy for DPF regeneration, such as the use of the Ceria-based, Fuel-Borne Catalysts. The paper describes the practical approach developed to install and optimize the DPF System on the urban buses. Preliminary evaluation are based on the study of regeneration behavior of a Silicon Carbide-based DPF with the Ceria-based, Fuel-Borne Catalysts on the EURO 2 diesel engine test bench, to check the soot burn-off temperature, the kinetic of DPF regeneration and the optimum of diesel fuel treatment with the Ceria-based, Fuel-Borne Catalyst. The second step consists of instrumentation and data logging on 4 representative EURO 1 and EURO 2 buses of the local urban cycle in order to optimize the DPF System regeneration. The third part is to run 4 months of real service of buses, following the evolution of back-pressure, exhaust temperature, DPF inspection and efficiency of the DPF System. In parallel, a specific strategy for diesel fuel treatment with the Ceria-based, Fuel-Borne Catalyst has been set up, using an automatic detection of the DPF-equipped urban buses, in order to avoid diesel fuel treatment for those without DPF fitting. The stationary automatic dosing system can treat the diesel fuel directly and automatically in the diesel fuel tank of the bus equipped with the DPF System. The DPF maintenance is also presented in the paper, using an adapted washing process that local workers can use after a short training course. In conclusion, based on this first step of fleet evaluation, the CDA La Rochelle is planning to extend the DPF System technology to their whole EURO 1 and EURO 2 urban bus fleet. In parallel, the present DPF System is under improvement in order to be implemented on more recent urban bus, such as EURO 3.