Abstract
Abstract
The activities of retrofitting of busses in public transportation with Diesel Particle Filters (DPF’s)*) in Switzerland increased in the last years due to the present concerns about public health and environment. The retrofitting activities in the Canton Berne, City of Biel were supported by the Swiss Agency for Environment, Forests and Landscape (SAEFL) and the Office of Public Transportation of Canton Berne. The Laboratory for Exhaust Emissions Control (AFHB) of the University of Applied Sciences Biel-Bienne accompanied the activities with several technical services and research. Following objectives were pursued with the Biel City Bus Transport Company in the 4 years project (CBB):
• clearing up of the usefulness of water-emulsion fuel,
• exhaust gas measurements of busses before and after DPF retrofit,
• control of DPF’s during the service time by means of datalogger monitoring,
• testing additive-supported regeneration on an EURO1-bus,
• testing a coated CRT on an EURO1-bus.
As most important statements it can be pointed out:
• water emulsion fuel combined with CRT reduces significantly all emission components including particle mass and counts,
• water emulsion fuel supports the DPF regeneration,
• water emulsion fuel is problematic with modern injection systems: - danger of thermic decomposition - changed injection duration → influence on EGR and on injection timing,
• busses EURO 2 and EURO 3 work without problems with CRT, the necessary CRT cleaning periods are longer than 150 000 km,
• CRT doesn’t work satisfactorily on the EURO 1 busses, a Pt-coated CRT shows improvement with limited lifetime (55 000 km).