On-Road Experience with Trap Oxidiser Systems Installed on Urban Buses

A trap oxidiser system using exhaust gas throttling as main regeneration system, coupled to a by-pass control of ceramic temperature, was installed on five experimental buses of the Athens bus fleet. Cerium Naphthenate was also used as fuel additive at different concentrations, in order to ensure safe and reliable regeneration at relatively low temperatures. The behaviour of the systems was constantly monitored through data loggers, during regular on-road operation. In order to examine the performance of all available materials, parallel tests were carried out using wall flow ceramics of different configurations and foam type ceramic monoliths.

The paper presents the evaluation of the results obtained after 9 months of systems operation, with an accumulated minimum of 45,000 km of useful life per system. The results include the behaviour of the trap oxidisers in terms of smoke reduction, back-pressure profiles and thermal response, as well as the analysis of the different operation phases of the system.