Search Results

1 A methodology for correctly matching trap systems to the vehicle types was developed within the scope of a feasibility study to retrofit the entire Swiss fleet of on-road HDV. Representative test vehicles from 11 vehicle categories were equipped with high capacity data loggers during a period of 4-6 weeks. Statistical evaluation of exhaust temperatures indicate that data on averages, peaks and frequency distributions alone can be misleading, because these tend to over-estimate the available exhaust enthalpy. Analysis of dwell time intervals, at certain temperature levels, is a better method to assess the energy available for the regeneration. Such verification of duty cycles is indispensable before retrofitting traps and choosing either active or passive regeneration systems.

Transport Refrigeration Units (TRU) powered by small diesel engines emit high PM and cause locally high PM levels. The concomitant health risks spurred efforts to devise a cost-effective curtailment of these emissions. Diesel particulate filters (DPF) of ceramic honeycomb construction very efficiently trap PM emissions, even ultrafines in the lung penetrating size range of below 300 nm. A fuel borne catalyst (FBC) can facilitate trap regeneration, by lowering the exhaust temperature requirements, but cannot alone guarantee reliable regeneration under all operating conditions of the TRU. A Swiss development team together with industrial partners therefore developed a fully automatic active regeneration system for the California Air Resources Board.