Trap the particulates: Scania CRT for city operation
In line with customer demand, a CRT-filter can now be fitted to Scania 9-litre engines. Emissions of hydrocarbons, carbon monoxide and particulates are cut by 90 percent compared to a modern diesel engine. This enables operators to make sure that harmful emissions from their vehicles are reduced as far as current technology permits.
CRT - continuously regenerating trap - is a catalytic converter that is fitted to the exhaust system, replacing the silencer. Fuel consumption is unchanged and there is no additional maintenance.
Low-sulphur diesel fuel is required. To work well long-term, the sulphur content should not exceed 50 ppm (parts per million). For optimum cleaning capacity, Scania recommends a sulphur content of max. 10 ppm.
Tackle emissions at source
Scania's R&D philosophy is that environmental aspects should be brought back to the source, where the action should be concentrated, if possible. The objective is to gradually reduce emissions while refining combustion technology to preserve acceptable fuel economy. This aspect is a prerequisite for operators to be interested, since operating economy is such a vital part of the transport business.
Current combustion technology permits emissions of hydrocarbons, nitrogen oxides and particulates to be cut by around one-third to the proposed Euro 3 levels without any significant sacrifice in fuel consumption. Euro 3 is expected to come into force for new models from October 2000 and for all new vehicles one year later.
This progress is demonstrated by Scania's low-emission engines launched in January and November this year, despite the fact that the directive has not been adopted. These engines comply with the proposed Euro 3 standard already today.
CRT after-treats the exhaust gases in three ways. A catalytic process oxidises hydrocarbons (HC) and carbon monoxide (CO) to water vapour and carbon dioxide CO2. Simultaneously nitrogen oxide (NOx) is formed. Particulates are then filtered off mechanically. With the aid of the nitrogen oxide, the particulates are then burnt off during driving. Emissions of HC, CO and particulates are reduced by 90 percent. Nitrogen oxide emissions are unchanged. CRT is also available for retrofitting on older vehicles.