Soot particles have been able to be filtered from diesel exhaust gases down to the limit of detection for some time now. HJS developed the diesel particulate filter made of sintered metal (SMF® sintered metal filter) specifically for this purpose and was rewarded with the 'Deutscher Umweltpreis' (Germany Environment Prize) for its efforts.
Now, to reduce gaseous pollutants in combination with the diesel particulate filter, HJS has played a crucial role in developing SCRT® – Selective Catalytic Reduction Technology. This modular system is capable of removing almost all nitrogen oxide emissions from diesel exhaust gases.
HJS's proven SMF® technology with passive regeneration is used to break down the soot that collects in the SMF®. The oxidation catalytic converter installed upstream converts the nitrogen oxide (NO) in the exhaust gases to nitrogen dioxide (NO2). The particulate filter then uses this nitrogen dioxide (NO2) to continuously oxidise and burn off the particulate matter residues (PM or soot oxidation).
The SCR (Selective Catalytic Reduction) system installed downstream now plays its part in reducing the level of nitrogen oxides (NOx). The urea-based additive (a reduction agent) carried on board and known by the brand name AdBlue® is admixed to the exhaust gases after the diesel particulate filter (SMF®). This reduction agent is thermally and catalytically converted to ammonia (NH3). This ammonia is then used – in combination with the SCR catalytic converter – to convert the nitrogen oxides (NOx) into the harmless substances nitrogen (N2) and water (H2O). In this way the SCR unit reduces the diesel engine's emissions of nitrogen oxides – which pollute the environment and damage people's health – by up to 90 per cent. Together with the HJS particulate filter, the SCR system reduces almost all pollutants in the diesel exhaust gases (SCRT® = DPF + SCR system).
Die Funktionsweise des HJS SCRT®-Systems anschaulich erklärt in einer Animation. Video anzeigen ...
This new generation of exhaust-gas aftertreatment system gives automobile, commercial-vehicle and engine manufacturers, vehicle owners and operators the opportunity to comply with future, globally applicable and the strictest ever exhaust emissions legislation.
The system has been designed such that it can be fitted not only in passenger cars but also commercial vehicles. What's more, it can also be used for 'non-road' diesel engines, that is, construction machines, agricultural and forestry machinery, ships and rail vehicles. The technology is suitable both as original equipment (OE) and for retrofitting.