Particle Oxidation Catalyst (POC) for Diesel Vehicles

Contrary to gasoline cars only few of the new diesel vehicles are equipped with exhaust gas after treatment devices. Diesel engine producers have managed so far to meet the emission limits by improving the engine and its control. The new emission standards are worldwide forcing producers to implement exhaust gas after treatment systems. In diesel vehicles exhaust gas after treatment is much more complicated than in gasoline cars. The most demanding tasks are simultaneous reduction of particles and NO_x in low temperature and lean condition. The best results can be achieved with the systems including a lean deNO_x catalyst and filter. This technology is now available, but it is very expensive. The next coming emission limits like the Euro 4 can be met in most cases with advanced diesel oxidation catalyst technology. This paper presents a new Particle Oxidation Catalyst (POC) with enhanced properties to burn particles. The POC comprises a new low temperature wash coat and a new kind of metallic substrate called EcoCat. It is possible to reach 60% particle reduction and simultaneously 80 to 90% HC and CO conversion. Tests have been carried out with several light and heavy duty engines and vehicles including engine variety from Euro 0 to Euro 4 emission homologations. The biggest advantages of this solution are a relatively low price and no need for maintenance. Low sulphur level in diesel fuel is required.