PM Metalit® – the partial-flow deep-bed filter for diesel particulates
In contrast to other wall-flow only filter systems, the PM METALIT® works on a wall-flow and partial-flow principle. This guarantees trouble-free engine operations even in the absence of regeneration. Separated particulates are reduced by continuous reaction with NO2 from the upstream oxidation catalyst. The new particle separator diverts the exhaust gas stream into the adjacent channels. The particulates are temporarily deposited on a fleece and continuously burnt off at temperatures from approximately 200 °C. The second effect is based on the exhaust gas flowing through the filter material in a longitudinal direction, resulting primarily in the separation of nanoparticles.
Advantages:
- Corrects partial flow structures and prevents blockages
- Maintenance-free
- Negligible rise in backpressure under load
- No increase in fuel consumption due to forced regeneration
- Highly efficient with regard to nanoparticles
- Can be added to existing oxidation catalysts in cars
- A modular structure with an upstream oxidation catalyst is particularly effective for truck retrofitting
- Can be coated to optimise the system
- Small ash deposits permit high mileages without any increase in backpressure or loss of efficiency
- Mechanical durability demonstrated through series application in cars and trucks
The PM Metalit® represents a complementary step in the overall concept of exhaust gas aftertreatment of diesel engines. The system consists of a pre-turbocharger catalyst that oxidises CO and HC, a Hybridkat™ that oxidises NO and a downstream open PM Metalit®. Particle separators can operate efficiently only in an optimally adjusted overall concept. This means that HC and CO emissions have to be reduced before NO can be oxidised to form NO2. The next development stage is expected to be a combined catalyst system that operates both as an oxidation catalyst to convert the harmful diesel exhaust gases CO and HC and as a PM Metalit® to dramatically reduce soot particles. This new multi-functional development operates as a soot trap, improves mass transfer and the gas mixture and homogenises the flow.
