Soot particulate filter


Reduction of diesel pollutants 

Diesel engines are powerful, long-lasting and consume little fuel. It is particularly because of this that they are permanently in use for small and large construction sites. However pollutants such as soot particles are created during the combustion process of fuel in the engine. The smaller they are, the more easily they find their way over the lungs into the bloodstream and thereby into other vital human organs. Therefore soot particles from diesel engines are known to represent a significant health hazard. For this reason, step by step, numerous measures are coming into force on a European and national levels for reduction of the pollutant emissions. 

These include, for example, the Air Quality Directive (EU Guideline 2008/50/EEC) which has been valid throughout the EU since the beginning of 2005. The object of this regulation, its subsidiary directives as well as the respective implementation in the Federal Pollution Control Act, is to measurably improve the air quality, especially in European metropolitan areas. The regulations require that cities and communities take action against increased pollution levels. Previous implemented measures, amongst others, include setting up of environmental zones in Germany and further European countries and the so-called filter obligation for building machines in Switzerland. 


SMF (sintered metal filter) ® - An overview of the advantages

• Reduction of soot and fine particles by more than 99%  (based on the number of particles)
• Suitable for OE and retrofitting applications 
• A tried and tested system already in use more than 20,000 building machines
• A high ash storage capacity and lower exhaust back pressure
• Low maintenance and economic
• Reliable with high service life
• Easy cleaning


Advantages of automatic monitoring and a maintenance indicator

• Continuous monitoring of the exhaust back pressure and temperature
• Overloading recognition of the particulate filter
• Automatic display of the cleaning requirement 
• Reduction of the maintenance costs


Function description

In an SMF® AR System the exhaust gas is filtered until the optimum amount of soot has been gathered on the filter for regeneration. The system uses the positive active properties of a fuel additive so that on the one hand, it lowers the soot ignition temperature and, on the other hand, it increases the soot combustion speed. The stored soot can then be burnt off by itself at an exhaust gas temperature of about 400°C during a regeneration. If the required temperature is not reached - which is often the case in a low load case - the active regeneration support comes in the form of the system's thermo-electric heating.


Active thermo-electric regeneration

The control unit initiates (active) regeneration through the heating elements that are arranged in a circle. The gathered soot is ignited by the radiation energy of the heating elements. The regeneration process  proceeds automatically after initial ignition of the soot layer. The soot burning takes place at regular intervals. With the aid of the control unit, not only ignition of the soot is initiated but also the additive is added in an optimal manner, the required filter loading is determined and the most favourable point in time for regeneration is determined. Furthermore a self taught-in running cycle recognition ensures that the regeneration is triggered for optimal operating conditions. Due to the high soot storage capacity of the SMF® AR system, the regeneration does not occur just at one “unique", ideal point in time, but rather within a large time window. Therefore a one-time abort of regeneration due to switching off of the engine is not a problem with regard to safe working of the SMF® AR system. Another SMF® plus point is its high ash storage capacity, which allows long maintenance or cleaning intervals.


SMF® AR – An overview of the advantages

• For OE and retrofitting applications
• Reduction of soot and fine particles by more than 99%  (based on the number of particles)
• Particularly suitable for low temperature applications
• Fully automatic, active regeneration
• Robust design due to the use of sintered metal (SMF®)  => suitable for construction machines
• Operationally safe function
• Low maintenance
• Long service life
• NO2 - neutral regeneration 
• Easy cleaning of the filter with a high pressure cleaner