Particulate filter cleaning - methods for DPF cleaning.

01.Gentle and thorough particle filter cleaning by heating and free-burning.

“When cleaning soot particle filters and catalytic converters, we make use of a thermal-mechanical cleaning process that we have developed ourselves and that has been tested by TÜV.”

In this cleaning process, diesel particulate filters and gasoline particulate filters are slowly and gently heated and burned free in a furnace according to a proven temperature curve. The soot deposits inside the soot filter burn off layer by layer to form ash. The ash residues are then removed mechanically. The thermal-mechanical cleaning process is run through until the particulate filters are completely free of soot and ash and once again have the properties of a new filter.

The filter is completely burned out and freed from soot and ash without cutting, disassembling or chemically treating the filters.

Using endoscopic camera technology, we can inspect the condition of the particulate filter and catalytic converter in the closed housing. With an air flow and weight measurement, we determine the clogging/loading of the filter. After the initial analysis of the severity of the contamination, the filters are cleaned until they are approximately 98% free of the soot and ash residues and have reached the reference value of the air flow rate for the respective filter type. Depending on the degree of contamination, several cleaning passes are necessary.

Our process makes it possible to gently remove all residues – these are mainly soot and ash – by burning them out and to burn the particulate filter free. After each cleaning process, the filters are checked for the degree of cleaning achieved by means of a special air flow measurement. Only when this corresponds to our reference values is the soot filter considered to have been cleaned. After cleaning, the filter has the values of a new filter, which means that we can advise against the costly purchase of a new filter with the best conscience.

In the final inspection, the final values are recorded in our inspection protocol after successful cleaning. This test report, with the values before and after cleaning, is given to every customer. With this, we can prove and also guarantee that the soot filter, which was previously still heavily soiled, has the technical properties of a new filter again after cleaning.

We have thoroughly analyzed and tested many other processes and have come to the conclusion that we should continue to use our tried-and-tested, self-developed thermal-mechanical processes to hold on to. But we do not want to deprive you of the other options for filter cleaning, even if they have proven to be less effective.

02.DPF cleaning rinsing in cleaning machine.

Rinsing / cleaning diesel particulate filters in so-called flushing machines can provide partially and briefly satisfactory results. However, since soot is not water-soluble, the use of a chemical solution is therefore unavoidable here, even if this is often communicated otherwise. Filters coated with precious metals can suffer damage to the washcoat from the water and the cleaning agent. However, this ensures optimum exhaust gas splitting, exhaust gas cleaning and the durability of a filter. The water/cleaning solution injected under high pressure can also cause damage/cracks to the filter ceramic. It is also questionable whether the contaminated wastewater is disposed of properly.

03.DPF cleaning with compressed air.

Another possibility for cleaning soot filters is the ‘compressed air method’. In this process, potable aerosol is added to the filter system for a short time. This then reacts with the surface of the filter and removes any remaining dirt particles.

This is a very fast way of cleaning the DPF, but it does not completely remove ash from the filter.

04.DPF cleaning through the use of chemistry (also private use).

It is also possible to clean the particulate filter using chemicals. In chemical soot filter cleaning, the chemicals are injected into the filter by a steam jet and remove soot and ash deposited there.

A major disadvantage here, however, is that corrosive chemicals are often used, which destroy the structures inside the soot particle filter. Chemical DPF cleaning also only removes the soot residues deposited in the filter. The ash residues, on the other hand, remain behind.

In addition, highly toxic cleaning solutions are used here, which, if not disposed of properly, can end up in the soil as well as in the groundwater and thus cause severe damage to the environment in the long term!

05.Ultrasonic DPF cleaning.

For diesel particulate filter cleaning using the ultrasonic process, special piezo elements are mounted on the outside of the filter.

The ultrasonic process even allows the DPF to be cleaned while it is installed in the vehicle.

For this purpose, a corresponding cleaner is introduced into the DPF from the outside and the DPF is excited via a special frequency so that an ultrasound is generated.

This generally refers to a sound above a frequency of 20 kHz, which is not perceptible to the human ear and transmits very well in water, metal and ceramics.

Since the DPF is primarily made of steel and ceramics and is flooded with an aqueous cleaning fluid, the ultrasound reaches deep into the filter where it can exert its cleaning effect.

Thus, the ultrasonic waves create cavitations in the cleaning solution, eventually forming fine gas bubbles that grow and grow, eventually imploding and finally gently cleaning the filter.

Consequently, soot and ash are released from inside the soot particle filter and are subsequently flushed out with the cleaning agent via the exhaust system.

However, the filter is not removed during ultrasonic treatment. Due to the filter’s design, complete cleaning of the diesel particulate filter is only possible when it is removed, as the honeycombs are alternately sealed and must be treated from both directions to ensure that all channels are thoroughly cleaned.

06.Dry ice process for particulate filter cleaning.

Another option for diesel particulate filter cleaning is DPF cleaning using dry ice. Cleaning the soot particle filter with dry ice is also considered to be a particularly component-friendly and environmentally friendly alternative compared to the use of solvents or high-pressure water – but can only be carried out if both front sides of the filter are open.

To this end, modern snow blasting equipment is used to produce ultra-fine dry ice particles from liquid CO2 and compressed air, which are then applied to the particle filter using compact cleaning equipment and various nozzle shapes.

However, the cleaning effect of dry ice is only complete where the dry ice directly hits surfaces of the particle filter. Due to the design of the particulate filter, the full cleaning power of dry ice cannot be fully developed and therefore cannot clean the entire DPF, as it only penetrates a fraction of the areas to be cleaned.

Another advantage of using the dry ice process is that the CO² cleaning medium evaporates without leaving any residue, which makes further steps for subsequent cleaning unnecessary.

However, we have been cleaning particulate filters thermally (also called: Particle filter burn out, particle filter free burn or DPF regenerate )- and this will remain so in the future!
Feel free to contact us if you would also like us to clean your particulate filter – quickly, thoroughly and cost-effectively.