Regeneration of particulate filters. What is it about?

Currently, all new cars leaving the factory equipped with a diesel engine are equipped with particulate filters that need regeneration. How does the regeneration of particulate filters take place?

PARTICLE FILTER. WHAT IS THAT?

The particle filter, in many cases called DFP or FAP, is designed to purify exhaust gases coming from the soot engine. Unfortunately, the particulate filter fills up relatively quickly, and thus its regeneration is necessary. Most mounted filters in vehicles are subject to filter regeneration without the need to dismantle it. Unfortunately, in some cases, particulate filters are disposable, and after they are filled in, an exchange that is not the cheapest is necessary.

PASSIVE REGENERATION

Passive regeneration of the diesel particulate filter is the simplest possible because it takes place without the engine controller responsible for the functioning of the filter. It happens when the exhaust gas reaches a temperature in the range of 350 to 500 degrees Celsius. In this temperature range, the carbon black reacts chemically with the filter material. Nitrogen dioxide, which is found in the exhaust, reacts with the carbon of soot particles, resulting in the formation of carbon monoxide and nitrous oxide, which combine with oxygen to form carbon dioxide and nitrogen dioxide, which escapes the rest of the exhaust system into the atmosphere. The result of a chemical reaction is the cleaning of the particulate filter making it a ready-to-use element.

ACTIVE REGENERATION

Active regeneration is above all the higher temperature needed to “burn” the filter. The temperature that is required is 600 degrees Celsius and is achieved due to interference of the engine responsible for controlling the operation of the diesel particulate filter. Thanks to the sensor placed in the diesel particulate filter, information is sent to the controller if more than 50% of the filter is detected. When it is received, the controller increases the temperature of the exhaust gases. This is done by switching off the exhaust gas recirculation, which results in an increase in the amount of oxygen. Some controllers delay the injection angle and even perform an additional injection. All of these treatments affect the increase of the combustion temperature and start the regeneration process of the particle filter. The duration is about 5-10 minutes, and the frequency is around 200-600 kilometers and depends on the style and driving mode. If we are mostly going to travel on short urban distances, this process will be more frequent. In most cases, we are not informed about the filter regeneration process that has begun, so we can terminate it. In case of ignition of the control responsible for the diesel particulate filter, we must prepare the car properly to start the filter firing process – preferably the motorway and maintain the appropriate speed and engine speed. Unfortunately, in some cases, attempting to burn the filter yourself does not help. In this case, we are forced to go to a service / mechanic who, by connecting a special software, will attempt to burn the filter. If this procedure does not help, we are forced to replace the particulate filter.

WET PARTICLE FILTER

Wet diesel particulate filters are also installed in cars. For the regeneration process, a liquid is used, which is regularly added to the fuel. Due to its presence, the combustion temperature of the soot is reduced, which leads to regeneration. Depending on the vehicle model, the fluid used for regeneration should be supplemented from 60,000 to 200,000 kilometers. In the case of a wet particulate filter, it is a good habit to refuel completely because a single opening of the infusion causes the “injection” of the liquid into the fuel.