DPF stands for Diesel Particulate Filter. It’s a component found in modern diesel engines that is designed to reduce emissions of particulate matter (PM) or soot. PM is a major contributor to air pollution and can have harmful effects on human health and the environment. A DPF is a standard piece of emissions control utilised on most vehicles since the early 2000s.

What is a DPF?

The DPF works by trapping particulate matter in the exhaust gas and oxidizing it at high temperatures. This oxidation process converts the PM into less harmful gases, such as carbon dioxide and water vapor. The DPF must be cleaned periodically to remove the accumulated particulate matter, which is commonly known as a “regeneration” process.

Most diesel engines are equipped with a DPF as part of the emissions control system, and they play an important role in reducing PM emissions and helping to improve air quality. However, like other components in the emissions control system, the DPF can also impact engine performance if it’s not functioning correctly or if it’s clogged with particulate matter.

Why is a DPF necessary?

Overall, the DPF is an important part of a diesel engine’s emissions control system and is critical for helping diesel engines meet increasingly strict emissions standards. This is important to improve air quality and lessen the effect of particulate matter on the environment, animals and humans. The primary purpose of the DPF is to reduce particulate matter emissions, which are a major contributor to air pollution and has been linked to various health problems.

How does DPF filter soot?

The DPF filters the soot particles by forcing the exhaust gases through a ceramic or metal wall-flow filter. The soot particles are trapped in the filter’s pores, while the clean exhaust gases are expelled into the atmosphere. Over time, the soot particles will accumulate in the filter, and the filter will need to be cleaned. This is typically how DPF Regeneration occurs.

The regeneration process occurs automatically, either by heating up the soot in the DPF through normal driving conditions or by injecting fuel additives into the exhaust stream.

How does DPF Regeneration work?

During an Active Regeneration process, the diesel particulate filter is cleaned by burning off the trapped soot. The engine management system increases the temperature of the exhaust gas to cause the trapped soot to ignite and burn off. This process can take several minutes to complete and requires a steady supply of fuel to keep the filter hot enough for the soot to burn off. Exhuast temperatures of up to 800C can occur throughout this process.

Passive Regeneration occurs during normal driving conditions when the engine is running at a high temperature for an extended period. This can happen when you’re driving on the highway, for example. The high exhaust temperatures will cause the soot to ignite and burn off, but it may take longer, and is a Catalytic Reaction of the gases mixed with the precious metals of the Diesel Oxidation Catalyst, which can be a part of the DPF assembly or a totally seperate unit. Diesel Oxidation Catalysts are often implemented upstream of the DPF but have become increasingly popular by implementing a unit after the DPF as a third stage of treatment. They can also be used in conjunction with Selective Catalytic Reduction (SCR), commonly referred to as AdBlue. Read more about AdBlue here.

DPFs play a vital role in reducing emissions from Diesel engines, but they also require regular maintenance to ensure they continue to work effectively. Failing to maintain a DPF can result in reduced engine performance, increased fuel consumption, and increased emissions. If a DPF becomes clogged or damaged, it will need to be replaced or cleaned.

Warning signs of a DPF blockage

There are several signs that can indicate a blocked diesel particulate filter (DPF):

Warning light on the dashboard: If your vehicle is equipped with a DPF, it may have a warning light on the dashboard to indicate when the filter is becoming blocked.
Decreased engine power: A blocked DPF can restrict the flow of exhaust gases, which can result in decreased engine power.
Increased fuel consumption: If your engine is working harder due to decreased power, it may consume more fuel.
Regeneration problems: A DPF typically cleans itself through a process called regeneration, where high temperatures burn off accumulated particulates. If this process is not functioning properly, it may indicate a blockage in the filter.
Strange noises: You may hear strange rattling or hissing noises coming from the exhaust system, which could indicate a blockage in the DPF.
Oil leaks,: Excessivly blocked DPFs can cause an increase in crankcase pressure and oil leaks from low-pressure seals. This is usually in extreme cases, however, should not be undermined.

If you suspect that your DPF is blocked. In that case, it’s important to have it inspected by the team at Diesel Tuning Brisbane to avoid further damage to your engine and to ensure that your vehicle meets emissions standards. We have all the necessary equipment required to diagnose, clean and replace the DPF filter often for a fraction of dealership prices.

How to maintain your DPF

It’s important to use the correct type of engine oil with the correct additive package. Using the wrong oil can cause problems with the DPF and other parts of the engine. In addition, regular maintenance and cleaning of the DPF is important to ensure it continues to function correctly. A DPF is a filter just like any other and should be cleaned, maintained and replaced accordingly. Regular services, during which the DPF can be cleaned and checked, will help to prevent blockages and ensure optimal performance of the filter. If you are unsure about the proper maintenance procedures for your DPF, just ask the experts at Diesel Tuning Brisbane about our DPF cleaning service, which can often be done on the car, for small cost, and completed as a same-day service with your normal logbook service schedule.