Active vs. Passive Regeneration in Diesel Exhaust Aftertreatment Systems

Apr 17th 2023

Active vs. Passive Regeneration in Diesel Exhaust Aftertreatment Systems

With respect to diesel engine exhaust aftertreatment systems, one of the most important elements is the regeneration that takes place with the system. Regeneration is the process of removing soot and other pollutants from the diesel particulate filter, or DPF. The two main methods for regeneration are active and passive regeneration.

What is Active Regeneration?

Active regeneration is a process that is used to clean a diesel engine’s exhaust aftertreatment system. It’s a type of regeneration that uses a combination of fuel injection and air injection to burn off soot and other pollutants that have built up in the exhaust system. This process helps reduce the amount of pollutants that are released from the engine, allowing it to meet emissions regulations.

How Does Active Regeneration Work?

Active regeneration works by using a combination of fuel injection and air injection. The fuel injection system injects fuel into the exhaust stream, which helps to raise the temperature of the exhaust system. This causes the soot and other pollutants to burn off, reducing the amount of pollutants that are released from the engine.

At the same time, the air injection system injects air into the exhaust stream. This helps to ensure more complete combustion of the fuel, which helps to further reduce the concentration of pollutants that are released from the engine.

Why is Active Regeneration Important?

Active regeneration is an important part of a diesel engine’s exhaust aftertreatment system. Without it, the engine would not be able to meet emissions regulations, as the amount of pollutants that are released from the engine would be too high. By using active regeneration, the engine is able to reduce the amount of pollutants that are released, helping it to meet emissions regulations.

What is Passive Regeneration?

Passive regeneration is another technology used in exhaust aftertreatment systems to reduce harmful emissions from diesel engines. It works by using a catalytic converter to convert nitrogen oxides (NOx) and particulate matter (PM) in the exhaust into harmless nitrogen and water vapor. The catalytic converter is heated by the exhaust gases, which causes a chemical reaction that breaks down the pollutants.

The process of passive regeneration is relatively simple and requires no additional energy input. This makes it an efficient and cost-effective method of reducing emissions from diesel engines.

Benefits of Passive Regeneration

The main benefit of passive regeneration is that it is an effective way of reducing emissions from diesel engines. This helps to reduce the environmental impact of diesel engines and meet the strict regulations that are in place for vehicle emissions.

Additionally, passive regeneration does not require any additional energy input, which means that it does not have a significant impact on the engine’s performance or fuel efficiency. This makes passive regeneration a cost-effective way of reducing diesel emissions.

Potential Challenges of Passive Regeneration

Although passive regeneration is an effective way of reducing emissions from diesel engines, there are some potential challenges that can arise from its use.

One of the main challenges is that the catalytic converter can become blocked with soot, which can reduce its effectiveness. This can be caused by incomplete combustion in the engine, which can occur if the engine is not running efficiently. Additionally, the catalytic converter can become clogged with fuel deposits, which can also reduce its effectiveness.

To prevent these issues, it is important to ensure that the engine is running efficiently and that the fuel system is free from deposits. Additionally, regular maintenance (see below) of the exhaust aftertreatment system is important to ensure that it is functioning correctly.

                      DPF filter replacement

Do DPF Filters Need to Be Maintained?

While both passive and active regeneration help to reduce emissions, but the DPF system, specifically the DPF filter, will need to be serviced from time to time. Maintaining diesel particulate filters (DPF) is an important part of keeping your engine running at peak efficiency. Without regular maintenance, the filter can become clogged with soot, reducing engine performance and even leading to costly repairs.

DPF filters are designed to capture soot particles generated during combustion, preventing them from being released into the environment. Over time, however, the filter can become clogged, reducing the engine's efficiency and potentially leading to costly repairs. To avoid this, regular maintenance of the DPF filter is essential.

The first step in maintaining a DPF filter is to have it inspected regularly. This can be done by a qualified mechanic or technician. During the inspection, the mechanic will check for signs of soot buildup, cracks, and other damage. If any of these issues are found, the filter should be replaced immediately with a DPF filter replacement.

In addition to regular inspections, it's important to keep the DPF clean. The best way to do this is to use a DPF cleaner, which is a special cleaner designed to remove soot and other particles from the filter. This can be done at home or by a professional.

Finally, it's important to make sure the filter is properly sized for the engine. If it's too small, it won't be able to capture enough soot, leading to reduced performance and increased emissions. On the other hand, if it's too large, it can lead to reduced fuel efficiency and increased engine wear.

Need a DPF Filter Replacement?

At Filter Service and Supply, we carry a wide range of high-quality diesel oxidation catalysts and DPF filter replacements. We carry replacement DPF filters from Skyline Emissions, Dinex, Cummins, Caterpillar, and others. We also offer DPF filter cleaning services.

For more information on any of our products, if you have any questions about how a DPF works, or just want to make sure you’re getting the right replacement, don’t hesitate to reach out to us at 760-455-0263.