How Long Does DPF Regeneration Take


Many diesel truck owners, both new and experienced, want to know the answer: How long does DPF regeneration take?

DPF regeneration, depending on how much soot has accumulated in the filter, can take between 30 and 45 minutes. It will take between 5-10 minutes to complete. It can be a problem if the journey is too short or the regeneration does not complete. You may see cooling fans running during active regeneration.

This guide will help you understand why DPF regeneration takes so long and what happens during regeneration. As a result, your knowledge of diesel truck owners will be more accurate. Both active and parked regeneration takes around 45 minutes. It depends on the temperature your DPF filter must reach to remove soot.

A fuel-borne catalyst makes it easier for trucks to use less fuel and takes less time. A car without a catalyst for energy needs to reach 650 degrees Fahrenheit to complete its regeneration.

Active regeneration is a process that requires the truck to operate at highway speeds during the entire procedure.

For heavy-duty truck owners, this may seem straightforward. However, medium-duty truck owners might need to resort to the stationary or parked regen.

What is DPF Regeneration?

DPF regeneration refers to removing soot built up over time in the diesel particulate filters. You can choose to do it in passive, parked, or active modes. The type of filter installed in your truck will determine how long it takes for a DPF to reset. Many filter constructions include cordierite wall flow, silicon carbine wall-flow, partial, metal fiber flow through and ceramic fiber.

If you have a Freightliner truck, you will notice a particular icon light on your dashboard indicating that you need a regen. Most modern vehicles have either active or passive regen options. However, sometimes a parked regen may be necessary.

How Does DPF Regeneration Work?

Regeneration of the DPF Filter varies and depends on the manufacturer and how they configured the onboard filter management systems.

One-way regeneration is achieved by increasing exhaust temperature. This heat burns the soot and injects fuel into the exhaust stroke cycle. A fuel-borne catalyst converter can also reduce the temperature required to extinguish the soot and keep the truck cool during regeneration.

You can also use a fuel burner, catalytic oxygen, or resistive heating coils to increase the exhaust temperature to turn the soot into ashes. All active regenerations onboard trucks use more fuel than non-DPF trucks, usually heating the filter through the DPF’s electric system or directly.

Installing a fuel-borne catalyst is a practical and highly recommended way to reduce fuel consumption due to regeneration. As mentioned, fuel-borne catalysts reduce the temperature required to burn the soot. As such, fuel-borne catalysts are less efficient than traditional heating methods.

Let’s now discuss the chemical reactions during DPF regeneration because they will vary depending on which DPF configuration you have in your truck.

However, chemical reactions are common in passive DPF regen cycles. The after-treatment system, which includes the DPF, DOC, and SCR, contains the DPF, DOC, and SCR. When the exhaust gas enters DPF, the nitrogen dioxide becomes nitrogen monoxide and burns to make soot ash.

Is Active Regeneration a Sign That The DPF is Failing?

Only very rarely should Active Regeneration be needed. Active regen required’ may appear on your truck’s dashboard to indicate that the DPF is approaching its end. Low exhaust temperatures cause active regeneration, which isn’t high enough to allow the soot to undergo passive regeneration.

Verify the fuel-borne catalyst. If not, your DPF filter could become unusable. You can perform a diagnostic test to determine if your DPF is over-filled or not. Although many vehicle manufacturers have incorporated a warning light sequence into their vehicles, it is still advisable to consult the manual.

DPF light should be on when regeneration is needed. Each vehicle manufacturer includes a handbook that is essential to read carefully. The manual may contain a solution to different problems.

You should replace DPF if it has a 90% fill or a 45g accumulation. The ‘limp home mode will activate when the engine management and coil lights turn on together with the loss in power. The warning sign will be ‘DPF soot overloading too high.’

Regeneration Process

DPFs are subject to a process known as regeneration to increase their efficiency.

Here are three possible regeneration methods:

  • Active Regeneration Process
  • Passive Regeneration Process
  • Force Regeneration Process

When the car is off-line, active regeneration takes place. Regeneration time completes in 10 minutes, passive regeneration happens during driving, and force regeneration is the only option when too much ash accumulation in the DPF. You can either have force regeneration performed by a professional using a computer or manually.


To avoid any damage to your engine or DPF system, you should seek assistance from a local technician if there appears to be an issue with the regeneration. Make sure you use low-ash, low-sulfur engine oils when performing DPF regeneration.

Regularly check your EGR valve to avoid disruption of the regeneration cycle, keep the DEF at 1/4, and have sufficient diesel in the tank to provide enough fuel to the after-treatment system to burn the soot.


Please enter your comment!
Please enter your name here