Essentials of Diesel Engine and Diesel Particulate Filter (DPF)
If you own a diesel-powered vehicle with Euro 4 or 5 emission standards, the engine may be equipped with a Diesel Particulate Filter (DPF). However, you may not know exactly what this is or how to maintain the DPF properly.
The Diesel Particulate Filter (DPF) is equipped on most diesel engines with Euro 4, 5, and 6 emission standards. If this component is not maintained or tampered with, it can affect the vehicle’s operation and lead to unfortunate damage.
Let’s explore what DPF is, why it’s needed, and how to use and maintain a diesel particulate filter (DPF).
What is DPF ( Diesel Particulate Filter)?
The DPF (Diesel Particulate Filter) serves as a collector and storage unit for the particulate matter emitted from diesel engine exhaust (some refer to them as soot traps) in order to reduce the amount of pollutants released into the environment.
However, due to the limited size of the DPF, the accumulation of particulate matter inside the DPF will gradually lead to blockages, so it needs to be cleaned or ‘regenerated’ periodically to restore the DPF’s functionality.
The DPF regeneration process aims to cleanly burn off excess soot accumulated within the filter, reducing harmful emissions and helping to prevent the black smoke often seen from vehicles powered by diesel engines, especially during acceleration.
The Euro 5 standard, implemented in Vietnam since 2022, is the government’s effort to reduce the CO2 emissions of vehicles into the environment, hence the mandatory installation of DPFs on diesel vehicles.
How can I tell if my diesel particulate filter is clogged?
If the DPF is blocked due to soot buildup or related system faults, an orange warning light typically appears on the dashboard as shown in the image below.
The appearance of this warning light may vary slightly depending on the manufacturer – please refer to the user manual for additional information.
What causes DPF blockage?
Operating the vehicle with short distances and low speeds is the primary cause of DPF blockage. This is why car manufacturers often produce urban versions of vehicles with gasoline engines instead of diesel engines.
The most important thing is to use the correct type of engine oil and lubricants recommended by the vehicle manufacturer – using an inappropriate type of oil can accelerate this blocking process.
The third reason is that the vehicle is not properly maintained and serviced at regular intervals.
Tuning the engine power to operate it in an overloaded condition is also a cause of DPF damage.
Modifying the engine power differently from the original design can also damage the DPF.
How can I maintain the operation of the DPF?
The best way to maintain normal DPF operation is to ensure that it can self-regenerate when filled with soot (when the warning light appears).
There are two types of DPF regeneration: passive and active.
Passive regeneration:
Passive regeneration occurs when the vehicle is driven at high speeds and long distances on the highway, allowing the exhaust temperature to increase significantly. This elevated temperature helps burn off excess soot accumulated in the filter. Therefore, drivers should regularly drive at a consistent speed for 30 to 50 minutes on the highway to help clean the filter.
However, not all vehicles can operate regularly on the highway – that’s why engine manufacturers have designed an alternative form of DPF regeneration to replace it.
Active regeneration:
Active regeneration means that the vehicle’s ECU will control and inject an additional amount of fuel when the filter reaches a predetermined clogging limit (usually around 45%) to increase exhaust temperature and burn off accumulated soot.
However, issues can arise if the distance the vehicle travels is too short, as the regeneration process may not have enough time to complete. In this case, the warning light will continue to illuminate because the filter is still partially blocked.
You can complete the regeneration cycle and the warning light will turn off by driving for 10 minutes or longer at speeds exceeding 60 km/h.
You will recognize whether active regeneration is occurring in the vehicle by the following signs:
The cooling fan running at a higher speed than usual.
A slight increase in fuel consumption.
Idle speed increases.
Disabling automatic Stop/Start.
Exhaust gases are hotter and smell stronger than usual.
What should I do if both active and passive regeneration processes fail?
If the DPF warning light in the vehicle illuminates, do not attempt to continue driving for too long before taking the vehicle for inspection. Running the vehicle after the DPF warning light comes on can lead to extensive damage, resulting in costly repairs.
The inability of the DPF to regenerate is the cause of phenomena such as increased emissions, decreased engine performance, overheating, and increased fuel consumption… At this point, you need to clean the DPF with specialized chemicals – this process is called forced regeneration.
This method typically costs around 2 million VND and is highly effective in removing excess soot buildup, allowing the DPF to function and regenerate automatically thereafter.
Customers can refer to the following DPF cleaning product from BlueOne.
DPF filters and frequently asked questions:
Can I continue driving when the DPF warning light is on?
No, you cannot drive when the DPF (Diesel Particulate Filter) light is on. The DPF light indicates an issue with this system, which can lead to increased emissions and decreased engine performance. Additionally, it may cause the engine to overheat and potentially lead to other damages.
If the DPF light is on, the most important thing to do is to have the system checked and repaired as soon as possible. The cause of the issue could be as simple as a blocked filter or it could be a more serious problem, such as a faulty sensor or another non-functioning component.
How to clean the DPF?
The DPF (Diesel Particulate Filter) is a crucial component in the vehicle’s exhaust system, designed to reduce the amount of soot and other particles emitted from the engine. Over time, the DPF can become blocked by these particles, which can cause issues with the engine’s performance and even damage the filter itself. However, there are several ways to clean the DPF to maintain the performance of your vehicle.
The most common method to clean the DPF is through a process called regeneration. Regeneration is a process controlled by the engine’s ECU, during which the engine runs at high temperatures to burn off trapped particles in the filter. This process is typically performed automatically by the vehicle, but can also be done manually.
Another way to clean the DPF is through a process called forced regeneration. This process typically involves using specialized chemicals to clean the DPF.
Finally, when none of the above methods are successful, replacing the DPF is necessary. This process involves removing the old filter, cleaning the housing, and then installing a new filter. It’s the most expensive option, but necessary if the filter is damaged or too clogged to be repaired.
Why does the DPF light continue to illuminate after performing the cleaning steps?
There are several possible reasons for this, including contaminated engine oil, exhaust leaks, a faulty DPF pressure sensor, damaged or shorted sensor wiring, or simply that the DPF has reached the end of its service life and cannot be regenerated.
In any case, if the DPF light continues to illuminate, it is important that you take your vehicle to a garage for inspection to find the most accurate cause.
Can I clean the DPF filter myself?
The answer is YES, provided that you are equipped with some specialized tools and have certain knowledge about car repairs.
