What is the particulate filter and what is it for?
The particulate filter is a device located in the exhaust system of diesel cars (and some direct injection gasoline engines). Its mission is to capture solid particles (PM) produced during combustion, which would otherwise be released into the environment.Thanks to the particulate filter:- Up to 90% of particulate emissions are reduced.
- Vehicles comply with environmental regulations.
- Visible black smoke from the exhaust is eliminated.
How does the particulate filter work?
The process is simple but effective:- Exhaust gases filled with soot pass through the filter.
- Particles get trapped in the porous ceramic or silicon carbide structure.
- When the filter becomes full, regeneration begins: a controlled combustion process that eliminates accumulated soot.
- Passive: occurs during long drives at high RPMs, when the engine reaches optimal temperature.
- Active: the ECU injects additional fuel to increase exhaust temperature and burn deposits.
- Forced: performed at a workshop using diagnostics or after disassembly, when the filter is too saturated to clean itself automatically.
Types of particulate filters
FAP (Particulate filter with additive)
Common in PSA Group vehicles (Peugeot, Citroën). They require a cerium-based additive that mixes with diesel fuel to make particle combustion easier.DPF (Diesel Particulate Filter)
More widely used in most brands. They don’t use additives and rely solely on temperature for regeneration.Symptoms of a failing particulate filter
A faulty particulate filter can show different symptoms:- Power loss: the engine goes into “limp mode” to protect itself.
- Increased fuel consumption: the ECU injects more fuel in an attempt to regenerate the filter.
- Warning light on the dashboard: usually a yellow icon shaped like an exhaust.
- Frequent regenerations: if they happen every few miles, it is a sign of saturation.
- Excessive exhaust smoke: the filter cannot filter particles properly.
Oxyhtech products for professional filter cleaning
At Oxyhtech, we have developed our own patented solutions for DPF/FAP cleaning. They are the real alternative to filter replacement and stand out from conventional methods.DPF Cleaner Plus
Our flagship product for deep cleaning of saturated filters. Designed for use with Oxyhtech cleaning machines, it allows:- Dissolving soot and hardened ash.
- Restoring the filter’s original capacity.
- Reducing back pressure and restoring gas flow.
- Guaranteeing consistent results in record time.
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DPF Cleaner
A specific product for preventive maintenance and regular cleaning. Its function is to prevent carbon buildup from reaching critical levels, making regeneration easier and extending filter life.Ideal for workshops that want to offer a periodic, profitable service to fleets and private customers, avoiding costly breakdowns and replacements.Request your quote
Tips to preserve the particulate filter
- Drive on highways at medium/high RPMs: at least once a week to promote passive regeneration.
- Avoid short, frequent trips: they are the main cause of clogging.
- Always refuel with quality diesel: it reduces the amount of generated residues.
- Keep oil and filters in good condition: improper oil generates more ash that ends up in the DPF.
- Perform regular decarbonizations at the workshop: they help keep the entire intake and exhaust system clean.
When is it necessary to replace your car’s filter?
Although a well-maintained filter can last between 90,000 and 125,000 miles, there are situations where replacement is unavoidable:- Complete saturation without the possibility of regeneration.
- Physical damage to the ceramic structure.
- Use of poor-quality fuels or additives that deteriorate the material.
How much does it cost to replace a particulate filter?
The cost depends on the make and model of the vehicle:- Small cars: $800–$1,200.
- Medium vehicles: $1,200–$1,800.
- SUVs or vans: $2,000 or more.
