WHAT IS A DPF?

A DPF is a soot, or particulate matter filter for diesel engines. They are used to reduce the exhaust emissions as required by many governmental emission legislative bodies. DPFs are becoming more and more common on diesel engines.

HOW DO THEY WORK?

Diesel Particulate filters (DPF) or ‘traps’ do just that, they catch bits of soot in the exhaust.

As with any filter (think of the bag in your vacuum cleaner) they have to be emptied regularly to maintain performance. For a DPF this process is called ‘regeneration’ – the accumulated soot is burnt off at high temperature to leave only a tiny ash residue. Regeneration may be either passive or active.

PASSIVE REGENERATION

Passive regeneration takes place automatically on motorway-type runs when the exhaust temperature is high. Many cars don’t get this sort of use though so manufacturers have to design-in ‘active’ regeneration where the engine management computer (ECU) takes control of the process.

ACTIVE REGENERATION

When the soot loading in the filter reaches a set limit (about 45%) the ECU can make small adjustments to the fuel injection timing to increase the exhaust temperature and initiate regeneration. If the journey’s a bit stop/start the regeneration may not complete and the warning light will illuminate to show that the DPF is partially blocked.

If you ignore the light and keep driving in a relatively slow, stop/start pattern soot loading will continue to build up until around 75% when you can expect to see other dashboard warning lights illuminate too. At this point driving at speed alone will not be sufficient and the car will have to go to a dealer for regeneration.

HOW IS THE DPF CLEANED AND WHAT IS DPF “REGENERATION”?

A DPF filter can hold a certain amount of soot, but not a huge quantity, so it needs to regularly go through a process of cleaning itself or “regeneration” in order to clear out the soot and allow the vehicle to operate properly. Regeneration occurs ONLY when the filter reaches a sufficiently high temperature allowing the soot to be converted to a much smaller and less harmful by-product, ash.

To allow the filter to automatically regenerate, the engine has to be used regularly at a sufficient engine speed, to ensure a high enough temperature of the exhaust gas. The engine must be under sufficient load to ensure that the exhaust gas temperature is naturally raised. Although it may vary from manufacturer to manufacturer, typically a vehicle must be driven at 80km/h or above for at least 20 minutes in order to automatically regenerate the filter. During the regeneration phase, high temperatures in the filter may cause a slight smell, especially during the first regeneration. Many people would have smelt and complained to the manufacturer about this.

WHAT HAPPENS IF IT DOESN’T REGENERATE?

If the vehicle is not driven in a way that automatically regenerates the particulate filter, it will build up an excessive amount of soot, which, if not resolved, will reduce the performance of the vehicle and damage the filter.

If the filter does build up too much soot, a vehicle warning light will appear to alert you. The problem can usually be solved by allowing the filter to automatically regenerate until the warning light goes out – i.e. by driving the vehicle at 80km/h or above for at least 20 minutes. Check the vehicle handbook for specific guidance on a particular vehicle.

If traffic conditions and speed limits do not allow the vehicle do be driven so that the filter regenerates, it will have to be returned to a dealer for a forced regeneration in order to clear the filter.

If the warning light is ignored and the vehicle is driven without regenerating the filter, it will cause damage to the vehicle, which may not be covered by the vehicle manufacturer’s warranty.

How the vehicle manufacturers get away with not offering warranty on their failures is most concerning to the writer! Seems like the only cover some owners are going to see from their manufacturers is when they cover their own ass!

In some active DPFs active cleaner is made by injecting diesel through an extra injector placed prior to the DPF. These active type DPFs run into their own issues. Problem has been identified whereby stop / start deliveries, for example, will never allow the system to complete the regeneration cycle. When the truck is started again the active DPF system re-institutes an active regeneration and if this happens again and again the catalytic convertor and or the DPF can pool the unburnt diesel within and can actually at times be seen coming out of the exhaust. Warning lights by this stage will come on and a very expensive DPF repair is on the cards. Not a cheap exercise.

100% MOT Safe. Comes with a certificate of cleanliness, engraving to the exhaust and your registration is registered with us for full "tracking" and remember, because your DPF is nearly 100% clean, it's less likely to fail the new MOT emissions tests than those cleaned by our competition ... we know all about the new MOT emissions tests because we're an authorised MOT Station.

Don't confuse what we do with "methods" that you've tried before, our system works. We remove the DPF from its casing for cleaning, we then clean the DPF in an ultrasonic bath until it's clean, then we weld the DPF back into it's case, test it for flow and return it to you.

Over 35% of DPF's that come to us have apparently been cleaned elsewhere.

Ultrasonic DPF Cleaning is the "only system that works across the board", cars, vans, commercial vehicles such as lorries, tractors and plant. If you're having issues with your DPF, call us today, we have the solution.

We offer a 12 month warranty on all "Full Cleans" done at our workshop. 100% MOT Safe.

Removal is not a legal option

It is suggested from time to time that the answer to failed DPF regeneration is get the DPF removed from the exhaust system rather than pay to get it repaired/renewed. Indeed there are companies advertising just such a service including reprogramming of the engine management software, but is it legal?

DPFs are fitted to meet European emissions regulations designed to reduce vehicle emissions of particulate matter (soot) associated with respiratory disease and cancer.

According to the Department for Transport, it is an offence under theRoad vehicles (Construction and Use) Regulations (Regulation 61a(3)) to use a vehicle which has been modified in such a way that it no longer complies with the air pollutant emissions standards it was designed to meet. Removal of a DPF will almost invariably contravene these requirements, making the vehicle illegal for road use.

Insurance

You must notify your insurer if the vehicle is modified but such a modification could in turn invalidate any insurance cover because it makes the vehicle illegal for road use.

MOT

From February 2014 the inspection of the exhaust system carried out during the MOT test will include a check for the presence of a DPF. A missing DPF, where one was fitted when the vehicle was built, will result in an MOT failure.

With an original equipment DPF removed from the exhaust the car may or may not pass an MOT smoke test - a Euro V (September 2009 diesel) is more likely to fail than one designed to comply with earlier emissions standards.

Source: www.aa.com

What is a DPF?

The Diesel Particulate Filter (DPF) is housed in the exhaust and is designed to capture the soot particles emitted from modern diesel engines.

Sadly, many of the DPF equipped cars are developing problems due to the DPF either failing, clogging up or just failing to carry out a regeneration properly.

This can be down to the age of the vehicle, mileage or could be simply down to the driving style of the owner. Whatever it is, when a DPF warning light illuminates it often means a pretty expensive bill is on its way.

If this does happen, there are some upsides. A DPF clean can increase your vehicles fuel economy, performance and decrease the likely hood of a breakdown or your car ending up in "limp mode" and save you a pretty large sum of of money if the time has come to replace your Diesel Particulate Filter which can be considered normal for some car manufacturers at 60 to 75 thousand miles and costing upwards of a £1000 and over to replace.

Is my DPF covered under warranty?

The DPF is seen as a consumable by many manufacturers and warranty providers. The cost of replacing or regenerating the filter is normally not covered but we would suggest seeking advice if you are experiencing DPF related issues.

Frequently Asked Questions

What is Ultrasonic DPF Cleaning?

Ultrasonic cleaners employ oscillating sound pressure waves at frequencies beyond those perceptible by the human ear (Ultrasound). As the soundwaves act on the tank and agitate the contained liquid, cavitation (the implosion of tiny air bubbles within the liquid) is induced.

This acts against contaminants adhered to objects contained in the vessel, separating the two much more gently, efficiently and precisely than would be the case with conventional cleaning methods aided by brushes or solvents.

The ultrasonic cleaning process is used in conjunction with solutions in suitable carrier liquids (often water). As the ultrasonic-induced cavitation occurs, the effectiveness of the aqueous solution is greatly improved to deliver an outstanding clean.

Ultrasonic cleaning is the ideal solution for DPF cleaning, especially forFleet Car DPF Cleaningit leaves no contamination or build-up on the DPF filter meaning essentially, the DPF after cleaning is "as new".

What Is A dpf? |Dpf Cleaning | Ultrasonic DPF Cleaning