Diesel Particulate Filters

What does a diesel particulate filter do?

A diesel particulate filter catches soot particles from the exhaust and this reduces carbon emissions (CO2) from entering the atmosphere.

How is the soot removed from the diesel particulate filter?

The process for removing the soot is called a “regeneration” this is automatically carried out by your cars engine management system. Once your vehicle’s diesel particulate filter reaches a temperature of approximately 550 degrees centigrade the process starts.

This intense heat turns the soot mass to ash and this then escapes through the small outlet hole in the filter and harmlessly exits the tail pipe.
Reaching the optimum temperature is the key to ensuring that your car “regenerates”. Optimum conditions for regeneration are achieved by travelling at 60 km/h (37.2 Mph) with engine revs above 2000 rpm for around 10-15 minutes.

How do you know that your diesel particulate filter is blocked ?

Your vehicle performance will become reduced and the diesel particulate warning light will come on the console.
The vehicle may enter Limp Mode to protect itself.

What can cause my diesel particulate filter to block?

There are several reasons that can cause DPF failure.
Driver lack of awareness

Driving short distances and city driving It is likely that your diesel particulate filter will not reach the temperature required to regenerate.

Exhaust Gas Recirculation Valve (EGR) sticking. Your EGR valve controls the Recirculation of exhaust gas back into the combustion process this helps your engine to run cooler and helps to reduce fuel consumption. If this valve sticks open or closed it will effect the mixture of air and fuel and will cause your car to run either rich or lean. A rich mixture will clog your DPF significantly faster than an engine that is working effectively.
Poor quality fuel and/or poorly working fuel injectors. Both of these will cause your vehicle to under perform and the deterioration in performance will dramatically increase the level of contamination and soot.

What should I do if I know it is blocked?

Your main dealer can normally do a forced regeneration with their specialised diagnostic equipment but this will depend on the level of soot mass that has accumulated in the diesel particulate filter.

A symbol will probably have appeared in your warning console by this time. You should take your car for inspection immediately!
Your options are replacement or cleaning.

A new diesel particulate filter is available from parts please ask service reception for prices.

The cleaning method uses an insertion tool that sprays a special chemical into the diesel particulate filter housing, the process has a high mechanical and chemical cleaning effect allowing clogged soot to regenerate and exit the exhaust to ash.
Prevention is better than cure! Recommendations for proper care of the DPF are:

Optimum conditions for regeneration are achieved by travelling at 60 km/h (37.2 Mph) with engine revs above 2000 rpm for around 10-15 minutes.
Ensure you use diesel fuel that conforms to EN590

Ensure you have your vehicle serviced in line with the manufactures recommendations for mileage, time and specification of lubricants.

Ensure that you have your EGR valve checked at each service interval.

Use an approved diesel fuel additive Tunap 183/983 this will ensure your vehicle’s fuel system is protected and will ensure a clean combustion dramatically reducing soot levels.

Take advantage of the low cost DPF service available at this Specialist .