Protecting your Diesel Particulate Filter

Most people who buy a diesel powered car have an eye on fuel economy and the low road tax bracket available to low emission vehicles. If keeping your motoring costs to a minimum is your main aim then your driving style probably reflects that; smooth driving, easy on the throttle and driving at conservative speeds. While all that is great for your fuel economy, it could spell trouble for your diesel particulate filter, or DPF.

The DPF is present to reduce sooty particle emissions to the required legal level and, as it says on the tin, it filters them out of the exhaust gases from the engine. Over time, the sooty particulates build up and must be periodically burnt off by high exhaust temperatures in a process called regeneration. Low speed driving and the kind of stop/ start driving found on many a drivers daily commute will not generate the required heat to burn off the particulates.

Most modern diesel motors feature active regeneration where the cars ECU initiates an engine program to increase the exhaust temperatures but even this can prove ineffective when only short, stop/ start trips occur. In this case the DPF may start to become clogged and the DPF warning light will turn on. The manufacturers hand book should have a procedure for you to follow to eliminate the particulates and clear the filter should the warning light show. Don’t ignore the warning light as your filter could become so clogged that it requires replacement. It’s a good idea to run your diesel car at higher revs occasionally, particularly if you do no motorway driving, as this will help keep your DPF clear and avoid a breakdown.