How does an exhaust diesel particulate filter (DPF) work? 

For my Ford truck the parameters that must be met and maintained consist of sufficient exhaust gas temperature (the engine has been driven long enough to produce hot enough EGTs), and maintaining a constant speed of 50 mph or greater until the regeneration has been completed. Active regens on my truck usually take about 20 mins to fully complete.

@@LargeNinCharge I'm guessing then that there's little real difference between passive and active regeneration requirements in terms of how it affects the DPF? My understanding is that active regeneration only differs in that the ECU contributes to the EGT by dosing the exhaust with fuel by injecting fuel during the exhaust stroke, either that or utilising a vaporiser/injector that is fitted directly to the exhaust in the case of some fords etc. My query I suppose is really what's the difference in time needed to complete either cycle. I was presuming that the active regeneration would be initiated and completed more quickly than the passive? After all, an active regeneration is only called for if driving conditions have not been met in order for passive regeneration to occur? Many thanks for your help.

are you deaf? listen to the video mate, you have to drive longer and at faster speeds so your engine gets hot and the exhaust gases can burn the soot that got trapped

@@dogsters Don't think you read my post properly. I already know what you've said. I was asking what the difference is between active and passive regeneration cycles in terms of operation and time required. Can you answer that question?

If you drive properly and dont do 10 min drives every day and keep the DPF clean, then there is no evidence to suggest that it has a negative effect on the engine.

It's not about the cost though, it's about not poisoning the people around you. Whoever buys diesel and gunks it up with city driving didn't do their research before the purchase.