Volvo Owners Club Forum - View Single Post - Service Issues: - XC90 D5 engine DPF (Diesel Particulate Filter)

volvic40 · May 10th, 2015, 21:53

Hello Shimon, I must say your explanations of dpf technology are the best I have seen to date
I have spoken to all sorts of dealerships and mechanics, and never get the impression anyone really knows what is happening.

I wonder if you or anyone else, could clarify something for me please? I understand that to perform a routine regeneration, the exhaust has to get hot and this prompts the car to add fuel to the exhaust to assist combustion of the particulates. This is typically described as a 10-15 minute "blast" in a lowish gear to get the revs above 2000 or so. What i want to ask is, what prompts the system to abort the process, and dump diesel into the sump or whatever? Is it the temperature dropping or pressure or revs?

What I am getting at is if you drive along an A road for 20 minutes at 50mph in 4th gear so the revs are around 3000, will that all be negated by negotiating a few roundabouts where you drop down to low speed, stop to give way, and then take off again?

Obviously the temperature will stay pretty constant for those 10 second interludes, but the revs/speed/ will drop.

So would that type of trip be enough to regen the dpf on a regular basis? I do a fair bit of inter-urban driving on A roads but only occasionally go on a motorway trip (every month or so). i am currently weighing up whether to go for petrol or diesel model. The petrol variants are rather rare in the used market but there are loads of diesels around I have received some excellent advice from members and I am just finalising my thoughts

Any advice would be most appreciated.

May 10th, 2015, 21:53	#81
volvic40 New Member Last Online: Jul 28th, 2015 22:27 Join Date: May 2015 Location: Nottingham	Hello Shimon, I must say your explanations of dpf technology are the best I have seen to date I have spoken to all sorts of dealerships and mechanics, and never get the impression anyone really knows what is happening. I wonder if you or anyone else, could clarify something for me please? I understand that to perform a routine regeneration, the exhaust has to get hot and this prompts the car to add fuel to the exhaust to assist combustion of the particulates. This is typically described as a 10-15 minute "blast" in a lowish gear to get the revs above 2000 or so. What i want to ask is, what prompts the system to abort the process, and dump diesel into the sump or whatever? Is it the temperature dropping or pressure or revs? What I am getting at is if you drive along an A road for 20 minutes at 50mph in 4th gear so the revs are around 3000, will that all be negated by negotiating a few roundabouts where you drop down to low speed, stop to give way, and then take off again? Obviously the temperature will stay pretty constant for those 10 second interludes, but the revs/speed/ will drop. So would that type of trip be enough to regen the dpf on a regular basis? I do a fair bit of inter-urban driving on A roads but only occasionally go on a motorway trip (every month or so). i am currently weighing up whether to go for petrol or diesel model. The petrol variants are rather rare in the used market but there are loads of diesels around I have received some excellent advice from members and I am just finalising my thoughts Any advice would be most appreciated.