Diesel particulates

[Egbutt Wash]

A serious question.

With particulates in mind, is it right to drive a diesel VW or any diesels?

[The Doc]

Great topical posts but all MK6 golfs have DPF's, a diesel particulate filter that as the name suggests filters out most of the nasty particulates and also reduces the size of them.

[mac7]

Great topical posts but all MK6 gold have DPF's, a diesel particulate filter that as the name suggests filters out the nasty particulates that cause all of the problems mentioned.

DPF catches some of the particulate, but not all of it. When you consider the increase in the number of diesel cars on the roads, I reckon you're back to square one.

[Agreeable Slick]

You do realise just how much particulate they filter don't you.

Current emissions law mean less than 0.02g/kWh is allowed to pass in order for the car to be released.

[mac7]

You do realise just how much particulate they filter don't you.

Current emissions law mean less than 0.02g/kWh is allowed to pass in order for the car to be released.

Yeah, 0.02 sounds like a really small amount, until you look at the Euro 3 figures - it was 0.10g/kwh before DPF's were introduced, so it's 1/5th what it used to be. Ten years ago there was one diesel car in my road, now there's at least seven...

You might be able to answer another question for me though. When the DPF regenerates, by burning off the 'soot' from the filter, what exactly are the products of that (combustion?) process and where do they go?

[The Doc]

They are stored then burned in the dpf which reduces them by over 90% then ejected through the exhaust.

[Agreeable Slick]

Usual products of combustion, DPF is typically before the other parts of the cat, so like doc says; regen takes place and burns off the PM, thus it produces carbon monoxide, CO2 and HC

Depending on if the exhaust has a SCR system or chemical reduction, then the emissions are only CO2 and water.

These are then caught/cleaned up by the latter stages of the cat.

[Keithuk]

Diesel particulate filter (DPF) 

[R32.]

I love modern diesels 

[mac7]

Diesel particulate filter (DPF) 

Good link - thanks Keith. So the DPF fills up over 120,000 miles or so until a second/third/fifth owner pays a back-street mechanic to tip it all out into the atmosphere anyway...