The English Mechanic:
EGR is mainly used to lower in cylinder combustion temperature as this helps to reduce nox before it leaves the engine.
I probably make it sound more complicated than it is… 
OK, so EGR lowers the combustion temp. It does this by reducing the amount of free oxygen in the cylinder during combustion. So this results in less NOx because that only forms at high (2800F or 1500C) temps. But there is then some increase in particulates because of this, as there is no longer an excess of air to burn all the fuel. This presumably is why Euro6 engines have trouble being as economical as one might expect? Having lower overall emissions is at the cost of some loss of efficiency.
And again thanks for the explanation. You`re doing a good job of explaining it all.
Thanks for the replies. To cut a long story short whilst in regen ,it smokes like a trooper (comes off the back of the engine/exhaust manifold and the engine sound like a cross channel ferry). Its only one of a few issues that have been had with the lorry since new,so perhaps its just a duffer,or its not suited to the kind of work its employed on.
Suedehead:
Thanks for the replies. To cut a long story short whilst in regen ,it smokes like a trooper (comes off the back of the engine/exhaust manifold and the engine sound like a cross channel ferry. Its only one of a few issues that have been had with the lorry since new,so perhaps its just a duffer.
I get the sound but you shouldn’t get the smoke I don’t
So the smoke is from the outside of the exhaust and engine? Not from the exhaust outlet?
If thats so could it be some sort of oil or cleaner or paint or WTF burning off? If its oil or hydraulic fluid Id guess there could be a fire risk. Heres a question: what does it smell like? Not quite a stupid question (I hope) as we can all recognize the different scent of hot Gunk from the smell of rubber or plastic can`t we?
blue estate:
Franglais:
So the smoke is from the outside of the exhaust and engine? Not from the exhaust outlet?
If thats so could it be some sort of oil or cleaner or paint or WTF burning off? If its oil or hydraulic fluid Id guess there could be a fire risk. Heres a question: what does it smell like? Not quite a stupid question (I hope) as we can all recognize the different scent of hot Gunk from the smell of rubber or plastic can`t we?
Well some can’t 
Well us Old Skool silly ■■■■■ can!
Will have a look tomorrow .
Weigh Anchors.
Suedehead:
Will have a look tomorrow .
Weigh Anchors.
Maybe check out AndrewG’s thread about cooking too?
Have you left a joint of meat in the oven too long? [emoji2]
The English Mechanic:
Suedehead:
When
Any other question feel free to ask… 
Has the move to euro 5/6 seen the end of the traditional style Eminox exhaust stacks?, all new “show trucks” seem to be fitted with side pipes or straight through verticle pipes. And if so why?, surely all these huge euro6 exhausts that take up all the chassis space of quite a large diesel tank are quite impractical. Could this all not be in a vertical exhaust up the back of the cab freeing up the chassis space for other things?.
Franglais:
Suedehead:
Will have a look tomorrow .
Weigh Anchors.
Maybe check out AndrewG’s thread about cooking too? ssibg
Have you left a joint of meat in the oven too long? [emoji2]
So what am I missing here ?
Was only after a bit of info you frecin gob.
DAF just released this video.
Much the same as the others I posted but still good information.
youtu.be/2nnc3UHpyYs