Exhaust gas recirculation should be burnt!

[mollins]

This is one area where you "mechanical" types wish you had a computer, as the 1.9 TDI guys in the USA just VAG COM the exhaust gas recirculation down to practically zero.

a blanking plate works also

Recirculation of exhaust gas keeps combustion temps down, and also lowers the emission of Nitrogen if I recall correctly.

could you explain how it keeps temps down. intuitively i would think it would be putting hot air into the chamber making temps higher?? Nitrogen reduction is understandable of course.

Read and be warned MK V'ers, it's a matter of time with the amount of oil blowby into the inlet, hence my PROVENT : )

hear hear. the carbon itself isnt a problem as it will flake off as it does in exhausts, but its the oil that catches the soot and makes the sludge coating

oil catchers all the way

[gldgti]

That is a really cool word..

My gumption is considering where to put my new vege garden.. And not wanting to play with my 300 000km old pug too much in case it falls into a million pieces..

i cant argue with that. good work mate

[gldgti]

Love the "lets use fire" concept of mechanical repair.

This is one area where you "mechanical" types wish you had a computer, as the 1.9 TDI guys in the USA just VAG COM the exhaust gas recirculation down to practically zero.

Recirculation of exhaust gas keeps combustion temps down, and also lowers the emission of Nitrogen if I recall correctly. You turbo tweakers would want to thank this system for keeping your turbo cooler, and possibly operational, albeit at the expense of some HP.

Read and be warned MK V'ers, it's a matter of time with the amount of oil blowby into the inlet, hence my PROVENT : )

please explain to me how EGR keeps combustion temps down.

thanks

[Mischa]

please explain to me how EGR keeps combustion temps down.

thanks

i would also like to know

[Greg Roles]

Guys, I'm just rehashing what VW say in the 125kw engine training manual I downloaded from Erwin. Here's the guff:

Task of EGR:

The objective is to reduce nitrogen oxide emissions. This happens because:

1. Less Oxygen is available for combustion due to the recirculated exhaust gas,
2. The combustion speed and therefore increase in temperature are reduced by the exhaust gas that is introduced.

Remember that, in the later diesels at least, the exhaust goes via a cooler first.

But yeah, I too struggle with the idea of going to the trouble of intercooling the charge air, only to add hot exhaust gas post intercooler!

[gldgti]

i think its a load of baloney TBH. you put in some exhaust gas to replace the nice oxygen rich charge air that you go to all the work of comrpessing and cooling - so you reduce the efficiency of the cycle as a whole, but your instantaneous nitrous emissions are decreased a bit - whoopy doo.

i cant get over the amount of nonsense that goes on with emission control.

just make the engine as high performing and efficient as possible, then REDUCE the capacity as much as you can!

[bluey]

Love the "lets use fire" concept of mechanical repair.

This is one area where you "mechanical" types wish you had a computer, as the 1.9 TDI guys in the USA just VAG COM the exhaust gas recirculation down to practically zero.[...]

This FAQ mentioned using VAG COM to up the air supply to prevent this problem, because EGR is otherwise important for NOX and temperature control.
http://tdiclub.com/TDIFAQ/

But how do we know VW hasn't already fixed it???

[gldgti]

hmmm. i now have DATA about EGT's.

a post in my power quest thread soon boys and girls