Leaking EGR Valve

Iceweasel

arcon5 wrote: »

I'm not sure you understand how EGR works.

Exhaust gasses pass from the exhaust manifold or block at the manifold to a valve, when open allowing exhaust gasses back to the inlet.

Air doesn't pass from the turbo to intercooler to EGR valve at all.

Does it not?

It does on the several EGR equipped cars I've owned.

Air intake - air-filter - turbo - intercooler - EGR - inlet manifold - combustion chamber.

Under certain conditions the EGR valve will open to allow spent exhaust gases to mix with the air coming from the intercooler passing through the EGR and then onwards to the manifold and combustion chamber.

I fail to see how it can work any differently, so you've got me puzzled now - what engine engine does as you describe?

arcon5

Egr passes gasses to the inlet, all inlet air does not pass through an egr valve. Massive difference.
Based on your logic all air alsopasses through crankcase breather hoses since that also links back to the inlet

Iceweasel

arcon5 wrote: »

Egr passes gasses to the inlet, all inlet air does not pass through an egr valve. Massive difference.
Based on your logic all air alsopasses through crankcase breather hoses since that also links back to the inlet

We may be talking at cross purposes.

All the air that reaches my combustion chambers does pass through the EGR valve unit body - there is no other way for air to get to the manifold.

My EGR looks like this:



The exhaust gases enter the body of the EGR unit when the vacuum operates the inlet valve part.

forgotmyname

Air passes through the large port, and the valve in the centre lower part of the above picture allows the exhaust gas to mix with the inlet air.

100% of the air that passes through the air filter goes through the EGR unless you have a leak.

bigjl

Not all EGR systems will be engineered the same way.

Apparently some VAGs (may be Bluemotions) can run with only recirculated air.

I read that in an article online but the explanation seemed credible.

My understanding was they improved emissions by recirculating some exhaust gases under certain conditions. You can watch how open or closed your EGR is using an OBD dongle and an App.

They do usually gunk up with thick black tar like rubbish as does the inlet manifold.

I cleaned the EGR on my old mk3 Mondeo and the stuff in there was just plain nasty.

I can't see how all air would have to pass through the valve in all EGR equipped engines as then it would not be possible to fit a blanking plate surely? Though I could be completely wrong on that as I have never actually thought about the EGR system that way

Also it would not be possible to remove the EGR surely? As then the vehicle would not run?

It is possible that as vehicles have gone from Euro4 to Euro5 and now onto Euro6 that the design of the EGR will change to meet the ever more stringent emissions targets.

bigjl

Iceweasel wrote: »

We may be talking at cross purposes.

All the air that reaches my combustion chambers does pass through the EGR valve unit body - there is no other way for air to get to the manifold.

My EGR looks like this:



The exhaust gases enter the body of the EGR unit when the vacuum operates the inlet valve part.

What vehicle do you have?

bigjl

Did a quick Google out of curiosity and found a decent diagram of the EGR system on a late model Disco.

https://www.google.co.uk/search?q=land+rover+discovery+4+egr+valve&rlz=1CDGOYI_enGB647GB647&hl=en-GB&prmd=isvn&source=lnms&tbm=isch&sa=X&ved=0CAYQ_AUoAWoVChMIzou8y97yxwIVSbIUCh1ITAi5#imgrc=5QZKqWt_uCB98M%3A

Not sure if that link will work.

captainawsome

bigjl wrote: »

Not all EGR systems will be engineered the same way.

Apparently some VAGs (may be Bluemotions) can run with only recirculated air.

I read that in an article online but the explanation seemed credible.

My understanding was they improved emissions by recirculating some exhaust gases under certain conditions. You can watch how open or closed your EGR is using an OBD dongle and an App.

They do usually gunk up with thick black tar like rubbish as does the inlet manifold.

I cleaned the EGR on my old mk3 Mondeo and the stuff in there was just plain nasty.

I can't see how all air would have to pass through the valve in all EGR equipped engines as then it would not be possible to fit a blanking plate surely? Though I could be completely wrong on that as I have never actually thought about the EGR system that way

Also it would not be possible to remove the EGR surely? As then the vehicle would not run?

It is possible that as vehicles have gone from Euro4 to Euro5 and now onto Euro6 that the design of the EGR will change to meet the ever more stringent emissions targets.

When you fit a blanking plate you don't blank off the fresh air (the main large passage in the EGR body) you just blank off the exhaust gas feed at the most convenient place and disconnect the valve or remove it all together. All of the fresh air entering the engine HAS to pass through the EGR body as shown in the pic above, although some systems recirculate the gas directly into the inlet manifold and don't use a housing as shown above.

forgotmyname

All the inlet air passes through the EGR, The blanking plate stops the exhaust gas from recirculating.

All the air passes through the large hole into the engine though. The EGR just allows the exhaust gas to mix with it to improve emissions and help warm the engine faster and a better idle when cold.

Iceweasel

captainawsome wrote: »

When you fit a blanking plate you don't blank off the fresh air (the main large passage in the EGR body) you just blank off the exhaust gas feed at the most convenient place and disconnect the valve or remove it all together. All of the fresh air entering the engine HAS to pass through the EGR body as shown in the pic above, although some systems recirculate the gas directly into the inlet manifold and don't use a housing as shown above.

That is what I was not aware of - and what arcon5 may well be referring to.

I suspect we were describing different types - so we are both correct. Oops.

Most Fords LandRovers and BMWs etc. certainly have the type where the incoming air passes through the body of the unit and the vacuum piston controls the exhaust gas valve.

That must be the most common type I think.