EGR valve blanking/cheating (1 Viewer)

[Techno]

There are plenty of articles on the web detailing why EGR's are a load of tosh and a very poor way of trying to reduce "pollution"
There are millions of pre EGR diesels on the road

 

[Techno]

deleted

 

[Techno]

Emissions....... at the expense of power and economy and no other reason.

I think the thread has pretty much covered all the pros and cons if read right through. I side with John for one

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[Techno]

View attachment 51390

I see from this that recirculation does not occur at idle.

 

[buttons]

The EGR cooling unit is only circulated engine coolant (HOT) so it cannot reduce the temperature any lower than the intake air & fuel mix so adds nothing to the equation.
Nothing positive that is! but plenty of sh1te

The compressed air discharging from the turbo is far from cool, the conducted heat plus the compression process heats the inlet air considerably. The by-pass gasses on the other hand are de-pressurised loosing heat through the EGR v/v before entering the EGR gas cooler giving this cooling effect when entering the combustion chamber.

 

[andy63]

There are plenty of articles on the web detailing why EGR's are a load of tosh and a very poor way of trying to reduce "pollution"

That's what I read and went along with... I blanked mine off to prevent the carbon build up in the manifold and ports..

But was trying to reply to buttons post about valves been burnt out because of blanking...or at least that's the way I read his post..

There are millions of pre EGR diesels on the road

That is so but as the diesel engine was developed and became more effecient they introduced a new problem..ie the increased production of the oxides of nitrogen and the industry reaction was to develop egr to help prevent that..
That's the way I picked it up anyway .
Andy..

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[buttons]

That's what I read and went along with... I blanked mine off to prevent the carbon build up in the manifold and ports..

But was trying to reply to buttons post about valves been burnt out because of blanking...or at least that's the way I read his post..


That is so but as the diesel engine was developed and became more effecient they introduced a new problem..ie the increased production of the oxides of nitrogen and the industry reaction was to develop egr to help prevent that..
That's the way I picked it up anyway .
Andy..

Hi andy63, dont let me put you off what you are doing, I have never had anything to do with piston or reciprocating engines so shouldn't really comment, but I have been involved with industrial gas turbines in the past which have a similar gas bypass process where blade tip damage can occur through over heating. I thought it was worth a mention. Perhaps someone better placed could comment.

 

[andy63]

Hi andy63, dont let me put you off what you are doing, I have never had anything to do with piston or reciprocating engines so shouldn't really comment, but I have been involved with industrial gas turbines in the passed which have a similar gas bypass process where blade tip damage can occur through over heating. I thought it was worth a mention. Perhaps someone better placed could comment.

Cheers buttons... I've not got a clue but when I read your post it wasn't a concern I'd ever heard mentioned in connection with blanking EGR's. .. I did mine a good while ago and never had any problems..
Andy

 

[buttons]

Cheers buttons... I've not got a clue but when I read your post it wasn't a concern I'd ever heard mentioned in connection with blanking EGR's. .. I did mine a good while ago and never had any problems..
Andy

Dont act on my limited knowledge andy but maybe worth asking around out of interest.

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[Techno]

As I reposted above see last paragraph. The vast majority of the rev range the EGR is closed so clearly burnt out valves is not an issue and if anything more fuel has to be injected to overcome the dilution with exhaust gas
http://www.motorhomefun.co.uk/forum/attachments/egr-description-jpg.51390/

 

[buttons]

Im getting lost here lol...
By recycling exhaust gas into the combustion space that has the effect of cooling the combustion process...ie those gases can not be re burnt and help reduce combustion temperature... That in turn helps prevent the production of various oxides of nitrogen helping prevent pollution...
Are we in disagreement over that...?
Andy..

I am in agreement this is similar to how a gas turbine process works too.

 

[andy63]

and if anything more fuel has to be injected to overcome the dilution with exhaust gas

That's the bit I don't understand... The more exhaust gas that's recirculated into the combustion process the less fuel will be required as part of the cylinder charge now consists of gas that can take no part in the combustion process...
By increasing the fuelling you get a mix that is too rich and can not burn completely.
That's my logic anyway..
Andy

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[unimog]

Interestingly Egr valves reduce NOx but increase particulate emissions. Euro 6 engines running AdBlu will not be fitted with Egr valves
This is interesting reading http://www.dieselcar.com/features/euro-6-understanding-the-new-regulations/

 

[mitzimad]

Interestingly Egr valves reduce NOx but increase particulate emissions. Euro 6 engines running AdBlu will not be fitted with Egr valves
This is interesting reading http://www.dieselcar.com/features/euro-6-understanding-the-new-regulations/

after reading that i forsee the point where we will all be walking everywhere

 

[Jenben]

That's the bit I don't understand... The more exhaust gas that's recirculated into the combustion process the less fuel will be required as part of the cylinder charge now consists of gas that can take no part in the combustion process...
By increasing the fuelling you get a mix that is too rich and can not burn completely.
That's my logic anyway..
Andy

My understanding is that a lot of the latest ecu's take into account the recirculated gas and reduce the amount of fuel injected when the EGR valve is open. This is something to be careful as some of the kits you can buy just fix the check engine light problem and might leave you in danger of damaging your engine with a weak mixture.

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[MC 55 FUN]

Interestingly Egr valves reduce NOx but increase particulate emissions. Euro 6 engines running AdBlu will not be fitted with Egr valves
This is interesting reading http://www.dieselcar.com/features/euro-6-understanding-the-new-regulations/

Which is why, to comply with ever stricter E.U. emission controls d.p.f.'s & c.d.p.f.'s are now fitted to trap particulate matter.

 

[andy63]

My understanding is that a lot of the latest ecu's take into account the recirculated gas and reduce the amount if fuel injected when the EGR valve is open. This is something to be careful as some of the kits you can buy just fix the check engine light problem and might leave you in danger of damaging your engine with a weak mixture.

Yes that's more or less the case with the mk7 transit I have... unlike the mk 6 where you could just blank it off the mk7 egr valve is electronically actuated from the ecu and also senses when it opens by way of the mass/temp air flow sensor... (I think)..
Just blanking it can cause a fault code an limp...
My solution was to have it remapped with the egr function removed from the ecu ... The hardware.ie egr valve is still in place but the egr valve is permanently shut..
Andy

 

[tonyidle]

Yes that's more or less the case with the mk7 transit I have... unlike the mk 6 where you could just blank it off the mk7 egr valve is electronically actuated from the ecu and also senses when it opens by way of the mass/temp air flow sensor... (I think)..
Just blanking it can cause a fault code an limp...
My solution was to have it remapped with the egr function removed from the ecu ... The hardware.ie egr valve is still in place but the egr valve is permanently shut..
Andy

It is impossible to damage a Diesel engine with a weak mixture. Until recently all Diesel engines were unthrottled and some still are now. Throttling, where used, is designed to smooth idle and plays no part in controlling engine output. Output power is governed entirely by the amount of fuel injected.

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[gus-lopez]

The compressed air discharging from the turbo is far from cool, the conducted heat plus the compression process heats the inlet air considerably. The by-pass gasses on the other hand are de-pressurised loosing heat through the EGR v/v before entering the EGR gas cooler giving this cooling effect when entering the combustion chamber.

That is only on later vehicles that have a heat exchanger fitted. Early vehicles just dumped exhaust gases straight into the inlet manifold.

That's the bit I don't understand... The more exhaust gas that's recirculated into the combustion process the less fuel will be required as part of the cylinder charge now consists of gas that can take no part in the combustion process...
By increasing the fuelling you get a mix that is too rich and can not burn completely.
That's my logic anyway..
Andy

You cannot reduce the fuel by increasing exhaust gas input as it doesn't burn & has no use even as 'air.'

Which is why, to comply with ever stricter E.U. emission controls d.p.f.'s & c.d.p.f.'s are now fitted to trap particulate matter.

Which all rely on the customer footing the bill for repair of them as most will fail/not work properly/ not fit for intended usage etc; at some stage.
The only way "Euro 6" & 6+ can actually 'work' is using smoke & mirrors. Unfortunately they have been caught at it.
Most manufacturer's will tell you ,off the record, that it isn't possible to make a diesel engine any cleaner.

 

[MC 55 FUN]

Which all rely on the customer footing the bill for repair of them as most will fail/not work properly/ not fit for intended usage etc; at some stage.
The only way "Euro 6" & 6+ can actually 'work' is using smoke & mirrors. Unfortunately they have been caught at it.
Most manufacturer's will tell you ,off the record, that it isn't possible to make a diesel engine any cleaner.

True.

E.G.R.V.'s & D.P.F.'s / C.D.P.F.'s are engine / turbo killers & were the only easy-ish & affordable work around the engine manufacturers could use to comply with E.U. directives on diesel emission levels i.m.o.

 

[Jenben]

It is impossible to damage a Diesel engine with a weak mixture. Until recently all Diesel engines were unthrottled and some still are now. Throttling, where used, is designed to smooth idle and plays no part in controlling engine output. Output power is governed entirely by the amount of fuel injected.

Good point. Thinking weak mixtures are bad was just me harking back to years of petrol engine experience....presumably they adjust the mixture to reduce emissions when the EGR valve is open then?

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[Techno]

New unit just delivered will swap them tomorrow

 

[Techno]

Looks to be improved a bit too

Original version

 

[tonyidle]

Good point. Thinking weak mixtures are bad was just me harking back to years of petrol engine experience....presumably they adjust the mixture to reduce emissions when the EGR valve is open then?

As there will almost always be more air going in than is needed I suspect no change to fuelling is needed - I don't know the answer but that's my take on it. EGR only operates at certain times - probably when there's enough air for it not to interfere with the combustion process too much.

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[andy63]

As there will almost always be more air going in than is needed I suspect no change to fuelling is needed - I don't know the answer but that's my take on it. EGR only operates at certain times - probably when there's enough air for it not to interfere with the combustion process too much.

I thought the fuelling would be adjusted to ensure as close to perfect combustion as possible for the cylinders charge of air at that pressure.. The egr valve only opens when the engine is running at its most efficient and lightly loaded... ..That was my understanding... If the egr valve is contributing to the cylinder charge then there would be no need for increased fuelling.. which I thought Andy's post implied..ie

and if anything more fuel has to be injected to overcome the dilution with exhaust gas

Whether I understand it or not I'm convinced that the egr system can cause excessive carbon build up in the intake side.. as has been discussed in this thread.
Andy...

 

[Techno]

Whether I understand it or not I'm convinced that the egr system can cause excessive carbon build up in the intake side.. as has been discussed in this thread.
Andy...

That's the whole point of blanking it

 

[andy63]

That's the whole point of blanking it

Indeed..
But there are still loads of engines that don't appear to have the carbon build up after thousands of miles of motoring and others that suffer from carbon build up after only a few thousand...
So is it does appear that the egr system suits some types of use..
When I did mine I was disappointed.. mine didn't appear to be too bad.. but did it anyway. It's early days but ill keep an eye on the inlet side and see how it goes..
Andy

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[tonyidle]

I thought the fuelling would be adjusted to ensure as close to perfect combustion as possible for the cylinders charge of air at that pressure.. The egr valve only opens when the engine is running at its most efficient and lightly loaded... ..That was my understanding... If the egr valve is contributing to the cylinder charge then there would be no need for increased fuelling.. which I thought Andy's post implied..ie


Whether I understand it or not I'm convinced that the egr system can cause excessive carbon build up in the intake side.. as has been discussed in this thread.
Andy...

That can never be true for an unthrottled Diesel - up to wide open throttle there will invariably more air entering than is required. As I said earlier power output is controlled entirely by altering the amount of fuel injected. There is no control over air intake.

 

[andy63]

There is no control over air intake.

I see what you are saying , but on today's modern diesel I thought there would be control to some extent on every aspect to ensure perfect combustion.
Surely the turbo boost pressure goes some way to setting or varying the air charge... depending on requirements or conditions..

power output is controlled entirely by altering the amount of fuel injected. There is no control over air intake.

I just don't see that... The engine will be fueled very precisely to ensure the power required I'd delivered but in line with what I'm sure will be a known charge of air depending on boost ,and air temp etc..
Andy.

 

[Techno]

Looks to be improved a bit too View attachment 103411

Original version

Fitted this morning and all back to normal. ECU faults cleared ok

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