EGR upgrades, intercooler?

[Daox]

Originally Posted by slugbeast

The ECM would have a base formula of some kind to know when the egr is opened, how much recirculated gas to expect. It can't correct on its own, the egr gas is released post maf sensor. If someone could expand on what I think I know that might be helpful though... Perhaps the 02 sensor plays a role.

The O2 sensor will keep the AFR steady as it always does.

If I'm theorizing right, simply adding a cooler would increase the volume of recirculated exhaust gas. Since the gas is cooled and not heated It would lean out the mixture slightly, but then again the gas is cooled I don't think it would increase risk of detonation.

Increasing EGR flow doesn't lean anything because all you're adding is inert gas, not oxygen. Dillute is a more applicable word I suppose.

I can see it having emissions benefits, lowering the combustion temperature could be good for engine durability but then it would take a little longer to reach peak operating temperature... all negligible. To get the MPG benefits I was going for you would have to increase the volume of gas more significantly than just an egr cooler, like a bigger egr valve and a control unit to tell it to open it more and then trick the ecm to tell the car to lean it out even further. Or maybe release the exhaust gas pre-MAF? It would get fouled up pretty quick, maybe even add an in line filter in there like off of a snorkeled jeep type deal.

As more EGR is added you can also optimize ignition timing which will increase efficiency.

[oil pan 4]

Originally Posted by WesternStarSCR

does cooling EGR have mpg, emissions, or engine durability benefits?

Since all the OEM diesels have had EGR coolers for many years now I would think so.
But one of the first things diesel owners do is delete the EGR, se we don't dwell on it much. We do this because EGR does not increse MPG unless in cold climates on vehicles that are not worked very hard, even then it more of a function of the EGR cooler warming coolant than the EGR its self.

[mwebb]

EGR primary function
is to reduce combustion pressure

EGR does this by diluting incoming Air fuel mixture with INert gas
exhaust gas by definition

by reducing combustion pressure
combustion temperature is also reduced
which also reduces NOX

[WesternStarSCR]

Originally Posted by Daox

As more EGR is added you can also optimize ignition timing which will increase efficiency.

Thank you all for thinking about this as well.

But since I am NOT adding more EGR, just cooling it, and not adjusting ECM programming / timing, it may be a "can't hurt, not sure if it will help" scenario?

Since the ONLY thing in my case would be the adding of a cooler to an already functioning, GASOLINE egr system, then the inert charge taking up space in the cylinder will be denser as compared to a non cooled EGR.

So perhaps some even less sensitivity to knock? Even less chance of NOx?

If O2 sees sees a bit less NOx, due to results of a cooler & denser EGR inert volume, then (perhaps) it knows it can advance timing more (more MPG)?

But, if there is no ECM software logic designed to lean it out and / or advance timing more to increase efficiency, while still keeping NOx low, then there may not be any MPG advantage?

I suppose that is where Mazda and Ford are taking advantage of cooled EGR with SkyActiv and EcoBoost. Their computer actually will know it is cooled, and take full advantage of it to increase MPG.

So many variables, so few sensors, so little control over our ECMs...

[mwebb]

...."
If O2 sensor ?sees sees a bit less NOx, due to results of a cooler & denser EGR inert volume, then (perhaps) it knows it can advance timing more (more MPG)?...."

the 02 sensor does not / can not see 02
the 02 sensor measures presence of combustibles

despite the name

the 02 sensor has no (direct) authority over ignition timing
the 02 sensor does have authority over Air Fuel Ratio and has authority over weather or not the system will be in
"closed Loop" as with no input from the 02 sensor
(or the AFR sensor in later systems )
the feedback needed to confirm actual AFR is not present .

a better name for an 02 sensor is
Lambda sensor
since 02 sensors change state at Lambda ,
they either report leaner than lambda or richer then lambda
so the system will always be in flux , slightly lean to slightly rich of Lambda
never stopping at Lambda
Lambda = AFR of 13.64 to 1
---------------------------------------------
NOX sensors are used in later Diesel systems
______________________________
EGR improves FE by reducing combustion chamber volume
by diluting incoming air fuel mixture with INert gas
while EGR is active
effectively reducing engine size and suction throttling loss because throttle must be opened more to provide the same amount of
go

the gas pedal is really an
air pedal

[oil pan 4]

The reduction of combustion temperature and pressure in a diesel reduces power and fuel economy.
Need to keep the gas/diesel seperation clear, we have people trying to run warm air intakes and more EGR trying to increase diesel fuel milage because they read stuff the gas guys are doing and have had sucess with.

[WesternStarSCR]

Agreed!!! Lets be clear for everyone else...

In general, a well running EGR system in a GASOLINE engine can have secondary positive impact on fuel economy, in addition to its primary job of reduced emissions.

Also, in general, a well running EGR system in a DIESEL engine can have secondary negative impact to fuel econnomy, while perfroming its primary job of reduced emissions.

Hence, diesel owners that may do an EGR delete to improve FE and performance (at a cost in emissions), and gasoline owners (and Ford and Mazda) looking to do an EGR add to improve FE on gasoline engines.

[oil pan 4]

The EGR on a diesel tends to reduce NOx but increases soot.

[mario.silva]

Cooled EGR system works:

Basically, if it's not cooled you loose compression power by its volume in the cylinders.

If it's cooled, you bring back up compression. A simple intercooler should do it.

After that, you may even increase the factory compression ratio of your engine if you have the money to do that, to level up the horse power of your original engine.

Adding more EGR makes this possible. There is less nox, the engine runs more cool and less knocking. Actually, you can see this kind of systems in newer eco but powerfull cars.

See it here:

http://docs.google.com/viewer?a=v&q=...Ca_N3pn0Jqz_pw

[Teemo]

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All the best.