EGR's effect on performance

[crowbar]

EGR is actually important to combustion for not just NOx reduction, but some are saying it can INCREASE power while leaning AFR under boost. EGR is sort of water injection it seems.

As a side note - Volvo recently released some SAE papers documenting the use
of cooled EGR to both reduce detonation and return to a stoic mixture under
boost in the 15 psi range - while maintaining approximately the same power
output. Notice - they reduced fuel and still get the same power output.

When you consider that EGR consists primarily of nitrogen, CO2, and water ( to
the tune of about two gallons formed from each gallon of water burned ), you
might draw the conclusion that it also was not "inert". They peaked their
tests at about 18% cooled EGR - which would work out to about 36% water
injection and got about the same results under similar conditions that the
early NACA research got.

[homestar]

crowbar wrote: EGR is actually important to combustion for not just NOx reduction, but some are saying it can INCREASE power while leaning AFR under boost. EGR is sort of water injection it seems.

As a side note - Volvo recently released some SAE papers documenting the use
of cooled EGR to both reduce detonation and return to a stoic mixture under
boost in the 15 psi range - while maintaining approximately the same power
output. Notice - they reduced fuel and still get the same power output.

When you consider that EGR consists primarily of nitrogen, CO2, and water ( to
the tune of about two gallons formed from each gallon of water burned ), you
might draw the conclusion that it also was not "inert". They peaked their
tests at about 18% cooled EGR - which would work out to about 36% water
injection and got about the same results under similar conditions that the
early NACA research got.

can you post a source?

[crowbar]

http://www.sae.org/technical/papers/2007-01-1257

Using exhaust gas recirculation in internal combustion engines: a review.
Energy Conversion and Management, Volume 43, Issue 8, Pages 1027-1042
G. Abd-Alla

http://emp-corp.com/media/SAEPapers/2005-01-1380.pdf

[Firehawk]

Damian_Z31 wrote: If you decide to do that and still need to pass emissions then there is a cat you can buy from BMW that the many tuners run on highly tuned motors and still pass emissions. From what I gather BMW's don't have all of the emission crap on their cars so they make up for it by running this badas$ cat that reduces emissions immensly. You can run it in place of a test pipe and it works from what I hear.

I'll do some more searching on the topic if needed.

I doubt that they have some special cat. You can get the effects of egr with cam overlap. Other cars do not have egr tubes but still pass, and this is how they do it.

[casner]

crowbar wrote: EGR is actually important to combustion for not just NOx reduction, but some are saying it can INCREASE power while leaning AFR under boost. EGR is sort of water injection it seems.

I wonder why the engineers at nissan put them on the cars bound for the u.s.? usually we only get the most powerless vehicles made... :?

[G-E]

japan has always had better fuels available comparatively, higher octane and lower contaminents, so they could get away with more tuning and higher output while still having low pollution

europe until the last 15yrs or so had crummy fuel, and while the fuel situation can still be hit or miss, the more industrialized countries (scandinavia, western europe) have a steady supply of cleaner fuels like clean diesel, and they overall prefer small engines over there anyway

so what north america gets is lots of integrated hardware to offset the low-grade highly contaminated fuel somewhat, and to make up for the lack of efficiency the engines are big

you can't just say apples to apples that you don't need egr because japan doesn't... but then consider how cheap fuel is in north america compared to everywhere else

[MrwassmanNA2T]

How is an EGR like water injection?

[Z31SPL]

The only way you could be flowing EGR under boost was if your ECU was programmed to do that I would assume. Atleast in a new car that is.. what is our EGR controlled by vaccum? The EGR in theory is like a water injection because it "cools" the cylinder even though its burning hot exhaust gas.. lol In new models coming out EGR is disappearing in its place there is the wide usage of variable valve timing (vvt-i, Vtec, etc.) That BMW cat if it is so special I would assume its big bucks $$$

[crowbar]

MrwassmanNA2T wrote: How is an EGR like water injection?

Combustion produces H20. H20 is also a vital part of the combustion process.

In dry climates, like colorado, I would NEVER disconnect this.

[300zxt]

Nissan only installed an EGR system when it was deemed neccessary to have one due to emissions regulations, that says enough I think.