Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

old jupiter · 04-13-2011, 01:25 AM

[QUOTE=mwebb;231261]

EGR does NOT increase Power output
EGR does not reduce maximum power output because EGR does not operate at WOT or close to WOT
WOT = Wide Open Throttle
EGR on a gasoline engine does NOT operate at idle

(end quote)

Agreed. If EGR did operate at wide open throttle, it would reduce power. Since it does operate through the part-throttle range, it reduces the fuel economy that can be obtained by removing it AND re-tuning the engine for the changed configuration. The engine will then do the same work with slightly reduced throttle settings, i.e., it will be slightly more fuel-efficient. And it will release more of the pollutant that contributes to photochemical smog.

My wisecrack should properly have suggested you try improving your part-throttle fuel economy with argon . . .

So, EGR is both good and bad. I'm an old guy and remember when the first two generations of emission controls cluttered up our previously wide-open engine bays with bundles of vacuum lines and semi-mysterious valves and air pumps. Worse, to eliminate a small amount of HCs, the factories had to ditch Harry Ricardo's wonderful high-compression, closed-chamber, squish-type combustion chambers and go to low-compression (for the lousy gasoline) open-chamber "smog heads," all of which killed performance AND fuel efficiency. There was a lot of ranting among hot rodders about "the smog crap," and the magazines offered articles on how best to get rid of it.

But some of us didn't particularly feel good about putting unnecessary glop into the air, and were willing to learn how all those new systems worked. And to our surprise, we sometimes ended up admiring the relative simplicity and cleverness of some of these systems (especially the first one, the EGR valve, which reduced the total emissions of the engine by nearly 30% all by itself, with no drawbacks other than very occasional maintenance!). A few of us fine citizens (Moi

) even ADD some of these systems to pre-emissions vehicles

.

EGR isn't a system I'd add to an old car, and the manufacturers of cars, big diesel trucks, or anything between wouldn't put it on their machinery either if not forced to it by emissions regulations. But until a better method is found, EGR is a net positive. I alluded to a better method, available (still is, I think) to the DIYer. Bottom line, CarbonAltima: getting rid of the EGR won't do your fuel economy or your engine any good unless you re-calibrate and re-tune, especially the ignition, and even then the improvement will likely be disappointing.

04-13-2011, 01:25 AM	#38 (permalink)
old jupiter EcoModding Lurker Join Date: Apr 2011 Location: the Emerald City Posts: 27 Thanks: 0 Thanked 5 Times in 5 Posts	[QUOTE=mwebb;231261] EGR does NOT increase Power output EGR does not reduce maximum power output because EGR does not operate at WOT or close to WOT WOT = Wide Open Throttle EGR on a gasoline engine does NOT operate at idle (end quote) Agreed. If EGR did operate at wide open throttle, it would reduce power. Since it does operate through the part-throttle range, it reduces the fuel economy that can be obtained by removing it AND re-tuning the engine for the changed configuration. The engine will then do the same work with slightly reduced throttle settings, i.e., it will be slightly more fuel-efficient. And it will release more of the pollutant that contributes to photochemical smog. My wisecrack should properly have suggested you try improving your part-throttle fuel economy with argon . . . So, EGR is both good and bad. I'm an old guy and remember when the first two generations of emission controls cluttered up our previously wide-open engine bays with bundles of vacuum lines and semi-mysterious valves and air pumps. Worse, to eliminate a small amount of HCs, the factories had to ditch Harry Ricardo's wonderful high-compression, closed-chamber, squish-type combustion chambers and go to low-compression (for the lousy gasoline) open-chamber "smog heads," all of which killed performance AND fuel efficiency. There was a lot of ranting among hot rodders about "the smog crap," and the magazines offered articles on how best to get rid of it. But some of us didn't particularly feel good about putting unnecessary glop into the air, and were willing to learn how all those new systems worked. And to our surprise, we sometimes ended up admiring the relative simplicity and cleverness of some of these systems (especially the first one, the EGR valve, which reduced the total emissions of the engine by nearly 30% all by itself, with no drawbacks other than very occasional maintenance!). A few of us fine citizens (Moi) even ADD some of these systems to pre-emissions vehicles . EGR isn't a system I'd add to an old car, and the manufacturers of cars, big diesel trucks, or anything between wouldn't put it on their machinery either if not forced to it by emissions regulations. But until a better method is found, EGR is a net positive. I alluded to a better method, available (still is, I think) to the DIYer. Bottom line, CarbonAltima: getting rid of the EGR won't do your fuel economy or your engine any good unless you re-calibrate and re-tune, especially the ignition, and even then the improvement will likely be disappointing.