So for emissions control, EGR is a near total SCAM, eh?

[fixizin]

I mean think about it, the right bank, jugs 1-2-3, just dumps its exhaust straight down the line, but the left cyl bank gets a little bit piped off for "re-burn", creating all sorts of complexity, not to mention SOOT FOULING of various points and components in the induction path, WTF?

In some ways this is worse than the "cheater" pumps of the 1970s.

Has anyone ever seen real engineering data on how much the practice of EGR actually reduces emissions? Is there really anything there that will burn again?

 

[gw33gp]

The EGR system recirculates a small portion of the exhaust gas mostly to dilute the incoming fuel charge a little to reduce NOx. I don't think there is any significant effect of reburning any residual unburt gasses. Engines that are designed to run without an EGR system tend to ping which I think is due to the fuel ratio needed to keep the NOx low.

I agree that the EGR system can be a problematic way to go long term. I tend to prefer the engines without it.

 

[almostclueless]

EGR is NOT a scam. NOx is a signficant part of smog, and EGR is the only way to reduce NOx. It shuts off at WOT, SLIGHTLY reduces mileage, and does eventually carbon up an intake tract.


But if I could legally put it on my hotrod, I'd do it.

 

[fixizin]

... and yet places that are smog-prone STILL have smog.

And doesn't anything that REDUCES mileage (like those exhaust-diluting "cheater" pumps) end up INCREASING net pollution????

 

[almostclueless]

... and yet places that are smog-prone STILL have smog.

And doesn't anything that REDUCES mileage (like those exhaust-diluting "cheater" pumps) end up INCREASING net pollution????

Smog prone places are that way because there are too many lemmings living and working there. It's a volume thing

And no, "cheater" pumps (where the hell did you come up with that stupid name anyway?) don't cause more smog. The way your brain works is rather interesting.

 

[Ranger44]

Yeah it reduces the combustion chamber temps, and helps prevent the nitrogen and oxygen from fusing in the extreme temps of the cylinder. It's not usless.

 

[aipaul]

My 94 3.0 didn't come with any EGR system at all. I notice there are flat spots and bolt holes on the driver side exhaust manifold where this could be installed. Why was EGR only put on some Rangers within the same model year?

 

[MAKG]

Because only some needed it. There ARE other ways to control cylinder temps, but they aren't usually better (in an emissions or performance sense). Like, retarding the timing.

The only real downside of EGRs is cost of design and production. They are additional variables in the engine "mapping," additional parts that require testing, and so on.

 

[fixizin]

Smog prone places are that way because there are too many lemmings living and working there. It's a volume thing

And no, "cheater" pumps (where the hell did you come up with that stupid name anyway?) don't cause more smog. The way your brain works is rather interesting.

Uh, I think you mean a population DENSITY thing, not volume. Of course there are many other factors in smog formation, notably geologic topology, weather patterns, humidity, seasonal sunlight levels, chemical contributions from industry, cattle farts, etc.

Perhaps you are too young to remember cheater pumps. In the 1970s, some vehicles, in order to pass emissions tests, had a belt-driven air pump that dumped its output directly into the exhaust manifold. The OSTENSIBLE purpose was to "add oxygen" in order to "re-ignite" and "burn off" alleged raw or "uncombusted" fuel. Of course in reality, as engineers later admitted, all it did was DILUTE the exhaust, so that a LOWER DENSITY of exhaust reached the sniffer probe in the tailpipe.

You HAVE seen a gov't-sanctioned "emissions" test, haven't you? That sniffer is not gas-tight over the tailpipe; it just lies in the exhaust stream, sensing the DENSITY of certain compounds, not the total VOLUME. Once again, gov't dolts get a wedgie from private industry... Pretty funny, in hindsight.

OK, so now we're back to the first law of thermodynamics, i.e. Conservation of Energy. If the air compressor ("cheater pump"), similar to your A/C compressor, takes, let's say, 8 HP to turn over, yet adds nothing to the efficiency of the pistons, then my friend, you have burned MORE fuel to go distance X at speed Y (like hauling a couple sacks of cement in the trunk), thus you have INCREASED the amount of pollution output per mile.

 

[almostclueless]

Uh, I think you mean a population DENSITY thing, not volume. Of course there are many other factors in smog formation, notably geologic topology, weather patterns, humidity, seasonal sunlight levels, chemical contributions from industry, cattle farts, etc.

Perhaps you are too young to remember cheater pumps. In the 1970s, some vehicles, in order to pass emissions tests, had a belt-driven air pump that dumped its output directly into the exhaust manifold. The OSTENSIBLE purpose was to "add oxygen" in order to "re-ignite" and "burn off" alleged raw or "uncombusted" fuel. Of course in reality, as engineers later admitted, all it did was DILUTE the exhaust, so that a LOWER DENSITY of exhaust reached the sniffer probe in the tailpipe.

You HAVE seen a gov't-sanctioned "emissions" test, haven't you? That sniffer is not gas-tight over the tailpipe; it just lies in the exhaust stream, sensing the DENSITY of certain compounds, not the total VOLUME. Once again, gov't dolts get a wedgie from private industry... Pretty funny, in hindsight.

OK, so now we're back to the first law of thermodynamics, i.e. Conservation of Energy. If the air compressor ("cheater pump"), similar to your A/C compressor, takes, let's say, 8 HP to turn over, yet adds nothing to the efficiency of the pistons, then my friend, you have burned MORE fuel to go distance X at speed Y (like hauling a couple sacks of cement in the trunk), thus you have INCREASED the amount of pollution output per mile.

Thank you for bringing your expert opinion here....

Air injection pumps frequently have FIBERGLASS vanes. They pump against exhaust pressure, which is almost insignificant. The fuel wasted by air injection is virtually negligible except in the minds of folks who were gullible enough to think ripping all the pollution controls off a vehicle was going to get them something.


The real power losses in 70's engines were;

1. The changed power rating system
2. retarded cam timing
3. altered ignition timing
4. carburetor recalibration
5. restrictive EGR provisions in intake manifolds
6. pellet type cats

I would put mst of the external pollution controls from the 70's on my hot rod if it wasn't illegal.