egr 101 question - Page 2 - PeachParts Mercedes-Benz Forum

eatont9999 · #16 07-19-2013, 04:05 PM

Quote:

Originally Posted by connerm

0-60 = 25 seconds.
Driving around northern Virginia, I have pedal to the floor a lot.
Can't get past 3500 rpm on interstate...about 80-85 mph.
Can't rev past 4200 in neutral
And to get it to shift to the next gear, I have to let off the throttle a tiny bit, then mash the pedal again.
Sux

That sounds a lot like your transmission is upshifting too soon. A possible cause could be mis-adjusted throttle linkages. That would account for not revving to max as well.

Dan Stokes · #17 07-19-2013, 04:41 PM

I know a lot of you guys THINK you have "the truth" about Diesel emissions but I was an actual expert in the field, having worked 31 1/2 years for the EPA doing emissions testing with much of that applied to Diesels.

First of all, the EPA never "makes" any company install any particular technology. Standards are set based on health needs with the requirement (as set by Congress) to reduce emissions inventories - that is, the quantity of any given pollutant in the atmosphere. This is necessary as humans have an unfortunate habit of breathing air. Each company decides how they intend to achieve these reductions and they frequently choose similar technologies.

BTW - EPA will suggest to the industry at least one possible technology to achieve the required standard but the manufacturers are free to pick alternate technologies as long as they can demonstrate that they work and are durable.

Anyhow, as someone else noted the function of EGR is to lower Oxides of Nitrogen (NoX) emissions. NoX is a function of temperature, pressure, and time and Diesels are BAD about NoX production. Combustion chamber temps in Diesels are high (one of the reasons for our high fuel economy), pressures of course are much higher than in an Otto-cycle engine, and with our relatively slower crank and piston speeds the time for NoX to form is much longer. So, lots of NoX.

EGR, and especially cooled EGR, significantly lowers combustion chamber temps WITHOUT EFFECT ON OTHER EMISSIONS. I've done the testing using lab-grade instrumentation - this is no BS. Why folks think EGR raises CO emissions I have no clue. There is a SLIGHT impact on CO2 emissions which equals slightly lower fuel economy but not much.

The new Diesel aftertreatment systems use a catalyzed Diesel Particulate Filter (DPF) to remove particulate (which is what the general public gripes about - they write their Congresspeople) as well as reducing unburned hydrocarbons (HC) and carbon monoxide (CO) to levels often lower than the surrounding ambient air. Then a NoX trap ADSORBS (look it up) the NoX that remains after the EGR has done its job. The trap must be periodically cleaned (regenerated) and there are several ways to do this including adding DEF (a urea-based fluid) or simply driving the system rich for a short period of time. BTW - I'm named on the patent for the second method (just to establish my credibility). VW uses the fuel method on its lower HP engines and DEF on its higher output products. I have no idea why.

Anyhow, it may well be that over time the intake gets fouled as a result of EGR though I haven't personally experienced this with hundreds - maybe thousands - or hours of running these systems on the dyno. So clean the darn thing every 200K or so! But pulling the EGR will cost you something - FUEL ECONOMY! Lower combustion chamber temps lead to better FE and this is measured in lab conditions where you can actually tell the difference.

As a side note - fuel economy is VERY difficult to repeatedly measure. I could go on and on as to why but for this chat I'll just say that I won't respond to "my buddy pulled his EGR and got 2 (or 20) more MPG". You can't get more than a rough idea on the road - we've tried.

Dan

connerm · #18 07-19-2013, 05:12 PM

Quote:

Originally Posted by DieselPaul

Have you verified your timing?

No. I haven't checked timing because the thing starts so easily, doesn't smoke, and has a silky idle.

Give me a thumbnail sketch on timing. I admit, I don't know anything about it.

eatont9999 · #19 07-19-2013, 05:15 PM

Quote:

Originally Posted by Dan Stokes

I know a lot of you guys THINK you have "the truth" about Diesel emissions but I was an actual expert in the field, having worked 31 1/2 years for the EPA doing emissions testing with much of that applied to Diesels.

First of all, the EPA never "makes" any company install any particular technology. Standards are set based on health needs with the requirement (as set by Congress) to reduce emissions inventories - that is, the quantity of any given pollutant in the atmosphere. This is necessary as humans have an unfortunate habit of breathing air. Each company decides how they intend to achieve these reductions and they frequently choose similar technologies.

BTW - EPA will suggest to the industry at least one possible technology to achieve the required standard but the manufacturers are free to pick alternate technologies as long as they can demonstrate that they work and are durable.

Anyhow, as someone else noted the function of EGR is to lower Oxides of Nitrogen (NoX) emissions. NoX is a function of temperature, pressure, and time and Diesels are BAD about NoX production. Combustion chamber temps in Diesels are high (one of the reasons for our high fuel economy), pressures of course are much higher than in an Otto-cycle engine, and with our relatively slower crank and piston speeds the time for NoX to form is much longer. So, lots of NoX.

EGR, and especially cooled EGR, significantly lowers combustion chamber temps WITHOUT EFFECT ON OTHER EMISSIONS. I've done the testing using lab-grade instrumentation - this is no BS. Why folks think EGR raises CO emissions I have no clue. There is a SLIGHT impact on CO2 emissions which equals slightly lower fuel economy but not much.

The new Diesel aftertreatment systems use a catalyzed Diesel Particulate Filter (DPF) to remove particulate (which is what the general public gripes about - they write their Congresspeople) as well as reducing unburned hydrocarbons (HC) and carbon monoxide (CO) to levels often lower than the surrounding ambient air. Then a NoX trap ADSORBS (look it up) the NoX that remains after the EGR has done its job. The trap must be periodically cleaned (regenerated) and there are several ways to do this including adding DEF (a urea-based fluid) or simply driving the system rich for a short period of time. BTW - I'm named on the patent for the second method (just to establish my credibility). VW uses the fuel method on its lower HP engines and DEF on its higher output products. I have no idea why.

Anyhow, it may well be that over time the intake gets fouled as a result of EGR though I haven't personally experienced this with hundreds - maybe thousands - or hours of running these systems on the dyno. So clean the darn thing every 200K or so! But pulling the EGR will cost you something - FUEL ECONOMY! Lower combustion chamber temps lead to better FE and this is measured in lab conditions where you can actually tell the difference.

As a side note - fuel economy is VERY difficult to repeatedly measure. I could go on and on as to why but for this chat I'll just say that I won't respond to "my buddy pulled his EGR and got 2 (or 20) more MPG". You can't get more than a rough idea on the road - we've tried.

Dan

Dan,

You are correct about the way the EPA works in setting standards that auto manufacturers must follow. Manufacturers do get to choose how they meet the requirements but if they don't, they are not allowed to sell the vehicle in the US.

I have to disagree with you on the idea of lower combustion temps = better FE. If that were true, cars would not have thermostats and the cooling systems would be free flowing to cool the cylinders. Your theory would only be applicable to cooled EGR anyway. Our cars do not cool the EGR gas, so they would be introducing hot exhaust gas into the intake which is contrary to your theory.

From the articles that I have read in the past, I cannot agree about there being no significant trade-off of gasses when using EGR. I could be wrong about all of this but I have been under the impression that EGR is to serve emissions, not the health or economy of the engine.

martureo · #20 07-19-2013, 05:16 PM

Quote:

Originally Posted by Dan Stokes

I know a lot of you guys THINK you have "the truth" about Diesel emissions but I was an actual expert in the field, having worked 31 1/2 years for the EPA doing emissions testing with much of that applied to Diesels.

First of all, the EPA never "makes" any company install any particular technology. Standards are set based on health needs with the requirement (as set by Congress) to reduce emissions inventories - that is, the quantity of any given pollutant in the atmosphere. This is necessary as humans have an unfortunate habit of breathing air. Each company decides how they intend to achieve these reductions and they frequently choose similar technologies.

BTW - EPA will suggest to the industry at least one possible technology to achieve the required standard but the manufacturers are free to pick alternate technologies as long as they can demonstrate that they work and are durable.

Anyhow, as someone else noted the function of EGR is to lower Oxides of Nitrogen (NoX) emissions. NoX is a function of temperature, pressure, and time and Diesels are BAD about NoX production. Combustion chamber temps in Diesels are high (one of the reasons for our high fuel economy), pressures of course are much higher than in an Otto-cycle engine, and with our relatively slower crank and piston speeds the time for NoX to form is much longer. So, lots of NoX.

EGR, and especially cooled EGR, significantly lowers combustion chamber temps WITHOUT EFFECT ON OTHER EMISSIONS. I've done the testing using lab-grade instrumentation - this is no BS. Why folks think EGR raises CO emissions I have no clue. There is a SLIGHT impact on CO2 emissions which equals slightly lower fuel economy but not much.

The new Diesel aftertreatment systems use a catalyzed Diesel Particulate Filter (DPF) to remove particulate (which is what the general public gripes about - they write their Congresspeople) as well as reducing unburned hydrocarbons (HC) and carbon monoxide (CO) to levels often lower than the surrounding ambient air. Then a NoX trap ADSORBS (look it up) the NoX that remains after the EGR has done its job. The trap must be periodically cleaned (regenerated) and there are several ways to do this including adding DEF (a urea-based fluid) or simply driving the system rich for a short period of time. BTW - I'm named on the patent for the second method (just to establish my credibility). VW uses the fuel method on its lower HP engines and DEF on its higher output products. I have no idea why.

Anyhow, it may well be that over time the intake gets fouled as a result of EGR though I haven't personally experienced this with hundreds - maybe thousands - or hours of running these systems on the dyno. So clean the darn thing every 200K or so! But pulling the EGR will cost you something - FUEL ECONOMY! Lower combustion chamber temps lead to better FE and this is measured in lab conditions where you can actually tell the difference.

As a side note - fuel economy is VERY difficult to repeatedly measure. I could go on and on as to why but for this chat I'll just say that I won't respond to "my buddy pulled his EGR and got 2 (or 20) more MPG". You can't get more than a rough idea on the road - we've tried.

Dan

And sending your engine into a rebuild shop how many miles earlier is better?

All of what you said above is correct, except you forgot one little point. Engines are happier without any emissions controls.

I worked for Volvo Powertrain and my primary job was fitting/designing EGR and emissions equipment to engines for the North American markets. I loved the few times I got to see an engine we were building for some South American country, no emissions controls whatsoever, and wow... that was nice.

Turning your alda back and driving more carefully will get you better increases in fuel economy than any EGR could ever do.

Shortsguy1 · #21 07-19-2013, 05:58 PM

Quote:

Originally Posted by Dan Stokes

I've done the testing using lab-grade instrumentation - this is no BS. Why folks think EGR raises CO emissions I have no clue. There is a SLIGHT impact on CO2 emissions which equals slightly lower fuel economy but not much.

But pulling the EGR will cost you something - FUEL ECONOMY! Lower combustion chamber temps lead to better FE and this is measured in lab conditions where you can actually tell the difference.

Dan, could you clarify these two comments of yours? I thought the first part indicated that adding EGR would decrease mpg, and the second comment suggests that removing EGR would decrease mpg.

1983/300CD · #22 07-19-2013, 08:03 PM

Quote:

Originally Posted by eatont9999

... Our cars do not cool the EGR gas, so they would be introducing hot exhaust gas into the intake which is contrary to your theory.

From the articles that I have read in the past, I cannot agree about there being no significant trade-off of gasses when using EGR. I could be wrong about all of this but I have been under the impression that EGR is to serve emissions, not the health or economy of the engine.

The lower temps result from the different burn from a oxygen-poor air in the combustion chamber.

Yes, it's all about emissions. Remember, the 617 was designed without an EGR.

Dan Stokes · #23 07-19-2013, 10:39 PM

Quote:

Originally Posted by Shortsguy1

Dan, could you clarify these two comments of yours? I thought the first part indicated that adding EGR would decrease mpg, and the second comment suggests that removing EGR would decrease mpg.

I knew someone would pick up on this - and rightfully so. Lower combustion chamber temps DO tend to improve FE even though the CO2 emissions tend to increase. The issue is that proper TUNING can get back the FE plus more. In other words, the system has to be optimized for the EGR rates and so on. Simply adding or deleting EGR without the tuning optimization is not likely to obtain the results desired.

We can all pine for the Good Old Days when Diesels spewed PM (particulate matter) and made enough NoX to choke a horse but those days (fortunately) are gone. They're not legal in Europe, the US, Canada, Japan, and many other areas around the world. Before we wax nostalgic about the South American calibrations I suggest you take a trip to Mexico City. While not all of the poor air quality can be attributed to Diesels but much of it can. And even Mexico is finally working on emissions standards for Otto and Diesel cycle engines. About darn time.

All this said, I am not running EGR nor aftertreatment on my OM617. However, it's going in a race-only, non-street legal vehicle that will never see a highway except on a trailer that's pulled by a legal Dodge Cummins. My usual yearly mileage - about 15-20 miles per year in the race truck. The reason I deleted the EGR is that I have no chance of tuning it for performance. I lack the equipment and specific knowledge.

Dan

bricktron · #24 07-19-2013, 10:55 PM

i agree that the OP's issue is more or less unrelated to EGR.

dan, thanks for your informed posts. would you care to comment on whether the operator of an OM617, concerned about being a good citizen, might ever install a DPF?

cooljjay · #25 07-19-2013, 11:14 PM

So this explains why my 78 is such a dog and the engine idles like crap....I don't have an egr.....anyone want to help me install one?

tjts1 · #26 07-20-2013, 02:25 AM

Quote:

Originally Posted by Dan Stokes

I know a lot of you guys THINK you have "the truth" about Diesel emissions but I was an actual expert in the field, having worked 31 1/2 years for the EPA doing emissions testing with much of that applied to Diesels.

First of all, the EPA never "makes" any company install any particular technology. Standards are set based on health needs with the requirement (as set by Congress) to reduce emissions inventories - that is, the quantity of any given pollutant in the atmosphere. This is necessary as humans have an unfortunate habit of breathing air. Each company decides how they intend to achieve these reductions and they frequently choose similar technologies.

BTW - EPA will suggest to the industry at least one possible technology to achieve the required standard but the manufacturers are free to pick alternate technologies as long as they can demonstrate that they work and are durable.

Anyhow, as someone else noted the function of EGR is to lower Oxides of Nitrogen (NoX) emissions. NoX is a function of temperature, pressure, and time and Diesels are BAD about NoX production. Combustion chamber temps in Diesels are high (one of the reasons for our high fuel economy), pressures of course are much higher than in an Otto-cycle engine, and with our relatively slower crank and piston speeds the time for NoX to form is much longer. So, lots of NoX.

EGR, and especially cooled EGR, significantly lowers combustion chamber temps WITHOUT EFFECT ON OTHER EMISSIONS. I've done the testing using lab-grade instrumentation - this is no BS. Why folks think EGR raises CO emissions I have no clue. There is a SLIGHT impact on CO2 emissions which equals slightly lower fuel economy but not much.

The new Diesel aftertreatment systems use a catalyzed Diesel Particulate Filter (DPF) to remove particulate (which is what the general public gripes about - they write their Congresspeople) as well as reducing unburned hydrocarbons (HC) and carbon monoxide (CO) to levels often lower than the surrounding ambient air. Then a NoX trap ADSORBS (look it up) the NoX that remains after the EGR has done its job. The trap must be periodically cleaned (regenerated) and there are several ways to do this including adding DEF (a urea-based fluid) or simply driving the system rich for a short period of time. BTW - I'm named on the patent for the second method (just to establish my credibility). VW uses the fuel method on its lower HP engines and DEF on its higher output products. I have no idea why.

Anyhow, it may well be that over time the intake gets fouled as a result of EGR though I haven't personally experienced this with hundreds - maybe thousands - or hours of running these systems on the dyno. So clean the darn thing every 200K or so! But pulling the EGR will cost you something - FUEL ECONOMY! Lower combustion chamber temps lead to better FE and this is measured in lab conditions where you can actually tell the difference.

As a side note - fuel economy is VERY difficult to repeatedly measure. I could go on and on as to why but for this chat I'll just say that I won't respond to "my buddy pulled his EGR and got 2 (or 20) more MPG". You can't get more than a rough idea on the road - we've tried.

Dan

Thank you for posting this. People that haven't spent time in a non emissions controlled country don't realize how much quality of life they owe to engineers like you.

connerm · #27 07-20-2013, 08:08 AM

Quote:

Originally Posted by bricktron

i agree that the OP's issue is more or less unrelated to EGR.

Thanks to all who contributed here. I feel confident that I can eliminate one more possible issue causing my performance issues.

shertex · #28 07-20-2013, 08:44 AM

Quote:

Originally Posted by connerm

Thanks to all who contributed here. I feel confident that I can eliminate one more possible issue causing my performance issues.

And that would be?

connerm · #29 07-20-2013, 02:50 PM

Quote:

Originally Posted by shertex

And that would be?

Not getting the combination of air from the filter box AND egr valve. My take is that air from air filter box is adequate.

Dan Stokes · #30 07-20-2013, 03:43 PM

Quote:

Originally Posted by tjts1

Thank you for posting this. People that haven't spent time in a non emissions controlled country don't realize how much quality of life they owe to engineers like you.

Oh Lord NO!!!! I was a Mechanical Engineering Technician. My standard smart a$$ response is that "I opted for competence rather than a degree" - although truly a lot of the engineers I worked with were great and skilled folks.

One of my favorite bits of info is this:
The LA basin would be uninhabitable TODAY if not for the emissions regulations put in place starting in the late 60's (PCV) and ramping up to the current state of affairs. This is not future forecasting, just math. Take the emissions output of a stock pre-emissions car and multiply by the number of cars in the basin these days and you get unbreathable air.

The current state of Diesel emissions technology is much like that of Otto cycle emissions systems in, say, 1980. No longer a total disaster but a far cry from the way things are today with Otto cycle engines making WAY more power than they ever did in the muscle car days and with improved driveability, vast improvements in fuel economy, and EXTREMELY low emissions. I predict that in a few years folks will wonder why there was ever a backlash against Diesel emissions control technology.

Dan