Lowering Emissions. EGR for low NOX vs. better mileage

Bill.Barg · **Posted:** Sun Sep 09, 2007 12:58 am

I thought y'all might find this interesting. Keep in mind that the essay does not list many supporting references, nor can I attest to its technical validity.

http://autoengineer.wordpress.com/2006/ ... nsibility/

Also note the comment on plugged particulate filters (we dont have these, but maybe our catalytic converters are getting cloged (see http://en.wikipedia.org/wiki/Catalytic_converter)).

I would like to know if the ORM reduces the NOX / Mile due to improved mileage, and I would like to know if may catalytic converter is full of soot created by the EGR, also reducing mileage.

Bill

DarbyWalters · **Posted:** Sun Sep 09, 2007 9:02 am

From the article...

From my understanding, Sulphur was not a lubricant in diesel fuel. The removal of Sulphur did however reduce other lubricants in diesel because of the process to remove sulphur. Supposedly, they added back some lubricants to counteract this effect.

The NOx vs CO2 has been a hot topic for a while. Right now, I think the CO2 is a bigger problem. Just recently the ICE at the South Pole was tested and is now mear 100% saturated with CO2. As we know Diesels are very good when it somes to lower CO2 production.

I do think that reducing fuel consumption by 10% reduces emissions in more than a few ways. The transportation/production/exploration of that extra 10% of fuel adds to the carbon footprint in itself. Also with better control of soot in a diesel, you can extend the oil change intervals and the wear on a diesel engine will be greatly reduced...especially the top end ( aluminum and such). That in turn will extend the useful life span of a vehicle which reduces overall polution.

The benefits of the ORM when it comes to reduced EGR operation directly relates to CO2 and NOx production as well as fuel mileage and engine wear. In 3 of these four areas, the ORM (or reduced EGR) is beneficial by reducing Soot Production in tailpipe, reducing Engine Wear from reduced soot production and Increasing Diesel Efficiency. The one area where we "could" be worse concerns NOx production. I don't know whether the increased NOx is worse overall after you factor in the other emissions required to transport/produce ect. the extra 10% of fuel used with heavier EGR. Also with the reduction of waste oil from longer oil drain intervals, the ORM is helpful.

IMHO, the benefits outweight the drawbacks when it comes to the ORM/EGR reduction. You would think with this setup AND a Particulate Filter added (passive that does not require/use fuel to "clean burn"), you could really reduce further the SOOT that is expelled. There again, the Particulate Filter would need to be monitored closely to watch any pressure increase caused by "cloggin" by soot particles. No matter what, it is a complicated scenario no matter how you approach the issue.

retmil46 · **Posted:** Sun Sep 09, 2007 10:28 am

One thing that is not mentioned - the current administration is once again pushing a pilot program under NAFTA, to start allowing Mexican trucking companies to cross the border and make deliveries throughout the U.S.

Congress slammed the brakes on this 10 years ago because the Mexican trucks and drivers came nowhere close to meeting our environmental regs, safety regs, weight limit regs, and driver training requirements. And this situation has not essentially changed in the last 10 years.

The added cost of the extra equipment and changes that have to be made to a Class 8 truck to meet the '07 regs amounts to roughly $10K per vehicle, an additional $4K on just the engine alone. And in one part, the article was dead on - the trucking companies ordered Class 8 trucks like they were hotcakes last year, we were slamming 220 trucks per DAY out of the Freightliner Cleveland plant alone. Now that only '07 trucks are available, the orders have dried up to the extent that we've laid off third shift back in March, only worked one week out of four in April May and June, and have only been running one shift per week/8 hours per day since the first of July. In the meantime, the Mexico plant which is primarily building non-'07 compliant trucks for markets outside the U.S. is still running full blast.

So the EPA is forcing the U.S. trucking industry to bear all these additional costs, which are eventually going to get passed on to the end customer, while at the same time the administration is wanting to give the Mexican trucking industry a free pass on the same requirements? If I were fond of conspiracy theories, I'd say this was nothing less than an effort to run the U.S. trucking industry out of business in favor of their cheap-as-possible Mexican counterparts.

If the situation goes forward as is, I can see several results - other businesses that depend on the trucking industry will literally stampede to make use of Mexican trucking companies due to the lower cost of their not having to comply with U.S. regs. For lack of business and customers, U.S. based trucking companies will try cutting costs any way they can, including cutting driver pay to a minimum and turning a blind eye toward any corner-cutting on legal requirements, such as the limit on the number of hours per day they can be on the road. Most independent truckers will simply be run out of business. In the end, it will be the same story as with many other industries - many trucking companies will simply move their base of operations to Mexico, so they can avoid compliance with U.S. regs and thus incur lower costs and stay in business.

DarbyWalters · **Posted:** Sun Sep 09, 2007 10:58 am

Yeah, I don't understand the two sets of standards myself...seems like we punish ourselves and others get to take advantage of that fact. It is time to "reward" the US companies that abide by the stricter standards and hold outsiders up to our standards. Will stop here so this doesn't become a "political thread".

danoid · **Posted:** Tue Sep 11, 2007 11:41 am

retmil46 wrote:

So the EPA is forcing the U.S. trucking industry to bear all these additional costs, which are eventually going to get passed on to the end customer, while at the same time the administration is wanting to give the Mexican trucking industry a free pass on the same requirements? If I were fond of conspiracy theories, I'd say this was nothing less than an effort to run the U.S. trucking industry out of business in favor of their cheap-as-possible Mexican counterparts.

It's already been done. When's the last time you saw a cargo ship (or cruise ship) with a US regristry?

CATCRD · **Posted:** Tue Sep 11, 2007 12:20 pm

danoid wrote:

It's already been done. When's the last time you saw a cargo ship (or cruise ship) with a US regristry?

Yeah, seriously, they're all registered out of some banana republic with lower taxes and fees.

But back on the topic, I agree wholeheartedly with the author of the article linked. He's not correct about the sulfur being the lubricant, but it's not really what the article was about. The rest of it agrees with my engineering knowledge and judgement.

flash7210 · **Posted:** Tue Sep 11, 2007 12:53 pm

I wonder if anybody has ever done a cradle-to-grave analysis of diesel vs.
gasolene vehicle pollution? such as...

Pollutants created from from the refining of oil to make gasolene and diesel plus transportation?

Pollutants created from the manufacture of the vehicles themselves?

... from vehicle use? (exhaust, lubricants, coolants, tires, etc.)

Average life span of each type of vehicle plus destruction/recycling?

I wonder if such a thorough study would change the views of the EPA?

Dont worry, the Federal Government will always be there to protect you
and always has YOUR best interest in mind

Thats whay my elected Congressman told me

retmil46 · **Posted:** Tue Sep 11, 2007 6:13 pm

flash7210 wrote:

I wonder if such a thorough study would change the views of the EPA?

Three words - when pigs fly.

nursecosmo · **Posted:** Wed Sep 12, 2007 12:25 am

The author of that article was dead on about Nox being an imaginary environmental issue. Low sulfur fuel has been a good thing though. Unlike Nox which rapidly breaks down in the atmosphere, sulfur becomes sulphuric acid which can only precipitate out as acid rain. When Europe went to ULSD the acid rain problem was dramatically reduced even though Nox remained the s
ame.

The lubrication additives are added at the distributer not each individual gas station.

One thing that I have wondered about is why an electric scrubber couldn't be used on diesel exhaust systems like they use on coal plants? It would be cleanable and last indefinitely.

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

I disagree that NOx isn't an issue. The Europeans have standards for reducing NOx emissions as well, they just go about it a less draconian fashion than the US has. In any event, if the claims being made by VW, Honda, GM, Cummins are true, the next generation of diesels will make the whole debate moot.

On particulate matter (part of what scrubbers on power plants address), our EGRs serve is "scrubbers", but our engines pay the price for it in longevity. One can also get at it through the use of bio-diesel, which produces less of the stuff when burned. I've read studies showing b99 reducing particulate emissions by 75%. I feel less bad about running the ORM because I run high % of biodiesel most of the time.

Bill.Barg · **Posted:** Wed Sep 12, 2007 1:20 am

But Threeweight, does'nt BioD produce more NOX?
see http://www.nrel.gov/vehiclesandfuels/np ... /38296.pdf for instance with a 10% increase.

If this is the case then the EGR is more important for BioD, right.

flash7210 · **Posted:** Wed Sep 12, 2007 8:59 am

Back in July I had a discussion with my chemistry proffessor about
oxides of nitrogen (NOX) and internal combustion engines. Keep in mind
that he is an organic chemist and not an automotive engineer.
He said that NO and NO2 form nitrous acid (HNO2) when water vapor is
present in the atmosphere. He said that nitrous acid is a strong acid but
was not sure how readily this occurs or what its environmental impact truly
is. He also said that NOX only forms when combustion happens in a
compressed metal chamber and that the catalytic converter is supposed
to reduce NOX emissions but does a very poor job. So, in theory, an
engine block made out of a ceramic material would have zero NOX.
Like I said, organic chemist not engineer.

Also, about ULSD...
When talking about this whole global warming thing, many scintists have
come up with some crazy ideas about how to reverse it. One even
suggested atificially introducing sulfur (H2S) into the atmosphere to
reproduce the global cooling effects of a volcanic eruption. So, if sulfur
was put back in our fuel, wouldn't this be the same?

ATXKJ · **Posted:** Wed Sep 12, 2007 1:08 pm

I don't know that I agree with your professor - he's implying that the metallic chamber is a catalyst in a reaction that otherwise would not occur - it would be nice if that happened -there are available ceramic coatings for high performance engines that would be easy to apply in production - however I believe it's incorrect.

Once you exceed the 945 Kcal/Mol bonding energy in a Nitrogen/Nitrogen bond - you break it into Ions that are react with the Oxygen Ions in the combustion chamber giving you an assotment of NOx.

in the Air - NOx by itself seems to be have balanced reactions but in combination with hydrocarbons - forms Ozone i.e. smog
http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=11586

Haven't looked at the H2S idea but the Sulfur in the fuel starts coating the Platinum in the converter & kills it.
http://en.wikipedia.org/wiki/Catalytic_converter

Threeweight · **Joined:** Mon May 14, 2007 5:57 pm **Posts:** 679

Nothing's perfect

I started running the ORM as an experiment, and haven't plugged it back in yet (7k miles on it). It will get plugged back in soon (and my biodiesel sticker will be removed from the back window) as I need to take the rig into my dealer for the blower recall. I've been weighing my personal concerns w/ CO2 vs. NOx as well, and was initially very concerned about the abrasion damage that oil laden with fine particulates would do to the inside of our engines.

I don't think the car exhaust idea for using sulfur (particulate matter) to reflect sunlight would work very well. You need the stuff up high in the upper atmosphere, rather than down low where car exhaust generally sits. Maybe volcanos...

What is good for reflecting sunlight is not so good for fish in the local lakes and rivers, and forests as well (acid rain). There are some heartbreaking places in Smokey Mountains National Park now with giant swaths of dead trees, killed by sulfur from power plants in Tennessee and places further west. Big problem in the Northeast as well.

nursecosmo · **Posted:** Wed Sep 12, 2007 1:40 pm

Hi Threeweight. EGR systems increase particulate matter in exhaust because they offset the oxygen/fuel mixture in order to reduce combustion temperature and free O2, which = less Nox. This leaves a small percentage of unburned fuel which is where the soot comes from. the new generation of ultrahigh pressure common rail diesels are capable of making such a clean burn that they don't need particulate filters in order to meet PM Bin 5 requirements, however because the EGR systems are added for Nox they produce enough soot to need a particulate filter. EGR systems do the opposite work of a scrubber leaving some unburned fuel as soot. Bio-D increases the % of Nox in the exhaust because of it's high oxygen content in the MEOH head of the molecule(as much as 10% more oxygen). This higher oxygen content in the fuel helps equalize the lower O2 content caused by the EGR, thus lowering PM. I'm glad that you are running high % Bio-D it is a fantastic way to reduce the emissions which are actually harmful.

nursecosmo · **Posted:** Wed Sep 12, 2007 1:45 pm

Hello flash7210. The Nox emitted by combustion engines has nothing to do with the materials that the engine is made from(unless your engine is made from a catalytic metal like platinum). It is part of the chemical reaction of combustion. remember that oxygen and fuel are not the only things present in the combustion chamber, 78% of the volume present is nitrogen. When this N2 becomes very hot (as in the temperatures found in a diesel engine) it becomes free nitrogen (N2+heat = N N, likewise O2 + heat = O O) (O+N = NO and NO2) The temperature where this usually occurs is approximately 1600c but when under high compression (like in a diesel) the reaction occurs at lower temps.
While it is true that Nox does become nitric and nitrous acid when they meet water in the atmosphere, the acid exists for only a short time because sunlight converts it to ammonia, which on a side note is very good for vegetation. This is why when acid rain content is analyzed only a very small percentage is nitric, the majority is sulfuric acid (almost exclusively from sulfur in coal, but also sulfur in fuel). In areas where particulate emissions have been reduced (Sulfur and hydrocarbon fragments are the main components of PM) acid rain has been virtually eliminated.

Reflex · **Joined:** Mon Jan 29, 2007 8:48 pm **Posts:** 567

It just blows me away that people think NOX is a non-issue. There is zero doubt in the mainstream scientific community about its effects as a creator of smog. Other nations with laxer or non-existent NOX regulations are measurably worse in smog despite lower rates of vehicle use. Evidence is both corrolative and causative. There really is no doubt.

I agree that laws in this country do not target CO2 often enough, but that is not an argument for relaxing NOX emissions rules, but instead an argument for tightening CO2 emissions. Raising CAFE standards would accomplish this and encourage clean diesels in the process.

flash7210 · **Posted:** Wed Sep 12, 2007 2:22 pm

Well the class was about Energetic Compounds. In all compounds and
reactions we studied all the nitrogen came out as N2. So I asked him why.
When, in all these reactions heat and pressure were far greater than in
an ICE.
Look, I have a lot of respect for this guy in that he still has all his
fingers, eyes, and hair. But the ICE really is not his specialty and I can
understand how he could be wrong.
So we will just leave it there.

UFO · **Posted:** Wed Sep 12, 2007 2:52 pm

Reflex wrote:

It just blows me away that people think NOX is a non-issue. There is zero doubt in the mainstream scientific community about its effects as a creator of smog. Other nations with laxer or non-existent NOX regulations are measurably worse in smog despite lower rates of vehicle use. Evidence is both corrolative and causative. There really is no doubt.

I agree that laws in this country do not target CO2 often enough, but that is not an argument for relaxing NOX emissions rules, but instead an argument for tightening CO2 emissions. Raising CAFE standards would accomplish this and encourage clean diesels in the process.

NOx is not a prime cause of smog. It is NOx in conjunction with hydrocarbons that causes smog, and hydrocarbon emissions have dropped dramically due to tightened emission laws over the last 30 years. NOx by itself is not a serious issue.

DarbyWalters · **Posted:** Wed Sep 12, 2007 3:17 pm

EGRs definitely do not act like scrubbers or reduce PM in any way...they just inject uncombustibles into the cyclinder to reduce combustion temps and lower the production of NOx by taking up available space that clean air could have occupied. PMs are reduced by blocking off the EGR and letting combustion temps rise to burn more completely...but that it turn increases NOx production.

Lowering Emissions. EGR for low NOX vs. better mileage

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