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Old 01-31-2012, 02:05 PM   #31 (permalink)
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brucey -

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Originally Posted by brucey View Post
This sounds like such a perfect test for Mythbusters, unless one of you guys have a mobile emissions testing center.

I'm still in the "FE is more important than emissions." camp myself. If you burn half as much fuel but produce twice as much emissions doing it, you're still ahead because that fuel is not having to be extracted and and pumped and refined and piped and stored and shipped and pumped and burned.
I'm definitely with SentraSE-R on this issue, but you are stating your case very well. Because SentraSE-R doesn't *know* how much he's spewing out his exhaust, he doesn't know if he is violating his principles.

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Old 01-31-2012, 02:34 PM   #32 (permalink)
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Originally Posted by SentraSE-R View Post
The CARB emissions test goes something like this. The smog test operator drives your car onto a set of rollers and sticks a sniffer up its tailpipe.
So a sniffer is still used? After your first post I thought that they only hooked up a diagnostic tool and looked for emissions related codes. I read that is the case in certain states and thought that Cali was one of them.
On-board diagnostics - Emission testing:
Quote:
Originally Posted by Wikipedia
In the United States, many states now use OBD-II testing instead of tailpipe testing in OBD-II compliant vehicles (1996 and newer). Since OBD-II stores trouble codes for emissions equipment, the testing computer can query the vehicle's onboard computer and verify there are no emission related trouble codes and that the vehicle is in compliance with emission standards for the model year it was manufactured.
This got me wondering about how accurate pure OBD testing is, compared to physically analyzing the emissions.

Darrell, thank you for starting this discussion Emissions vs. fuel consumption has come up here before, but it's good to stir it every so often. I too am very curious where this goes, whether increasing your own emissions locally really would reduce global pollution, as rmay and brucey suggested. Unfortunately we still lack data, and even then we'd have to crunch a lot of numbers.

Would a smaller cat warm up faster and/or to a higher temperature? Not something you could easily replace with all the CARB restrictions, tho.
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Old 01-31-2012, 03:04 PM   #33 (permalink)
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SentraSE-R -

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Originally Posted by SentraSE-R View Post
Darin, you have the power to change the title, so go ahead. I can't figure out how to do it, probably because I can't.
Done.

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Old 01-31-2012, 07:51 PM   #34 (permalink)
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Quote:
Originally Posted by brucey View Post
This sounds like such a perfect test for Mythbusters, unless one of you guys have a mobile emissions testing center.

I'm still in the "FE is more important than emissions." camp myself. If you burn half as much fuel but produce twice as much emissions doing it, you're still ahead because that fuel is not having to be extracted and pumped and refined and piped and stored and shipped and pumped and burned.
Exactly, the trouble is how would Mythbusters setup the parameters.

There is a hoard of resources that are indirectly tied to the oil by the labor force that works for the oil companies, would they be included? How do we quantify emissions into the ground or emissions that would be "other" since they aren't normally in a cars exhaust, like mercury, arsenic, cobalt and other exotics that tend to get freed.

Also our crude to fuel process goes, oil exploration, drill, extract in the US, put on the open market for the highest bidder, send 50-90% US oil overseas because it is of a higher quality than most crude. Pay the lowest bidder to refine low quality crude on antique equipment that is overseas and exempt from US regulations to make that crude usable for us in various forms. Transport back to the US (more pollution), refine further (more pollution) ship and distribute (more pollution).

I think really if we want to do the right thing for the country we need to scrap this system sending crude and gas 2-3k miles each way, seems asinine from a resource consumption standpoint, yet because of the many special interests its how we do it the wrong way and make more profit.

Ah well.
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Old 01-31-2012, 08:17 PM   #35 (permalink)
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Quote:
Originally Posted by SentraSE-R View Post
Inactivity or the normal way I drive may be raising my emissions, as my HC levels are 3-15X more than average, CO levels are 1-6X the average, and NO levels are 4-7X more than average.
You'd expect these to return to normal with normal driving, right ?

If they don't, it looks like there's some issue with the catalyst.

CO could be due to incomplete combustion, but with excessive NOx you'd also expect high temperatures (and better combustion along with it).


Quote:
I drove the car 900 miles RT to/from SoCal last week
Did you P&G all the way on such a long trip ?

Quote:
I know today's cars burn much cleaner than older cars, but I lived through pre-Clean Air Act smog conditions, and I don't like the idea of my car dumping out 3-15X the average air pollution when it's driven normally. I can only guess how bad it is with an unlit cat.
I recall a thread where someone measured the emission when using P&G - the emissions were far higher than what he measured during steady state driving.

He then raised the question wether P&G should be renamed Pulse & Pollute ...
http://ecomodder.com/forum/showthrea...ute-14571.html

Quote:
Originally Posted by rmay635703 View Post
NOx by itself is a non-issue.(when combined with other pollutions in a city it is) We regulate the heck out of it but it will degrade in the environment as do aeormatics and heavier emissions, heck A WATER MIST IN YOUR EXHAUST WILL ELIMINATE NEARLY ALL NOX, if you are worried
Some non-issue !
The water mist will make it into acid - I wouldn't call that eliminated.

NOx is just about the worst thing to come out of your exhaust.
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Old 01-31-2012, 09:05 PM   #36 (permalink)
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Four things I would consider.

PCV valve partially clogged, easy to clean it, it sticks out of the valve cover with a hose attached. Drivers side I think. Pull it out and clean it thoroughly. Easy job, takes a few minutes. mcrews had an excellent post on how to check crankcase ventilation, put a balloon over the dipstick tube and see if the crankcase pressure inflates the balloon fairly rapidly. If so suspect PCV issues.

EGR passageways partially plugged, not enough to activate a Check engine light but enough to increase emissions.
Carbon in engine.
Cat partially contaminated due to frequent starts and shut downs.

Basically the frequency of starts and shut downs is just about the same as the worst case scenario as far as short haul short distance types of driving considered severe operating conditions in the owners manual.

If your car has an EGR system then the frequent on-off cycles mean a much greater potential for EGR passageways getting clogged with carbon build up. Low EGR flow is a principal cause of high NO emissions and will cause the timing to be retarded which will contribute to incomplete combustion.

High crankcase pressures (PCV partially plugged) will cause unburned fuel and crankcase vapors to be pushed up past the rings into the combustion chamber where they could contribute to incomplete combustion.

If it has an EGR system then I would look at the tube from the exhaust manifold to the EGR valve itself. If it is clogged, even partially then clean the tube and the EGR valve.

To clean the carbon out of the engine and the Cat, I would try an additive like techron or seafoam in the fuel and (I know you won't like this) take it out and run the crap out of it for a long time, something like 100 miles. It will kill your mileage, but might wake up the Cat and blow the carbon out of the pistons and cylinder head. Full bore acceleration runs whenever possible, wind her arse out.

If it is not to costly then have the emissions checked again to see what that has done.

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Old 01-31-2012, 09:15 PM   #37 (permalink)
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Quote:
Originally Posted by euromodder View Post
Some non-issue !
The water mist will make it into acid - I wouldn't call that eliminated.
It is as soon as it hits cement or any number of other substances including dust, also remember the QTY of acid you will actually make, we aren't talking gallons here, think grams. A decent lifetime exhaust system will handle a couple grams of nitric.

If you don't like nitric which turns into fertalizer when it hits soil, you could have a driveway saltwater mist into the exhaust post cat, then you end up with again more fertalizer.

Or of coarse there is always the diesel solution, urea!

Quote:
Originally Posted by euromodder View Post
NOx is just about the worst thing to come out of your exhaust.
I disagree, the mercury vapors that come out of some poorly constructed overseas oil refineries is much worse.

Anyway...
NOx breaks down more quickly on its own than any of the other types of pollutants including CO2 which lasts longest. NOx is a synergistic compound, it can have climate benefits in the right conditions and it can also cause negatives in large cities when combined with other forms of pollution. On its own absent the exotics and aeromatics it doesn't form anything too frightening, acid in the right places is a non-issue. For example my folks dumped acid on their garden for years and had some nice blueberries and rhubarb.

Its all a matter of scale and location. I won't say its the best thing since sliced bread but many things attributed to NOx in of itself are not paticularly accurate or are exaggerated. NOx in of itself does not cause smog, other things that don't belong in the air also have to be present for that reaction to happen.

Remember too our wonderfull graph if he burns 50% less gas and makes even 25% more NOx, is he really any worse than the guy driving the pickup next to him?

At stioch your normal average modern car still makes plenty of NOx, the difference between lean and normal is splitting hairs on a 50mpg+ vehicle.
Its only the very latest that show promise with GDI and variable valves to start reducing the stoich value of NOx. All others behave pretty much per the curve with a handfull of notable exceptions, including the insight I.

To really reduce NOx we really need to reduce the number of gas guzzlers, since all cars make NOx regardless of lean or not.
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Old 01-31-2012, 10:45 PM   #38 (permalink)
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Could a high performance ( as in us mpg guys) chip be made to electronically fool
the cat to be lit all the time?

If enough emphasis went into this one issue, wouldn't that pretty much end all this?

Any logical way of multipling an external plug in source of a cat pre-heat before
cold engine start?

I'm far from being Mr. Science, but thought stirring of the minds might help!

How about a custom cat with a baffle set of plates that open only one at a time,
maximizing early heat somewhat restricting the passage until heat is such that all
baffles open. Have it restrict again as rpm levels go down such as stoplight/signs;
and idling, only as safely needed.
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Old 01-31-2012, 11:09 PM   #39 (permalink)
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Quote:
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Do you have the results from your last test (before this round)?
Daox, my car's never been smog tested before. New cars get a 5 year exemption from smog testing in CA.

------------------------------------------------------------------------------
FWIW, here's how I view my fuel consumption/emissions footprint. My xB has 2008 EPA estimated 26/30/28 city/highway/combined fuel consumption estimates. Since I bought my xb, I've averaged 49.4 mpg for every mile I've driven in it. I've used 590 gallons to drive ~30k miles, saving 450 gallons compared to the average xB driver. I used 55.7% of the average xB's fuel to go the same distance.

But, as seen above, I'm dumping 3-15 times the average hydrocarbons, 4-7 times the NOx, and up to 6 times the CO of the average xB, when my cat is lit, which is almost never, in local driving. Even if I use 55% of the average xB's fuel, it's inescapable logic to me that I'm producing ten times as much air pollution with an unlit cat. Preheating the O2 sensors doesn't fire the cat. I have to run the engine constantly to keep it lit.
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Old 01-31-2012, 11:09 PM   #40 (permalink)
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Cats are lit by temperature of exhaust gas flow. Oxygen sensors (newer versions) are electrically heated to get them to operating temperature, which is something like 800 degrees. Frequent on off cycles allow the cat to cool below the point of proper function.
If I read correctly the XB passed emissions, on the second test, but did not function in the ideal range of what is normally expected. The second oxygen sensor in the exhaust system is there to monitor the function of the cat and the first sensor.

I Don't think Sentra had any codes except for the misfire codes he posted, which means the system should be functioning within acceptable parameters, but the range of acceptable parameters could be far higher than the ideal, which he made clear he was not happy with readings that did not closely match "ideal".

I'm not posting here to question his judgement in that area. Apparently he has a high threshold of personal responsibility when it comes to pollution, which I find to be an admirable sense of personal responsibility.

It may be that to find a balance between his extraordinary efforts at efficiency he has gone outside of the parameters of the design of emission controls that the factory provides.

The question is where is the balance of emissions and efficiency that satisfies him and only him.

It could be as simple as coasting with the engine idling, but that would affect his mileage significantly. I have tried the techniques of engine off and for the amount of work involved to me it was excessive and had some negative consequences as far as longevity of components.

Not a criticism of any one's efforts at conservation just my personal experience. It's also the reason why when I am travelling alone I usually ride my 2011 CBR, weather permitting, which has a cat, fuel injection and a feedback system like late model cars. I can get 72-85 MPG while employing mild techniques and enjoy the ride at the same time.

Again, Sentra, I hope you can find an acceptable solution. I spent some time thinking about your situation, and try to provide some suggestions based on my knowledge and experience. It does not mean I am right and everyone else is wrong, just some thoughts about possible solutions. They could be right or wrong, I hope they help.

reagrds
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