Diesel emission problem solved! Inject urea into a cat converter.(I'm serious). - PeachParts Mercedes-Benz Forum

Carrameow · #1 04-11-2008, 01:22 AM

From a world renowned magazine on Economics
"To meet California’s tough emission standards, carmakers have had to find ways to mop up the diesel’s unwanted NOx and trap its soot. The answer is to inject urea into a catalytic converter in the exhaust. The heat turns the atomised urea into ammonia, which, in turn, converts the hot exhaust gases into nitrogen and water. The soot is trapped by a fine mesh in a particulate filter added to the tailpipe.

Sounds complicated, but the diesel’s extra requirements cost less than you might think. For instance, Mercedes-Benz’s big new diesel sedan (the E320 Bluetec) has a sticker price of $53,025, while the petrol version of the same car costs $52,025. The Mercedes diesel gets 23 miles per gallon in the city and 32 on the highway, compared with 17 and 24 for the petrol version"

compress ignite · #2 04-11-2008, 01:56 AM

Bermuda Triangle of the Internet.

I gotta stop hanging out here early in the Morning.The News Flash(s) are
taking on a "Back to the Future" effect.

Carrameow · #3 04-11-2008, 02:03 AM

I checked Google and its not a hoax..its coming soon

http://www.dieselnet.com/tginfo/abstracts.html

http://www.greencarcongress.com/2005/04/mitsubishi_fuso.html

http://www.autobloggreen.com/2008/02/04/paccar-to-use-urea-injection-and-egr-to-clean-up-emissions/

http://www.naftc.wvu.edu/NAFTC%20eNews/November%2005/ureainjectionsys.html

#4 04-11-2008, 03:02 AM

Old news. Its been around for a few years in Europe already.

Its really an embarrassment to MB and anyone that buys a vehicle with it. It says "We can't make a clean engine so we will put a bunch of junk in the exhaust to make it look clean." Same goes with catalytic converters and particulate (soot) traps.

tompaah7503 · #5 04-11-2008, 04:53 AM

Quote:

Originally Posted by ForcedInduction

Its really an embarrassment to MB and anyone that buys a vehicle with it. It says "We can't make a clean engine so we will put a bunch of junk in the exhaust to make it look clean." Same goes with catalytic converters and particulate (soot) traps.

Why is this an embarrassment? I am not too enlightened in the field of diesel engine combustion theory, but I keep thinking thinking maybe there's an inherent design problem with these engines that never really can be overcome, and thus they require some sort of cleaning of the exhaust.

I understand that PM is created by pyrolysis, increasing the injection pressure might help that but it's already been done to a great extent as I understand. Maybe superheating the fuel before injection could produce more complete oxidation?

And for that pesky NOx problem.. it forms in high temperatures and that's a bit harder to solve..

Cervan · #6 04-11-2008, 04:56 AM

2 cycle "screaming jimmys" wich are detroit's heat the fuel up so much that they require a fuel cooler to keep the diesel under flashpoint. i dont think it makes much diffrence other than viscosity

#7 04-11-2008, 05:03 AM

Quote:

Originally Posted by tompaah7503

And for that pesky NOx problem.. it forms in high temperatures and that's a bit harder to solve..

That is the problem. They are splitting hairs.

PM and NOx emissions are already stupidly low. The levels they are going to reduce it further in '09 only increase fuel consumption, put more wear/stress on the engine, add cost, add complexity, increase maintenance costs, reduce resale value, reduce the useful lifespan and reduce reliability. For what? Reducing emissions that produce an insignificant overall benefit to anything.

Don't you think we should be focusing on reducing our fuel/oil consumption, which would produce a major gain for everyone, instead of focusing on reducing emissions that have debatable results with such small amounts?

This is just politicians playing engineers. They are trying to force naturally inefficient and dirty internal combustion engines to become zero emission engines when it simply isn't possible or reasonably feasible to accomplish.

Engine builders are being forced to hurry up and meet some arbitrary goal that is impossible to reasonably meet in such a short period. Its causing them to spend their time developing exhaust treatment junk to make engine appear clean instead of having the freedom to develop the engine at the necessary pace.

tompaah7503 · #8 04-11-2008, 05:41 AM

Quote:

Originally Posted by ForcedInduction

That is the problem. They are splitting hairs. [...] For what? Reducing emissions that produce an insignificant overall benefit to anything.

Okay, I really didn't have the "what good does it make in the overall picture"-angle, but you're correct. This page shows a number of pie charts of both CO2 and NOx emissions worldwide (and France as a case study), and it's quite clear that a 5%, 10% or even 50% reduction in NOx emissions in transportation doesn't do much good at all. I don't mean it's bad to reduce emissions, but compared to the huge amount that industry and power generation puts out.. it just pales in comparison.
http://www.manicore.com/anglais/documentation_a/greenhouse/evolution.html

Quote:

Don't you think we should be focusing on reducing our fuel/oil consumption, which would produce a major gain for everyone, instead of focusing on reducing emissions that have debatable results with such small amounts?

Absolutely. With peak oil production being just around the corner, it's even more urgent than ever. Be gone 50-mile commutes and the beloved trucking industry.

Even if most of us here at shopforum drive 30 year old vehicles, we should at least feel some pride, since our vehicles gets great mileage and we didn't waste any resources in "consuming" new cars.

ob1 canola · #9 04-11-2008, 08:05 AM

Quote:

Originally Posted by ForcedInduction

That is the problem. They are splitting hairs.

PM and NOx emissions are already stupidly low. The levels they are going to reduce it further in '09 only increase fuel consumption, put more wear/stress on the engine, add cost, add complexity, increase maintenance costs, reduce resale value, reduce the useful lifespan and reduce reliability. For what? Reducing emissions that produce an insignificant overall benefit to anything.

Don't you think we should be focusing on reducing our fuel/oil consumption, which would produce a major gain for everyone, instead of focusing on reducing emissions that have debatable results with such small amounts?

This is just politicians playing engineers. They are trying to force naturally inefficient and dirty internal combustion engines to become zero emission engines when it simply isn't possible or reasonably feasible to accomplish.

Engine builders are being forced to hurry up and meet some arbitrary goal that is impossible to reasonably meet in such a short period. Its causing them to spend their time developing exhaust treatment junk to make engine appear clean instead of having the freedom to develop the engine at the necessary pace.

I couldn't agree more.
I live in a CARB state. I can't buy a new vw tdi.
But i can go out and buy a brand new ford f350 powerstroke.
45 mpg compared to 12mpg.If i look at the lbs of pollution to
mile driven It just doesn't make sense to me. Are the oil companies
in cahoots with the epa?

LUVMBDiesels · #10 04-11-2008, 08:37 AM

I could not agree more... We have been splitting hairs here. Wait until BioD gets really going. BioD put out less PM but more NOx.

Of course when you are burning less fuel, doesn't that equal less pollution?

As far as the urea injection goes, I thought the EPA was not going to allow it as whatever system is used is supposed to last 100,000 miles with no intervention and filling up a pee tank at every other oil change is violates that rule...

TheDon · #11 04-11-2008, 09:33 AM

leathermang · #12 04-11-2008, 10:39 AM

Ok... there are two things which jump out at me in this thread... first... diesel fuel has carbon in it... thus it makes sense that soot is made when it burns....
Second.. the reference to 2 cycle Jimmy's needing a fuel cooler... of course they do... just as a gasoline engine with 21 to 1 compression ratio would need it... the fuel is in there when the air is being compressed... our diesels wait until the air is already compressed to inject the fuel... so the timing of the two getting together makes the fuel cooler moot.

pmckechnie · #13 04-11-2008, 12:20 PM

Any one who wants to know who is incharge of emission regulations and law making should just type in "Who Killed the Electric Car" into google and start reading. I just saw a short movie last tuesday night and I came away very angry. There was a fellow there with an all electric Dodge Decota PU that cost him about 3 cents per mile to drive. He never had to change the oil and filter, never needed an air filter, never had to replace the rusted exhaust and didn't polute. Agreed, some of the power plants polute, but some don't. Overall, they polute much much less than all the cars on the road. We have alternatives now but big oil, our goverment, big car companies, and foreign oil all work together to keep it from happening.
Paul

#14 04-11-2008, 04:56 PM

Quote:

Originally Posted by LUVMBDiesels

As far as the urea injection goes, I thought the EPA was not going to allow it as whatever system is used is supposed to last 100,000 miles with no intervention and filling up a pee tank at every other oil change is violates that rule...

AdBlue is going to be on all of MB's BlueTec Diesels here in '09.

oldiesel · #15 04-11-2008, 07:35 PM

2 cycle GMC engines DO NOT have fuel in the cylinder until the injection event which like all diesels occurs near tdc. The injectors are mechanically operated not unlike the PD Volkswagen although with a push rod and rocker arm instead of directly with the camshaft, They are direct injection without glow plugs and if not worn out start very well in cold weather as long as the fuel has not gelled,and been doing it since 1936. My $.02 Don