Low Sulfer Diesel... - PeachParts Mercedes-Benz Forum

190D22 · #1 05-04-2002, 09:55 PM

I've been reading in the paper some dispute over diesel engines and their future. So far... not looking to bright for the engines' future! The engine and car manufactorers are trying to argue that they will be able to soon make a low emission diesel engine and still have all the benefits of diesels that we all love (great mileage and high torque). But they were shot down by super strict regulations planned for 2007. The manufactorers argued that the figures are impossible for them to achieve, especially in 5 years time. So, they are going to start making low sulfer diesel.

What does low sulfer diesel mean for us? I know that sulfer really doesn't have any use, power wise, ::I think:: I imagine it will at least cut down on the smell of our exhaust. Prices will definately go up because of the extra refining process! arrrgh! I paid 1.259 today and I want to keep those beautiful numbers!

Thoughts? Answers?

Thanks.

Gilly · #2 05-04-2002, 10:28 PM

What I have heard is that MB (and possibly other companies) have engines that would meet emission standards for quite some time to come IF the engines were run on #1 Diesel fuel. Most of the country has #2 Diesel fuel. Up north here, we have #2, but in the winter it is "cut" with #1 to keep it from gelling in the pipelines, in the fuel tank truck, in the underground tanks, etc and in the car fuel tanks. It would probably take some doing to get the fuel companies to agree to always have straight #1 Diesel fuel available for the engines that require it to meet emissions. Would they come up with some special way to ensure #1 was put in those cars, like when unleaded fuel became required (fuel filler neck restrictors)? That's practically what it would take.
Gilly

190D22 · #3 05-04-2002, 10:32 PM

Here in ohio we do the 2 to 1 in the winter time. I know when #1 is here because it's WAY easier to start at freezing temp! Interesting you compared it to the unleaded fuel thing, because that's what the paper compared it to as well!

Gilly · #4 05-04-2002, 11:30 PM

Right, it is about the best comparison I can make. With the leaded vs unleaded, the main reason why the tank was designed with the restrictor plate (still in use today, even though in the US anyways TEL is long gone) is that the lead will plug the catalytic converter, so it's really "incompatable" with a vehicle with a catalytic converter.
With the newer Diesel engine problem, if they don't first of all get the oil companies to offer non-blended straight #1 Diesel fuel, it's a moot point. How can they offer the engine in a vehicle that will meet emissions standards, but only if it runs on a type of fuel that is widely unavailable? Secondly, if they do agree to it, then if they don't come up with something that will prevent misfuelling (the filling with #2 Diesel fuel) then probably the government won't allow it either, as there is no way to even slightly guarantee that the vehicle won't be misfuelled with #2 Diesel.
A big problem that I see is that to offer the #1 only will require another tank in the ground, another pump at the island, seperate chamber in the fuel hauler, etc etc all the way back to the refinery to keep the #1 seperate of the #2. And all for what? So Mercedes and a few other companies can offer these engines?
Hopefully within a few years they will work it out so it'll beat emissions standards on #2 Diesel.
Gilly

mplafleur · #5 05-05-2002, 10:28 AM

Not just Mercedes, but here at Ford we are well aware of the planned decrease in sulpher content that has been mandated. We sell a fair amount of trucks with diesel engines and as stated a few months ago by the COB, diesels are going to be a major thrust in the ongoing effort to increase corporate fule mileage. There are new diesel engines in the works including one for the F150 and all the SUVs. Mercedes will have the backing of the big three with them. Oh that's right, Mercedes is one of the big three now...

psfred · #6 05-05-2002, 12:16 PM

#2 diesel fuel is pretty crude fuel by modern standards -- nothing at all like Jet A (or B, if you can find it!). It is usually simply the middle fraction of crude oil -- the gasoline and some of the just heavier than gasoline components are distilled off, and the tar is left behind. Everything else is #2. Pour points can be pretty high (as anyone who has had their fuel gel can testify), although good stuff has a pour point as low as -30F.

The sulfur is there in complex organic molecules, and has a number of effects -- first and foremost, these compounds tend to provide a large amount of the lubricating qualities of the diesel fuel. Second, the presence of sulfur seems to catalyze combustion, especially uuder high load conditions, and reduce both injector knock and soot formation. These are all good things.

The bads things are emissions of sulfates and other particulates, usually "breathable" -- meaning the particles are small enough to go right down your lungs and stay there), some SO3 is emitted (sulfuric acid -- one of the nasties in acid rain), and I think the production of metal sulfides rather than metal oxides -- the sulfides are more of an environmental problem.

#1 diesel is both more volatile (burns better) and has considerably less heavy end material, so produced less soot from incomplete combustion. Takes more of it to give the same power, though -- less BTU/lb.

I personally suspect the answer is oxygenated fuel (biofuels -- plant or animal fats/oils) to reduce the soot and enhance cleaner combustion over all. Biofuels may also produce less aromatic residue (benzene and substituted benzenes), all of which are bad guys.

Diesel fuel in the US isn't a high quality product, lots of room for improvement there.

Peter

#7 05-05-2002, 06:18 PM

From what I've interpreted from the up and coming emissions levels, and the new fuel regulations, is that these will be GOOD news for the new diesels. The problem, as already stated, is the quality of US fuel. The current US sulphur quantities are damaging to the emissions equipment being offered on European diesel engines. The new regluations will be very near, if not equal to, the specifications that the European markets now follow. This, in turn, will open up the market for more diesel powered vehicles stateside. I'm keeping my fingers crossed...........

The information in the paper that you read is likely misprinted. The new regulations are impossible to meet on current fuel quality - not the new fuel regs due to take place in '07

190D22 · #8 05-05-2002, 07:18 PM

I must have misinterpreted it. But that is a very good thing, the new fuel will open up a market in the US for more diesel vehicles. I am still trying to talk my father into a mercedes, he seems to be swinging more towards Lexus... If they come out with more diesels I may be able to talk him into a diesel C class. I love my diesel! If I had the money I'd go out and buy a ford F-250 7.5L turbo diesel and have the dual alternators so I can load that bad boy up with accesories!

lrg · #9 05-06-2002, 02:06 AM

California has had low sulphur diesel for several years now. It is the only diesel available in the state for trucks and autos and as I recall caused a 5-10c increase in the "at the pump" price of our fuel. The lubricity issue is easily addressed with additives (which most of us use anyway) but the other byproduct is that it tends to cause some fuel system leaks, especially for older cars with somewhat dried out rubber hoses. In my case these were all easily fixed and I've had no problems since shortly after the mandated change. I don't know if the Federal standards are going to be different than the California standards are now but I'll bet they are close if not the same. All said and done I've not noticed a big difference since the new fuel was mandated (except price) and would welcome the federal change because when more refineries are producing low sulphur diesel it will likely help drive our prices down a bit.....or am I dreaming?

#10 05-06-2002, 02:18 AM

Actually, current CA regs for sulphur content have been in use nationwide for some time now. The new regs, are very similar to European specs for sulphur content.

lrg · #11 05-06-2002, 02:21 AM

Interesting, I didn't know that. Thanks.