Wow! 2 stroke Diesels dont pollute

[ciper]

Why doesn’t everything use turbo 2 stroke diesels? Diesel fuel is less volatile, contains more energy for the same volume AND the engines are more efficient.

Cold start issues are a thing of the past, high end engines dont even need glow plugs any longer.

Imagine how much power you would get even from a 1.8 liter engine. It would produce insane amounts of torque and still get excellent gas mileage.

Its a damn conspiracy I tell you, the automakers and fuel refineries are in bed together.

[Yukonart]

Its a damn conspiracy I tell you, the automakers and fuel refineries are in bed together.

But then, we've know this for years. . . .

Totally agree with you, BTW. Pound for pound, diesels are far more powerful and efficient.

[camshaftprelube]

Which 2-stroke diesel are you referring to as far as pollution? I know Detriot diesel, which was the world's largest manufacturer of 2-stroke diesels, was recently bought by diamler-chrysler. The whole 2-stroke line was dropped because they are big polluters.

Unless of course you were being sarcastic, in which case I now look like a jackass.

[ciper]

No, the two stroke diesel doesnt have the same issue as a 2 stroke gas engine because fuel is introduced AFTER the valves close and AFTER the air is compressed.

The only "issue" is that they must have some form of forced induction to push the exhaust out.

Do a goodle for information on the web and you will see that 2 stroke and 4 stroke diesels can be equal as far as pollution per amount of fuel used.

[camshaftprelube]

Seriously though, who makes 2-stroke diesels now? I was under the impression that pollution was doing them in, which sucks, because I'm a big detroit fan.

[ciper]

Im not sure who makes them other than for special purpose uses. If you read the raw data about them its easy to see there are very few drawbacks. Alot of marine applications can be found if you are looking for specific info. Also look for racing airplanes that use them (no joke).

Here is a couple good sites to read
http://www.bsaviation.nl/engine.htm
http://waw.wardsauto.com/ar/auto_chrysler_says_au/
http://www.bestengine.co.kr/eng/busines ... r_low.html
http://www.jgs-ltd.com/valves.html
http://www.rotecdesign.com/

[camshaftprelube]

They used to be popular in city buses, big rigs, generators, etc. because they make awesome power, but they were also big polluters. No new tractor trailers or buses have them, and the epa is cracking down on marine usage. Granted, most of the older ones were mechanically fuel injected, which adds to the problem, but even newer electronically controlled 2-stroke diesels were having hard times with emissions. Perhaps newer add-on emissions-reducing devices could lower the emissions to a point where the epa would be happy, but a new design probably won't happen. None of the major U.S. based manufacturers even make them anymore (like Detroit) or never did. To my knowledge, Cummins, Caterpillar, International never made a 2-stroke, or one that was popular, anyway.
I did a Google search on 2-stroke diesels, and couldn't find a manufacturer for any automotive ones, or big truck. Just smaller marine and airplane.

[evolutionmovement]

Most new cars being sold in Europe are now diesels for the very reason of mileage and power vs. gas. They run forever, aren't as loud anymore and use direct injection which greatly improves driveability and emmissions. The Europeans all are foaming at the mouth to bring them here, but there's a bad perception of diesels here and I think the domestic automakers are trying to delay this as much as possible since they build no good small diesels. The issue at stake is that we need low sulfur diesel so that the particulate traps they install in Europe will work here (they clog with our diesel). Without the traps, diesels are free to spew all that black shit and are a nasty source of pollution (particulates are the biggest form of diesel pollution and a carcinogen as well as a major contributer to our atmospheric problems. Almost if not all other emissions are less than that of gas engines for at least the fact that not as much fuel is burned per cycle, although more complete combustion is another factor.) The Bush administration was sitting on this (what else is new, the oil companies can make more profits from cheaper diesel as well as keep more fuel hungry gas cars on the road), but I believe it finally went through that low sulfur diesel is required for 2007. Who needs hybrids with this new generation of diesels?

Of course I'm talking 4-stroke. I don't see how 2-stroke diesel wouldn't have the same issues of high HC emissions as gas 2-strokes.

Steve

[camshaftprelube]

They don't have high hc emissions, but particulates and NOx, yes.
They don't have fuel travelling around the crankcase like a gas 2-stroke, they have a blower evacuate the cylinder during the exhaust/intake stroke.

[Legacy777]

you can take care of NOx with a catalyst & according evolution.... with the low sulfur desiel & particulate traps you can take care of the particulate matter.

[camshaftprelube]

I think it may be too late for 2-stroke diesels as we know them, unless some redesigning is done to lower emissions without the aid of add-on stuff. Also, low sulpher diesel is good, but would disrupt the balance in the diesel world. I don't think Low sulpher diesel lubricates very well, and it could mess with current engines in use.

[evolutionmovement]

Of course NOX due to the high air/fuel ratio. Forgot to mention it. Multiple cats and proper combustion chamber design would probably be able to clean that. So what is a 2-stroke deisel? Is it valveless like a gasoline 2-stroke? How do they eliminate the intake exhaust overlap or do they? Is that what the scavenging pump is for? I remember Pininfarina had a few 2-stroke sports cars it developed that were supposed to be way ahead of their time, but no one wanted to help them produce it.

Steve

[vrg3]

A 2-stroke diesel has exhaust valves but not intake valves. Fuel is supplied via direct injection, so during the "overlap" period, only air passes through. And the air is supercharged, so it blows out any exhaust gases still present.

[evolutionmovement]

Thanks. I figured they used direct injection, but couldn't figure out how it would work without a valve. Thanks to diesel technology, they're starting to use direct injection in gas engines in Europe now. It works like a modern effective version of stratified charge injection.

I've never followed 2-strokes that closely as I hate the noise and pollution they generate in gas form. Everytime my assmonkey neighbor takes out his huge collection of gas-powered gardening tools I want crush his skull with them, including the fat grandson with his 2-stroke scooter who goes up and down the driveway on the side of my house.

Steve

[vrg3]

2-stroke diesels have nothing to do with 2-stroke spark ignition engines. They're not that different in the end from 4-stroke diesels; in fact, the company ciper linked to last (Rotec Design) makes kits to convert 4-strokes to 2-strokes.

I found a good explanation of 2-stroke diesels:

http://www.howstuffworks.com/diesel-two-stroke1.htm

HowStuffWorks rocks.

[123c]

People, don't get me started on Diesel's

[ciper]

The howstuffworks page agrees with me, the two stroke diesels can pollute equal or less than a standard diesel.

What people dont realize is a properly running diesel is better for the enviroment in many ways, one good example would be the life of the average gasoline engine versus the average diesel.

Plus look at all the the old diesels that run left over resteraunt oil. Even standard diesel barely evaporates and isnt as reactive as gasoline.

[123c]

Yes, Diesels will last a very long time, the most important thing with a diesel is to change the oil hot and often. The typical MB diesel will last 300,000 miles, and some will go to 500,000, and a few have gone 1,000,000 miles. The VW diesels are ok, but they are such high compression, that they are prone to head gasket failure, or even worse the bolts coming lose . Another good thing about diesels, is that they can run on many fuels, and mix in stuff with the fuel. I was going to start mixing in used oil with the MB, but never got around to do that.

The one truck that I wish I could own right now is a Mercedes Unimog 606/616. Those have a nice big 5.9 litre diesel engine in them, and will go almost anywhere.

[ciper]

Here are some great images of older Mogs in the US
http://www.rockymountainmoggers.com/unimogs.html

[vrg3]

ciper - Yeah, the ability to run renewable fuels is huge. My friend's starting to make biodiesel for his Jetta TDI. I save my used cooking grease and oil for him. :)

You can actually put out a match in diesel fuel. Waaay safer than gasoline. Tastes yucky, though. :)

[ciper]

Diesel also takes less refining. If more people used it the price would drop even farther.

Some of these fry oil guys actually get all the fuel for free!

[123c]

Ok, here I go...

Diesel is much safer than gasoline, and I actually like the taste better of diesel than gasoline... It's imposible to get the stuff to burn, unless the heat and pressure is great enough...

I would actually like to maybe own a VW tdi someday, but I can't afford one right now. They are very nice engines, and are super efficent, even more so than many of those gas-electric hybrids on the market today. They also act more like a gasoline car than a diesel, and are very quiet. Maybe I will buy one of these sometime to replace the MB...

As for Unimogs, they are so awsome, and the noise from them is even more awsome. I almost crapped my pants the first time I heard/saw one, I could hear it coming from like a mile away... They even get faily decent milage, considering their size and gearing. I have heard that many owners get about 16mpg or so, but the only drawback is the top speed for the 606/616's is less than 60mph. I would like to find one someday, but to find one in drivable condition for under $5000 is a very hard thing to do...

[evolutionmovement]

Up here the bastards charge more for diesel than low grade gas. The price would probably have to come down with more demand, though. I think another reason for diesel longevity is the low speed operating range (as well as the obviously higher strength components). Like steam engines - they barely turn over, but since they make so much torque they don't need to. Biofuel has actually the same problem as diesel with the particulates, but then with those particulate traps...

I'd love to see a EJ series diesel nad have been wondering about one for the last year or so. Honda just introduced an alloy block and head diesel for their European Accord, so now I'm wondering... The heads would have to be completely reengineered, but with new pistons, I wonder if the Legacy turbo block and bottom end could handle it.

Steve

[camshaftprelube]

All of my arguements are based on the over-the-road diesel market. Diesels definately have a place in cars, and I would buy one if I knew that it was serviced well.

2-stroke diesels have a stigma attached to them. The most famous were the detriot diesels. 6v53, 8v71, 8v92, etc.etc. Extremely powerful for their size, and the most unique sound in the world. They all leaked like sieves, slobbered like hell, and smoked like a b_tch. With a modern redesign, and something other than mechanical fuel injection, they might be clean enough to consider.

Something about having a power stroke every revolution does bad things with emission production. Granted, modern add-on emission lowering devices have a positive effect on this, but the epa and engine manufacturers don't want these things on new engines. They want to be able to slap a cat on it and call it good. But the current designs won't allow it.

One of the big steps taken in the lowering of NOx emissions is to put EGR on diesels. It's a pain in the ass, and it destroys the motor oil (particulates in the oil), and it also has a negative effect on longevity. It also cuts power. Diesels love high cylinder pressure and temps, but the things that does to NOx formation is devastating.

[vrg3]

With a modern redesign, and something other than mechanical fuel injection, they might be clean enough to consider.

Right... No modern diesel engine is like the old ones in efficiency, emissions, noise, or.... well, almost any complaint people had about old diesel engines.

Something about having a power stroke every revolution does bad things with emission production.

Not with diesels!

With spark-ignition it does because lubricant mixes with the intake charge and some intake charge goes out the exhaust uncombusted. Neither is true with diesel 2-strokes.

One of the big steps taken in the lowering of NOx emissions is to put EGR on diesels. It's a pain in the ass, and it destroys the motor oil (particulates in the oil)

Destroying the oil doesn't happen so much since we have really well-engineered oils and the engine lube can be changed regularly. However, a problematic side effect of the extra gunk in the oil is that crankcase vapors get really disgusting. They'll coat the inside of the intercooler of a turbodiesel much worse than any of our Subarus coat the insides of ours.