Print 29 comment(s) - last by aqaq55.. on Dec 15 at 8:00 AM

NEMo, a new 2 ton diesel engine produced at a university in Munich, Germany, may be able to meet strict new EU restrictions that call for less soot and nitrogen pollution.  (Source: Sebastian Pflaum, TU Muenchen)

Graduate engineer Sebastian Pflaum is among the researchers who have tuned the engine to maximize performance, while minimizing pollution without having to resort to a catalytic converter.  (Source: Sebastian Pflaum, TU Muenchen)

The team has invented a special probe which takes samples of diesel gas mid-combustion. The information they collect can be used to reduce the amount of soot the engine produces.  (Source: Sebastian Pflaum, TU Muenchen)
Who says that big diesel trucks can't be green and clean?

Diesel-powered vehicles like the 2010 Audi A3 TDI won Green Car of the Year at the 2009 LA Auto Show, and many other cars like the Volkswagen Golf have received praise for their efficiency.  Diesels promise much better fuel economies than traditional gasoline engines.  However, their potential is held back by their emissions, particularly in the U.S. where many European diesels are disallowed.

In Europe, standards are about to get tougher, though, forcing diesel makers into a race against time.  One option is to use catalytic converters to remove pollutants, but they degrade over time and more importantly damage performance.  However, meeting the new Euro 6 caps standard without a catalytic converter is a steep challenge.

Researchers at Technische Universitaet Muenchen (TUM), located in Munich, Germany, have developed a new engine that just may be able to meet the tough new standards without necessitating a catalytic converter.  The engine, which may usher in a new era of green performance weighs in at two tons, has hardly any odor of exhaust fumes even when running at full blast.

To design the engine, researchers had to go back to the drawing board.  Modern diesels meet Europe's Euro 5 Norm for emissions by recirculating the polluting nitrogen oxides produced from the combustion of diesel fuel back into the engine.  Mixed with fresh air and re-reacted at a lower temperature, the result is less nitrogen pollution, but more polluting soot.  The new standard calls for a reduction in soot, as well, making this approach impractical.

Instead, the new engine, dubbed NEMo (Niedrigst-Emissions-LKW-Dieselmotor, the German acronym for "lowest emission truck diesel engine), uses a combination of turbocharging and direct injection to burn the fuel more completely.

During recirculation the exhaust gases are compressed to ten times the pressure of the Earth's atmosphere (10 bar), giving enough oxygen for the diesel fuel to burn cleanly.  While the pressure is over twice what current engines can handle, NEMo can handle it with ease.

Improved direct injection also plays a pivotal role.  Traditionally injectors spray large droplets.  Fuel is burned from these droplets, stripping away a layer of fuel akin to "peeling a layer off an onion".  As you peel off more layers, the fuel becomes more dense and compressed, and it becomes difficult for the oxygen to react with the fuel.  The result is soot.  By using higher pressure direct injection, the engine sprays finer droplets, leading to more complete combustion and less soot.  NEMo ups the DI pressure from 1,800 bar to 3,000 bar, allowing this cleaner burn.

Led by Georg Wachtmeister from the Chair of Internal Combustion Engines at the university, the engine team has tune NEMo to almost meet the upcoming standard.  The emissions from the engine are so low they had to invent a new in-engine probe to measure them more accurately.

The team wants to improve their design even more.  They're currently trying to better understand how soot particles form.  To do this they've created the aforementioned probe -- a speedy sample collector that sucks up a tiny sample of combustion chamber gas in one millisecond.  Using the gas sampling valve, 13 samples can be taken during a single ignition, giving the researchers a wealth of new data to better understand and combat soot growth.

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Sounds good...
By Motoman on 12/8/2009 5:05:38 PM , Rating: 2
...hope it can work out in a motor somewhat smaller than 2 tons though. I don't think that would fit in my pickup truck...

RE: Sounds good...
By atlmann10 on 12/8/2009 5:09:29 PM , Rating: 2
Yeah I was thinking about that when I was writing my other reply. However; I am pretty sure a Semi engine would have to produce a lot more horse power, and a ton more torque. They are also large block engines (which is actually :large" and understatement on a semi engine as well. So the adaptation as well as the carry weight for a car or a light duty truck would therefore also be different.

RE: Sounds good...
By corduroygt on 12/8/2009 5:58:06 PM , Rating: 3
10 bar is about 147 psi, it takes a very beefy block, pistons, crankshaft, etc. to withstand that pressure. On turbo street cars, 20 psi is considered pretty highly boosted.

RE: Sounds good...
By Motoman on 12/8/2009 7:53:38 PM , Rating: 2
Are they talking about boost pressure, or the compression ratio at that point? I'm not clear on that...

RE: Sounds good...
By rcr on 12/9/2009 2:01:39 AM , Rating: 1
it is the pressure from the supercharger, so it doesn't really matter for the pistons and so on, because the combusting pressure will be the same (I guess) at around 150bar as at all the other TDIs

RE: Sounds good...
By roostitup on 12/9/09, Rating: -1
RE: Sounds good...
By Runiteshark on 12/9/2009 5:11:05 AM , Rating: 5
150lbs of boost is the pressure going in, not the explosive pressure.

I don't see what the compression ratio, bore, or stroke is on this, but usual diesels are anywhere from 16-22:1. This means anywhere from 2400 to 3300 PSI or around 163-225atm.

RE: Sounds good...
By roostitup on 12/10/2009 3:06:21 AM , Rating: 2
Alright, I stand corrected...sorry.

RE: Sounds good...
By Spuke on 12/8/09, Rating: -1
RE: Sounds good...
By SoCalBoomer on 12/9/2009 2:30:32 PM , Rating: 2
They're working on a Semi engine - heck, the motor in my Dodge 2500 Cummins Turbo-diesel weighs in at nearly 3/4 ton (not including the trans) and if you've seen the Peterbilt Trike episode of Monster Garage (that was an awesome episode) you'll notice that semi truck engines are HUGE. . . so 2 tons isn't that unreasonable. . .

Also, the compression ratio that they're talking about here is astronomical compared to what they're presently using, so it would require stronger cylinder walls and so forth to contain it all.

Exciting, though. I love diesels that WORK.

RE: Sounds good...
By kkshoe1210 on 12/9/09, Rating: -1
RE: Sounds good...
By kkuulr on 12/12/09, Rating: -1
RE: Sounds good...
By aqaq55 on 12/15/09, Rating: 0
As a semi-truck driver..
By TheEinstein on 12/8/2009 11:48:19 PM , Rating: 5
This engine is actually kinda light sounding... My Semi weighs 12,500 on the steers and 16,000ish (Fuel differences) on the drives when I am bobtailing.

Lots of weight in the frame of course, but I reckon the engines weigh about 2-5 tons mattering on type (I have a D-16 in my Volvo 780)

There is a number of ways US truck manufactorers are looking to 'solve the California problem'. California keeps upping standards so fast, so hard, it's a challenge to think ahead of them to future needs.

One result is to have 2 burn stages. The normal engine stage where you provide your motion, then a second stage when the results go to exhaust out, where they are subjected to intense and severe temperatures which burn up the soot and only emit CO2. Another aspect involves using a variety of potential future additives in a cleaning stage which will bind unwanted materials with other materials to form 'unharmful' variations. A final variant looks at somehow making the diesel (as shown above) into smaller particles thus getting better burn.

Standards are really running amok under Obama... I say this with all belief it is true. 10% of semi-trucks will be rendered unable to drive(These the older, but more reliable trucks, with 2+ million miles on them), and 15% of drivers will be unable to drive due to new regulations. This is 15% will be lifetime removed from having their CDL's for a huge swath of potential issues, including weigh stations run amok.

April is supposed to be trigger month for a lot of this. If prices in May skyrocket, you know why...

RE: As a semi-truck driver..
By Lord 666 on 12/9/2009 2:41:16 AM , Rating: 2
Great input. However, thought that existing diesel vehicles (light and heavy duty) were grandfathered until 2030 for emissions. Was actually counting on this with my 2006 Jetta TDI and the PD motor able to burn about any mix.

Not that the current administration wouldn't think twice about double talking and going back on previously agreed laws, but the regulation I'm thinking of was established in 2005.

RE: As a semi-truck driver..
By TheEinstein on 12/9/2009 6:39:11 AM , Rating: 5
Every truck is getting hit with other sorts of 'requirements'.

For instance a new law on Refrigeration units requires a new part on all pre-existing ones starting Jan 1st. This is to 'reduce their smog potential'. It's not Federal, but it is Federally allowed under current administration...


Well it is called "TRU" for short, standing for Transportation Refrigeration Unit. It is a California law which will probably affect 40,000 total trailers.

My company, with 2,000 trucks, is one of the medium sized refrigeration units. I would estimate there is about 100,000 total refrigeration trucks and maybe 300,000 trailers.

The regulation affects any trailers going into California. This means that a lot of carriers are deciding if they need California versus the costs of doing business in California.

40,000 out of 300,000 may not seem to be many, but consider it is 13% of the total. This will cost affect all of America in the long run. This is just one end run around all sorts of protections they are running.

You might be ok with your grandfathered vehicle, in about 8 States, if the Libs and Greens have their way. But in the others, expect all sorts of required 'additions', 'taxes' (or other things that do not sound like taxes, but equate to the same thing), 'fees', 'penalties' and such. They will try to force you to give up your vehicle as they are currently trying to force some of the independent drivers to give up their greater than 8 years old of semi-trucks.

Verrry Intaresstingggg
By atlmann10 on 12/8/2009 5:05:11 PM , Rating: 2
This is what I thought they would be talking about when I saw the Audi most fuel efficient post. I wonder why this higher compression ratio spray is not used or at least researched in a car. I also thought an American auto make was researching (GM I Think it was) it for their trucks.

RE: Verrry Intaresstingggg
By bupkus on 12/8/2009 5:34:14 PM , Rating: 2
By the photos I believe this 2-ton engine is a laboratory prototype with no effort to minimize it's mass. I'm sure now that they have proven the technology works additional efforts will begin to shrink it down to practical sizes after they reach their remaining research goals.

RE: Verrry Intaresstingggg
By teldar on 12/8/2009 5:33:34 PM , Rating: 2

I believe these injectors are used in car engines like the VW (Audi) TDI's. Ford's EcoBoost uses a pump that is able to create up to about 2100 psi. A pittance in comparison, but still much more efficient than lower pressure port injection.

Bosch currently uses piezoelectric injectors in its third-generation common rail system to introduce five or more injections per cycle with a maximum injection pressure of 1,600 bar. Higher performance and heavier vehicles–those weighing 3,900 lb or more –require injection pressures of 1,800 bar. "Our next-generation common rail system uses a hydraulically amplified diesel injector that can produce injection pressure of up to 2,500 bar

So these high pressure injectors are out there. The only problem with them is cost and weight due to them being advanced machinery which require high precision and high quality materials to be able to stand up to what they are designed to do.

And it appears that Bosch spent 5 billion euros developing these pizoelectric injectors, just part of the high pressure injection system. So NOT cheap.

RE: Verrry Intaresstingggg
By Spuke on 12/8/09, Rating: -1
RE: Verrry Intaresstingggg
By Spuke on 12/9/2009 2:40:02 PM , Rating: 2
Rating me down does not remove the fact that this technology already exists in production diesel engines. ALL pickups trucks use this. My 2006 Ford uses common rail tech. This isn't new stuff guys.

Good effort for sure
By Beenthere on 12/9/2009 9:37:26 AM , Rating: 1
This newer Diesel design incorporates some of the tech that VW/BMW/M-B currently employ in both their Diesel and Direct injection gas engines. It's a logical next step. The Blue Diesels sold for pass car use in the U.S. are very clean and practical. No reason why big rigs can't raise the bar a little higher, especially with the mpg and miles traveled per year.

RE: Good effort for sure
By tastyratz on 12/11/2009 9:01:20 AM , Rating: 2
I find the lack of emissions control and standards on big rigs apalling. Many times I have been caught behind a big rig which emits a cloud of emissions enough to seriously impact visibility for many car lengths of space. I cant imagine how many hundreds or thousands of cars worth of emissions are being output by a vehicle like that. I believe we have been a little too hard on regular automakers with emissions being so astronomically low now, while these larger trucks have gone lax. There is 0 reason we SHOULDN'T be trying to target them for a reduction in emissions.

Granted I usually don't ever agree with any outrageous laws from the republic of California, and they are certainly taking this concept to the extreme... but I think somewhere in the middle is pretty justified as well as long overdue.
By caseyverdant on 12/11/2009 3:35:16 PM , Rating: 2
Better catalytic converters can improve biofuel efficiency, but there are even better alternative fuels available. If you’re interested in clean cars or any other alternative energies or green technologies, check out It has hundreds of case studies on emerging green technology. It's also the largest b2b green directory on the web.

By etrading65 on 12/11/2009 7:20:35 AM , Rating: 1

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