TheEEStory.com

student wrote:

Y_Po wrote:

student wrote:

Y_Po wrote:

I need explanation for their claims, not claims themselves. I really see no benefit of that engine layout.

Explanations have been equation light.

Motors have efficiency curves. Basic concept of modularity is to bring portion of usage higher on the motor efficiency curve. This allows the motor to average higher on the curve.

You are not answering the question.

Claim is fewer kWh in fuel per kWh at the wheels. Above is a list of methods. I'd enjoy more details myself. Still waiting on the demo which was supposed to occur by the end of last year. The newly inked deal is nice but I'm looking forward to the 100 mpg on the EPA combined cycle demo.

The big advantages are from reduction in friction. The pistons travel 1/2 as far (total) for any two stroke when compared to a four stroke.

In this design each piston travels only 1/2 of a given cylinders stroke (but there are 2 of them per cylinder) this reduces the piston surface velocity (a speed limiting constraint).

The engine is without traditional mechanical valves. Did you ever try to turn a camshaft by hand? The commensurate reduction in friction and torque requirements that valve train mechanism would require is a big winner.

The crankshaft is offset so that the throw of the pistons in nearly opposite each other reducing main bearing loads to mainly torque. This torque load is substantial, but carried by the crankshaft rather than twisting and pushing against an engine block. This balanced load therefore reduces the friction resistance on the main bearings as well.

While not helping the thermal efficiency in a compelling way, the fact that the power to weight ratio is high would improve any vehicle systems range (less weight to drag around and accelerate).

The advantage in modular design (particularly attractive for extended range operation - think original A-160 drone coptor). The design concept would include two modules coupled for full power(takeoff and travel)and would shut off a module for lower power operation. This eliminates parasitic drag from rotating the unused module and allows the operating engine to operate at a more efficient output than it would if it were sharing the load. I have wondered is the module displacement might be even more flexible if their output was say 1/3 and 2/3's or 40% and 60% so there would be a greater range of efficient output for operation.

Last edited Wed, 23 Feb 2011, 6:35am by devotEE

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devotEE wrote:

student wrote:

Y_Po wrote:

student wrote:

Y_Po wrote:

I need explanation for their claims, not claims themselves. I really see no benefit of that engine layout.

Explanations have been equation light.

Motors have efficiency curves. Basic concept of modularity is to bring portion of usage higher on the motor efficiency curve. This allows the motor to average higher on the curve.

You are not answering the question.

Claim is fewer kWh in fuel per kWh at the wheels. Above is a list of methods. I'd enjoy more details myself. Still waiting on the demo which was supposed to occur by the end of last year. The newly inked deal is nice but I'm looking forward to the 100 mpg on the EPA combined cycle demo.

The big advantages are from reduction in friction. The pistons travel 1/2 as far (total) for any two stroke when compared to a four stroke.

In this design each piston travels only 1/2 of a given cylinders stroke (but there are 2 of them per cylinder) this reduces the piston surface velocity (a speed limiting constraint).

The engine is without traditional mechanical valves. Did you ever try to turn a camshaft by hand? The commensurate reduction in friction and torque requirements that valve train mechanism would require is a big winner.

The crankshaft is offset so that the throw of the pistons in nearly opposite each other reducing main bearing loads to mainly torque. This torque load is substantial, but carried by the crankshaft rather than twisting and pushing against an engine block. This balanced load therefore reduces the friction resistance on the main bearings as well.

While not helping the thermal efficiency in a compelling way, the fact that the power to weight ratio is high would improve any vehicle systems range (less weight to drag around and accelerate).

Bullshit! Your math is bullshit.
There is no reduction in friction in cylinders.
This thing is equivalent to 2-cylinder engine.
And overall friction losses are greater, because you have two shafts with set of gears, and friction in shafts itself is greater (compared to conventional multicylinder engines).

It has absolutely no advantage to two-cylinder 2-stroke engine the whole headless design is bullshit.

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Y_Po wrote:

devotEE wrote:

student wrote:

Y_Po wrote:

student wrote:

Y_Po wrote:

I need explanation for their claims, not claims themselves. I really see no benefit of that engine layout.

Explanations have been equation light.

Motors have efficiency curves. Basic concept of modularity is to bring portion of usage higher on the motor efficiency curve. This allows the motor to average higher on the curve.

You are not answering the question.

Claim is fewer kWh in fuel per kWh at the wheels. Above is a list of methods. I'd enjoy more details myself. Still waiting on the demo which was supposed to occur by the end of last year. The newly inked deal is nice but I'm looking forward to the 100 mpg on the EPA combined cycle demo.

The big advantages are from reduction in friction. The pistons travel 1/2 as far (total) for any two stroke when compared to a four stroke.

In this design each piston travels only 1/2 of a given cylinders stroke (but there are 2 of them per cylinder) this reduces the piston surface velocity (a speed limiting constraint).

The engine is without traditional mechanical valves. Did you ever try to turn a camshaft by hand? The commensurate reduction in friction and torque requirements that valve train mechanism would require is a big winner.

The crankshaft is offset so that the throw of the pistons in nearly opposite each other reducing main bearing loads to mainly torque. This torque load is substantial, but carried by the crankshaft rather than twisting and pushing against an engine block. This balanced load therefore reduces the friction resistance on the main bearings as well.

While not helping the thermal efficiency in a compelling way, the fact that the power to weight ratio is high would improve any vehicle systems range (less weight to drag around and accelerate).

Bullshit! Your math is bullshit.
There is no reduction in friction in cylinders.
This thing is equivalent to 2-cylinder engine.
And overall friction losses are greater, because you have two shafts with set of gears, and friction in shafts itself is greater (compared to conventional multicylinder engines).

It has absolutely no advantage to two-cylinder 2-stroke engine the whole headless design is bullshit.

Relax Po. Go back to school. If you bothered to read I said: "The pistons travel 1/2 as far (total) for any two stroke when compared to a four stroke." This is a two stroke v. four stroke comparison.

Then if you bothered to read I said: "In this design each piston travels only 1/2 of a given cylinders stroke (but there are 2 of them per cylinder) this reduces the piston surface velocity (a speed limiting constraint). This comment relates to engine speed not that friction isn't an issue, but the advantage is power output v. thermal losses. Since the entire package is smaller it looses less heat than a big engine. You did study the 2nd law?

Finally Po, "Did you ever try to turn a camshaft by hand? " Reply to this and then tell the world why is does not matter.

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devotEE, OK then.
2-stroke has always had that "advantage" so why are they not used instead of 4-stroke?
I want to see advantage this bullshit gives.

And again, VW refused to fund this engine.

And yes, I did crank crankshaft. Not terribly hard considering it is not properly oiled at rest.

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There is nothing new under the sun this is old shit and was tried out over 50 years ago and found wanting, why I don't know and secondly I don't really care. Lets just leave it at that. Here is the design for a similar engine from 1954 that was even put into production.

http://www.sa.hillman.org.au/TS3.htm

Y_Po wrote:

devotEE, OK then.
2-stroke has always had that "advantage" so why are they not used instead of 4-stroke?
I want to see advantage this bullshit gives.

And again, VW refused to fund this engine.

And yes, I did crank crankshaft. Not terribly hard considering it is not properly oiled at rest.

Historically 2 strokes have polluted more and have a reputation for a shorter life. But that is mainly due to a lack of sufficient engineering development. Perhaps insufficient technology was available at the time both 2 and 4 stroke engines were put in play. In the end, it is a matter of one tech winning over the other and infrastructure being built for 4 stroke. Sort of like Beta-max versus VHS video tapes.

from #34

Y_Po wrote:

devotEE, OK then.

Po, You can just stop there.

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RmW wrote:

Y_Po wrote:

devotEE, OK then.
2-stroke has always had that "advantage" so why are they not used instead of 4-stroke?
I want to see advantage this bullshit gives.

And again, VW refused to fund this engine.

And yes, I did crank crankshaft. Not terribly hard considering it is not properly oiled at rest.

Historically 2 strokes have polluted more and have a reputation for a shorter life. But that is mainly due to a lack of sufficient engineering development. Perhaps insufficient technology was available at the time both 2 and 4 stroke engines were put in play. In the end, it is a matter of one tech winning over the other and infrastructure being built for 4 stroke. Sort of like Beta-max versus VHS video tapes.

You think Honda, Ducati, Yamaha, Suzuki, BMW, Kawasaki didn't have sufficient technology and engineering know-how to improve 2 stroke motors during the 40 years they were a popular choice to power both race and recreation motorcycles?

Y_Po wrote:

I vaguely remember that old german dude saying that VW did not want this engine when he was working there. I wonder why they did not want it.

It has always been possible to make cars with appreciably more fuel-efficient engines than mass produced cars use. The reason they are not mass produced is that they are considerably more expensive to manufacture, and often use modifications** which cause the pistons to wear out quickly.

If you look around on the Internet, you can easily find highly customized full-sized cars which get 100+ MPG.

And BTW, most or all of the European so-called "efficient diesels", which the diesel-heads on this forum make wildly inflated claims for, *do* use more expensive motors.

**Such as running an ultra-lean fuel mixture, which causes extreme temperatures inside the pistons, temperatures actually high enough to melt the surface of the metal.

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Cobraphx wrote:

RmW wrote:

Y_Po wrote:

devotEE, OK then.
2-stroke has always had that "advantage" so why are they not used instead of 4-stroke?
I want to see advantage this bullshit gives.

And again, VW refused to fund this engine.

And yes, I did crank crankshaft. Not terribly hard considering it is not properly oiled at rest.

Historically 2 strokes have polluted more and have a reputation for a shorter life. But that is mainly due to a lack of sufficient engineering development. Perhaps insufficient technology was available at the time both 2 and 4 stroke engines were put in play. In the end, it is a matter of one tech winning over the other and infrastructure being built for 4 stroke. Sort of like Beta-max versus VHS video tapes.

You think Honda, Ducati, Yamaha, Suzuki, BMW, Kawasaki didn't have sufficient technology and engineering know-how to improve 2 stroke motors during the 40 years they were a popular choice to power both race and recreation motorcycles?

That is correct. Japanese & European markets were dominated by the US market. Japanese cars were built to enter the US market. The EU brought about a consolidated european market, only over the past 15 or so years.

The whole thing kinda reminds Weir and EEstor.
Old geezer who does not seem to have done anything significant in his life retires and starts the company which will turn the world around. Where have he been before? why could not he leave VW earlier? If this thing is such a great thing.

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Lensman wrote:

(with snip edits)
And BTW, most or all of the European so-called "efficient diesels", which the diesel-heads on this forum make wildly inflated claims for, *do* use more expensive motors.

**Such as running an ultra-lean fuel mixture, which causes extreme temperatures inside the pistons, temperatures actually high enough to melt the surface of the metal.

Lens, I'm sure you are aware that A L L diesels always are lean(fuel air ratio on the lean side of stoichiometric)except at WOT (wide open throttle).

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Y_Po wrote:

The whole thing kinda reminds Weir and EEstor.
Old geezer who does not seem to have done anything significant in his life retires and starts the company which will turn the world around. Where have he been before? why could not he leave VW earlier? If this thing is such a great thing.

It looks like he did leave VW earlier and started his own design shop about 14 years ago. VW paid him to do the 2009 Jetta TDI. He's done work for other companies like Viessmann Werke. He's been on the board of Rheinmetall/Pierburg GmbH and Viessman as well as general director of Turbodyne. Renault, Borg Warner, and Mannheimer Ingenieurdienstleister ACP are all looking into his electrically controlled turbocharger for inclusion in Formula 1 as early as 2013.

It looks like Hofbauer's rolling in cash. He's not doing EcoMotors for the money. He's also apparently Austrian and teaches (taught?) at Oakland University in Rochester. His patent on the OPOC is under Advanced Propulsion Technologies Inc and licensed to EcoMotors. It looks like his own gig as well.

No comparison to EEStor. EcoMotors people are career motor people and have demonstrated most design targets on the dynamometer.

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devotEE wrote:

Lensman wrote:

(with snip edits)
And BTW, most or all of the European so-called "efficient diesels", which the diesel-heads on this forum make wildly inflated claims for, *do* use more expensive motors.

**Such as running an ultra-lean fuel mixture, which causes extreme temperatures inside the pistons, temperatures actually high enough to melt the surface of the metal.

Lens, I'm sure you are aware that A L L diesels always are lean(fuel air ratio on the lean side of stoichiometric)except at WOT (wide open throttle).

Thanks, DevotEE. Yes, I was rather careless in not differentiating between gasoline powered ICEs and diesel powered ones in my post. Gasoline-powered cars may be customized for ultra-high MPG by tweaking them to run an ultra-lean fuel/air mixture, but AFAIK this doesn't work with diesel-powered cars.

But, for full disclosure, you're giving me credit for knowing more about the operation of the ICE than I actually do.

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RmW wrote:

Cobraphx wrote:

RmW wrote:

Historically 2 strokes have polluted more and have a reputation for a shorter life. But that is mainly due to a lack of sufficient engineering development. Perhaps insufficient technology was available at the time both 2 and 4 stroke engines were put in play. In the end, it is a matter of one tech winning over the other and infrastructure being built for 4 stroke. Sort of like Beta-max versus VHS video tapes.

You think Honda, Ducati, Yamaha, Suzuki, BMW, Kawasaki didn't have sufficient technology and engineering know-how to improve 2 stroke motors during the 40 years they were a popular choice to power both race and recreation motorcycles?

That is correct. Japanese & European markets were dominated by the US market. Japanese cars were built to enter the US market. The EU brought about a consolidated european market, only over the past 15 or so years.

You've lost me... Motorcycle manufacturers designed, manufactured and sold millions of two stroke motorcycles in the last century.

You're saying that because they were selling them primarily in the US market they were hamstrung? Were there US regulations in place preventing manufacturers from investing in R&D to improve the motors? What specifically about the US market kept them from engineering better two stroke motors for the 40 years (1960-2000) they were popular? The work done to develop two stroke racing engines for MotoGP, Motocross, Baja and other motorcycle racing series didn't require engineering know how? You're certain that none of the experience in racing improved two stroke motors?

Two stroke motors DID improved since being introduced in the early 1900's. They are smaller, lighter, less complex and more power dense, than four stroke motors. Unfortunately they also pollute more, and are less reliable over the long haul.

OPOC might be a great motor. If it works as described, it will certainly make a great ICE for a future Volt like vehicle.

From Car and Driver:

Imaginative new engine concepts are a dime a dozen. Our technical director usually keeps a fat file full of them labeled “crackpot engines.” Most never even reach the prototype stage. And even the ones that do get built generally flame out due to problems involving durability, construction complexity, or efficiency. The very few that get beyond that stage face an uphill battle with automakers who have billions invested in building conventional engines of proven reliability and performance.
One of the few new engine concepts that looks promising is the OPOC two-stroke from EcoMotors. OPOC stands for “opposed piston opposed cylinder.” To visualize the engine, start with a horizontally opposed four-cylinder like the Subaru Legacy’s. Then extend the cylinders and lose the cylinder heads to make room for a second set of pistons within each cylinder that move opposite of the conventional pistons. Long connecting rods transfer the motion of these additional pistons to throws on the crankshaft.
As in a typical two-stroke, breathing occurs through ports in the sides of the cylinders. But in the OPOC engine, the intake and exhaust ports are at opposite ends of the cylinders. As the pistons move, the exhausts are uncovered before the intakes and turbochargers blow air through the cylinders to push out the exhaust gas and fill them with clean air. Since the engine needs positive pressure to do this, the turbochargers have electric motors to power them at low rpm when exhaust energy is low.
Though the first OPOC engines are diesels, the concept can also work with gasoline. Either way, the direct-fuel injector is in the middle of the cylinder where the two piston crowns almost meet, and that’s where a spark plug would be in a gas version.
If the OPOC’s design seems radical, it has solid people backing it. The engine designer is Peter Hofbauer, Volkswagen’s former chief engine engineer. The EcoMotors CEO is Don Runkle, a former top executive at Delphi and GM. The president is John Coletti, the legendary former boss of Ford’s SVT division. And exhaust-maker extraordinaire, Alex Borla, is on the board of directors. Much of the company’s funding comes from Vinod Khosla, a Silicon Valley mega-investor.
Thus far, prototypes of the OPOC engine have delivered 12-to-15-percent better efficiency than conventional piston engines, due primarily to the absence of cylinder heads, eliminating a large surface through which the heat of combustion is lost to the coolant, and the absence of the valvetrain, which reduces friction by some 40 percent.
Furthermore, because each two- cylinder, four-piston module is perfectly balanced, it is possible with a four-cylinder version of the engine to completely decouple one cylinder pair under light loads. This not only reduces pumping losses but also completely eliminates the friction from the disabled cylinder, improving fuel efficiency by an additional 15 percent.
Thus far, Coletti says that there are no obvious problems: “Emissions look good, and so does oil consumption. There’s nothing that has me worried.” Runkle adds that due to the fewer parts—no heads or valvetrain—the engine should be 20-percent cheaper to build than a modern V-6. “We’re working on two engine families. The EM100d is a diesel with a 100-millimeter bore developing 325 horsepower, and the EM65ff has a 65-millimeter bore and makes about 75 horsepower in two-cylinder form on gasoline.”
The engine is years away from production. For a small, growing company without a huge investment in conventional engines—think Chinese or Indian—the OPOC engine is attractive. A military contract would also pave the way toward civilian acceptability.

Have you heard this before?

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Just for Y_F_Po:

Thus far, prototypes of the OPOC engine have delivered 12-to-15-percent better efficiency than conventional piston engines, due primarily to the absence of cylinder heads, eliminating a large surface through which the heat of combustion is lost to the coolant, and the absence of the valvetrain, which reduces friction by some 40 percent.
Furthermore, because each two- cylinder, four-piston module is perfectly balanced, it is possible with a four-cylinder version of the engine to completely decouple one cylinder pair under light loads. This not only reduces pumping losses but also completely eliminates the friction from the disabled cylinder, improving fuel efficiency by an additional 15 percent.

Remember the 2nd Law??

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I can buy heat elimination heat losses. The rest is a fluff. Ordinary opposing cylinders can be decoupled the same way.

But heat losses are OK. I think GM had heat losses decrease in the same ballpark with their ceramic engines.

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C/D: How far off  is the OPOC engine?

JC: We’re just finishing generation six. It’s probably time for it to come out of the cave and go into a product for demonstration.

I'd say so.

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The engine being designed at Ecomotors is my second favorite new tech ICE. My favorite is at www.liquidpiston.com. The liquid Piston site has plenty of technical explanation for you skeptics, including an animation (give it time) and several research papers by the two PhD physicists (father and son team) who patented it and are developing it to commercialization. Really cool design and incorporates pieces of several other designs but is not really like anything else that I have studied.