new valveless opposed piston engine

[sdowney717]

claims a lot of improvements
For one thing the pistons are traveling only half the distance of a normal engine.

For a given power level, the opoc™ engine is 30-percent lighter, one-quarter the size, and achieves 50-percent better fuel economy compared with a state-of-the-art, conventional turbo-diesel engine. Because of this breakthrough, we are enthusiastic about the internal combustion engine’s future. It’s a breakthrough based on the strength of extraordinary power density.
http://www.ecomotors.com/technology

 

[Al]

Nice..similar in concept to Fairbank Morse opposed piston engines.

 

[sdowney717]

that one has 2 crankshafts, and valves. Interesting ideas that have been around a long time.
Getting rid of the valve train and springs saves power.

 

[spock1]

Wow....very impressive!Remarkable power density.

 

[A_Harman]

OP engines date back about 100 years.
Noteworthy examples:
Junkers Jumo 205 & 207
Napier Deltic
Rootes TS3
Fairbanks-Morse (which are still in production in Beloit, Wis.)

 

[spock1]

Originally Posted By: A_Harman
OP engines date back about 100 years.
Noteworthy examples:
Junkers Jumo 205 & 207
Napier Deltic
Rootes TS3
Fairbanks-Morse (which are still in production in Beloit, Wis.)

What are their major shortcomings?Why aren't they being produced and sold?

 

[sdowney717]

added complexity. Obviously US military and others liked them.

The rest of us get the same old same old, dont rock the boat design.

 

[spock1]

Originally Posted By: sdowney717
added complexity. Obviously US military and others liked them.

The rest of us get the same old same old, dont rock the boat design.

These engines seem to have far fewer parts and thus, should be easier to manufacture and install.
Do they require expensive exotic materials?Why wouldn't the major auto manufacturers use them?Are we dealing with a factor called inertia.

 

[Papa Bear]

It's got something to do with money somewhere........

 

[spock1]

Originally Posted By: Papa Bear
It's got something to do with money somewhere........

You are probably right...all those nift

y designs seem to get sidetracked somehow.Who has the most to lose?

 

[A_Harman]

Originally Posted By: spock1
Originally Posted By: A_Harman
OP engines date back about 100 years.
Noteworthy examples:
Junkers Jumo 205 & 207
Napier Deltic
Rootes TS3
Fairbanks-Morse (which are still in production in Beloit, Wis.)

What are their major shortcomings?Why aren't they being produced and sold?


As far as 2-stroke engines go, the OP engine is about the best of the lot. I finished reading SAE's book a few months ago, and a common complaint was that oil consumption was high. The success of an OP engine design is almost entirely dependent on the design of the liner, which is very long and complex. Cooling of the exhaust piston is a challenge. Any 2-stroke engine in this era is going to have trouble meeting NOx emission standards. This is what killed Detroit Diesel 2-strokes in the US.

But the biggest problem in my opinion which is inherent to the type is the impossibility of obtaining a good fuel injection spray pattern. Since there is no cylinder head, the fuel must be sprayed in from the cylinder wall, making it subject to wall wetting on the pistons, and slow burning late in the power stroke.

But anyway, do some searching on the 'net for info on the Napier Deltic. It was a monumental piece of engineering. 3 crankshafts arranged in an equilateral triangle with 3 banks of OP cylinders between them. 18 cylinders. 36 pistons. 88 liters of displacement.

 

[HerrStig]

GM built something like this to power the first high speed
spindle hull submarine, the Albacore. The shape was similar to the reactors to be installed in the second of the series, the Skipjack so that the internal plant layout could remain the same. The Albacore is beached in Porthmouth, NH and open to visitors. In the stern you can see the two "verticle" engines, and that's where the reactors when in the Skipjack.

 

[HerrStig]

Are these guys selling stock?

 

[spock1]

Originally Posted By: A_Harman
Originally Posted By: spock1
Originally Posted By: A_Harman
OP engines date back about 100 years.
Noteworthy examples:
Junkers Jumo 205 & 207
Napier Deltic
Rootes TS3
Fairbanks-Morse (which are still in production in Beloit, Wis.)

What are their major shortcomings?Why aren't they being produced and sold?


As far as 2-stroke engines go, the OP engine is about the best of the lot. I finished reading SAE's book a few months ago, and a common complaint was that oil consumption was high. The success of an OP engine design is almost entirely dependent on the design of the liner, which is very long and complex. Cooling of the exhaust piston is a challenge. Any 2-stroke engine in this era is going to have trouble meeting NOx emission standards. This is what killed Detroit Diesel 2-strokes in the US.

But the biggest problem in my opinion which is inherent to the type is the impossibility of obtaining a good fuel injection spray pattern. Since there is no cylinder head, the fuel must be sprayed in from the cylinder wall, making it subject to wall wetting on the pistons, and slow burning late in the power stroke.

But anyway, do some searching on the 'net for info on the Napier Deltic. It was a monumental piece of engineering. 3 crankshafts arranged in an equilateral triangle with 3 banks of OP cylinders between them. 18 cylinders. 36 pistons. 88 liters of displacement.

What are the odds of that engine being produced?Are the problems you mentioned insurmountable?

 

[A_Harman]

Liner and piston issues can be addressed with careful design and material selection.

Oil consumption is a more difficult issue. Any engine where the pistons rings run over ports in the cylinder wall has a designed-in tendency to use oil at a high rate. Maybe a ring pack can be designed to completely dry up the liner surfaces at the ports, but then that would make high wear a possibility.

Fuel injection and combustion issues may put a limitation on the power that the engine can make in order to meet emissions standards. Then how much fuel economy must be sacrificed and how much extra cost added for putting on aftertreatment systems? These issues would tend to reduce the power density advantage that the OP engine has.

 

[spock1]

Thanks for your very knowledgeable output.

 

[fsskier]

Minimizing oil Consumption, with side ports:

This is an interesting challenge, I am amazed at the reduction in oil and fuel consumption displayed by our new Evinrude Etec two stroke outboards - compared to older designs. (We are currently running 12 of them in our waterski show operation)

For those unfamiliar with this technology, these new two-strokes never mix any oil with the gas. These direct injection engines just inject gasoline..... the crankcase/rod/cylinder walls are lubricated by pressure fed oil, then scavenged and used over again. Emissions are remarkable low, often cleaner than comparable 4 strokes.

Still, some oil is lost, like most two strokes the Evinrude crankcase is also used as a compression box, with all the intake air being pumped through it. This of course results in some of the misted/sprayed crankcase oil still being lost through the intake port and forced into the cylinder. Although oil consumption is very small, it is still more than most new car owners are used to.... it would be maybe a qt every 2000 miles. I suspect that this would not bother commercial trucking operations that perform regular maintenance.

I do not believe any of the new OPOC designs force the intake air though the crankcase, this should lower oil consumption considerably, compared to our outboards..... but this of course requires an external supercharger/airpump of some sort.

The OPOC engines greatly decrease the all-important surface to volume ratio of the combustion chamber (hey, no heads!) And basic physics generally wins when efficiency is being measured!! Watching the new tech (and using some of it) with considerable interest.....

fsskier

 

[morris]

HAY i didnt get my money.

 

[mpvue]

the reason that most all engines are 4 stroke piston designs is because they WORK.
and not just function, but address all the aspects of making a production engine:
affordable to operate
cost to produce
emissions
repairability
reliability

lots of other designs have come and gone; turbine, rotary, etc. because they cannot address those concerns like a piston engine can.

I think this is another of those 'looks good on paper' ideas.

 

[sunfire]

I want one!