Filed under: Hybrids/Alternative, Green, Tech
Oscillating Piston Engine: That thing got a toroid in it?
The Oscillating Piston Engine (OPE) is a revolutionary (pun intentional) engine design that the patent holder Rotoblock promises will reduce weight and complexity, as well as offer an improved power to weight ratio over a standard internal combustion engine.. We could explain at length how the OPE works, but we'd spend the next three days moderating comments about all the things we got wrong. So, watch the flash animation above from Rotoblock's Web site and check out an in-depth explanation of the engine at Green Car Congress. There's also a video of the engine running here. It sounds oddly like an aviation powerplant.While it's a novel engine design, the OPE is not all that new. Designs for toroidal internal combustion engines have been around since at least 1968, and the patent now owned by Rotoblock was filed in 1993. What exactly Rotoblock plans to do with its patented engine isn't clear. The Web site says it can be used for almost everything from RC cars to generators to family sedans. The company's site also claims the engine can be adapted to run alternative fuels, including hydrogen. Rotoblock has even announced a partnership with Apollo Energy Systems to develop a hybrid drive train using the OPE.
Thanks for the tip, Chieze!
[Sources: Rotoblock, Green Car Congress]
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Reader Comments (Page 1 of 2)
tj 6:34PM (2/11/2008)
patent durations are only 20 years, so it sounds like they better get their butts in gear (pun definitely intended)
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why not the LS2LS7? 9:31PM (2/11/2008)
17 when this was patented.
Brent 6:36PM (2/11/2008)
....waiting for people to dismiss this technology.
I , on the other hand, love new ideas!
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meshies 6:56PM (2/11/2008)
I'm with you! This is the first time I have seen this, and I am very anxious to see it applied.
nardvark 6:43PM (2/11/2008)
Wouldn't forcing the piston into a rotational path (as opposed to a linear path in a "normal" engine) create extra drag / friction / losses on the outer wall?
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Derek 7:07PM (2/11/2008)
It appears that the pistons are held in their circular path by the parts in the center. If there is any centrifugal loading, I doubt it would be any worse than the side loading already present in a linear piston engine due to rod angularity. (the rod is usually not aligned directly underneath the piston, causing the pressure of combustion to press the piston against the side of the cylinder wall opposite the side the crankpin is on. Some engines use a wristpin offset in order to reduce this loading.)
Chris 6:50PM (2/11/2008)
How exactly are the combustion events balanced?
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Derek 7:07PM (2/11/2008)
I expect you would use two, uh, tori? Put one out of phase with the other and the torsional effects of the oscillating pistons should be balanced.
L.WOOD 6:53PM (2/11/2008)
I guess this is a classic case of what goes around comes around...................or is it comes around the mountain when it comes? I get my internals confused when combustion comes up as the subject.
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Chris 6:55PM (2/11/2008)
Yes, but keep in mind how much friction is in your standard otto cycle ICE...
Also, moving the gasses in a non-vertical motion will result in losses.
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HotRodzNKustoms 7:04PM (2/11/2008)
I love it. It reminds me of a gasoline powered watch.
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Derek 7:08PM (2/11/2008)
Very interesting. No valves, kinda like a crossbreed between a rotary and a piston engine?
On the plus side, the animation is showing what would effectively be an eight cylinder! I'm pretty sure that the effective displacement of the engine would also be greater than the volume inside the torus, because the space used by one pair of pistons overlaps the area used by its neighbors. Talk about a superb power/weight ratio! Also doesn't seem like it would have the same problems as a rotary with getting a high static compression ratio.
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Yar 7:09PM (2/11/2008)
I don't think this is going to work...
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Dondonel 7:16PM (2/11/2008)
It's not going to work because achieving better power/weight numbers are hampered by metallurgy and fuel economy requirements, not by engine design.
Dondonel 7:11PM (2/11/2008)
Very old idea, look for ww2 Lutz swing piston engine. Although what Lutz tested was a gas generator for a turbine engine, he was also planned for an actual engine.
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Rochester 3:19PM (7/10/2008)
I've been looking for schematics or patent, or any information that would show how exactly Lutz's cranking mechanism works. Unfortunately can not find any information. Would you happen to have a diagram of his mechanism, or could you post a link where I can see it?
Perhaps it's identical to what is patented by someone else?
Rochester 3:28PM (7/10/2008)
Hi Dondonel - I've been looking for schematics or patent, or any information that would show how exactly Lutz's cranking mechanism works. Unfortunately can not find any information.
Would you have a diagram of this mechanism, or could you post a link where I can see it?
Perhaps it's identical to what is patented by someone else?
Thanks
rgseidl 7:51PM (2/11/2008)
The hard problems here are, in no particular order:
a) transferring torque to the coaxial drive shafts while maintaining gas tight seals for the combustion chambers,
b) keeping the pistons from melting under sustained high load, and
c) meeting emissions regs with slit valves, which tend to coke up and cause blue smoke in the exhaust due to partially burnt engine oil.
Kudos to the engineers involved if they can solve all these (and many more) but I'm not holding my breath. What sounds ingenious on paper usually turns out to be an engineering nightmare once you get into the nitty gritty. Ye olde crank-slide mechanism certainly has its faults but it does work very well.
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Thetruck454 8:20PM (2/11/2008)
I was actually able to see one of these in person. I wasn't able to see it run because they had melted the seal between the two halves of the torus. The biggest problem the engineers told me was making a dynamic seal that held up to the temperatures and repeated use. They were exploring metalurgy options last I knew. The engine would fit on any regular desk and it was supposedly able to make just shy of 300hp... not a bad power density if you ask me. They used some sort of ratcheting drive shaft to turn that oscilatiing motion into a smoothish rotational motion
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Rogue_G 8:48PM (2/11/2008)
"It's not going to work because achieving better power/weight numbers are hampered by metallurgy and fuel economy requirements, not by engine design."
At least someone has their head on right here. While that engine is a cute design, you wouldn't be able to eek out much more than 40-50hp with todays material science. This argument can be said, really, for just about every new engine design though. On paper, yeah, but unless you use some kind of horrendously expensive composite using titanium or close to it, it just won't work. But hey, I'm sure that'll make some wicked thesis for someone!
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