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How do they plan to seal all the edges of those balls? Also, how the heck do they expect manufacturers to crank out parts with the requisite precision?

Neat toy, but I'd wager a large sum that no-one will take the time to work out all the bugs.

Piston engines, for all their faults, are very, very well understood and cheap to design, manufacture and service.

That's why every other challenge has pretty much failed - swash plates, rotary valves, etc. Only the Wankel has challenged it, and that only after huuuuuuuge sums of money were spent working out the bugs.
 

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quote:
How do they plan to seal all the edges of those balls? Also, how the heck do they expect manufacturers to crank out parts with the requisite precision?

Neat toy and a brilliant design, but I'd wager a large sum that no-one will take the time to work out all the bugs.

Piston engines, for all their faults, are very, very well understood and cheap to design, manufacture and service.

That's why every other challenge has pretty much failed - swash plates, rotary valves, etc. Only the Wankel has challenged it, and that only after huuuuuuuge sums of money were spent working out the bugs.
 

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i think it is a very cool idea. thanks borzwazie!

tex
 

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Robert,
I agree. Very cool concept but rife with problems I think. First of all efficiency has got to be way low...despite their claims. Look at the mechanics of trying to force those balls along their path when the vector of the force created by combustion is like 60 degree off the path of the grooves. It would be like trying force a piston sideways in the bore. It has to create tremendous side loading on the grooves and little balls.
Also looks like there is considerable direction change in the moving components, similar to a reciprocating engine. While the main ball continues in the same direction, the opening and close chambers must change direction for every cycle.
Exhaust gases traveling over the pivot shaft doesn't seem like it would be conducive to longevity.
While the total surface area for wear may be less than a typical reciprocating engine, the forces at the wear points must be tremendous. Think about the forces on the grooves and balls under a high torque load....the way they have it setup it's like a sail boat tacking into the wind....yes some high velocities can be generated but forces are very high and efficiency is very low. Like a tacking (sp) sailboat...it's moving fast, but the distance in forward progress is much less than the total distance traveled, a scenario which is unacceptable from an efficiency standpoint...unless your power source is somewhat unlimited...like wind.

A very cool and ingenious curiosity. But I'd say the standard rotary engine has it beat to hell. However....it may be that it is very well suited to particular uses.
The dude must have been doing some way whack frashizzle drugs when he thought it up.
JohnnyB
 

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quote:
Robert,
Look at the mechanics of trying to force those balls along their path when the vector of the force created by combustion is like 60 degree off the path of the grooves. It would be like trying force a piston sideways in the bore. It has to create tremendous side loading on the grooves and little balls.
Johnny, I thought the same thing when I saw it too. I can't imagine those grooves putting up with that. I think you're right about torque load too, that seems like it would just be too much. Seems to me the only way it could work well is if you try to exploit the continuous motion. So, spin it really fast and try to keep it spinning fast with lots of little explosions.
If it's really light and compact it might work for lawn equipment or something, right? Say, for a weedwacker or a leafblower, if you combined the engine with some kind of slipper clutch, so those ceramic balls and grooves weren't subjected directly to severe torque loads. ??
I am SO not an engineer, but it does look like a neat idea.

Z
 

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Zack, you should be an engineer. I was going to point out that very thing....that it looks to me like...if you kept it rotating, giving litle pushes with the combusion that it might work ok. But then that would make it a high rpm, low torque..the opposite of what the article said.....so I held back.

When I was little I wanted to grow up to be an engineer....now that I'm grown I want to be a big giant engineer. (old joke).
JohnnyB
 

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Good point about wear and friction - how do you lubricate it? Unless you run the balls in oil and seal the edges of the chambers, but that brings up the sealing issue again.

Isn't that why Honda gave up on oval pistons? Sealing the corners is nearly impossible.
 

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I'd guess in production that engine would require some very exotic materials to hold up for any length of time.

Cool idea for sure. But then all of us running our homes on tiny nuclear plants would be cool too. Making it practical is a whole nother thing.

JohnnyB
 

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Sure, it has inherent sealing issues, but none that weren't already solved through several generations of the wenkel rotary and the new rotax. The answer - at seal points: apex seals. Most common material: teflon. I'm an electrical engineer and don't dive much into mechanics, but here's what I see being a problem and a comparative example: The wenkel rotary motor always overheated simply from the friction created from the rotation of the rotors in the rotor housing. In this design, "rotor" contact with the housing is present 100% of the time throughout operation. I counted 8 separate motions where the ball-piston structures were moving and in contact with the housing. My bet, this thing will never, ever, ever stay cool. It will heat up, seals will melt away and bam - detonation.
 

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quote:
Good point about wear and friction - how do you lubricate it? Unless you run the balls in oil and seal the edges of the chambers, but that brings up the sealing issue again.

Isn't that why Honda gave up on oval pistons? Sealing the corners is nearly impossible.
Honda gave up on the oval piston mainly because of the manufacturing costs, as well as the lack of precision machining of the piston rings. They had to be built by hand, because the technology of the day wasn't up to par with what they were doing. And so like you said, sealing the combustion chamber was extremely difficult and prone to early wear. With today's technology, I believe that the oval piston could be realised, but why do it, when what they have works.
 
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