Cool new 4-cycle engine design....
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From: Longmont, CO
Originally Posted by Station' date='Feb 10 2005, 11:58 AM
I read this in their FAQ:
A: A CCE engine can have from one to as many as eight cylinders. Each cylinder can fire 3 to 9+ times per rev. Three times is typically used in automotive. A four cylinder, four-stroke, trilobate cam produces six power strokes per rev. (12 cylinder four stroke equiv)
Maybe I misunderstood. Doesn't this mean it would produce the same power as a V12?
I agree...the benefit of no loads on the cylinder walls are huge. High rpm should be easy for this motor (at least the bottom end). I wonder how they grind cams though. Piston acceleration/deceleration would be so different from a conventional engine that cams with a normal profile don't work. The camlobes would have to be radically different to allow slower opening of the valves, thus avoiding piston contact. Would that reduce the engine's ability to breathe at high revs?
Also, how fast would the cams be spinning? If the engine redlined at a normal car's 6K (crankshaft), the pistons would be bouncing up and down three times per rev (18K
) and the cams would be half that speed at 9K, right? 
Well, the bottom end looks like it could easily handle the revs, but I don't think the valvetrain would work that well at 9K.
The F20C is rpm-limited by the top end, and at 9K the cams are spinning at "only" 4500. I think this will be a low-rpm motor. I love the design, though. It should have been done years ago. 
A: A CCE engine can have from one to as many as eight cylinders. Each cylinder can fire 3 to 9+ times per rev. Three times is typically used in automotive. A four cylinder, four-stroke, trilobate cam produces six power strokes per rev. (12 cylinder four stroke equiv)
Maybe I misunderstood. Doesn't this mean it would produce the same power as a V12?
I agree...the benefit of no loads on the cylinder walls are huge. High rpm should be easy for this motor (at least the bottom end). I wonder how they grind cams though. Piston acceleration/deceleration would be so different from a conventional engine that cams with a normal profile don't work. The camlobes would have to be radically different to allow slower opening of the valves, thus avoiding piston contact. Would that reduce the engine's ability to breathe at high revs?
Also, how fast would the cams be spinning? If the engine redlined at a normal car's 6K (crankshaft), the pistons would be bouncing up and down three times per rev (18K
) and the cams would be half that speed at 9K, right? Well, the bottom end looks like it could easily handle the revs, but I don't think the valvetrain would work that well at 9K.
The F20C is rpm-limited by the top end, and at 9K the cams are spinning at "only" 4500. I think this will be a low-rpm motor. I love the design, though. It should have been done years ago. So consider this - at 9000rpm, the F20C's pistons each travel up and down the cylinder bore 150 times a second. Run the RET's pistons at the same speed and you'll get only 3000 crank revolutions every minute.
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From: Elk Grove
Originally Posted by Elistan' date='Feb 10 2005, 10:42 AM
When they say "revs," they mean a full revolution of the crankshaft - the thingy those trilobes are connected to.....
.....So consider this - at 9000rpm, the F20C's pistons each travel up and down the cylinder bore 150 times a second. Run the RET's pistons at the same speed and you'll get only 3000 crank revolutions every minute.
.....So consider this - at 9000rpm, the F20C's pistons each travel up and down the cylinder bore 150 times a second. Run the RET's pistons at the same speed and you'll get only 3000 crank revolutions every minute.
from my post:
[QUOTE]Also, how fast would the cams be spinning? If the engine redlined at a normal car's 6K (crankshaft), the pistons would be bouncing up and down three times per rev (18K
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From: Longmont, CO
Originally Posted by Slamnasty' date='Feb 10 2005, 12:31 PM
What I am missing is exactly how it fires 3-9 times per rev.
The piston rises, the chamber fires, the piston goes down. Is that article saying it fires 3-9 times at the maximum length of the stroke? If so, what does this do for MPG?
It looks like this design, for now, would only work somewhat easily in boxer form. I wonder what an engine like this would sound like.
The piston rises, the chamber fires, the piston goes down. Is that article saying it fires 3-9 times at the maximum length of the stroke? If so, what does this do for MPG?
It looks like this design, for now, would only work somewhat easily in boxer form. I wonder what an engine like this would sound like.
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From: Longmont, CO
Originally Posted by Station' date='Feb 10 2005, 12:50 PM
That's pretty much exactly the point I made in the post you quoted.
from my post:
from my post:
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From: Vienna, VA
each "cylinder" in this motor has 2 pistons on each side of the trilobe. that's how you get 3 fires/rev with a 4-stroke. the pic from station's first post is a 1-cylinder. it is classified as such becase both pistons are connected by the same rod to each other.
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From: Longmont, CO
Originally Posted by pantyraider' date='Feb 10 2005, 01:21 PM
So this seems only suited for Boxer type engines?
What's cool is the low sidewall forces, but now the bearings become the point of failure instead of the conrods.
What's cool is the low sidewall forces, but now the bearings become the point of failure instead of the conrods.
From what I can tell, such a configuration would not work in a V formation, unless you do some sort of flexible connection like a chain, which would introduce all sorts of other issues I'd imagine.
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From: City
Originally Posted by Elistan' date='Feb 10 2005, 11:24 AM
What I think is one of the coolest aspects of this engine is the fact that there are no cylinder wall forces from a conrod pushing a piston sideways. So given a proper valvetrain, high piston speeds should be possible, resulting in a combination of a long stroke high-torque configuration along with high rpms.
I don't see how it could be any oher way
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From: San Fran
Originally Posted by no_really' date='Feb 10 2005, 06:34 PM
I think you are wrong here - if the piston shaft pushes a wheel that forces a camlobe to the side, the opposite force is going to be applied to the piston shaft, and eventually to the cylinder walls, causing the piston to rock in the cylinder.
I don't see how it could be any oher way
I don't see how it could be any oher way
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From: Murrieta
It HAS to be some type of horizontally opposed engine to run like that... that's the only way they can cancel the forces out.
Also, the reason it revs down so fast is because there's no flywheel action.. since, there's no flywheel... not to mention that the two rotating thingies (hehe) cancel each other out.
Also, the reason it revs down so fast is because there's no flywheel action.. since, there's no flywheel... not to mention that the two rotating thingies (hehe) cancel each other out.