The Revetec Controlled Combustion Engine

Revetec Website ^ | 10/19/05

[Jack of all Trades]

The REVETEC Engine design consists of two counter-rotating “trilobate” (three lobed) cams geared together, so both cams contribute to forward motion. Two bearings run along the profile of both cams (four bearings in all) and stay in contact with the cams at all times. The bearings are mounted on the underside of the two inter-connected pistons, which maintain the desired clearance throughout the stroke.

The two cams rotate and raise the piston with a scissor-like action to the bearings. Once at the top of the stroke the air/fuel mixture is fired. The expanded gas then forces the bearings down the ramps of the cams spreading them apart ending the stroke. The point of maximum mechanical advantage or transfer is around 10deg ATDC (the piston moving approximately 5% of its travel) making the most of the high cylinder pressure.

This compares to a conventional engine that reaches maximum mechanical advantage around 60deg ATDC. (after the piston has moved through 40% of its travel, losing valuable cylinder pressure). The effective cranking distance is determined by the length from the point of bearing contact to the centre of the output shaft (NOT the stroke). A conventional engine's turning distance is half of the piston stroke. The piston acceleration throughout the stroke is controlled by the cam “grind” which can be altered to give acceleration to suit a certain fuel and/or torque application. This also allows different port timing on opposite strokes, increasing efficiency on 2-Stroke engines.

The piston assembly slides rigidly through the block eliminating piston to cylinder-bore contact. This reduces wear and lubrication requirements. This also reduces piston shock to a negligible amount making ceramic technology suitable. One module which comprises of a minimum of five  moving components, produces six power strokes per revolution. Increasing the number of lobes on each cam to five produces ten power strokes without increasing the number of components. The CCE integrates well with existing power plants and can utilise almost all existing engine technology with increased efficiency.

Summaries of CCE advantages are as follows;

• approximately one quarter the size and weight of a conventional engine (for similar applications) combined with improved output substantially increases power/weight and torque/weight ratio.
• fewer moving and total components. As a result of fewer components, more easily manufactured than conventional engines.

• identical cylinder head assembly (“top end”) to conventional engines. Most existing head technology can be either adapted or utilised.
• Flexible design - can be four-stroke, two-stroke, petrol, diesel or gas, natural of forced aspiration.
• Eliminated irregularly reciprocating components such as connecting rods.
• Output shaft can be run in either direction if multilobed cams with symmetrical lobes are employed.
• All rotational forces are counteracted via the counter rotating cam – eliminates the need for a heavy flywheel.
• Torque and power output can be varied using a fixed capacity and piston stroke.
• The CCE can be designed to operate at greatly reduced operating speeds while delivering high torque output.

• Substantial reduction in stroke reduces heat loss through cylinder wall.
• Extended piston dwell is possible because engine design allows a lower than normal compression ratio to be used reducing power loss from compression cycle.
• Maximum mechanical advantage can be applied to output shaft at only 10 degrees ATDC utilising high cylinder pressure early in the stroke, compared to around 60 degrees ATDC for conventional engines.
• Lower emissions can be achieved due to increased control over combustion.
• Extremely low idle speed due to increase in mechanical efficiency at the top of the stroke.
• Little or no bore contact/piston side thrust, which reduces wear on cylinder bore.
• Can have different port timing on compression stroke than power stroke allowing better control two-stroke).
• Lower centre of gravity.
• Due to controlled piston acceleration rates the CCE reduces engine vibration.

• A hollow output shaft can be utilised for specialty applications, such as peristaltic pumps.

[Jack of all Trades]

I've been searching around the Web for information on engine controllers and stumbled across this company. I'm not vouching for the technology, but it sure looks pretty cool: more power, fewer parts, better efficieny and emissions vs. a traditional IC engine.

[Jack of all Trades]

Forgot to mention: one of these engines is scheduled to race in an Indy V8 Ute class this weekend at the Lexmark 300.

[Jack of all Trades]

I don't post much, is there a "gearhead" ping list?

[Fiddlstix]

BTTT

[keat]

That is prety cool. The IC engine still has a few tricks up its sleeve and won't be going away anytime soon.

Seems like the bearings might be the weak point.

[brownsfan]

"I don't post much, is there a "gearhead" ping list?"

Don't gearheads hate pings? (I'd get some gasoline additive).

[Jack of all Trades]

Doh! I didn't see that one coming.

[Youngman442002]

seems to me it would vibrate....

[CodeToad]

Seems that bar moving back and forth is generating as much loss as a piston engine.

[Red Badger]

THANKS for the post! I am always interested in new technology!..........

[eraser2005]

If you ran just 2 cylinders, the engine would definitely be seriously out of balance. My first impression is that a 4 cylinder version would not be nearly as smooth as conventional 4s, as you still could not balance the forces and moments as well. A flat 8 from this could potentially be pretty smooth, though, as that's the point in which you could balance forces well. A Y6 might be an option (not V, but Y)... but I haven't done any calcs....

[B.Bumbleberry]

Interesting find. Thanks for the post.

[Jack of all Trades]

That was my first thought too, but now I'm not so sure especially for a multicylinder version. As I look at the cam rotate, I see two lobes of the cam at BDC each time the piston is at TDC. It might balance out. One thing is for sure, I'd love to hear one run.

[L98Fiero]

"I don't post much, is there a "gearhead" ping list?"

I'm not sure. If there is, I wouldn't mind being on it.

Good post. Very interesting.

[Yardstick]

Wow, that is pure elegance. Most of these breakthrough improvements to the piston engine are flops, but this looks truly promising. It's always good when you can improve through simplification.

[Paradox]

Looks interesting. It remains to be seen however if its advantages can put it above the conventional 4 stroke IC engine.

I remember the Wankel hype. It just seemed so elegantly simple, but the details is where that engine lets us down.

[KansasConservative1]

Very interesting

[Jack Black]

Very cool. What is missing from the animation is the cylinder, which is still what is driving the whole thing. So whats really different is the replacement of the main shaft set up with the direct cam things. It's not a Wankle variant as I first thought.

I don't get this comment at all "The piston assembly slides rigidly through the block eliminating piston to cylinder-bore contact."

How can you eliminate piston to bore contact. Presumably the piston still has to be tight to the cylinder to facilitate controlled combustion, and preventing fuel from blowing back into the cams (which must require lubrication).

Anyone get what they are talking about?

It looks too bulky for motorycle application.

What's wrong with the Wankle? Why did only Mazda use it?

[Joe Beerman]

I don't post much, is there a "gearhead" ping list?

I'd like to be added to the gearhead list if you start one. I'm new to FR and am an avid hot rodder.
.

[Yardstick]

Funny you say that. I had the Wankel engine in mind as I wrote my comment. I wonder if this thing has an Achilles heel.