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Old 02-12-2009, 11:07 PM
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Springless Valve System

Very interesting technology from Decuir Engine Technologies.
Link:

http://www.decuirenginetechnologies.com/

I wonder when these will be available from camshaft manufacturers?
What do you all think?
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Old 02-12-2009, 11:20 PM
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Also found these cylinder heads:

http://www.coatesengine.com/index.html
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Old 02-12-2009, 11:39 PM
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Looks like something that would be a nightmare to alter valve lash... but a good idea.

Yamaha had a very similar idea 10 years ago, except they used two different lobes; one to open the valve and one to force it closed. Lash was individually adjustable on each lobe. They used it on 1000cc bike engines that ran as high as 16,000 rpms and offered it with a 3 year warranty.

The coates valves have been around for nearly 20 years. Nothing new. If it hasn't caught on by now, it never will. Too many limitations, but it was a good idea.
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Old 02-13-2009, 12:42 AM
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The desmodromic valve actuation system is over a hundred years old.....
http://en.wikipedia.org/wiki/Desmodromic_valve
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Old 02-13-2009, 07:12 AM
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Quote:
Originally Posted by techinspector1
The desmodromic valve actuation system is over a hundred years old.....
http://en.wikipedia.org/wiki/Desmodromic_valve
It has also been on a production (well Italian production) motorcycle for 30+ years,Ducati. Opening and closing cams. Ford experimented with a head for the 289 in the mid 60s. It was more in line with the original Desmo design with a mechanism on the cam that actuated the valve.
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Old 02-13-2009, 11:04 AM
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Quote:
Originally Posted by sixty9santa
Very interesting technology from Decuir Engine Technologies.
Link:

http://www.decuirenginetechnologies.com/

I wonder when these will be available from camshaft manufacturers?
What do you all think?
Probably never, racing groups sanction what mechanisms can be used, they tend to hang around springs.

Future production in the next few years will do away with the cam entirely. Valves will be pneumatically or electrically actuated as is currently done in Formula 1 engines. For street engines this holds the promise of variable valve timing to the load on the engine and when combined with multiple ports and valves on a cylinder can be used to manage port velocity by adding or subtracting ports by whether the valve at the end is even actuated. This combined with sequentially timed fuel injection will give unlimited control from idle to WOT. Even the throttle body is going away as this system will also provide throttle control.

Bogie
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Old 02-13-2009, 11:25 AM
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Quote:
Originally Posted by oldbogie
Even the throttle body is going away as this system will also provide throttle control.

Bogie
BMW has had this on production cars for a few years now. The throttle is one of the fundamental inefficiencies of gasoline engines. That's also one reason why diesels are more efficient - they do away with the pumping losses of the throttle plate(s). The BMW design uses variable cam timing to vary airflow instead of a throttle plate, so pumping losses go down, HP and MPG go up.

http://www.usautoparts.net/bmw/techn...alvetronic.htm
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Old 02-13-2009, 03:33 PM
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More food for thought

I would be worried about valve lash in a valve train configuration such as this. What happens to the tolerances when all of the parts reach their normal operating temperature. It seems to me that you would have to have zero lash when the valve is closed trough out all of the operating temperatures. If not then there would be a loss of compression. To tight and the valve could hammer out the seat or worse it could brake a stem. There is no shock absorbing effect or margin for error like there is with a spring. Knowing the way that different metals heat up and change their shape I don't think that this configuration would really work. This type of an idea has been around for at least thirty years.

Now what I'm waiting to see is a fully hydraulic operated valve train and from what I have read several companies are working on it. One that uses hydraulic pressure in a piston to open and close the valve. With this type of system you could completely eliminate the springs and cam(s) and everything else that goes with it. At one time all diesel injectors were actuated mechanically now most of them are actuated hydraulically and I think it's just a mater of time before this technology makes it's way into the valve train. The hydraulic function could be regulated through the ECM the same way that it is being done for the diesel injectors. It would allow for variable valve timing and on an individual basis. This would completely eliminate the need for a throttle plate. Now this statement gets really deep, "If it also had direct combustion chamber injection or injection that was real close to the intake valve, you could start this type of an engine with out a starter". The drivabilty of an engine like this would be remarkable. The reason a high performance cam has an erratic idle is to increase volumetric efficiency at higher RPM's. It is a give and take. Because of the dynamic timing ability of a system such as this, you would'nt need an erratic idle to obtain higher performance levels. In fact it could be configured to idle like a sewing machine and still run top end like a top fuel dragster.

Just some more food for thought!
Chris
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Old 02-13-2009, 04:44 PM
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Quote:
Originally Posted by Chris Kemp
....Now what I'm waiting to see is a fully hydraulic operated valve train and from what I have read several companies are working on it.....
Chris
http://scarbsf1.com/valves.html

They use hydraulic and pneumatic valve actuators in Formula 1. So the technology is out there.
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Old 02-13-2009, 05:00 PM
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Quote:
Originally Posted by Joe G
http://scarbsf1.com/valves.html

They use hydraulic and pneumatic valve actuators in Formula 1. So the technology is out there.
Very good reading Joe, I can't wait till we get something like this for the street! Just think about the endless possibilities!
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