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Old 10-10-2022, 02:20 AM   #11 (permalink)
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Quote:
Originally Posted by aerohead View Post
As a 'passive' component, in today's sophisticated world of sensors, ECUs, and servos, a non-controlled device like this might be a non-starter, and also redundant.
If you have VVT of some sort; possibly aerohead.
But
I feel that the fact that its passive and relies on the air pressure difference between ambient air the pressure downstream of the valve is in fact the beauty/simplicity of the concept:

Hot and even stock cams open the intake valve before TDC for 2 reasons;
1: To take advantage of the pressure wave in a tuned length intake to start forcing a bit more air in
and
2: to take advantage of a tuned length exhaust pulse sucking exhaust gas out, better scavenging the cylinder.

At low revs (as used by ecomodders) this does not work and you get exhaust going up the intake tract.
That will/can not happen with a reed valve in place.

Similarly; at the end of the intake stroke the valve closes a bit late as the momentum of the inrushing air-fuel gives the engine a slight turboing effect.

At low rpms there is not enough momentum, so some of the air-fuel is pushed out the intake again.
Unless there's a reed valve...

Even the exhaust cam can be somewhat hotter as the reed valve will stop the backward flow at the end/beginning of exhaust/intake stroke.

Basically the intake valve only has to be closed for the power stroke with a reed valve fitted.
The reed valve will provide infinitely variable and almost perfect valve timing at any/all rpms...

IMHO
Any ECU etc would find benefit from and auto adjust to the advantages of the reed valve/s.

And, as said, the restriction of the reeds has been tested and only loses you about 1kw of top end/rpm power.


Last edited by Logic; 10-10-2022 at 02:53 AM..
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Old 10-10-2022, 02:35 AM   #12 (permalink)
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Quote:
Originally Posted by freebeard View Post
IIRC carbon fiber is notoriously brittle.
As I understand it; Carbon Fiber is extremely flexible.
More so than glass
BUT
if you tie a knot in 1 fiber; the fiber will break as soon as the knot is pulled tight.

ie:
Carbon Fiber is extremely flexible up to a certain 'angle'.
That's why other fibers are used in the safety shell of F1 cars etc where said 'sharp bend angles' will occur if the resin is cracked. Fibers that don't break at sharp bends so to speak.

Last edited by Logic; 10-10-2022 at 02:49 AM..
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Old 10-10-2022, 02:48 AM   #13 (permalink)
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Quote:
Originally Posted by cRiPpLe_rOoStEr View Post
AFAIK some very ancient engines with an IOE valvetrain had a passively-actuated intake valve which was of the conventional poppet layout, pulled open by the vacuum at the intake stroke. But I'm not sure how a reed valve could be so beneficial in a 4-stroke engine which already resorts to mechanically-driven intake valves.
No reason not to do it this way in the old, very low rpm, engines of yore.
But at moderate to high rpms you need way more spring pressure to get the valve to close timeously.
(has way more weight/momentum than a reed)
And that pressure will stop the valve from opening when it should from the pressure difference alone...

The Reed Valve, with a very hot cam, basically gives you 'infinitely variable', valve timing, based on pressure difference...
But a reed valve cannot handle the extreme pressure and heat of the power stroke, so a normal valve is still reqd for that.

I explained more in my replies to aerohead.

Last edited by Logic; 10-10-2022 at 02:55 AM..
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Old 10-10-2022, 03:09 AM   #14 (permalink)
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Quote:
Originally Posted by aerohead View Post
let's see if this works
http://https://ecomodder.com/forum/s...ille-7838.html
Didn't work!
A search for 'lamellar self-blocking grille' located it
A reed valve is a pressure difference driven valve that closes completely aerohead, not an aerodynamic impediment to reverse flow. (what you trying to stop)

https://youtu.be/FohhtYJpQ7Q?t=73

If you want an aerodynamic impediment to reverse flow, look up the Tesla Valve and exhaust anti reversion.
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Old 10-11-2022, 01:42 AM   #15 (permalink)
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Quote:
Originally Posted by Logic View Post
And, as said, the restriction of the reeds has been tested and only loses you about 1kw of top end/rpm power.
Seems like it wouldn't be much of an issue at all, as hypermilers would avoid to rev the hell out of the engine anyway

Makes me wonder what this approach could do for the Wankel engines...

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