Cool Video

[Stephen Lindberg]

Originally Posted by kentb

The exhaust valve opens while the burn is still happening.
Question: with the intake valve floating while the burn is happening, how come the burn doesn't go back into the intake manifold? Wouldn't the next charge of fuel be contaminated some?

Kent

It does, and it is...but not too much.

[Rotary10-RV]

Originally Posted by rv6ejguy

Fascinating look slow mo inside combustion chamber:

http://video.google.com/videoplay?do...93860613&hl=en

Ross did you notice that the video was clipped? It doesn't show the piston come to tdc on the exhaust stroke. I also don't believe that the intake valve is really opening at all, more likely that the charge lingers more in the area of the intake valve, which is why you see more visible burn in the area of the intake.
Bill

[Brantel]

The thing I noticed the most was that the intake valve was actually rotating. Seemed to be rotating at a faster rate than the piston was stroking.

[kentb]

I first thought that it was an optical illusion, but after playing it over a few more time, I think you're right.
It appears to rotate no matter if it is open or if it is seated.
How could it rotate on the seat?
Wouldn't there be a lot of wear from this constant rotation?
What could cause it to rotate?

This is a really cool video.

The more I learn the more I question.

Kent

[rv6ejguy]

Originally Posted by Rotary10-RV

Ross did you notice that the video was clipped? It doesn't show the piston come to tdc on the exhaust stroke. I also don't believe that the intake valve is really opening at all, more likely that the charge lingers more in the area of the intake valve, which is why you see more visible burn in the area of the intake.
Bill

Yes, I noticed that the end of the exhaust stroke was omitted, the vid was captioned as intake and combustion I think. It was sent to me by a fellow engine builder so I don't know much about what was being studied. I don't see the intake opening out of camshaft phase if you watch the shadow of the valve face against the seat. An optical illusion I think with the lighting and piston movement or as a result of editing or doctoring the video.

Combustion happens so quick, even at this speed, it is hard to tell how the burn progresses. NACA was doing high speed, still frame chamber photography back in the early '40s which shows exactly how the flame front progressed vs. piston position and even how detonation events progressed.

The whole thing could be contrived somehow.

Valves are often rotated by offset rocker contact on some engine designs but I suspect this is at a very slow rate. Overhead cam engines using bucket type valve trains don't do this and live very well.

Certainly interesting even if fabricated somehow.