Fascinating look slow mo inside combustion chamber:
http://video.google.com/videoplay?docid=-5815350492893860613&hl=en
http://video.google.com/videoplay?docid=-5815350492893860613&hl=en
Van's Air Force
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Cool Video
- Thread starter rv6ejguy
- Start date
I watched a setup like this at Cummins Diesel back in the 70's--think it may have been the first HS movie of diesel combustion. I remember that the "engine" was brought up to speed, then fuel was injected for only one power stroke. Then everything was cleaned and done over. The movie showed that a drop or two of fuel was injected after it was supposed to be, causing much of the diesel smoke that was common back then. Injectors were redesigned because of it. I don't know what they used for light, but you didn't watch when it fired up. Very cool to see this with a spark ignition.
Bob Kelly
Bob Kelly
az_gila
Well Known Member
Quartz window?
A long time ago (early disco era...
...), when I owned a 64 Lotus Elan, I had to buy a quartz spark plug to tune the two dual Webers. It was used to set the idle mixture, as the mixture changed, the color of the combustion in the cylinders changed ..... IIRC, it was good to 2000 rpm or so.
I guess they could put a similar quartz window in the cylinder head, and have the camera look through it....
It's a neat video...
gil A
Very cool!
Wonder how they did it? Like what camera could stand that and how'd they light the inside of the cylinder like that so you could see?
Neat!
A long time ago (early disco era...
...), when I owned a 64 Lotus Elan, I had to buy a quartz spark plug to tune the two dual Webers. It was used to set the idle mixture, as the mixture changed, the color of the combustion in the cylinders changed ..... IIRC, it was good to 2000 rpm or so.I guess they could put a similar quartz window in the cylinder head, and have the camera look through it....
It's a neat video...
gil A
Rotary10-RV
Well Known Member
Quartz and Saphire windows
Some of the early setups used quartz windows. Later they used synthetic saphire. Much tougher and stayed clean longer. My guess is the window was split in half for a light and lens. My Dad did metalizing of some of the early windows. (Attaching them to a metal tube that was screwed in like a spark plug) Very interesting stuff. There was a setup that had a strobe so they could photograph stuff like the oil flows in a bottom end. Very advanced stuff back in the day! Don't remember who it was that he did it for. Probably classified at the time. Circa 1970 or so I was just a kidd.
Bill Jepson
Some of the early setups used quartz windows. Later they used synthetic saphire. Much tougher and stayed clean longer. My guess is the window was split in half for a light and lens. My Dad did metalizing of some of the early windows. (Attaching them to a metal tube that was screwed in like a spark plug) Very interesting stuff. There was a setup that had a strobe so they could photograph stuff like the oil flows in a bottom end. Very advanced stuff back in the day! Don't remember who it was that he did it for. Probably classified at the time. Circa 1970 or so I was just a kidd.
Bill Jepson
I noticed that too - but I doubt it's leaking charge INTO the cylinder during the power stroke - the pressure inside the cylinder will be much higher than behind the valve. My guess would be possible raw liquid fuel (or a very stratified charge in a tight surface layer) on the valve lip from the intake stroke. Remember, we don't know the operating speed or temperature of the engine for this video - it could be at idle RPM with a cold engine with some choke, running a very rich mixture, which could allow fuel to condense from the intake manifold onto the face and perimeter of the valve.
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Stephen Lindberg
Well Known Member
It does, and it is...but not too much.
Rotary10-RV
Well Known Member
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
kentb
Well Known Member
Rotation?
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
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
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.
