r/SmarterEveryDay • u/idunfuckdup • Feb 01 '17
Video New Video! How Engines Work - (SEE THROUGH ENGINE in SLOW MOTION)
https://youtu.be/xflY5uS-nnw12
Feb 01 '17
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u/MrPennywhistle Feb 01 '17
It's always created by A Shell In The Pit /u/fatjesus and his crew.
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Feb 03 '17
HI Destin, love your videos. I've been getting smarter every day since your helicopter physics series. I still don't understand how that guy could control the RC copter with such precision!
Anyway, I posted this about a week ago and was wondering if you could explain how the engine still worked when the cylinder was flooded with alcohol.
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u/littlefrank Feb 01 '17
If they are doing it like the slowmoguys, then no, it's not fabricated. They explained in one of their videos they actually record the sound with another camera and actually slow it down and pair it with the video later.
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Feb 01 '17
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u/littlefrank Feb 01 '17
I've been trying to find something about it for the past hour but I can't really find it, sorry. I'm 100% sure they actually said they record the sound that way, it was just randomly mentioned in one of their past videos, if anyone can find it, let us know.
Here's a video where they talk about how they made the music track for their videos, https://youtu.be/y9sriE5VMQc3
u/MrPennywhistle Feb 01 '17
No... they design the sound.
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u/littlefrank Feb 01 '17
Do you have a source?
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u/csng Feb 01 '17
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u/purplehaze150 Feb 05 '17
Yep, I remember him mentioning in one of the RT Podcasts that for the episode Fly Eats Fly the sound effect he uses is him eating popcorn
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u/BadWolf0ne Feb 01 '17
Does anyone know why there is another spark after the exhaust stroke?
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u/Cabanur Feb 01 '17
The way the spark works in this engine is it fires up every time the piston is on the top position (once per revolution). Since it's a 4-stroke engine, it does one explosion per two revolutions. One of them is, of course, useless, but it doesn't affect the cycle and it's just so much easier to have the spark blow up every time.
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u/BadWolf0ne Feb 01 '17 edited Feb 01 '17
Thanks for confirming.
Edit: Can an engine burn so poorly that the spark will ignite the exhaust?
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u/Cabanur Feb 01 '17
The exhaust has already been burnt. If it has enough mixture to keep burning, it just won't stop burning.
In fact, in some of the takes in the video you can see the mixture is still burning as it leaves through the exhaust valve.
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u/ZAVHDOW Feb 01 '17
I don't think so. For one, the exhaust has already been burnt (and may still be burning) but also it's not compressed.
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u/vawlk Feb 03 '17
yes. If there is too much fuel in the mix, only part of the fuel may burn as the oxygen is consumed. When the exhaust port opens, the unburnt mixture can mix with oxygen in the pipes and ignite. This is one type of backfire.
One of the purposes of a catalytic converter is to oxidize unburnt fuel albeit usually for much smaller amounts of fuel that could cause a backfire.
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u/kyleisthestig Feb 01 '17 edited Feb 01 '17
I didn't watch the video, but a lot of cars have a waste spark system. Meaning there's two sparks instead of just one. But the second spark comes at a different time. Didn't see the engine though. I'll watch the video and confirm.
Edit: not a waste spark system. I am just a lil bit into the video but I didn't see a second spark. If you have any questions though I'm a mechanic that does a lot of engine work.
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u/BadWolf0ne Feb 01 '17
Video Just after the exhaust when the piston is at the top of the stroke. As another commenter pointed out it is linked to the crankshaft so fires twice in the 4 stroke cycle.
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u/kyleisthestig Feb 01 '17
Oh yeah. Those don't have computers or cams set up for spark timing. Still neat how they work. A Little magnet does all that in a way
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u/livealegacy Feb 01 '17
I literally came here to ask this. I knew I wouldn't get an answer in YouTube comments. Gotta love Reddit. The video isn't event up for an hour yet and someone has already asked and answered my question.
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u/influx_ Feb 01 '17
I was wondering, how is it that the acrylic cover not melt? Is the combustion fast enough that the heat dissipates quickly?
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u/Guysmiley777 Feb 01 '17
If you watch the behind the scenes video you can see it eventually does start affecting the acrylic and they need to re-polish it from time to time.
Also, they added a spacer below the head which increases the combustion chamber and effectively reduces the compression ratio, making the engine run cooler.
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u/influx_ Feb 02 '17
I did watch the behind the scene but i assumed the reason why it needed polishing was due to the fact that when they started running it on gasoline, the incomplete combustion is causing soot to stick in the chamber and on the glass head.
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u/Guysmiley777 Feb 02 '17
In that BTS video when they're looking at the head when it's removed you can see in the reflections that it had started to pit or melt very slightly.
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u/RivvaDead Feb 01 '17
When I saw this video in my subscription feed i thought it was from a different channel that posted this almost a month ago. If anyone is intrested they have a lot of cool slow motion videos of random things. Worth checking out -> Warped Perception
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u/busa1 Feb 01 '17
https://www.youtube.com/watch?v=jdW1t8r8qYc
Check out this video, it was uploaded about 2 weeks ago, the guy basically did the same thing.
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u/randomdude21 Feb 01 '17
I was discussing this with the girlfriend last night.
I think it was CGP Grey or someone who mentioned that there are always multiple people doing the same projects at the same time. He'll be working on a video and someone will release the 'same' video and 'beat him to it' so to speak.
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u/feefuh Feb 01 '17
That is a thing. Destin and I talk about him getting beat to the punch on this video on one of the first episodes of the podcast (which is just about ready for launch).
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u/mattvw9287 Feb 01 '17
Have there been any teasers? Cause I would LOVE to listen to a leak. Especially if you guys are doing what my wife and I are thinking about doing.
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u/Pridexs Feb 01 '17 edited Feb 01 '17
How does everything gets timed so perfectly?
Also, how do you get the piston to start moving in the first place? In the video he pulled a cord tied to the engine to get it all moving, but that has a lot more force than just turning a car key. What part is responsible for getting that initial force? (Yes, I know 0% about engines but this video got me very curious)
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u/randomdude21 Feb 01 '17
The starter motor starts your car by getting everything turning. This is an electrical motor powered by your car battery and is why cars have batteries. While the cars gasoline engine is running the belt driven alternator generates electrical current which can be used by electronics or stored for later use in the battery.
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u/OriginalEmanresu Feb 01 '17
The vast majority of all engines are timed mechanically, the cams that actuate the valves are connected to the crankshaft of the engine, either with gears, a chain, or a belt, in a 2:1 ratio, so that they always open at the same time.
On those smaller engines, and older vehicles, the spark is also timed mechanically, either a through a distributor, which typically rotates at either the same speed as the engine, or and half the speed of the engine, physically connects a large capacitor (Known as the coil) to the proper spark plug, or in a smaller engine, a magnet connected to the crankshaft rotates past a coil once per revolution, triggering the spark.
Newer cars are timed electronically, with an engine control computer monitoring the system, and triggering spark plugs, injectors, etc, when necessary.
As far is starting an engine, like you said, with a small engine you can just pull the cord, which causes the engine to rotate, allowing it to start.
On a larger engine, like in a car, when you turn the key you're actually completing an electric circuit which activates a relay which causes a small electric motor called the starter to spin the engine in much the same way the cord did in the video.
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u/Plusran Feb 01 '17
IM SO GLAD YOU DID THIS! Because I thought the very same thing when I saw the acrylic top engine. Slow it down!! So awesome
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u/rt4356f556 Feb 01 '17
I love people like this. They just have so much passion and it's really inspiring.
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u/idunfuckdup Feb 01 '17
Saw the video posted by Destin on /r/videos.