Watch: Combustion Engine in Super Idle – News
It’s both intriguing and satisfying to watch different processes in slow motion.
And thanks to a super-fast camera, a transparent cylinder and a YouTube channel TROdesigns, we can see what’s going on inside a four-stroke engine during operation.
The engine is from a Honda XR75 from 1977. The cylinder has been replaced with a transparent acrylic version, which allows us to monitor the combustion process.
The video was shot in 4k which gives us a very clear and detailed picture of what exactly is going on inside the engine. The intake, compression, power and exhaust strokes are all easy to visualize. Flames inside the cylinder can be seen, as well as the puff of exhaust on the last stroke of the cycle. The details are even clear enough to see the droplets of the fuel / air charge, the ignition timing and the piston rings doing their best to seal against the cylinder walls.
It has the original piston, although polished to minimize scuffing on the plastic cylinder walls, and the piston rings have been custom-machined from Teflon to reduce friction. The compression ratio went from 9.5: 1 to 8.7: 1 by lengthening the stock cylinder in an attempt to maximize the time the engine was running before it was destroyed.
The real beauty happens at 1:00 p.m., so go ahead if you’re right here for the bucks. But if you look from the start, you’ll see a lot of details, from the piston rings to the painstaking assembly of the engine.
It’s pretty cool to see how well this all works out in practice. After running for a while, there isn’t a lot of staining or cloudiness in the acrylic cylinder, and it’s still clear to see what’s going on.