Flammenfresser

[mklotz]

Flame Eater (Flamenfresser in German) is an atmospheric engine.

As the piston reaches TDC, a fast-acting cam snaps the valve leaf open, exposing the interior of the cylinder to the alcohol flame. As the inertia of the flywheels drive the piston down a vacuum is created in the cylinder and the flame is sucked into the cylinder cavity.

As the piston reaches BDC the valve snaps shut. The hot gas trapped in the cylinder rapidly loses heat to the cooler cylinder walls, creating a partial vacuum inside the cylinder. This vacuum allows the atmosphere, pushing on the bottom of the piston, to drive the piston forward in the power stroke, hence the term "atmospheric engine", since the engine's power is derived from the atmospheric pressure.

With a working pressure of something less than 14.7 psi, this engine is no powerhouse. Ball bearings for the main shaft are essential as is frequent oiling. [The small brass cup on the top of the cylinder is an oil cup that keeps the piston lubricated during operation.] The cam-follower is also a small ball bearing.

What is incredible to me is the speed this engine can attain. It just doesn't seem possible that the heating/cooling gas cycle described above can be happening fast enough to sustain the speed evident in the video.