I hadn't previously been exposed to the Gnome engine from earlier in this thread,
Animated Engines - Gnome Rotary - and some of the discussion got me thinking, what would happen if this idea was modernized, and then applied to a gas-electric hybrid configuration (i.e. Prius-style) to capitalize on its necessary small displacement and likely high operating RPM
Broken down for clarity:
Benefits- Very little reciprocating mass, just the "wagging" of the piston skirts and connecting rods as they accelerate/decelerate, and the movement of the valvetrain.
- Could return impressive volumetric efficiency if modernized
- Should run very smoothly, and be capable of very high RPM due to lack of significant reciprocating mass
Drawbacks (and how they may be addressed)- Gyroscopic effect (when used as a WW1 aircraft engine) -
- Probably not relevant in a car. Mount it on a vertical axis and this effect may actually improve vehicle dynamics, rather than detract from it. This then becomes a packaging problem, which is easier to solve.
- Total loss oiling system
- This is a tough one - perhaps because there is no piston reciprocation it's conceivable that a "permanently lubricated" design may offer suitable lifetime - you could probably get away with ball or roller bearings on both rotational axis' (piston axis and cylinders axis) because of the elimination of reciprocation.
- Management of exhaust gases
- This is also tough... I suppose on the airplanes, exhaust simply left the 'head' into the atmosphere and that was that. Unacceptable on a car, of course. What if the cylinders were "headless" and rotated within a single, stationary ring shaped head? Clearances/scrub seals would be a nightmare, but you could have one spark plug, and the exhaust 'valve' could be just a slot in the "ring" head that the top of the cylinder moves past during its circuit. Like some sort of wankel-gnome amalgam.. thing.
- Management of fuel
- I'm thinking, you could mount a fuel injector in a stationary position at the center, that fires past the open intake valve same as a familar automobile engine... they didn't have that 100 years ago.
It also seems to me that somehow the space between the cylinders and the fact that the whole assembly is rotating, could be used as a duct to supercharge the engine as it runs, "ram air" so to speak.
Thinking out loud, flame all you want
