Comments by "David Elliott" (@davidelliott5843) on "Rotary Valves Make Normal Valves Look Silly - Why Aren't We Using Them?" video.

  1. Wankel fails because the spark plug provides a blowby point, the long combustion chamber has a high quench and blowdown is too short resulting in extreme noise and extremely hot exhaust. Opposed piston two stroke is the most efficient. It can also add a port height adjuster to boost mid range power.
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  2. Direct inject two strokes are very clean. They don’t have fuel washing oil of cylinders and bearings so can run a much smaller oil flow. Fuel is injected after all ports have closed so there’s never any unburnt fuel going down the exhaust. Exhaust power valves maintain midrange power and there’s no partial combustion to slap the piston around - much less bore wear. The Rotax ETECH is cleaner than competitors four strokes and has better fuel consumption. It can use stratified charge solving NOx issues. The pre combustion chamber used on F1 engines is an ideal fit as the excess air can be varied via inlet valves.
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  3. Back in the 1980s someone made a single rotary valve for a Yamaha XL500 single. One cross valve provided inlet and exhaust ports.
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  4. Liquid piston (silly name) swapped the oval and triangle I used in Wankel. Its stator is triangular with a spark plug on each corner. Rotor is oval. Seals are fixed in the stator and can be easily replaced. It solves the flame quench and short blowdown of wankel but the rotor can overheat.
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