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Interesting take on the combustion engine - LiquidPiston
daqq:
They claim that they are 30% more efficient and 10x more power dense than the competition. While this does raise a few alarms in my head, they seem pretty serious and they seem to work:
https://www.liquidpiston.com/
I don't have enough knowledge on the matter to judge whether this sort of thing is fishy.
RoGeorge:
Looks like some sort of Wankel engine to me (not a mechanic).
https://en.wikipedia.org/wiki/Wankel_engine
However, the level of bullshit and fluffy words in those videos raised me a flag. I couldn't bare it, skipped through the two videos without sound, sorry. Same about the musical background. Cringe advertising like one would need to do for a scam, not saying it's a scam just that it looks like one, maybe they just hired a really bad advertising team.
I would be very cautious, and go there to see and test the engine myself before investing.
Benta:
"Inverse" Wankel. Has exactly the same same thermodynamic issues. Certainly not my choice when buying stock. And ICEs are slowly dying anyway.
I'd call it a "conversation piece".
Stray Electron:
--- Quote from: RoGeorge on February 15, 2021, 08:10:58 pm ---Looks like some sort of Wankel engine to me (not a mechanic).
https://en.wikipedia.org/wiki/Wankel_engine
However, the level of bullshit and fluffy words in those videos raised me a flag. I couldn't bare it, skipped through the two videos without sound, sorry. Same about the musical background. Cringe advertising like one would need to do for a scam, not saying it's a scam just that it looks like one, maybe they just hired a really bad advertising team.
I would be very cautious, and go there to see and test the engine myself before investing.
--- End quote ---
It's still a Wankel engine and will suffer from all of the problems of a Wankel engine. The high speed at the tips of the rotor will cause rapid seal wear and wear of the interior of the engine block (the equivalent of the cylinder bore in a normal piston engine). That wear will cause exhaust leaks and dilation of the intake fuel-air mixture which will get worse with time. Both of those will cause emissions issues and will prevent it from being approved in most countries. Among other things, Wankels are basically like a 2 stroke engine in that they don't have a separate crank case and combustion chamber so they need to have oil added to the fuel mixture, either manually or via an injection system. The oil is consumed in the combustion and that will cause even more hydrocarbon emissions.
This MIGHT be a good engine but it will never be approved for production in any modern country due to emissions problems. A good modern piston IC engine can easily run for 250,000 miles but no Wankel has ever come close to that due to the oiling and the wear problems.
hans:
The 'how it works' page states: "While it is a rotary engine, LiquidPiston’s X Engine is NOT a Wankel engine. It has a fundamentally different thermodynamic cycle, architecture and operation."
But it doesn't really state what is revolutionary. And when I hear rotary engine, I immediately think about sport car engines like the Mazda RX-8. Great for a fun car with smooth power delivery, but it needs tons of revs to perform (some RX-8 engines deliver peak torque at 5.5k rpm and power at 8.5k rpm) and are not economical at all (and thereby efficient).
I'm sure it can live up to the compactness factor to some degree; because it basically fits 3 cilinders around a rotating cilinder+crankshaft. One issue I think however is the geometry. If you decide to build a larger engine (e.g. 1.5L for a road car), you need to fit 3 large cilinders. The way those inlet/outlets are drawn makes it harder to build a 2-rotor design. The only way is to then go out in width/height, which is unpractical. It also needs a good bearing and seal between gasses and the crankshaft.
I believe the RX-8 wankel engine is also loved because you can mod it to a 3/4-rotor rebuilt design. AFAIK you can even reuse many parts of the original 2-rotor design, as it's quite a modular block.
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