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Old 01-02-2017, 09:06 PM   #21 (permalink)
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Originally Posted by cRiPpLe_rOoStEr View Post
Had them been reliable at all, don't you believe they would have taken over the stationary/industrial market already?
no

I doubt it's that simple.

There are numerous times a 'reliable' option .. sometimes even a more reliable option .. did not 'take over the market'.

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Old 01-12-2017, 10:05 PM   #22 (permalink)
It's all about Diesel
 
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Sure there might be "better" engine layouts that we don't have easy access owing either to an inherently higher overall cost or to political pressures, but the Wankel has proven itself not so dependable. Anyway, I'd still want to see how a similar engine employing the LiquidPiston configuration would fare in real-world driving conditions.
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Old 01-14-2017, 05:18 AM   #23 (permalink)
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Anyway, I'd still want to see how a similar engine employing the LiquidPiston configuration would fare in real-world driving conditions.
+1

I look forward to their continued development/improvement .. so it might someday be good enough to try in my own ride
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Old 03-11-2017, 09:04 PM   #24 (permalink)
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As long as they overcome those apex seal issues that plagued most Wankel engines, this engine design would be quite competitive. BTW even though the water cooling seems to fare better due to a more accurate thermal management, the simple air-cooling layout might sound attractive for the general aviation market that still relies mostly on outdated designs.
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Old 02-06-2020, 04:41 AM   #25 (permalink)
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I just saw this somewhere on Youtube or something and went through all their papers.

The concept looks decent. Apex seals in the housing instead of the rotor should make them more reliable I'm guessing.

Compression ratio can be pretty much as high as you want, that's good. Could set it at 18:1 expansion, 12:1 effective compression for similar VE to a Mazda Skyactiv-G.

Increased dwell actually isn't good for low speed given the surface area to volume ratio is still poor, but you can just run the engine at high speed only as a generator or something.

Since you have most of the combustion chamber in a quench/squish zone and a tiny pocket to ignite most of the fuel, combustion speed is not a problem. Then again, combustion speed is less important if you have a really big expansion ratio.

Now the bad:
XMv3 indicates 18% peak efficiency, 5 bar IMEP, 4 bar BMEP without Atkinson cycle intake "timing". That is BAD. A similar sized Wankel from AIE gets almost 7 bar BMEP: https://www.aieuk.com/40s-5bhp-wankel-rotary-engine/ The sealing must not be working, or something. A dyno chart would make it easier to figure out what's wrong.

The rotor has a similar problem to the Wankel: one side has the exhaust constantly going through it, the other side goes through intake/compression/expansion. There's definitely going to be a big temperature difference, which might contribute to poor sealing. Since you can't liquid cool the rotor, this is probably a big problem, since even if you're using inconel, the exhaust side would expand by several thousandths, that's going to create some bad vibration for the apex seals. A carbon ceramic rotor with dry lubricant ceramic seals might work, at very high expense. Another idea is to use intake air to cool the rotor, but that reduces power density and WOT efficiency.

It looks like the rotor air cooling blows out the exhaust? That can't work for any emissions controlled engine, can't be mixing fresh air into the exhaust.

I'd like to see what happens with a bigger sized demonstrator if they ever come out with one. The bigger size alone would make sealing, cooling loss, and pumping loss less of a problem.

Last edited by serialk11r; 02-06-2020 at 05:21 AM..
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Old 02-24-2020, 12:16 AM   #26 (permalink)
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Quote:
Originally Posted by serialk11r View Post
Increased dwell actually isn't good for low speed given the surface area to volume ratio is still poor, but you can just run the engine at high speed only as a generator or something.
Most likely it could serve the purpose of a hybrid, or being matched to a CVT.

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