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-   -   Pratt & Whitney Rotary Engine Patents!! (https://www.rx8club.com/rx-8-discussion-3/pratt-whitney-rotary-engine-patents-267187/)

neit_jnf 02-14-2018 09:13 AM

Pratt & Whitney Rotary Engine Patents!!
 
Did you guys know Pratt and Whitney is working on rotary engines?? There are lots of recent (2010-2018) patents related to or mentioning wankel rotary engines.

They have patents for rotors, apex seals, intake and exhaust ports, direct injection with pilot chamber, compound setups (turbine connected to eccentric shaft), you name it! I just found out about it.

P&W Wankel Engine Google Patents


https://cimg2.ibsrv.net/gimg/www.rx8...599a08c03e.png

9krpmrx8 02-14-2018 09:17 AM

https://cimg4.ibsrv.net/gimg/www.rx8...76aa77186e.png

sapibuntinx 02-14-2018 02:55 PM

Clean is the new cool, so let’s keep it that way.

Loki 02-14-2018 03:55 PM

There is an ongoing trickle of interest for rotaries for UAVs, potentially light piloted aircraft. They're a much better fit in aircraft than cars. When cruising at constant rpm for hours at a time, a rotary can be more fuel efficient than an equivalent aviation piston engine. More efficiency = more time on station.
Also no cats on airplanes so they can build it properly instead of compromising.

The turbine idea is interesting, maybe in a ducted fan set up of some sort. The rotary is potentially compact enough to fit inside a duct, where a piston engine would look awkward. Especially if its a 3 or 4 rotor with a small frontal area.

UnknownJinX 02-14-2018 04:35 PM

Important question:

*In Mighty Car Mods voice*Will this fit in my Mazda?

wannawankel 02-14-2018 05:51 PM

Yes it will - check the Will It Fit thread soon. because "race car"

boricua13 02-14-2018 06:44 PM

Loki, that's been an interest for a long time, like you said fuel economy, but more importantly power to weight ratio which is huge in aviation. The constant problem is reliability, there is no side of the road to pull over 5k feet in the air... You can glide, but only for so long. In aviation, reliability trumps cost/savings.

UnknownJinX 02-14-2018 08:32 PM


Originally Posted by boricua13 (Post 4852174)
Loki, that's been an interest for a long time, like you said fuel economy, but more importantly power to weight ratio which is huge in aviation. The constant problem is reliability, there is no side of the road to pull over 5k feet in the air... You can glide, but only for so long. In aviation, reliability trumps cost/savings.

On the other hand, I'd imagine these aviation engines are a lot better maintained and checked than your Average Joe car owner who doesn't even know how to check engine oil level...

Rotary is fairly reliable when properly maintained. If you want to talk about longevity, that might be another story, but given that these aviation engines usually run at constant load and speed, these engines may last longer than road rotary engines.

I mean, if you think about where the whole "RX-8 is unreliable" comes from, it's mostly because of the shitty early ignition coils that don't last long.

Loki 02-14-2018 10:41 PM


Originally Posted by boricua13 (Post 4852174)
Loki, that's been an interest for a long time, like you said fuel economy, but more importantly power to weight ratio which is huge in aviation. The constant problem is reliability, there is no side of the road to pull over 5k feet in the air... You can glide, but only for so long. In aviation, reliability trumps cost/savings.

Oh I know, I fly. But the rotary concept is not inherently unreliable, especially in a constant load application and with aviation spec service intervals. The implementations specific to automobiles have it unreliable. Fast load variation, emissions restrictions, etc. The Renesis's weak points are largely self-inflicted: hot, constricted exhaust port, complicated intake valving for a wide powerband, underengineered ignition parts, catalytic converter. None of that is necessary if you're flying, and you can believe there will be redundancies. Also if you lose a cylinder on a conventional engine, it's produces 0 power. If you lose compression in 1 rotor for some reason, the thing can keep turning with some productive output. No rods to throw and no timing to screw up.

IamFodi 02-15-2018 04:26 AM


Originally Posted by Loki (Post 4852180)
Also if you lose a cylinder on a conventional engine, it's produces 0 power. If you lose compression in 1 rotor for some reason, the thing can keep turning with some productive output. No rods to throw and no timing to screw up.

^ This. Very important point.

Also, fewer moving parts.

IamFodi 02-15-2018 05:43 AM


Originally Posted by UnknownJinX (Post 4852177)
On the other hand, I'd imagine these aviation engines are a lot better maintained and checked than your Average Joe car owner who doesn't even know how to check engine oil level...

Rotary is fairly reliable when properly maintained. If you want to talk about longevity, that might be another story, but given that these aviation engines usually run at constant load and speed, these engines may last longer than road rotary engines.

I mean, if you think about where the whole "RX-8 is unreliable" comes from, it's mostly because of the shitty early ignition coils that don't last long.

The failure rate seems WAY too high for maintenance to be the main issue. It's a factor for sure, but it doesn't explain how rarely these engines hold compression as long as a decent piston engine (in street applications).

boricua13 02-15-2018 07:11 AM

Good points all round, the problem I think is that they will never be in commercially available planes dues to the high maintenance. While most private pilots are well verse and keep up with the maintenance, piston engines are relatively easier to maintain. All it takes is the one dumbass to not follow the maintenance and try to fake the logbooks to bring a mfg down with a lawsuit. Even jet engines are less complicated and easier to maintain, just a whole lot more expensive due to the mats used, specially the turbine blades. Then again, all it takes is a lead pencil to blow up a jet engine, lol

neit_jnf 02-16-2018 11:23 AM

https://cimg4.ibsrv.net/gimg/www.rx8...c91be82ad5.png

Late compression Atkinson cycle ports (low volumetric compression)

https://cimg5.ibsrv.net/gimg/www.rx8...7955938525.png

oil injection 3 orifices

https://cimg6.ibsrv.net/gimg/www.rx8...3f8cf8162c.png

oil injection multi orifices

https://cimg7.ibsrv.net/gimg/www.rx8...b7ba73d615.png

oil injection slit

https://cimg8.ibsrv.net/gimg/www.rx8...1a1bb9bac1.png

look familiar? side/corner seals

https://cimg9.ibsrv.net/gimg/www.rx8...ec8434222f.png

peripheral port to prevent apex seal crash

https://cimg0.ibsrv.net/gimg/www.rx8...1dcc3a9054.png

direct injection spray pattern

https://cimg1.ibsrv.net/gimg/www.rx8...ad64aa7da8.png

no corner seal arrangement

https://cimg2.ibsrv.net/gimg/www.rx8...1ea98b20de.png

with corner seal

https://cimg4.ibsrv.net/gimg/www.rx8...8a4d28a106.png

double apex seals

https://cimg5.ibsrv.net/gimg/www.rx8...ff2a805ac8.png

2-rotor turbocharged with axial turbine compound setup

https://cimg6.ibsrv.net/gimg/www.rx8...54e9997c4e.png

4-rotor turbocharged with center axial turbine compound setup

https://cimg3.ibsrv.net/gimg/www.rx8...dbc1f86e44.png

4-rotor with opposing side ports and spark plugs

Loki 02-16-2018 11:30 AM

Whoa!

That opposing 4 rotor thing looks interesting. How would you arrange the intake ports in that case?
Hope to see it operate.

Hey according to the documents, P&W Canada is working on this... I'm looking at their Montreal facility out my window at this very moment. Time for some industrial espionage.

neit_jnf 02-16-2018 12:03 PM

Mazda has a similar opposing side engine but with side-ports and turbos!


https://cimg0.ibsrv.net/gimg/www.rx8...e836422c5c.gif

design eliminates siamesed ports

https://cimg1.ibsrv.net/gimg/www.rx8...eda3e963ef.gif

https://cimg2.ibsrv.net/gimg/www.rx8...9e67d68008.gif

lower intake upper exhaust for one rotor

https://cimg3.ibsrv.net/gimg/www.rx8...10e2a6d91a.gif

upper intake lower exhaust for the other rotor

https://cimg4.ibsrv.net/gimg/www.rx8...1cab6460b7.gif

both rotors same orientation on the eccentric shaft

strokercharged95gt 02-16-2018 05:56 PM

Interesting how the side seals flex against/inside the corner seal to keep a 100% sealing without creating any binding....

gwilliams6 02-22-2018 08:59 PM

There were rotary-engine powered aircraft back in the sixties and seventies.

https://en.wikipedia.org/wiki/Wankel...rcraft_engines

neit_jnf 02-23-2018 07:08 AM

Yes and now there are wankel powered UAVs, what surprised me about the PW patents is that they are recent, from 2010 and as recent as january 2018

furansu 03-29-2018 11:24 PM


Originally Posted by strokercharged95gt (Post 4852329)
Interesting how the side seals flex against/inside the corner seal to keep a 100% sealing without creating any binding....

I wonder if they've actually built any of these and how they ran. They went right to side ports like an MSP engine, but the ports are strangely shaped compared to Mazda trends (very bulbous and round on the end of the port).


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