What do you think of this new split apex seal design? I am not a mechanical engineer but it does make sense.

This is from, http://rotarynews.com/node/view/837

 

if it works it will be an exciting advancement for the rotary engine.

So how much for the split apex seal rotor?

 

Wow....... I hope it does in fact give the gains as published.
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Pepper cam

 

[Arm Chair]

It's interesting. But I think you'd need some kind of crazy material in order to build them. No matter what they would end up being more fragile than normal apex seals.

Perhaps the biggest problem is that these Apex seals would have to move a LOT compared to normal ones. Also this design would probably put a lot of lateral force and almost double the friction over current seals.

Also, I would be very surprised if Mazda hasn't already investigated using 2 Apex seals.


As far as leakage from passing over the sparks plugs this is probably very minor. I read on the website of a marine Wankel engine company that they did some tests and leakage was very small and not worth worrying about.

I believe that one of the major problems at low RPM is the size of the combustion chamber and maybe leakage around the sides of the rotor(not sure about that),

I really hope this guy is onto something but all in all there is way to much snakeoil out their to get my hopes up.


In order to show how much dual apex seals would have to move consider how radically the angle to the side of the chamber changes during the cycle.

Look here for a nice run through of how a Rotary Engine works. Also, there is a nice animation that runs through the cycle of a Rotary Engine, it's on the 2nd page about 3/4 of the way down.
http://auto.howstuffworks.com/rotary-engine.htm

[/Arm Chair]

 

Amazing............

Let's see some testing and implementation in production.

 

"which will increase compression and torque at low RPM and therefor reduce fuel consumption."

wow something like this could help the rotary engine to live on.

where is rotarygod???

 

Interesting read! Suprised I understood a fraction of it so early in the morning.

 

It's possible they'd be more fragile because from his PDF it looks like they'd be thinner, but I'm not sure it would make that much of a difference.

Move alot in what sense? The current apex seal bangs around inside it's freaking housing, how is that any less stress that his implementation?

If they did, it's almost certain they would have patented the idea.

There might be a significant flaw in this design we're all missing here, but lets hope thats not the case

Until we see an actual motor with these seals thats tested over thousands(hundreds of thousands?) of miles, we won't know for sure.

 

Looks like this new apex seal would eliminate the need for corner seals too. (pg.10)

Also it says it reduces excess force placed against the housing at higher RPM's, where the conventional seal is pushing too hard. (pg.12)

What's that last chart on p.14 all about though? Is is saying that a revised-seal wankel would hold combustion pressure longer than a piston motor? Or that it would have a longer time available to propagate the flame?

 

Or you could just try these:

http://www.hurley-engineering.ltd.uk/dutips.aspx

http://www.hurley-engineering.ltd.uk/swingtips.aspx

 

I'm talking in respect to their angle and distance from the walls. A normal Apex seal has 1 contact point.

Remember from the apex seal's point of view the angle to the wall changes \ _ /

Because these apex seals have two contact points each seal would be constantly extending or retracting. In a high temperature and high stress environment that's asking a lot.


Do we know their isn't a patent? Also, they may have tried it in the 70's when you didn't have to patent every idea you came up with. Only those you got to work.
If this was tried out then, then maybe new materials could make this possible.


- Increased mechanical complexity + more fragile = less reliable

- Increased friction = increased heat, increased wear and tear both on seals and housing.
increased heat means lower compression

Also, keep in mind the inside of an engine, especially a Rotary, is a dirty place. Quite a few people are having problems with carbon build up. How are you going to keep such a delicate system from clogging?



Agreed, at this point I would be happy just to see a physical example of his design.

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Now, keep in mind, I would LOVE for this to work. Yes, my heart beats a little faster when I think about it.

But I don't plan to hold my breath. If there was something I could do to help this guy out I would do it in a second.



Nice find RotaryGod. To bad they aren't for a Rensis. The second one looks kinda scary, like it would be easy to break.

I wonder if they will make them available for the Renisis.

I've emailed them to ask, here is my email:

 

So glad to see a new interesting thread.

 

hows he gonna lubricate them..? lots more surface area.. the split apex seals are gonna bake together, good luck ever seperating them.. forget carbon lock,, better leave your enginre running forever to keep the seals from carmelizing together.

 

Hey RG, do those hurley seals actually give more torque and fuel economy?
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Laguna Bay II Condos Prathumnak

 

I noticed this possible solution for lubrication

http://www.hurley-engineering.ltd.uk/hmelub.aspx

But this wont necessarily keep'em from gluing to each other.

 

Good question. Since they are for RX-7's I guess it's time to head on over to rx7club.com.

 

Yeah thats a great find, hopefully they'll have something for the renesis. If so, it sounds like this is a relative cheap mod for overall better torque and gas milage.

 

I wouldn't say cheap while the parts are cheap the labor to pull everything out of the engine bay and take apart your engine and then put it all back in would be killer.

Probably the same price as a turbo charger.

 

Quick search on RX-7club, conclusion : Hurley seals suck
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Live sex

 

Click on the link for the Concord in the second website, sounds like a scary machine!!!

 

as drawn they have a huge stress concentration point at the vertex of the obtuse angle before the dog leg

your going to have relative motion between the two seals which will lead to the two seals rubbing and either wearing each other away or polishing the 2 pieces (which doesn't sound good but the coefficient of friction will be extremely unstable and probably result in the 2 halfs sticking together alot)

 

I also searched. They suck for our purposes. They are good for racing engines(very high raving, over 9k, engines and engines that need to be rebuilt often)

The other good use for them is tuning your Turbo. Since they crumble rather then shatter if they fail. So, tune with them then open engine and put OEM seals in.

Also, the supposedly only last 20K miles or so.

 

oh well yeah. theres labor, but I do all the work on my car.

 

You've got to understand that on the 7 forum, everything sucks! I'm not kidding! Everything sucks over there unless it's some stupid bandaid of an ecu solution like an S-AFC or an R-Tek. Then they are the best thing on the planet. Superchargers suck over there. RX-8's suck over there. Don't put much faith on that forum. I don't really contribute there that much anymore as a result of all the whiners. It's too bad as there are some pretty smart people over there. Too bad it's the idiots that everyone listens to.

Those seals aren't specifically made for the RX-7. They are up to 4 mm wide. They need to modify the rotors. Hurley seals are easier on housings that stock Mazda seals since they are a little softer. This also means they are not as tolerant of detonation or forced induction. The RX-7 guys that have used them are all forced induction people that have blown them up. Those guys are good at blowing their cars up and are always looking for a tougher seal so they can break other parts of the engine instead.

I'm not necessarily defending Hurley. It just needs to be understood the type of crowd that has a problem with them.

 

Hmm interesting. So the could be mounted on a RENISIS?

If you can install them yourself that changes things a lot. Wish I could do that.