So I just had this idea floating in my head for a while and wanted to see the feedback on it.

The idea is instead of having apex seals, they would be replace by rollers which would still be pushed by springs to maintain compression though. The roller would be seated in U shaped seat (Could be extended more on the side to preven the roller to fall out but i don't even see it falling out like that.

The thought behind this would be that the rollers would increase the life of the engine and slightly more power due to the following few reasons:

1) Because its on rollers it would lover the temperature slightly due to the apex rolling again each other as oppose to "scrapping" each other.

2) More torque would be provided to the wheels since needing less to spin and also HP increases to the wheels.

3) When porting exhaust or PP intake, you might be able to get away with a bit more angling since you won't need to bevel the edges as the major problem with that is the apex seals might get caught and snap.

4) Alot more life out of the housings since the coating won't get scrapped off there.

5) More life out of the seals for the same reason as above, almost no wear.

6) Could maybe even eliminate the need of mixing oil in the intake for lubricating the seals as it would be almost un nessary.

7) And because its cool to have more rotating things and I wanted a 7th reason


Also as far a cooling, oil could be routed though the side and inside the roller to further more cool the seal. Anyways let me know what you guys think of an idea like that.

Sam

 

Mazda engineers have spent many years trying to develop a much improve engine and the only thing they can come up with is a renesis. maybe you're a thousand light years behind them.

 

Good idea, but Im pretty sure if it could be done, it would have. One thing I see right off wrong with that is since the seal is round, only a tiny tiny area is in contact with the housing and that would probably allow for a sizable decrease in compression. Also, the roller being so small, it would see very very high rotation speeds (If it even spun, at that point it would probably just slide and defeat the purpose) which would result in tons of heat as its being pressed between a carrier and the housing. The roller would have to be too small to allow for it to be hollow, so no oil passages for cooling. The carrier would have very thin spots along the edges that would crack off within the first few minutes probably and cause internal damage just like an apex seal breaking would do. Good idea but flawed IMO, you would be better off trying to develope a laser forcefield apex seal

 

Good point which i've thought though, but you're thinking inside the box of the rollers having to stay the same size as the apex seal. I was thinking something as big as around 3/4" or even an 1" for the roller. Like this too we could have the springs being able to be stiffer.

 

Oh I see. So sort of built into the rotor. You would still be left with the fact that the contact area would be pretty small and you would more than likely get compression blowing by the seal. Im still not sure how its supposed to roll though. Only way I can see it working is building the rolling dirently into the rotor and using fluid pressure to keep the roller in contact with the housing. Use some type of seals that stick out past the half way point on the roller to help keep the oil pressure in. Excuse the quick paintshop image



The pressure under the roller would try to push it outwards but the housing would keep it from moving so far that it passes the seals that hold the oil in. Having it only contact 1 surface directly would reduce friction and allow it to roll much easier since it will float on an oil bearing basicly. Not 100% sure on what or how the oil seal will work. It would have to be metal. I guess maybe something like a flat cup seal, but metal. Only problem is that I dont think the pressure could ever be high enough to counteract the combustion pressures. Since the roller is round, the pressure is allowed to get into the crack where it meets the housing and push the roller back inward towards the rotor. So you would have to find a way to make more pressure under the roller than the combustion pressure can on top. Which is why a square apex seal works, because pressure only pushes on the sides and not on top, so the spring has nothing to fight. THOUGH, it will have some centrifugal force on its side, Im not sure if it would be enough as the rotor is so small and the roller would only be maybe 6 inches from the center.



See what I mean

 

the thought of using just fluid pressure keeping it in I've htought about too, and I think that if anything goes wrong, it would just fill your whole engine with oil. the idea of going more than half would probably be a better idea to make sure there's no way it would come out, and would just slide in from the side seal.

 

Just another idea. I have no idea of the details, but I think a double roller of some type might be able to hold up to the pressure. But the carrier that would carry them would have to be spring loaded unless you just somehow built 2 of them into each point of the rotor and did away with a carrier. Also not sure how to get oil to them if they use a carrier like that. Just another idea. You got my engineering mind working



I also just realised, putting the seals above the half way point, like on the first model I did wouldnt work. Once you pass the half way point the oil would no longer supply any outward force, it would canel itself out. So thats useless. maybe put a carrier with a spring under the ball, that would be pretty much floating in oil. So the oil would still act as a liquid bearing, but you woild also have the advantage of a carrier and spring to give it extra outward force.



Like so

 

working minds are great minds. To be honest though, the main idea came when I was looking at the rotrex supercharger roller idea.

 

Yeah there is nothing wrong with thinking. Im all the time thinking of things like this. Ways to fix one thing or another, a way to do this or that. How to design it, make it, market it, ect. Im sure the roller apex seal could be made to work, but seeing as no matter how you do it, it will more than likely make the engine more complicated with more parts, which is never a good thing. Though you could do away with corner seals as you could lengthen the roller slightly and have it act as a built in corner seal. So really the parts would be about the same. But its almost like starting from scratch on a rotary engine.

 

Sounds great, because apex seals just aren't expensive enough as is.
.

 

Better doesn't always mean simpler nor cheaper for that matter. Its just that the rotary engine does not seem to have revolutioned as much as its counterpart the piston engine. SOHC to DOHC, Alll the stuff like Vtec, and things like that have helped fuel economy on cars along with more power and torque.

 

ya but if its going to get twice or even more the life our of your housings and maintaining higher compression would it still not be worth it?

 

Just looking at that double roller design I don't see it working properly do to the groving on the side. Carb would just seep in there overtime and not be able to wobble around.

 

Well, like I said that was a crude picture. It wouldnt be exactly like that but to show a seperation i made the gap large enough to see. It porbably wouldnt work anyway though

 

Interesting idea. The biggest downside that I see is a couple of things. In the single roller design, the rotor would need to house a race as a seat, with a spring underneath it to maintain the needed pressure for sealing on the housing face. The other, and more critical issue will be carbon build up. Once the carbon begins to build up, the roller might sieze, and then a flat spot will begin to wear on the roller.

Once that happens, the contact area will continue to widen, as will the friction and drag. If the roller were to slightly rotate, then stop once the flat spot has worn in, it could leave a somewhat sharp edge in contact with the housing face.

The other thing to consider is the speed at which the roller will rotate as it travels across the housing face. At high engine rpms, that rotational speed could be excessive for most any material the roller maight be constructed from.

Keep those ideas coming. While most won't work in the long run, there's always that occasional 'Eureka' that leads to a new developement.

 

yup all we need is just a little spark ...

but I have reason to disagree with the roller to being able to take on those kind of speeds. Considering the rollers in the rotrex charger being able to be driven at speeds of 12,000rpm how fast do yo uthink they will turn?

 

how fast are the rotors making a full rotation at 9k rpm? 3k? I can't remember. If we knew how far that the roller was traveling to make one revolution around the housing, we can find the speed of different size rollers.

The issue with making your roller bigger sizes, is your contact area stays the same. At some point you are just decreasing the quench area of your rotor.

 

What if you were not burning gasoline? something like propane, or ethanol which is cleaner to start with? If you ran it with two stroke oil in the crank like some motorcycle do, the oil that leaked past the "seals" could be used as lubricant for the rotor walls, and would not be as "apt" to carbon up.

just my 2.36 yen worth

kenn

 

Most of those idea's have already been tried and a few already patented if im recalling my reading right

edit

both the single and double roller. theres also one with 2 'apex' seals and a roller between them making sort of a V with the roller at the point of the V which is the part that touched the housing

 

Or maybe even LNG for a clean burn fuel. Feeding the lubricating fluid though what would be the race/cradle for the roller seal/bearing is a very interesting idea and might eliminate most, if not all of the carbon build up issue.

 

Care to share where that info might be found?

 

I would imagine a 1'' roller would probably make 20 maybe 25 rotations in 1 revolution of the rotor. So thats what? 60-75k rpm of the seal at 9,000 rpm at the engine? Probably alot of heat, but seeing as a turbo shaft (though only about half the width) can safely rotate at 100-150k rpm in some cases, maybe a 1'' roller at 60k rpm wouldnt be too bad.