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eamon hurley experimental apex design
Any one come across this in the real world. .. found it on gearheads...sounds complicated but maybe there's something in it The flaw in this design, is that the oil doesn't really seep down in between the rotor and the apex seal. It only penetrates the space by about a 3rd of the depth. Eamon Hurley, of Hurley Rotary Engineering, has designed a lubricating system that requires a few holes to be drilled through the apex seal slot bottom into the inner oil cavities. Going into those holes are 'needle' valves that are open and closed by the apex seal springs as the rotor revolves within the engine. That motion comes from the shape of the rotor housing; it is similar the shape of a peanut, but symmetrical along both, the X- and Y-axis. On the combustion side (lower driver side, if you will), the apex seal springs are compressed and the apex seal is seated as deep as possible into the apex seal slot. On the intake side (upper passenger side, if you will), the apex seals and springs are in the most 'relaxed' and 'open' positions.Via centrifugal force, as the apex seals and seal springs are 'relaxed' and 'open' on the intake side, oil seeps through the holes beneath the apex seals and supply PLENTY of oil to parts and spaces needing the lubrication. As the rotor rotates to the combustion side, the apex seal and springs are compressed and 'closed', thus closing the 'needle' valves and cutting off the oil lubrication supply. BRILLIANT! http://rotarygear-head.blogspot.ie/?m=1 #note brilliant is not dalippys opinion. ..just a quote from the author 😊 |
The bit about the apex seal being compressed on the hot side and relaxed on intake feels like a misconception. The rotor tip is not any closer to the housing on the hot side than the cool side. There is a different effect where the apex seal is compressed into the housing by combustion pressure, so it would actually be in the most "relaxed" position by their logic. But in any case, it's not moving. We're not opening a gap between 2 adjacent faces on every intake cycle.
In addition, the apex seal groove is where carbon accumulates, you don't really want to introduce more sticky goop in there than you have it. It's not hot enough to self-clean so the oil will just turn to wax. And then what happens to that oil supply? Plus, the oil inside the rotor is under centrifugal force proportional to rpm, so those needled valves could push the apex seal up if the forces aren't properly balanced. Maybe he made it work, I don't know. But it sounds finicky. |
Originally Posted by Loki
(Post 4816151)
The bit about the apex seal being compressed on the hot side and relaxed on intake feels like a misconception. The rotor tip is not any closer to the housing on the hot side than the cool side. There is a different effect where the apex seal is compressed into the housing by combustion pressure, so it would actually be in the most "relaxed" position by their logic. But in any case, it's not moving. We're not opening a gap between 2 adjacent faces on every intake cycle.
In addition, the apex seal groove is where carbon accumulates, you don't really want to introduce more sticky goop in there than you have it. It's not hot enough to self-clean so the oil will just turn to wax. And then what happens to that oil supply? Plus, the oil inside the rotor is under centrifugal force proportional to rpm, so those needled valves could push the apex seal up if the forces aren't properly balanced. Maybe he made it work, I don't know. But it sounds finicky. agreed. ..it sounds complicated as f@#k... With enough development it could extend apex seal life... One of the killers of Toyota vvtli engines is small drain holes behind the oil control rings become blocked. ..starving the rings of lubricant. ..and henceforth all the problems associated with it...oil burning. ..etc. id say these proposed needle valve holes in the rotors would become blocked eventually with carbon like the vvti s.....still if i had time and money id give it a go.. Unfortunately i have nethier..in fact my standard rx8 rebuild is on hold due to a severe chest infection |
Actually, I take one thing back: early on intake when pressure between adjacent chambers is equal, the apex seal is only held in place by the spring, so that would be the best time for such a system to do its thing. We're talking about fractions of milliseconds though.
Maybe something vacuum based that doesn't require the apex seal to actuate it would be better. Use vacuum created by the chamber during intake. You know, like the RX8s oil injectors :o |
Coincidentally, I had just been reading about the history of apex seal development.
If anyone is interested: Join Gives a perspective that it really is not straightforward. In solving one problem you are most likely creating another. |
I found this article the other day, apex seals which need no oil lube, petrol is enough! he originally developed the Norton race bikes in the 80's and blew the field away, then they got banned!
World exclusive: Rotary returns | MCN |
brilliant article
Originally Posted by Jastreb
(Post 4816160)
Coincidentally, I had just been reading about the history of apex seal development.
If anyone is interested: Join Gives a perspective that it really is not straightforward. In solving one problem you are most likely creating another. |
Another interesting (and sad) observation - the book excerpt in that link gives the impression that the Renesis development was basically led by the same engineers who started in the 60's with the first NSU Wankels. Those guys are all at or past retirement age now. With no new rotary being developed for production, the opportunity to pass their knowledge on to the next generation has passed. We may never see another production rotary from Mazda.
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