“That will work with both cutting tools and a grinder mounted like common ball cutters. The next problem is machining the seal slots in the outer body. To follow the inner body their location and contour needs to be fairly accurate, but the width needs to be very accurate. I can envision an end mill on a cnc mill cutting the groove in each half. I don't believe you can depend on springs to make up any inaccuracies.”
I was thinking of the manufacturing of the grooves exactly as you write it.
You also write:
“Also, the seal seems to transition from riding on the spherical surface to the flat surface on the ends of the inner element. That will be tough to seal with a one piece ring. Perhaps you would do better with a multi piece seal. I can envision a 1/2 circle segment for the outer section combined with circular arc face seal segments near the hub. They could be connected by a cylindrical piece like the Wankel apex seals.”
As shown in the ASME papers (previous posts), one of the big problems of the Wankel rotary is the excessive gas leakage through the gaps between the several parts comprising the Sealing Grid.
This is what the PatWankel tries to do. To apply the efficient sealing of the reciprocating piston engines to the rotary engines.
web page it has been added another version of sealing for “gerotor” rotary engines (Wankel, Colley, LiquidPiston etc), as follows:
A common characteristic of the prior art rotary engines is that some of the seals, and some of the seal grooves, are shared between neighbour working chambers.
In comparison to a reciprocating piston engine, a Wankel rotary engine uses two apex seals per working chamber, with the one apex seal (and its groove) shared with the leading working chamber, and with the other apex seal (and its groove) shared with the trailing working chamber. In this version, each combustion chamber utilizes not only its own seals, but also its own grooves for seals.
The apex seal "plays" inside its groove on the rotor, bouncing between the two flanks of its groove.
For instance, the "leading" apex seal of a chamber, when the exhaust starts in the leading chamber, leaves the "trailing flank" and moves towards the leading flank of its groove, allowing a significant leakage towards the exhaust. At the end of its "stroke" it slaps the "leading flank" of its groove.
There are similar problems in the Reverse_Wankel / LiquidPiston rotary engine: each "peak seal" with its groove is shared between two neighbouring working chambers.
A "peak seal" cannot help bounching between, and slapping on, the two flanks of its groove.
In the following design, each seal relates exlussively with one only combustion chamber:
The converging of the grooves enables the two different seals at the specific apex of the rotor to abut closer to the geometrically correct point on the epitrochoid working surface (on one hand, this reduces the required motion of the seals inside their grooves in order to remain permanently in contact with the working surface on the casing, on the other hand, this reduces the "dead" volume, i.e. the volume between neighbouring apex seals).
With the following design each peak seal of a Reverse_Wankel / LiquidPiston engine relates with the combustion in one only working chamber.
Among the advantages of the PatWankel_iGR design is the independence of the sealing of neighbouring chambers, also the elimination of the leakage towards the leading and trailing chambers: each seal seats onto the right side of its groove and uses the pressure in its own chamber to tightly abut on the working surface during the high pressure period of the cycle, i.e. as in the reciprocating piston engines.
Significant advantage is also that only the one face of each seal relates with high temperature gas; its other face abuts on the cool "bottom" of its groove; this way, the thermal load on the seal reduces substantially (the number of combustions it participates is half of those of a conventional apex seal), the mechanical stress of the seal is reduced substantially (there is neither bouncing of the seal among the flanks of the groove, nor slapping of the seal on the flanks of the groove when the one of the neighbouring chambers fires), the cooling of the seal is improved, etc.
All these improve the long-term reliability of the engine.
Here is a modified Wankel according the previous:
Here is a PatWankel wherein the working surface is on the outer body (not shown). The inner body (actually the rotor) is sliced, with the one seal in place and the other two seals disassembled:
Here ia another PatWankel wherein the working surface (whereon the seals abut and slide) is the external surface of the inner body:
There are a few new animations explaining the previous.