4 ms·

I wonder if it's literally an inverted Wankel engine, as in taking the geometry of the Wankel engine, applying inversion with respect to a circle[1] then fixing

I wonder if it's literally an inverted Wankel engine, as in taking the geometry of the Wankel engine, applying inversion with respect to a circle[1] then fixing the frame of reference to the outer geometry, which was originally the rotor in the Wankel engine. [1] https://en.wikipedia.org/wiki/Inversive_geometry https://en.wikipedia.org/wiki/Inversive_geometry edit: on second though this would probably be too simple to be true.

lrissman 6y ago
I wondered that too and then saw this from tfa: “ "If you recall the Wankel," says Schkolnik, "they have a triangular rotor inside a peanut-shaped housing. We have the opposite, a peanut-shaped rotor in a tri-lobed housing. So take everything you know about the Wankel and turn it literally inside out. They have a long, skinny, moving combustion chamber, we have a stationary combustion chamber that's nice and round. You can drive it to a high compression, just by making the chamber smaller. And because it's stationary, we can directly inject fuel where the Wankel could not. So those are the two key advantages of the diesel: high compression ratio and direct injection.”
- steerablesafe 6y ago
  I'm just wondering if there is a strong mathematical link between the two. Like flipping the sign somewhere in the description of the geometry of the Wankel engine results in this. I did some crude geometric measurement on the geometry based on the video and the chamber doesn't seem to have the shape of an Wankel rotor inverted with respect to a circle.
8draco8 6y ago
But what does that change? Major flaw of Wankel engines, apex seals are still there, only now they are fixed in place not on the piston. I think "flipping" the design allows for smaller engine but reliability seems to stay the same. Please correct me if I'm wrong.

4 ms·

I wonder if it's literally an inverted Wankel engine, as in taking the geometry of the Wankel engine, applying inversion with respect to a circle[1] then fixing

by steerablesafe 6y ago

lrissman 6y ago
I wondered that too and then saw this from tfa: “ "If you recall the Wankel," says Schkolnik, "they have a triangular rotor inside a peanut-shaped housing. We have the opposite, a peanut-shaped rotor in a tri-lobed housing. So take everything you know about the Wankel and turn it literally inside out. They have a long, skinny, moving combustion chamber, we have a stationary combustion chamber that's nice and round. You can drive it to a high compression, just by making the chamber smaller. And because it's stationary, we can directly inject fuel where the Wankel could not. So those are the two key advantages of the diesel: high compression ratio and direct injection.”
- steerablesafe 6y ago
  I'm just wondering if there is a strong mathematical link between the two. Like flipping the sign somewhere in the description of the geometry of the Wankel engine results in this. I did some crude geometric measurement on the geometry based on the video and the chamber doesn't seem to have the shape of an Wankel rotor inverted with respect to a circle.
8draco8 6y ago
But what does that change? Major flaw of Wankel engines, apex seals are still there, only now they are fixed in place not on the piston. I think "flipping" the design allows for smaller engine but reliability seems to stay the same. Please correct me if I'm wrong.