Quote: "I often wonder how the Mazda rotary IC engine managed to survive in automotive applications for as long as it has."
Same here. There are a few benefits to the rotary engine design, smoother with better balance and higher RPM's, for people that like to see higher tachometer readings. But as mentioned, the fuel economy, poor emissions and poor longevity, it is amazing they ran in production as long as they did.
I think they appealed to a niche market sector that wanted something unique and believed there was some benefit. And they put it in a nice package, the RX-7 and 8 was an attractive sporty car. I knew people that owned them and they loved them. One trick to do about every 20k miles was mist a bit of Type F trans fluid in the intake, it rejuvenated the rotor seals.
I've read a few knowledgeable folks talking about them possibly making good candidates for steam engines.
One idea I had (me and probably a hundred others) for a steam version is make the rotor two piece and pressurize the core of the rotor and with the larger surface areas than the expansion chamber, it would aid in sealing against the side walls of the chamber - like a slide valve. Seems like it would work - not gonna try it
It wouldn't work in an IC engine, but it would be possible with a steam engine where there is never any vacuum in the expansion chamber.
I've absolutely never understood the square piston design. What possible advantage could there be or they thought there could be?