Why are Mazda persisting with the Rotary Wankel engine?

[RayTay]

NMNeil said:

I haven't read all the postings, so this may have already been covered, but there's a new take on the wankel which is supposed to be far better.
https://www.youtube.com/watch?v=jLtyNtf9_ew
https://www.liquidpiston.com/

Used on the M777 US artillery gun. The gun was British developed (BAE) with parts of its made in the UK. The Liquid Piston rotary is used as a small generator for the gun. Liquid Piston is a wankel inside out. Far superior design. But probably too little too late for mass take up.

EVs are here. One in 5 new cars sold in the UK are EVs. If stocks were freely available, about 50% would be EVs. Electricians are run off their feet fitting EV chargers in drives.

[NMNeil]

RayTay said:

NMNeil said:

I haven't read all the postings, so this may have already been covered, but there's a new take on the wankel which is supposed to be far better.
https://www.youtube.com/watch?v=jLtyNtf9_ew
https://www.liquidpiston.com/

Used on the M777 US artillery gun. The gun was British developed (BAE) with parts of its made in the UK. The Liquid Piston rotary is used as a small generator for the gun. Liquid Piston is a wankel inside out. Far superior design. But probably too little too late for mass take up.

EVs are here. One in 5 new cars sold in the UK are EVs. If stocks were freely available, about 50% would be EVs. Electricians are run off their feet fitting EV chargers in drives.

Thanks for the info.
The only difference I could see is that the seals have been moved from the tips of the rotors to the casing. I was led to believe that the reason for putting the seals on the tips was that centrifugal force would allow them to seal better as the revs increased, so they needed only light spring pressure initially to hold them against the chamber walls, hence reducing wear.
I believe that it wasn't so much that the engine was bad, but that most garages, other than the dealers, had no idea how to fix them so turned them away.

[RayTay]

NMNeil said:

Thanks for the info.
The only difference I could see is that the seals have been moved from the tips of the rotors to the casing. I was led to believe that the reason for putting the seals on the tips was that centrifugal force would allow them to seal better as the revs increased, so they needed only light spring pressure initially to hold them against the chamber walls, hence reducing wear.
I believe that it wasn't so much that the engine was bad, but that most garages, other than the dealers, had no idea how to fix them so turned them away.

BTW, the M777 gun is now being used by Ukrainian forces. They trained on them in Devon.

The Liquid piston engine does have the seals in the engine housing. It is very different with a very different shaped rotor. The valves are also in the rotor. Clever design. BTW, the Soviets in the 70/80s made some rotary engines with seals in the housings. The Liquid Piston generator on the M777 gun is a small suitcase size, being very light. They are being assessed for the M1 tanks.

I feel, that Mazda using the wankel as a range extender and the Liquid Piston engine are far too late to compete with the EV advances. With EVs the best is yet to come as new battery technologies are brought to the market in the next five years.

[GT9]

NMNeil said:

I haven't read all the postings, so this may have already been covered, but there's a new take on the wankel which is supposed to be far better.
https://www.youtube.com/watch?v=jLtyNtf9_ew
https://www.liquidpiston.com/

LiquidPiston have been in development for 12 or 13 years I think, and build a handful of prototypes with a 45% efficiency target for their compression ignition cycle.

It must be a bit disheartening when the new kids on the block start throwing around 70% efficiency claims: https://carnotengines.com/technology/

I won't hold my breath, but it will be interesting to just see how realistic such claims are, the people behind it appear to be credible. It's not a good look though when you can't even spell brake correctly on your headline webpage....

[RayTay]

The idea of ceramic engines is not new. I believe a few were made 40 years ago with the cylinders being ceramic glaze, which is very hard.

The idea is keep as much heat, aiming it towards thermal expansion. Ceramics can easily be applied to say a Liquid Piston design. We make engines of metal because metals are cheap, easily worked, plentiful and well understood. A problem is that metal melts at temperatures ceramics would not. We are limited using metal.

Edited by RayTay on Wednesday 22 June 14:54

[GT9]

RayTay said:

Ceramics can easily be applied to say a Liquid Piston design

Ceramics are not easily applied to any sort of engine Ray. It takes a huge development effort to make them work reliably for extended periods under all the conditions the engine might see.