Hi Paul,
Reading back through the history of the Wankel engine it seems to me
that some of the very early decisions
are still the basis for many of the problems that exist today. NSU
only wanted to make a sports car and they
already had their gearbox design so the rotary was sizes to fit their
requirements.
Mazda then followed suite with again a sports car design.

It seems to a thumbnail engineer like me that the torque could be
increased ( actually squared)
by increasing the radius distance from the concentric centre to the
combustion chamber (stroke).
The power seems to be determined by the width of the rotor. Why not
increase the width and
duplicate the EFI to deliver stratified charge, Millar cycle, etc
Just sayin',
Ray Tolhurst     Sydney, Australia

There is some evidence that a wider rotor would lead to poorer
combustion characteristic. I think the jury is still out on that.

The other geometry needs to be what it is for apex seal leaning angle.
Too much angle and the seal might jam in the slot.

Certainly NSU and Audi's failure to fix the apex seal chatter problem or pay Mazda royalties for their excellent  apex seal solution had a lot to do with the bad reputation in Europe.

Cars and air planes go on HP and not torque. Torque is a function of
the gear box. Back in the old days when gear boxes were only 3 speed or
less torque was important. Now the only thing that matters is
HP to weight ratio. That the rotary excels in.

The remaining  problem is BSFC. It needs a 5% improvement.

I have some ideas on side by side spark plugs and splitting
the combustion chamber into side by side parts.

Also a stainless  steel liner instead of hard steel for the rotor housing
and rotor would help as stainless has a much lower heat transfer
coefficient.

Thermal conductivity:

"the quantity of heat transmitted through a unit thickness of a material - in a direction normal to a surface of unit area - due to a unit temperature gradient under steady state conditions"

Thermal conductivity units are /W/(m K)/ in the SI system.
K = Kelvin
m = meters
W = thickness


Aluminium     205

Chrome Nickel Steel (18% Cr, 8 % Ni) 16.3

Carbon Steel 54

Iron 80

Stainless Steel 16

"Stainless steel can be nickel-chrome plated in a high quality manner. The necessary preparation steps include a Wood's Nickel Strike,"

Paul Lamar

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