I cant help thinking about the dangers involved with
very high pressure petrol and very safety conscious
aviation folk. Not only is there the danger of compression
ignition of the fuel under high pressure, there is also a lot of high
pressure plumbing, with all its associated connections, coursing an
explosive mixture past your backside and on to your hot bits (engine
manifolds).

If a line ruptures, and the greater the pressure the greater the chance,
you'd get a nice spray of explosive mixture. Possibly why there are few
direct injection gasoline motors in production. I would just feel a lot
happier with a couple of Holley blues sending the fuel up to my SU's
at 3.5 psi, also with the redundancy of a nice big header tank.
No fancy flying maybe, but easily made safe.

The low heat area of a Wankel spans from the side intake entries, around
those standard injector holes, to a point above the spark plugs.  From there
obviously it gets warmer, right back across the bottom to another point just
above the exhaust port.  Atop the motor would be cool enough to inject
gasoline with possibly the standard injectors, but there is the water jacket
and quite a few engine bolts to deal with.  As Paul says with sound
reasoning, just use the standard holes.  You can make all the power you'll
ever need from there.

DI must happen right at the combustion chamber,
considering the fuel octane and quite a few environmental factors, somewhere
just before TDC.  A better place to DI would be at the Knock sensor point,
available in the later series Mazda engines.  BUT, that would only be
possible if you spent millions on the latest materials, and to design and
test an injector that could live under combustion temperatures and residues.
And, one that would successfully deliver petrol/air mixture resembling a
gas, to the entire combustion chamber, which is comparatively quite large in
a Wankel.  Still cool enough not to pre ignite.  Hehe, simple aye?


Sam Watson

I am with you. Keep it simple.


Paul Lamar