Next about the  P port engine, it seems the 'penny finally dropped'
when I
realized that port overlap means a little  intake air is helping to
push
the
exhaust gases out.

Hi Doug,
what makes you think that the intake charge pushes the exhaust out? I
would have said that the exhaust gas would be at a higher pressure, and
therefore flow into the intake a little and dilute the incoming charge.
Similar to a hot cam in a piston engine,I guess, it all smoothes out
with increasing rpm.  What do you say? Dave McC

Dave,
The exhaust does dilute the inlet charge at idle, can't get around that one
and as most car engines have some overlap( I forget the average), it's
obvious that a certain amount is tolerated, in regard to the performance of
the engine at idle.

At higher RPM the exhaust escapes at supersonic speed and therefore self
evacuates, however this could result in some inlet being pulled into the
exhaust flow, through the rotor depression.

This is why Tracy's idea of timing the injector event is important, so that
fresh fuel isn't drawn into the exhaust.

I think that what's there as unburnt fuel is already too much, as it is.
George (down under)

Thanks George,

Dave,

I am going out the door to catch a flight now  so I can't get into details,
but I suspect the supersonic speed and shock wave is the key, and curse of
the rotary engine performance.

Doug in Japan

Merry Christmas and have a nice trip. We will see you next year :)

Paul Lamar ...No rotor no motor.

This almost sounds like scavenging in a 2-cycle?
george wright


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