<< As Vance said it has been done. There are half a dozen SAE papers on

direct

 injection stratified charge rotary engines.  There is little or no BSFC
advantage
 at full or cruise power levels. Just a lot of expense. In effect the RX8
engine,
 with the side exhaust port, pretty well achieves the same thing as
stratified
 charge by recycling unburned fuel.

 Paul Lamar
  >>

Is there anything on overboosting a gasolene engine with direct injection?

Lynn E. Hanover

What do you mean by over boosting? Sounds like a prescription for
detonation.
As opposed to pre ignition. Two different things. Lets define detonation
as an extremely rapid burning of the fuel and pre ignition as the premature
ignition of the fuel relative to TDC.

Paul Lamar

The problem is neither per ignition or detonation, it is the flame front
arriving before the piston is after TDC.  In the situation Lynn is
describing this would be a function of the injection/ignition event timing.
Not the fuel burn speed.

I think you are talking about pre ignition. The burning and expansion starts 
about 20 degrees before TDC in the rotary. If it starts significantly earlier 
than that negative work is done on the e-shaft. Use of the words "flame front" is
very specific and only applies to one aspect of the combustion process.
It defines only one dimension of the fire. What is far more important
is how the combustion pressure is distributed over the face of the rotor
as a function of the e-shaft position relative to TDC.

The BIG advantage of direct injection Gas engines is Low Octane fuel giving
HUGE hp.in^3 as the octane rating is irrelevant.

Yes. That that is exactly what Wankel GMBH in Germany was after burning low
octane heavy fuel using spark assisted direct injection. AKA diesel fuel. 
However again, it did not result in a significant reduction if fuel burned
per HP generated.

http://www.wankel-rotary.com/

Paul Lamar
 
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