Paul,
 I believe you are correct about Mazda trying some of these things. Some of the injection techniques probably worked great "but" aren't economical in street car production. Direct injection is one of the ideas that is more expensive than port injection so if you can get port injection to work the cost of direct injection isn't justified.

 I like the direct injection idea for two reasons. First; there is no probability of manifold icing. In the design the car people have come to call the shower head, (into the bellmouth), there is still a real possibility of loss of power due to icing. Not failure like a carburator but signifigant restriction could occur. Second; Direct injection has always been good for power, as far back as the 30's Grand Prix cars. The original racing MB 300 gullwing 6 cylinders as well.
Bill Jepson

I think if it gave a significant increase in MPG they would use it. Say 5%.

Paul Lamar

Paul, One thing that will improve the efficiency is to use the technique used on diesels and relates to what Francois was saying about tuning methods. Use direct injection and no throttle plate at all. This hasn't been done in cars in the past since the throttle controlled injection is much easier. The fuel controlled "power lever" was used by Mecury on some of their direct injection 2 cycles. Works very well and obviously reduces throttling losses. Since a system without a throttle plate requires a full engine management system, it hasn't been used that much in spark ignition engines. The Mercury 2 cycles sound "wierd" in that thy don't 4 cycle at idle, but rather hit on every stroke. They sound like they are idling twice as fast.
Bill Jepson

The Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2004 All world wide rights reserved.