There are many reasons, the ability to control lean-of-peak operations better is one reason. That is with gasoline operation. The ability to run Jet A with minor loss of power is another. The high pressure DI charge can be directed to take advantage of the rotaries ability to run lean, (stratified charge) reducing GPH. The last possible item is the ability to eventually run without a throttle valve to improve efficiency due to lower pumping losses. The Audi guys are saying that they expect as much as 18% improvement in mileage. They achieve that using some techniques we wouldn't such as turning OFF the fuel completely during deceleration cycles.  Since we don't really "coast" anytime that isn't possible. Running LOP, operation with all kinds of fuels and minor power improvement with better atomization and less charge dilution are the biggest reasons. OH, yea, you can put fuel input on the side opposite the exhaust which simplifies the plumbing a minor amount.

Bill Jepson 

 

In a message dated 3/14/2007 12:09:11 A.M. Eastern Standard Time, WRJJRS@aol.com writes:

Lynn,

 I believe the best place for direct injection  would be in about the same place that Mazda ran the "far trailing" plug in the Le Mans engine. It is a possible place, some of the original NSU tests used the trailing plug hole and single ignition. I would prefer to stay with 2 plugs.

Bill Jepson

 

So this idea is to avoid detonation in the low octane fuel?

 

Lynn E. Hanover