GDI...
The VW group has already a few in their production engine line.
The technology works but it has it's downsides too.
From what I know the first GDI engine was the MB SLK300 "Silverwing".
( Somewhere arround 1955 )
It used an inline injection pump derived from a stock diesel injection pump.
When we talk about GDI there are two different systems.
One is for the High Hp engines, where the ineherent power gain due to the GDI is used. These engines get a second benefit too. The mileage is by about 10-12% better than with a traditional engine. In a race car like let's say Indy that means less fuel on board, less weight...
Audi has developed a V-8 GDI engine that has already won several 24H Le Mans races...
The downside here is mainly the develpment and higher production cost.
The second GDI version is the lean burner. Yup, the research is trying to run a gas engine as it was a diesel! The combustion chamber / process is very difficult to develop...
From what I know the actual VW engines use the lean burn process in the low load ranges and the shift over to the normal combustion process @ about 1/3 throttle. In the real world that translates into an 8% better mileage. They're asking themselfes now if that "small" MPG gain is worth the high development costs.
Marco
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