Hate to rain on your parade, but you need to look at this here graphic.
Graphic
Now looking at this, it seems that we lose 3% in combustion inefficiency, not sure how improving this is going to "Double" yer mileage. Is there some other part of the equation that this can help with?
Always amazed how people try to improve the 97% part of the equation and ignore the 30% thing.
Call me when you get an answer for the 70% thermal loss issue. You could triple mileage.