A internal combustion engine can only get so efficient. I think it's reached it maximum potential. Unless alternative power assist. My car, not hybrid gets almost as good gas mileage as my golf cart with 170 more hp and a lot more weight. Nothing stopping companies to Make there products more efficient it they want edge over there competition. Government needs to quit subsidies corn gas. Let them make it on there own. Why, millions acres of forest being bulldozed for corn field. Goggle earth the Midwest see corn field After corn field. All corn gas did was drive price of corn, beef, and dairy products up while burning more gas to make it and use it.