I do not know if I am the person that Rick & Connie allude to in terms of calling them "inexperienced fools" if that is the case, I sincerely apologize. It was not my intention to call anybody anything.
My only points were that the development of the gas engine is such that we can only expect marginal efficiency improvements on the thermal side. I think we will have better luck improving the propulsive efficiency that is: drag, transmission, rolling resistance, weight etc. Further improvements can come from the energy lost in braking and decelerating. In other words improving engine efficiency alone will no get us to 100 mpg. By adding the other two we have a good shot at achieving it.

JL