&gt;We&#x27;ve already hit the wall regarding how much energy we can squeeze out of a unit of liquid fuel (most of the energy gets wasted as heat).<p>far from it. Just for example - the gas turbine reaches 50+% efficiency and in sequence hybrids there is no limitations which killed gas turbine car 50 years ago. Of course gas turbine is expensive, so we aren&#x27;t going this way.<p>&gt;Note the VW emissions scandal.<p>A BigCo stuck in old ways tells nothing about what is technologically possible. I&#x27;d say you can&#x27;t do worse than current typical gas or diesel engine which basically hasn&#x27;t changed for 100+ years :) Even well known Atkinson cycle was implemented en-mass only recently. Once i file my patents, i&#x27;ll tell you in more details about other efficient designs and improvements :)<p>Without the efforts like CAFE and CA emission&#x2F;efficiency requirements, we&#x27;d still be stuck with 20% efficient carburetor gas ICE. The increase of the regulatory pressure creates market opportunity for efficient designs, and you&#x27;ll see what will come when CAFE hits 50mpg :)