[aerohead]

1) According to Emission Analytics, hydrogen fuel-cell cars are averaging 63.2-mpg-e.
2) From the 817 automobiles they've tested, ICE vehicles are demonstrating an average 25.6-mpg.
3) There's nothing the new engine could demonstrate in efficiency which could meaningfully close that gap.
4) Perhaps America Petroleum Institute unicorns in a desperate rear guard action to forestall the inevitable transition to electrified transportation. The Second law of thermodynamics is not their friend.