My grampa would have been a brilliant systems engineer. He knew the combustion engine inside and out, but what he really knew were systems. Systems that you learn on the farm, systems you learn in the military.
He retired in the mid-80's, and already hated modern cars. They were too complicated. He thought adding computers to cars was a mistake. Something I disagreed with him then, but after becoming a software developer now agree with him whole-heartedly.
He wanted a world of lighter 2 stroke engines, that you could run on Tree Gas
It's a slower world, with smaller, more versatail vehicles.
We already do this by burning oil -- tree gas fuel gives us a 1 to 1 system to carbon capture to burning
Two stroke engines have a higher weight to power ratio than our modern gasoline engines. the Fuel recovery problem has been fixed