alt Hacker News> can't run a direct injection gas engine without a digital engine control unit, because the injection timings are much to precise to do mechanically.
This is not accurate, the first production direct injection gasoline automotive engine was in the 1954 Mercedes-Benz 300SL. It's true, you probably won't be running piezoelectric injectors without computer controls, but there's nothing preventing direct injection.
But that would make it interesting. How many of the advances we've made in the past 75yrs could be accomplished some other way if you take the computer away? You don't need a computer to accomplish nanosecond timing. Maybe there's a clever analog way to run piezoelectric injectors.
To phrase it maybe a little more provocatively: how would you accomplish the precise timing necessary to achieve spherical implosion? This was possible with analog electronics in 1945. Surely in 2026 we can also build analog piezoelectric fuel injection systems.