eli5: why are ICE engines only able to achieve 20-30% thermal efficiency?

Question

I read that a massive portion of usable energy is wasted and turned to heat instead of being used to turn the crankshaft — would there be like any way of reducing the heat/cooling the engine so you could get 50-70% thermal efficiency?

In: 407

Answer 1

>so you could get 50-70% thermal efficiency?

Formula 1 engines get about 50%. The problem is the engines cost millions of dollars, use extremely expensive parts, and require an entire team of engineers just to start them.