Why can’t we use the heat from combustion to make cars more efficient?

Question

Can we use the heat to boil water to turn a turbine? Or would the water never cool enough to be used again?

What about using the heat to create pressure and then releasing the pressure to help move the fly wheel?

In: 1046

Answer 1

F1 cars do harness the heat energy and turn it into electricity. I read that an F1 power unit is about 50% efficient compared to a normal road car which is about 30%.