There is, especially in Racing. In Formula 1 some engines have reached 52% thermal efficiency [1], but the amount of hardware required in order to capture the e

There is, especially in Racing. In Formula 1 some engines have reached 52% thermal efficiency [1], but the amount of hardware required in order to capture the excess heat (see MGU-H)[2], makes this costly and difficult to improve upon, and currently with the new F1 engine regulations they are dropping some complex systems so the barrier to entry is less expensive. [1] https://www.racefans.net/2021/11/11/how-f1-can-push-the-worlds-most-efficient-engine-even-further/ https://www.racefans.net/2021/11/11/how-f1-can-push-the-worl... [2] https://www.quora.com/What-are-MGU-H-and-MGU-K-in-an-F1-car-How-does-it-work https://www.quora.com/What-are-MGU-H-and-MGU-K-in-an-F1-car-...