Which cycle is best in heat engine?

The ideal cycle for a heat engine is often considered to be the Carnot cycle, as it provides the maximum possible efficiency between two temperature reservoirs. This theoretical cycle operates through four reversible processes: two isothermal and two adiabatic. Although real engines cannot achieve Carnot efficiency due to practical limitations and irreversibilities, the Carnot cycle serves as a benchmark for evaluating the performance of actual heat engines. Other cycles, like the Otto or Diesel cycles, are commonly used in practice, but they are less efficient than the Carnot cycle.