The figures show the compression of Otto, Diesel and Dual cycles for the same compression ratio and heat rejection. The Otto cycle is

Explanation:

Thermodynamic Cycles in Internal Combustion Engines

• Thermodynamic cycles are the theoretical models used to describe the energy conversion process in internal combustion engines. Among the most common thermodynamic cycles are the Otto cycle, Diesel cycle, and Dual cycle. These cycles differ based on the way heat is added to the system and the type of fuel-air mixture combustion process used.

The given problem discusses the comparison of these cycles for the same compression ratio and heat rejection. We aim to identify the correct representation of the Otto cycle based on the provided information.

Otto Cycle:

• The Otto cycle is defined by constant volume heat addition and heat rejection.
• From the figure, the process 1-2 represents the isentropic (adiabatic) compression phase.
• Process 2-6 corresponds to the isochoric (constant volume) heat addition phase, which is the hallmark of the Otto cycle.
• Process 6-5 represents the isentropic (adiabatic) expansion phase, where the thermal energy is converted into mechanical work.
• The final process, 5-1, corresponds to the isochoric (constant volume) heat rejection phase, completing the cycle.

Thus, the sequence 1-2-6-5 accurately represents the Otto cycle in the context of the given problem