Understanding Thermodynamic Cycles: P-V Diagram of a Heat Engine Cycle #2009610 (License: Personal Use)

This P-V diagram depicts a complete thermodynamic cycle typical of a heat engine, where state points 1 through 4 define transitions involving isochoric (constant volume) and polytropic processes. The area enclosed by the loop represents net work output per cycle, with arrows indicating directionality and energy flow. Process 2→3 and 4→1 are vertical (constant volume), while 1→2 and 3→4 are curved, suggesting non-isothermal expansion/compression.

Used in physics and engineering education to teach Carnot-like or Otto/Diesel cycle fundamentals; appears in textbooks, lecture slides, and online courses explaining first law applications and engine efficiency calculations.