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Engine cycles: Otto, Diesel, Carnot, Stirling

What you are seeing: the PV diagram of an ideal thermodynamic cycle. The animated point traces the cycle while a piston bar shows the volume; efficiency is read off the closed-loop area divided by the heat input. Carnot is the upper bound; Otto and Diesel are the spark-ignition and compression-ignition limits.

Figure 1. Four idealized engine cycles drawn on the PV plane.
compression r8.0
cutoff rc (Diesel)2.0
cycle

WHAT TO TRY

  • Vary each control and watch the rail readouts respond.
  • Compare the diagnostic plot against the live scene.