Ideal Otto Engine Simulation

PV Diagram

TV Diagram


The behavior of a gasoline engine (the kind used in automobiles of today) can be approximated by making the following assumptions:

The above simulation shows the cycle and your choice of either the PV diagram or the TV diagram for each of the six processes of the engine:

  1. Ignition: The spark plug ignites the gas/air mixture.
  2. Power stroke: The hot combustion gasses expand, pushing the piston down.
  3. Valve exhaust: At the end of the combustion the gasses are still at a high pressure. The valve opens and the gasses begin to exhaust.
  4. Exhaust stroke: The piston pushes the remaining combustion gasses out of the piston.
  5. Intake stroke: Air and gasoline are drawn into the piston by the suction of the piston.
  6. Compression stroke: The mixture is compressed until the temperature and pressure rise.

At this point the cycle starts over.


Script by Wolfgang Christian. Engine was originally written by Sadie Lowry for the Motif environment. It was later ported to Java by Sasa Divjak. The Java code was later modified by Wolfgang Christian to support inter-applet communication. The DataGraph Physlet was written by Wolfgang Christian.

Description of the cycles came from 'Heat and Thermodynamics', Zemansky and Dittman.