Otto Cycle

Otto cycle consists of two isoentropic and two isochoric processes. Heat is supplied and heat is rejected by the cycle during isochoric process.

Pressure-volume and Temperature-entropy diagram for the otto cycle

ressure-volume and Temperature-entropy diagram for the otto cycle

1-2: Adiabatic compression
2-3: Isochoric heat addition
3-4: Adiabatic expansion
4-1: Isochoric heat rejection

Heat supplied during constant volume process 2-3
Heat supplied by the air during constant volume
Heat rejected during constant volume process 4-1
Heat rejected by the air during constant volume
The thermal efficiency of Otto cycle can be given by the formula
thermal efficiency of otto cycle

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All Comments

  • Thanks . I was looking for clear diagrams of Otto cycle P-V and T-s .

    Blackbird Feb 2, 2016 9:51 am Reply
  • This isn’t right…the logic does not follow…your final step is the efficiency of a Carnot Engine.

    The first two steps are fine but the final step should be:

    η = 1-(Τ4-Τ1)/(Τ3-Τ2)

    To finish this, you’ll need the compression ratio (r) and the ration of heat capacities (γ):

    η = 1-1/r^(γ-1)

    duffharrold Mar 7, 2021 8:09 am Reply

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