Otto Cycle Pressure Calculator

Otto Cycle Pressure Equation

During compression (process 1-2): $$ P_2 = P_1 \cdot \left(\frac{T_2}{T_1}\right) $$ During expansion (process 3-4): $$ P_4 = P_3 \cdot \left(\frac{T_4}{T_3}\right) $$
where:

P₁ = Pressure in the cylinder at the beginning of the compression stroke (Pa)

P₂ = Pressure in the cylinder after the compression stroke (Pa)

P₃ = Pressure in the cylinder at the beginning of the expansion stroke stroke (Pa)

P₄ = Pressure in the cylinder after the expansion stroke (Pa)

T₁ = Temperature at the beginning of the compression (K)

T₂ = Temperature after the compression stroke (K)

T₃ = Temperature at the beginning of the expansion stroke (K)

T₄ = Temperature after the expansion stroke (K)

Calculator

Property to Calculate:

Pressure in the cylinder at the beginning of the compression stroke (P₁):

Pressure in the cylinder after the compression stroke (P₂):

Pressure in the cylinder at the beginning of the expansion stroke stroke (P₃):

Pressure in the cylinder after the expansion stroke (P₄):

Temperature at the beginning of the compression stroke (T₁) :

Temperature after the compression stroke (T₂) :

Temperature at the beginning of the expansion stroke (T₃) :

Temperature after the expansion stroke (T₄) :

Equation Assumptions

The working fluid behaves as an ideal gas.
Specific heats remain constant.
Compression and expansion processes are adiabatic.
There is perfect mixing of the air and fuel.