Hydraulic Accumulator Sizing Calculator

Inputs

Usable oil volume (ΔV)

The oil volume the accumulator must deliver between the maximum and minimum pressure.

cm³

Gas precharge pressure (P₀)

Nitrogen precharge pressure, gauge. Commonly around 80–90% of minimum system pressure.

bar

Minimum system pressure (P₁)

Lowest system pressure at which the required oil volume must still be available.

bar

Maximum system pressure (P₂)

Highest charging pressure.

bar

Polytropic exponent (n)

Use 1.0 for slow/isothermal discharge, about 1.4 for rapid/adiabatic discharge.

Default result

Required gas volume(V₀)

2,774cm³

Nominal accumulator gas volume at precharge.

Also computed

Gas volume at minimum pressure(V₁)1,575cm³

Gas volume after discharging to minimum pressure.

Gas volume at maximum pressure(V₂)2,575cm³

Gas volume when charged to maximum pressure.

Precharge / minimum pressure0.901

Typical precharge range.

Maximum / precharge pressure2.21

Method notes 2 notes

The gas law must use absolute pressure; the calculator adds atmospheric pressure to the gauge inputs before solving.
Use n = 1.0 for slow thermal equalisation and n ≈ 1.4 for rapid discharge. Real sizing also checks bladder limits, gas temperature and manufacturer minimum/maximum ratios.