The Piston Gas Accumulator component consists of a precharged gas chamber, a floating piston, and a hydraulic chamber connected to a hydraulic port. When fluid pressure at the port exceeds the precharged gas pressure, fluid flows into the hydraulic chamber, moving the piston and compressing the gas. The amount of fluid stored in the accumulator depends on the size and charge. The stroke of the piston is restricted by end cushion parameters used to set the boundary of the component respectively.

$a_{\mathrm{rel}}\=\frac{\mathrm{d}{v}_{\mathrm{rel}}}{\mathrm{d}t}{v}_{\mathrm{rel}}\=\frac{\mathrm{d}{s}_{\mathrm{rel}}}{\mathrm{d}t}$

$f_{\mathrm{gas}}\=-A{p}_{\mathrm{gas}}$

$f_{c_1}\&equals;\{\begin{array}{cc}0& s_{\mathrm{rel}}<L_{\max }\\ c_{\mathrm{ES}}\left(s_{\mathrm{rel}}-L_{\max }\right)& \mathrm{otherwise}\end{array}{f}_{c_2}\&equals;\{\begin{array}{cc}0& 0\le s_{\mathrm{rel}}\\ c_{\mathrm{ES}}{s}_{\mathrm{rel}}& \mathrm{otherwise}\end{array}$

$f_{d_1}\&equals;\{\begin{array}{cc}0& s_{\mathrm{rel}}<L_{\max }\\ d_{\mathrm{ES}}\frac{\mathrm{d}{s}_{\mathrm{rel}}}{\mathrm{d}t}& \mathrm{otherwise}\end{array}{f}_{d_2}\&equals;\{\begin{array}{cc}0& 0\le s_{\mathrm{rel}}\\ d_{\mathrm{ES}}\frac{\mathrm{d}{s}_{\mathrm{rel}}}{\mathrm{d}t}& \mathrm{otherwise}\end{array}$

$f_{e_1}\&equals;\{\begin{array}{cc}0& f_{c_1}\&plus;f_{d_1}\le 0\\ f_{c_1}\&plus;\min \left(f_{c_1}\&comma;f_{d_1}\right)& \mathrm{otherwise}\end{array}{f}_{e_2}\&equals;\{\begin{array}{cc}0& 0\le f_{c_2}\&plus;f_{d_2}\\ f_{c_2}\&plus;\max \left(f_{c_2}\&comma;f_{d_2}\right)& \mathrm{otherwise}\end{array}$

$p\&equals;p_A$

$q\&equals;q_A\&equals;A{v}_{\mathrm{rel}}\&equals;\frac{\mathrm{d}{s}_{\mathrm{rel}}}{\mathrm{d}t}$

$f_{\mathrm{chamber}}\&equals;pA$

$m{a}_{\mathrm{rel}}\&equals;-d\cdot v_{\mathrm{rel}}\&plus;f_{\mathrm{gas}}-f_{e_1}-f_{e_2}\&plus;f_{\mathrm{chamber}}$

$p_{\mathrm{gas}}{\left(A{L}_{\max }-A{s}_{\mathrm{rel}}\&plus;v_{\mathrm{Dead}}\right)}^k\&equals;p_{\mathrm{preload}}{\left(A{L}_{\max }\&plus;v_{\mathrm{Dead}}\right)}^k$