Regenerative hydraulic shock absorber for vehicle applications: prototype design

This paper presents a novel prototype design solution of the regenerative hydraulic shock absorber and a novel unique methodology for the calculation of the dynamic strength of the proposed device. The proposed calculation methodology includes a definition of the dynamic load which acts on the device, the calculation of the piston rod buckling strength, the calculation of the welded joint, the calculation of the bolt connection, the calculation of the torsional spring, and the calculation of the screw connection. Additionally, the methodology for the selection of a hydraulic motor, electric generator (alternator) and electric battery is proposed which includes the definitions of the main dimensions of the hydraulic cylinder, selection of the vehicle driving mode and a schematic diagram of the simplified mathematical bond graph model of the proposed regenerative hydraulic shock absorber. A numerical example of regenerative hydraulic shock absorber dynamic strength calculation is made for a 1500 kg vehicle. The dimensions obtained by the proposed methodology have similar values to the dimensions of conventional suspensions or shock absorbers that are used today in real vehicles. The proposed calculation methodology can be used to construct different types of regenerative suspensions for real vehicle application. By simulating the mathematical bond graph model of the presented device, it was possible to harvest a maximum regenerative power of 526 W and an average regenerative power of 224 W.