ANALYSIS AND OPTIMIZATION OF AN ELECTROHYDRAULIC POWER PACK FOR USE IN A FULLY-ACTIVE VEHICLE SUSPENSION THROUGH THE USE OF COMPUTATIONAL FLUID DYNAMICS

摘要

Shock absorbers are essential to vehicle comfort and handling. Most shock absorbers use passive or "semi-active" valves to produce reactive force with limited ride benefits while dissipating hydraulic power as heat. Fully-active suspensions can fundamentally eliminate the discomfort of bumps and provide superior handling and safety. Existing active suspensions consume large amounts of power and are expensive and unwieldy. If these challenges are addressed, fully-active suspensions could revolutionize the ride control industry. A compact and full-active suspension system, GenShock, is being developed by Levant Power. The patented system relies upon an electrohydraulic power pack coupled with a gerotor motor/pump. Energy consumption is minimized by regenerative harvesting from suspension dynamics. The system is based around a proprietary electrohydraulic motor/pump mechanism that can both semi-actively damp body and wheel motion while recovering energy, and actuate to drive the wheel and chassis. This article describes the use of computational fluid dynamics (CFD) in the development and optimization of hydraulic components in GenShock. The CFD software PumpLinx enabled the complex non-linear GenShock system to be simulated within 5% of experimental tests, and enabled a threefold increase in system efficiency. Parametric simulations predict the torque, power, leakage behavior, and hydrodynamics of the system including effects of aeration and cavitation. Detailed analysis and correlations between experimental data and simulations are presented.