Correlation of Hydraulic Circuit Dynamic Simulation and Vehicle

Higher demands from automotive customers for quieter vehicles and the reduction of noise and vibration levels from major sources like the engine necessitate better performance of other sources of noise and vibrations in a vehicle. One of these sources that Original Equipment Manufacturers (OEM) demand making quieter is the power steering system. The pressure ripple generated by the power steering pump transfers to the fluid lines where it can generate objectionable noise and vibrations. This can become an excitation force to the structure of a vehicle or the steering gear and can become a source of discomfort to the vehicle occupants. Attenuation of the pressure ripple within the hose assembly can result in significant reduction in noise inside the vehicle. The NVH research team at the Fluid System Products of Dana Corporation has developed “Dana's Virtual Test Rig (DVTR™),” - a hydraulic system simulation software. This software has been used to develop and characterize power steering components and assemblies. Several systems were assembled consisting of a pump and a steering gear connected together by several different pressure line assemblies. These systems were fabricated and tested on a vehicle. The purpose of this paper is to show how the experimental and simulated values of fundamental hydraulic dynamic simulation parameters (e.g., pressure ripple) correlate for both simple and more complicated hydraulic circuits.