Analysis and Mitigation of Grunt Noise in Hydraulic Power Assisted Steering Systems

2024-26-0218

01/16/2024

Features
Event
Symposium on International Automotive Technology
Authors Abstract
Content
This paper addresses the "Grunt Noise" anomaly in Hydraulic Power Assisted Steering (HPAS) systems, detailing an extensive effort to resolve this disruptive issue. HPAS, while cost-efficient, faces challenges as it adapts to customer demands for reduced steering effort and enhanced handling. Intensified HPAS intervention requires components to withstand higher pressures and tighter tolerances, leading to occasional anomalies.
"Grunt Noise" arises from Torsion bar (T-bar) resonance with fluid pressure pulsations. A comprehensive study identifies load conditions, transfer paths, and frequency bands, extending from vehicle to Pinion Valve assembly levels. Root cause analysis traces the issue from Steering Wheel to T-bar, validating the approach. The T-bar's twisting operation renders torsional stiffness crucial for Grunt Noise. Lower stiffness T-bar, when overpowered by liquid force, causes microsecond imprecise valve openings, leading to cavitation-induced Rack & Pinion vibrations. Varying T-bar stiffness (via diameter alteration) is assessed to minimize variability.
By enhancing T-bar's torsional stiffness and dimensions, the study effectively mitigates Grunt Noise in HPAS systems. In summary, this paper offers a thorough HPAS Grunt Noise analysis, emphasizing the pivotal role of torsional stiffness in resolution.
Meta TagsDetails
DOI
https://doi.org/10.4271/2024-26-0218
Pages
7
Citation
Sethi, A., Titave, U., Vardhanan K, A., Zalaki, N. et al., "Analysis and Mitigation of Grunt Noise in Hydraulic Power Assisted Steering Systems," SAE Technical Paper 2024-26-0218, 2024, https://doi.org/10.4271/2024-26-0218.
Additional Details
Publisher
Published
Jan 16
Product Code
2024-26-0218
Content Type
Technical Paper
Language
English