Simple, Effective and Low Cost Solution for Power Steering Hydraulic Rattle Noise Isolation 2006-01-0936
In today's competitive scenario in automotive industry, the customer expectations about refinement levels are becoming independent of the class & cost of the car. Customers directly co-relate the quality of the vehicle to the overall refinement levels. At the same time there are ever increasing & hard pressing demands to achieve refinement targets in minimum possible cost.
One of the parameter for vehicle refinement is reduction of BSR (Buzz, Squeak & Rattle). It is observed that after suppressing the mechanical rattles, fluid borne noise surface out. In all fluid borne noise, hydraulic power steering system rattle noise is one of the critical refinement issues, having high ranking on customer irritant list.
Noise attenuation cables  in power steering hydraulic hose assemblies in pressure & return line is a proven solution to this problem but not a cost effective one.
Pressure pulse in return line is main source of the hydraulic rattle, which can be suppressed by using a compliant rubber hose element in return line. This is a simple, low cost and effective solution. Ease of packaging in cramped engine house is another advantage coupled with it.
This paper describes the approach adopted for the elimination of hydraulic rattle from a Station wagon class of vehicle through a case study. An attempt is also made to evolve simple design guidelines to address this problem at design stage itself.