Novel technique to address the humming noise with pulley driven Hydraulic power steering pump on light commercial vehicles

In the current customer centric automotive market, NVH is one of the prime focus for the automotive industry. Almost all light commercial vehicle in the market are with hydraulic power steering systems. Hydraulic power steering pump is the heart of the steering system which circulates the hydraulic oil into the system for assisting the driver with the help of hydraulic steering gear. One of the NVH problem which is inevitable with the hydraulic vane pump is the humming noise. This noise will be a customer irritant in quitter cab vehicles. This paper describes a novel technique for reducing the humming noise which is perceived at driver ear level. Existing steering components is analyzed at digital level (NVH CAE) and physical vehicle objective measurements are carried out to set the acceptance criteria. Various components of the hydraulic power steering system are instrumented on actual vehicle and measurements are taken. Existing design is optimized based on the CAE results and vehicle is updated with the recommendations and objective measurements are carried out. With this method noise levels are reduced at drive ear level as compared to base and brought within acceptable limits. This technique can be used for resolving all hydraulic power steering pump related noise issues