Diagnosis and Elimination of Vehicle Shudder in a Sports Utility Vehicle

Ground clearance plays an important role in Sports Utility Vehicles (SUV). Designers are good in designing their own systems but when it comes to integration of systems, the impact of one system on others and cascading effects become the major problems in full vehicle development.

The test vehicle is a monocoque construction with power train in transverse (east-west) direction. Vehicle shudder is observed in lateral direction exciting the steering column, floor during the low gear power train run up in Wide Open Throttle (WOT) condition. The shudder is felt predominantly on the front half of the vehicle. Being a low frequency phenomenon with high energy it becomes critical and the phenomenon is easily perceivable by passenger.

The paper discusses the measurement and analysis procedures to identify the root cause of shudder. Different modifications are tried out based on the analysis and an optimum solution is selected. The selected modification does not have any effect on other Noise Vibration and Harshness (NVH) attributes. Moreover the changes done are completely validated for its life cycle. The modifications are implemented with a slight increase in cost and without any modification in layout.