End-of-Line Vehicle Driveline Balancing Process Design and Improvement, and Variability in the Influence Method

Automotive driveline imbalance is a result of rotating components or assemblies being manufactured with their centers of mass not being coincident with their centers of rotation. For vehicle mass production, an end-of-line (EOL) driveline balancing process may be required, depending on vehicle sensitivity and component control costing. In this investigation, the process and facility design for an EOL automotive driveline balancing process is outlined, including important considerations in the measurement configuration of the balancing facility. Initial results from prototype vehicle testing with conventional influence balancing techniques, based on commercially available equipment, are given. The role of the influence coefficient in the balancing process and of car-to-car variability in the influence coefficient were investigated. An equation for the influence coefficient was derived, providing an improved understanding of the nature of the influence coefficient, along with sources of variability. A change to the conventional balancing process through a modified work-flow in the influence coefficient method, which is shown to give a more accurate process and, in addition, to reduce the balancing time, is outlined in detail. The results of balancing a large population of vehicles following the implementation of the modified process are then given and compared to a standard probability distribution.