Development of Customer Correlated and Accelerated Driveline Durability Test Cycle 2009-01-0412
Faster development cycles and longer design lifetimes, are the dominant factors for developing new testing methodologies. Especially durability testing being one of the main fields of interest has to deal with both these aspects. Physical verification of longer design lifetimes yields to longer testing time, whereas a shorter period is required to reduce the development time.
The methodology described in this paper addresses these aspects to ensure a fast, customer-correlated driveline testing without loosing the fatigue relevant impact. The fatigue relevant loading of a gear tooth of a rotating gear wheel depends on the applied torque and angular speed.
At present, Powertrain aggregates are tested on a rig with block loading cycle derived from designed peak torque. However, these tests neglect the dynamic behavior of the Powertrain system, as the test program does not cover high amplitude cycles from torque reversals. This may lead to underestimated results. Powertrain, as a system, is validated on vehicle level using highway and city endurance tests; typically open loop tests. These traditional methods of testing do not have any correlation with its intended real-time application.