Selection of Substitute Loadings for Service-Life Investigations of Vehicle Drivetrains

Laboratory testing of vehicle components is less expensive than driving trials, but correlation of results to actual driving characteristics demands a great amount of back-up data. Such data is not available for new designs. One test-stand approach is to subject components to block loadings or loadings equivalent to actual operational ones. Ease of adapting these methods to different drivetrain components is discussed. Apparatus suitable for measuring dynamic characteristics of drivetrains during actual street testing is described; the results allow evaluation of test-stand correlation functions.

It was concluded that block programs based on operational load distributions provide valid test-stand correlations of service-life. Statistical evaluations of engine speed distributions must also be taken into account. The relationship between loading torque and engine speed can be determined by regression analysis of test results, although adequate results can also be based on constant performance operation. New measurement apparatus provides faster programming of component correlations to test data.