Issues of Estimating Powertrain Mount Loads Using Measured Accelerations and Drive Torques for Durability Events

For powertrain mounts design and durability evaluation, directly measuring all the engine and transmission mount loads is a costly and time-consuming option. Analytical or semi-analytical approaches have been used for estimating maximum powertrain mount loads at the early design stage and also for calculating the dynamic loads when prototype test data is available. After reviewing various semi-analytical approaches or hybrid approaches using MATLAB^{® [1]}, this paper introduces a hybrid method using ADAMS^{® [2]} with input of measured engine and transmission accelerations as well as drive shaft or half shaft loads. In this hybrid method the engine is modeled as a rigid body supported by the base structure (vehicle subframe, frame or body) through powertrain mounts with measured nonlinear properties. The method has been studied in various vehicle prototypes, in which the mount loads were measured for analysis and test correlation. The results are discussed for a chuckhole durability test as well as a low-speed bumper impact test.