Front Loading NVH Test on the Highly Dynamic Powertrain Test Bed

Advanced powertrain test, which is simulating real road load condition, was performed on the dynamic test bed. This cutting edge system can reproduce real road resistance based upon the vehicle dynamic model and wheel slip model. This wheel slip function is simulating the real behavior of the powertrain wheel as close as possible at each wheel independently. Additionally, low inertia of dynamometer motor themselves is another advantage for this purpose. This test bed is capable of testing all kinds of 2WD and 4WD powertrain configuration regardless of transmission type. Also, vehicle configuration can be mounted and tested on this test bed with small addition of supporting system alternatively. For the application, a four wheel drive powertrain was mounted on the test bed and driveline noise and vibration behavior such as transfer rattling noise and tip in/out shock were reproduced on this test bed. For validating these tests, torsional vibration behavior was measured at both the powertrain/vehicle on the test bed and the vehicle on the real road respectively and their similarity will be shown. As another application, 4WD driveline performance tests were done on this test bed and on the real road such as 12% roller lane test and climbing start from rest on the 33% hill. Their identical behavior of speed and torque of each wheel shows the usefulness of these powertrain tests. On the basis of reproducing various driving modes, successful correlation between powertrain test and vehicle road test could be accomplished and these innovative results shed the light on the possibility of powertrain front loading development, which can provide us the opportunity to save development time/cost and to increase the reliability of the powertrain in earlier stage or before the start of vehicle development.