Cold Trip to Chassis Roller Dyno - The development and execution of the method to verify DCT Transmission Shift Performance on Climatic Chassis Dynamometer

摘要

When environmental testing does not align with development plans in Powertrain Engineering, often costly, time consuming, round-world test trips are required. A solution is to utilize a cold temperature chassis dyno to verify the transmission calibration and to confirm the transmission's functionality. The cooling equipment on the chassis dyno is able to replicate the temperatures of relevance for the verification work. No interference from environmental conditions means tests can be performed as scheduled without planning spare time for unsuitable weather. In many cases it would also be worthwhile to do pre-tests for cold trips to identify difficulties from other vehicle areas before the vehicles are shipped. In order to measure shift quality the vehicle is restrained on a dynamometer using a push-pull-bar with a load cell for measurement of longitudinal force. This force sensor provides the acceleration signals that are normally used to evaluate the comfort rating in gearshifts in road tests. Results and experience of cold testing of GETRAG POWERSHIFT in Ford applications on an AVL chassis dyno are presented. This paper describes the test facility requirements necessary as well as details of the tests completed. The measurement results, including a comparison with road data, are then analyzed. In conclusion a measure of added value and further potential is discussed. The opportunity to transfer the effort of transmission shift quality validation from road to rig is a significant improvement "Cold trip to Chassis Roller Dyno" is an enabler for efficient and systematic cold temperature validation and therefore ensuring timely developments of any automatic shifting transmission.