Automated Release Test Run in Transmission Development

摘要

With its automatic transmissions for passenger cars, the Car Powertrain Technology Division of ZF Friedrichshafen AG has set high standards both in shifting comfort and driving dynamics as well as in CO2 saving. One of the tasks during development is putting prototype transmissions through a release test run before they are delivered to customers or installed in test vehicles. The conventional method consists of performing these test-bench runs on electric motor test benches manually. The test bench is operated manually by the operator. This means the test procedure can be designed flexibly, but comparative analysis and evaluation are only possible to a limited extent. For this reason, a project for automating the release test run for prototype transmissions including automated analysis of the measurement data was implemented in the testing of the Development in the Automatic Transmissions Business Unit in Friedrichshafen. First of all, a step control program for the test bench control unit ensured a reproducible test procedure. This meant that additional, new test phases could be integrated that were not possible in manual operation. The measurement data is analyzed with the FAMOS measurement data analysis tool. A user-friendly user interface allows the test bench driver to visualize the results of the individual test modules as soon as they are completed. The permitted limit values are shown simultaneously. To document the results, a release test report is automatically issued, detailing the key functional data of the transmission. Automation of the release test run during development also represents a major step toward matching the test bench procedure to the end-of-line test concept in volume production. In the future, the objective is to develop and test possible test steps for later volume production on prototype transmissions during the early development stage.