Sustainable performance of wet clutch systems II
Purpose and goal
When wet clutches age, the frictional behavior is changing, which can lead to failure of other mechanical components in the powertrain or vibrations and noise. With the help of an ageing model developed in this project it is now possible to compensate with the control electronics for changes in friction and thus avoid costly breakdowns or unwanted behavior of the drivetrain. The aging model can also be used in the development process by modeling the dynamics of the car´s powertrain. This makes prediction of operating conditions which can lead to problems with vibrations and noise.
Results and expected effects
A method to predict the remaining life due to oxidation of the oil was developed in the project. A model was developed to simulate the heat generation which depends on the wet clutch operating conditions. This heat is then coupled to the experimentally produced oxidation model for the oil and the remaining useful life can thus be predicted. The service life of the wet clutch can then be predicted, for a specific set of operating conditions, before vibrations in the driveline occurs. This model has also been implemented in the vehicle control software to compensate friction changes with time.
Approach and implementation
The project was conducted in cooperation between Luleå University of Technology and the industrial partners BorgWarner TorqTransfer Systems and Statoil Fuel and Retail. Most of the work in the project has consisted of experimental activities, mainly in laboratory environment, but also in the full-scale vehicle test at Borg Warner. In a laboratory environment at Luleå University of technology a number of different test rigs have been used.