Improving the clutch design robustness by Virtual validation to Predict Clutch Energy Dissipation and Temperature in Clutch Housing

Clutch is a very important component of any vehicle equipped with the manual transmission (MT), automated manual transmission (AMT) or dual-clutch transmission (DCT). During launch of a vehicle(moving from “0” speed), clutch is being slowly engaged by the Driver or TCU(for AMT vehicle) for smooth torque transfer between engine and transmission. The clutch is design to transfer max engine torque with min heat generation. During the clutch engagement, the difference in the input (engine flywheel) and output shaft (clutch disc) speed of clutch called the clutch slipping phase which then leads to a huge amount of energy being dissipated in terms heat due to friction. As a result, clutch surface temperature increase consistently, when the surface temperature cross the threshold limit, the clutch wear out quickly or burns spontaneously. Hence it is crucial to predict the energy dissipation and temperature variation in various components of clutch assembly through virtual simulation. During the development process of the vehicle, the clutch is tested over many duty cycles to ensure the temperature, wear rate does not exceed the material thresholds. However, performing these tests for every prototype and for every variant can be expensive and time consuming. In this paper we have proposed a simulation methodology to replicate the vehicle test cycle (Hill- Fade test,) i.e launching the vehicle on 15% grade followed by a cooling cycle and repeated over 150 cycles, in the developed virtual simulation methodology using GT-SUITE application to accurately calculate the dissipated energy and the heat transfer through the components in the clutch housing. The developed simulation model can predict the surface temperature of clutch over the defined cycle, can predict the clutch life and can perform a DOE analysis to optimize the vehicle or clutch parameter to meet the required customer targets. With the developed simulation model results and real world vehicle testing results has been validated. The predicated simulation results have 90% correlation with the vehicle test data. The validated simulation model was then used to predict the temperature on other duty cycles to enable a virtual pass/fail test which is much faster as the simulation runs 11 times faster than real time and does not have test related lead times like prototypes and instrumentation.