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In manual transmission vehicles, Clutch has direct interaction with the driver and plays a significant role in defining the drivability and NVH of a vehicle. These key performance factors depend on the interaction of diaphragm and cushion springs of a clutch. For an automobile manufacturer, it’s essential to optimize the characteristics of these springs based vehicle performance requirements. A state of the art analytical model has been developed by modeling the diaphragm and cushion spring with exponential equations. Based on these models, response functions for release load, torque build-up, and pressure plate lift have been derived. Results achieved from these response functions are correlated with test data. Key contributing factors for peak clutch pedal load, vehicle launch acceleration, and disengagement point have been identified by sensitivity analysis. Multi-objective optimization is performed to select optimized parameters for vehicle performance improvement

Manual transmissions dominate the Indian market for their obvious benefit of low cost and higher mechanical efficiency resulting in higher fuel economy. Synchronizer system in manual transmission enables smoother and quieter gear shifting. Synchronizer ring is the key element which provides the necessary frictional torque to synchronize the speed of gear and sleeve for smooth shifting. During vehicle running, synchronizer rings are free to rattle inside the indexing clearance. High engine torsional excitation and low clutch dampening can result into increased fluctuation of the input shaft of transmission. High fluctuation or lower contact area of synchronizer ring can lead to damage on the index area. This damage may cause hard gear shifting and gear shift blockage in case of extreme damage.

Clutch actuation system in manual transmission is one of the key systems of power-train with which driver interacts frequently. Therefore its load and travel feeling are important to customer. Clutch actuation system consists of clutch pedal assembly, flexible cable mounted on body panel, and clutch release arm/ shaft assembly inside transmission unit assembly. Clutch pedal load, travel and engagement point are important parameters to specify the actuation feeling while designing the clutch actuation system. Validation of actual values is being done at proto vehicle testing stage, as final output calculation may not be accurate due to dependency on variables difficult to estimate. To overcome these difficulties a virtual dynamic model of the entire clutch actuation mechanism has been created in MBD software. Model input factors are based on actual testing results to improve the accuracy. The model predicts the clutch pedal load and travel values for a given set of vehicle inputs.