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Analytical and numerical study is carried out to study the behavior of stick-slip and judder phenomenon during engaging and disengaging of the automotive clutch. For this purpose, a four degree of freedom torsional power train lumped mass model is developed. This torsional vibration system includes engine-flywheel, clutch, gear box and vehicle drive line, which are connected to each other by shafts. Equation of motion of the system is developed and initially a stability analysis is carried out for various gradients of coefficient of friction using eigen value analysis. Later, a numerical simulation is carried out to analyze the judder and stick-slip phenomenon using commercially available mathematical tool MATLAB. It is observed that the clutch stick-slip is increased with increase in external torque and clutch pressure fluctuations.

Appropriate test cycle is required for engine testing. To do so, a new methodology is developed for deriving Engine Test Cycle based on real world duty cycle. Transient speed and load is to be collected from the functional engine on the field. The duty cycle for cyclic operation will be developed from the actual transient speed and load conditions. An iterative process and the comparison of chi-square statistical data is used to categorize typical microtrips, segments of engine operation collected during performance of certain activities. Different microtrips of all activities were combined together to make up a cycle of operation and test cycle as well. These data's are compared to statistical data which is used to illustrate the raw data. On successful comparison, the transient test cycle is validated on the test bed. To facilitate further engine testing, the cycle is transformed into a schedule of torque and speed points at One second intervals.