Derivation of Test Schedule for Clutch Using Road Load Data Analysis and Energy Dissipation as Basis

During every clutch engagement energy is dissipated in clutch assembly because of relative slippage of clutch disc w.r.t. flywheel and pressure plate. Energy dissipated in clutch is governed by many design parameters like driveline configuration of the vehicle vis-a-vis vehicle mass, and operational parameters like road conditions, traffic conditions. Clutch burning failure, which is the major failure mode of clutch assembly, is governed by energy dissipation phenomenon during clutch engagement. Clutch undergoes different duty cycles during usage in city traffic, highways or hilly regions during its lifetime. A test schedule was derived using energy dissipated during every clutch engagement event as a base and using road load data collected on the vehicle. Road load data was collected in different road mix conditions comprised of city traffic, highway, hilly region, rough road for few hundred kilometers. Using this data clutch energy was calculated in all the clutch engagement events observed in road load data. Cumulative energy calculated from all these events was extrapolated for stated life of the clutch, for vehicle application under consideration. A test cycle was derived considering maximum energy dissipated in engagement events, clutch engagement pattern and maximum temperature observed inside clutch housing, for rig testing. The life predictions and failure modes observed with this test schedule were evaluated against the field vehicles and it showed a good correlation. This paper proposes a methodology to derive test schedule for clutch life prediction based on energy dissipated in clutch and using road load data. The test on the rig with such schedules provides better avenues to shorten the development time line of clutch system as well as vehicle driveline.