Development of Test Methodology for Accelerated Fatigue Testing of Engine Pulley Bolt

Engine is the prime mover of an automobile. Tractor is also equipped with engine of higher capacity to meet the power requirement. Apart from powering the wheels, engine also runs different accessories such as water pump, alternator, AC pump, Oil pump and so on. The power from the engine is transferred to accessories via chain drive or belt drive through the crankshaft pulley. During field testing, in one of the tractors, engine pulley mounting bolt failure was reported. The failure resulted in immediate seizure of the engine making the tractor standstill in the field. The root cause of the failure was unknown. Hence, there was a need to develop a component or subsystem level test methodology to address the issue quickly. In the current scope, an attempt was made to develop a subsystem level laboratory test methodology to simulate the failure mode and to validate the design modifications in an accelerated manner. The failure mode was simulated in lab and different design iterations were also tested. On successful completion of testing and implementation of the improved design, this newly developed test methodology was added as a DVP requirement to all future projects.