A Unique Methodology to Evaluate the Metallic noise concern of a Dual-Mass Flywheel Under Real-World Usage Conditions

Dual mass flywheel (DMF) is an excellent solution to improve the noise, vibration and harshness (NVH) characteristic of any vehicle by isolating the driveline from the engine torsional vibrations. For the same reason, DMFs are widely used in high power-density diesel and gasoline engines. However, the real-world usage conditions pose a lot of challenges to the robustness of the DMF. In the present work, a new methodology is developed to evaluate the robustness of a DMF capturing the RWUP conditions fitted in a Sports utility vehicle (SUV) with front-wheel drive architecture. During engagement of clutch system, enormous amount of energy is dissipated. To sustain the operating temperature of the clutch system, generated energy is dissipated through conduction & convection. If the temperature of the clutch friction material is not retained, clutch burning & burst failures happens. Ventilation holes are provided on clutch housing to improve convective heat transfer. During rainy season in Cities like Mumbai, Chennai, Bangalore, roads are filled with stagnant water levels to the extent of 500mm. Prolonged usage of vehicle in such water trough can lead to a erosion of grease across the spring in the DMF resulting initially with metallic noise concern. Prolonged usage of DMF without grease will result in spring breakage concern which needs to be assessed during the development stage of a vehicle. In the present work, the authors propose a unique methodology to assess the robustness of any DMF. The methodology is a combination of testing the vehicle with a defined pattern inside 500 mm of water level with different profiles and subsequently subjecting the vehicle to city drive profile and high drive profile test of 2000 km. The correlation was established with real-world failures. In the present work, based on the results of this proposed methodology, the robustness of the DMF could be improved by modifying the internal child parts of the DMF. The paper explains the typical robustness measures needed inside the DMF to avoid real-world structural failures.