Dual-Mass Flywheel with Torque Limiter: An Effective Solution for Overtorque Suppression in Automotive Transmission 2020-01-1016

During some critical maneuvers, transmission systems using Dual Mass Flywheel (DMF) may experience overtorques, which could lead to structural damages of the transmission components. In a dual mass flywheel, total inertia is divided into two parts: a primary mass connected to the engine and a secondary mass to the transmission. The torque delivered by the engine is transferred from one mass to the other through a drive plate and a set of arc springs, the latter absorbing the torsional oscillations coming from internal combustion engine and the shocks caused by fast clutch engagements. This paper investigates overtorque issues and proposes a solution based on a torque limiter, consisting of a friction clutch inserted between the two masses, that limits the maximum torque transmitted through it. The basic idea is to replace the classic flat drive plate with a tapered drive plate that functions as a Belleville spring. The experimental analysis carried out on dedicated benches has tested the elastic characteristic of the tapered drive plate, the durability of friction pads and the variation of the slipping torque over time. This article analyzes the torque limiter benefits through a detailed torsional dynamic model implemented in Simcenter Amesim. Overtorque phenomena are excited during cranking-in-gear vehicle launch tests on different slopes. Furthermore, a simplified multi-degree of freedom transmission model developed in Matlab/Simulink is shown; it allows calculating frequency response functions, natural frequencies, mode shapes and overtorque limitation. The comparison between the two models revealed that even the simplified model is capable of predicting the main dynamic aspects involved in the overtorque phenomenon and the positive effect of the torque limiter.