Online and real-time monitoring system for remaining service life estimation of automotive transmissions – Application to a manual transmission

An original approach to introduce cost-efficient lightweight design in transmission engineering is being studied in this paper. This approach is predicated on the implementation in series-production cars of a real-time and online lifetime monitoring system able to estimate the remaining service life of transmission gearwheels, continuously and under operating conditions. The purpose is to develop a simple and application-oriented method, which could serve as an input for control strategies or transmission development. The system is aimed to monitor the transmission loads with the aid of torque identification method and to accumulate the resulting partial damages by each calculation step. This paper proposes the development and the validation of such a system. Firstly, a qualitative and quantitative study of true-to-life drivetrain load cases and their impact on a damage calculation is evaluated. These loads are generated from driving cycles derived from real driving conditions and driver profiles. Owing to these investigations, specification requirements are presented, regarding signal quality, characteristics and counting, and calculation step time. An observer-based torque identification method relying on an Extended Kalman Filter and coupled with a gear recognition function is also addressed. Finally, a global error study for a potential implementation of the method in vehicles is introduced.