On the optimisation of a double cone synchroniser for improved manual transmission shiftability

The paper presents a method to optimise the synchroniser of a road vehicle gearbox in order to improve shiftability and driver comfort. A multi-body physical model of the synchroniser has been developed and validated experimentally. The optimisation method is based on a Multi-objective Programming approach, and it allows to tune the thirty-two parameters of the synchroniser in order to achieve the desired dynamic behaviour of the system during a reference shift action, defined by seven performance indices. A Global Approximation procedure has been followed to solve numerically the optimisation problem. A special study has been performed and implemented in order to explore all of the feasible design solutions within the design variables domain. A global sensitivity method has been applied in order to analyse the relationships among the thirty-two design variables and the seven performance indices. Pareto-optimal design solutions have been computed in a very short time. These Pareto-optimal solutions have been checked for robustness by applying the minimum sensitivity method. The optimisation method has been applied with successful results. A number of optimised synchronisers have been defined, all of them featuring relevant improvements in the dynamic behaviour (shiftability) with respect to the reference synchroniser, aleady effective and under production.© 2002 ASME