Establish Procedure to Avoid Judder by Effective Gearbox Design

摘要

Nowadays fuel economy becomes very important for the brand image of the vehicles. This results in trends like downsizing the engines, usage of higher torques at lower rpms. Also transmissions are effected by this. It should operate as effective as possible with a minimum of losses while dealing with the new engine trends. To optimize the performances and losses, the torque converter should be used as little as possible, resulting in early engagement of the lock-up clutch. During the engagement of the lock-up clutch judder can occur and is noticed by the driver in the vehicle. In order to frontload the development, judder should be avoided in the early design stage. This paper describes a 3 step approach how a procedure is established to avoid this. In the first step test bench measurements are used together with simulation to study the judder phenomena on transmission level. The simulation models are correlated with the test bench data. In the second step judder is evaluated in full vehicle driving conditions. The necessary vehicle data for the simulation models is obtained by measurement in order to built accurate models. Correlation between measurements and simulation is carried out. The third step explains how the simulation models are used for sensitivity analysis to point out the most influencing components. By modifying those components judder can be avoided.