Abstract
A gasoline engine coupled to a robotized gearbox (Manual Transmission Automated) on the Elasis highly dynamic powertrain bench test has been installed. The purpose of the set-up was to study the behaviour of different components of the transmission during vehicle drive-off and gear shifting. The perfect repetition of all manoeuvres was essential, and this was assured by the test bench. For this purpose the gearbox was instrumented with a number of load and position transducers. Strain-gauges were mounted on the actuator fingers (to measure the load during the gear shift) and on the primary gearbox shaft (to measure the torque transmitted by the clutch). A linear potentiometer was also installed on the CSC (coaxial slave cylinder) to measure the axial clutch position. With the data obtained it was possible to study torque transmission from the input shaft to the wheels (according to the estimated clutch position and engine generated torque). Moreover, in order to guarantee maximum reliability over time, this data was used to define the optimal profiles of the load on the actuator fingers, during the disengage, synchronisation and engage phases. The experimentation also included a functional evaluation of the transmission control unit algorithms used to estimate the parameters under investigation. This set-up represents the state of the art in terms of optimization of an MTA gearbox on the bench, permitting significant strategies de-bugging activities and base calibrations even before vehicles become available. The advantages in terms of costs and Time To Market reduction are evident. With the potential offered by the equipment described in this document, the next target would be to set-up a bench testing system for vehicle driveability macro-tuning.
Keywords: Selespeed®, robotized-gearbox, measure, calibration, reliability.