Performance of multicone synchronizers for manual transmissions

Theoretical performance equations are derived for multicone synchronizers which have replaced the traditional single-cone device in certain upmarket passenger vehicles. The equations are used to demonstrate the potential improvements in shift quality for a typical vehicle. Experimental studies of equivalent single- and triple-cone synchronizers within the same gearbox test rig are also reported for transmission oil temperatures ranging from cold start (0 degrees C) to maximum operating conditions (75 degrees C). The results confirm the overall much improved performance of the multicone synchronizer compared with the single-cone equivalent, except at low oil temperatures, where some difficulty in dissipating the oil from the multiple friction surfaces was apparent.