Abstract
One of the most important pillars of functioning automotive system is its transmission system encompassing gearbox, synchronizers etc. Its reliable functioning is important for automotive user since it provides necessary mechanism for vehicle movement. Ironically gearbox and synchronizer damage due to improper driving is also one of the most encountered problems in automotive industry.
Some of the common transmission related problems that people have to frequently deal are that of gear not staying in its proper place, gearbox jammed, improper gearshift with respect to engine/vehicle speed etc. though all the problems and issues are taken care of, with careful design of contemporary gearbox and transmission control units, some issues such as gearbox damage due to gear shifting in improper speed are highly user dependent. Occurrence of it eventually varies with driver’s driving skill, driving conditions, driving terrain, type of gearbox etc. consequently most gearbox manufacturers and OEMs insist on careful and precise drivability to avoid any gearbox damages.
This paper discusses the development of gearbox interlock controller for reducing such failure by anticipating the user’s driving pattern (and other possible scenarios leading to such failures) by virtue of locking the gearbox movement safely (both for user and transmission system) such that gearbox and synchronizer will not get damaged due to gear shifting at undesired vehicle speed. This paper also describes the phased development of gearbox interlock controller, its uniqueness with respect to implementation in hardware and software strategies for making it suitable to be used independent of battery voltage and different gearbox ratios. The controller makes use of several input switches and speed signal for anticipating user behavior. Overall improvement in gearbox performance is also indicated.
Future unimplemented improvements such as interlocking decisions after synthesis of instantaneous vehicle speed signal and its hysteresis are also shown. In summary, this paper also depicts some of the field results obtained after deployment of gearbox interlock controller on one of the TATA Motors gearbox.
KEYWORDS: Gearbox, Transmission System, Embedded Control, Synchronizer, Microcontroller, efficiency improvement.