CONCEPTION OF ELECTRO-MECHANICAL DIFFERENTIALS IN DBW 4WD PROPULSION MECHATRONIC CONTROL SYSTEMS FOR JOINT LIGHT TACTICAL VEHICLES

摘要

This paper deals with conception of 'passive' and 'active' electromechanical (E-M) differentials in automotive mechatronics, in particular, for reduction of 'self-generated wind-up torques' in drive-by-wire (DBW) four-wheel-drive (4WD) propulsion mechatronic control systems for Joint Light Tactical Vehicles (JLTV). Self-generated windup torques are created by differing dynamic wheel-tyre diameters, kinetic slip between front-wheel-drive (FWD) and rear-wheel-drive (RWD) units during cornering and kinetic slip between the driven wheels or steered, motorised and/or generatorised wheels (SM&GW) of one FWD or RWD unit. However, dissimilar transmission ratios for FWD and RWD units of a rigid DBW 4WD propulsion mechatronic control systems, which also could create high self-generated wind-up torques, are usually not selected. The self-generated wind-up torques emerging in the DBW 4WD propulsion mechatronic control system can only be reduced by power that linearly increases with the wheel angular speed This power loss, in fact, cannot be utilised as tractive power for the all-terrain (on/off-road) all-electric vehicles (AEV), that is, hybrid-electric vehicles (HEV), battery electric vehicles (BEV) and fuel cell electric vehicles (FCEV). The generated power loss increases the electrical energy economy and/or specific fuel consumption (SFC), the wear and tear (W&T) of all DBW 4WD propulsion mechatronic control system components, and the wheel-tyre wear. Under extreme circumstances, over heating and overload can significantly moderate the fatigue life and lead to an early failure of all DBW 4WD propulsion mechatronic control system components.