Živko Ilijevski A Hybrid-Electric Drive Concept For High Speed Tracked Vehicles

Huge, ineffective and inefficient drive systems in the high-speed tracked vehicles are the most accountable for the contemporary behemoths of Main Battle Tanks (MBT). However, the main problem presently existing in the transmission system resides in the role of the high speed tracked vehicles. To ensure vehicle operations, such a vehicle requires a continuously variable output on both sides of the drive train in a very large range of speed and torque. Applying the most inefficient hydraulic power transmission units for that purpose, such a transmission system not only devours enormous quantity of energy, it also needs a powerful cooling system consuming 14 to 15% of the engine maximum power to dissipate the generated heat. New technology development in the field of electric motors and power electronics opens a new area for vehicle drive system development. However, a high speed tracked vehicle, due to a huge amount of circulating power throughout the transmission, needs components of great power density. Although achievements of new electric motors are impressive, their power density is not good enough to serve as a transmission on their own in a high speed tracked vehicle. A completely mechanical transmission concept for high speed tracked vehicles known as Transmission with Independent Turning Radii (TITR), applied for repowering of the Croatian tank M84, has shown exceptional effectiveness and efficiency in steering, and enabled to achieve an incomparable power density of the drive train. Its modular architecture enables various combination with electric machines in order to get a hybrid-electric drive train which can maximizes the synergistic effect of a mechanical and an electric drive. The paper reports on the compatibility of the TITR transmission concept with the specific needs of a high speed tracked vehicle proved on field testing. For further development, a hybrid-electric drive concept is shown in the bases of which are modules of TITR transmission concept. The overall characteristics and advantages of such a drive concept are pointed out.