BAE Systems and Northrop Grumman, recently awarded $450m to develop the US Army’s Ground Combat Vehicle (GCV), have gone to QinetiQ for a hybrid-electric track drive.

Called E-X-Drive, “the transmission for electric drive tracked vehicles marks a significant step forward from conventional hydro-mechanical transmissions in terms of efficiency, size, weight, reliability and flexibility,” claimed Qinetiq. “E-X-Drive for GCV offers improved acceleration, agility, fuel efficiency and maintainability compared to the drive-trains of current combat vehicles. It also delivers electrical power for on-board vehicle systems, or as export power for stationary applications.”

Having only electric cables between the engine/generator and the drive motors, also allows components within the vehicle to be re-arranged and “facilities the introduction of fuel cells and battery/energy storage technologies as they become available over the life-time of the vehicle”, said Qinetiq.

QinetiQ will deliver “several”, it said, transmissions during the two year GCV development phase.

Why is the drive ‘hybrid’?

“The combination of electric traction motors coupled with the use of mechanical power regeneration through the transmission main-shafts is the preferred alternative to independent sprocket drives,” said Qinetiq. “E-X-Drive transmits this steering power mechanically without the need for a separate cross-shaft, reducing the required motor and inverter power ratings.”

For a 50 tonne vehicle, the drive weighs 900Kg including inverters and brakes. Nominal input power is 800kW.

Article source: http://www.electronicsweekly.com/Articles/2012/02/02/52880/qinetiq-supplies-electric-drive-for-us-tank-tests.htm