BAE Systems announced a parallel electric-drive hybrid system for Class 6, 7 and 8 trucks that's based on HybriDrive series hybrid that's now working in 3,000 transit buses worldwide.

The new HybriDrive system consists of a motor-generator, an automatic transmission, lithium-ion batteries, and electronic controls. It will work with diesel engines and is designed for minimum impact on truck chassis, executives said at its introduction during the NTEA Work Truck Show in Indianapolis.

The HybriDrive parallel system is designed for vocational trucks with duty cycles that require higher operating speeds and less frequent stops. It will be competitively priced and promises a payback in five years without government purchasing incentives.

"Right-sized" systems come in two versions whose motors develop 94 horsepower and 300 pounds-feet, and 300 hp and 440 lbs-ft. These outputs are blended with the truck's diesel at launch, or the diesel alone can propel the vehicle at higher road speeds. It will support large-bore diesels from 350 to 600 hp and torque of 750 to 2,150 lbs-ft.

Li-ion batteries will be sourced from a North American supplier that will be announced later. Caterpillar's CX automatic, which heretofore has not found an application in on-highway trucks, is the chosen transmission. Executives hinted that Cat will offer the HybriDrive in its heavy vocational truck that will be unveiled later this month.

HybriDrive series and parallel systems both use simplified and proven components and controls to deliver their capabilities, said Steve Trichka, vice president of power and energy management for BAE Systems. The new parallel system's single electric machine is integrated between the engine and the transmission.

The system's energy management and control capabilities ensure efficient energy flow, resulting in lower fuel consumption and reduced emissions, he said.

BAE is discussing the system with truck builders and is signing agreements with some of them, executives said. The truck manufacturers will install HybriDrive on their assembly lines. They, Caterpillar or BAE will back the system's warranty, though which route has yet to be decided.

The HybriDrive parallel system, in final stages of development, will see it first road trials this spring and is expected to be deployed in markets around the world in 2012.