Automatic Belt Tensioners for BAS systems require unique attention and design considerations. BAS refers to “Belt Alternator-Starter”, sometimes also called ISG for “Integrated Starter Generator”. As part of a strategy to reduce fuel consumption and associated emissions, various OE’s employ BAS systems as a means to shut the engine off at idle and instantly restart it as the driver engages the vehicle to move. An alternator-starter replaces a conventional alternator within the FEAD belt system, and functions as such during normal driving. When the engine is stopped the unit functions as a starter to quickly turn the engine through the accessory belt. BAS systems may also employ regenerative braking functionality and acceleration boost if desired.
Because the torque reverses under various operating modes, and the tensions are high to avoid belt slippage, BAS system tensioning requires critical analysis and unique designs. Usually BAS systems require two tensioners, one on each side of the starter-alternator, for optimum function under all conditions.
Litens has extensive experience in the development of BAS system tensioning solutions including computer simulation and physical performance evaluations.
As with our standard FEAD tensioner strategies, Litens employs highly efficient mechanical friction/damping systems in the tensioner designs. Pulleys are available in steel, plastic, and with single or double row ball bearings. Easy installation, no maintenance, reliable, quiet; part of a total tension control solution.