At the suggestion of Green Hornet on another thread yesterday, I am starting this thread as a place on EM to collect some specs on GM's BAS mild-hybrid. I am putting it in the "hybrids" subforum, but maybe it will belong in the ecomodding central subforum. Depends on how/if EM members participate.
The system's advantage to GM has been that it is relatively cheap to implement, since the electric motor can replace the alternator and starter and fits on the engine, belted to the crank pulley. For a moderately ambitious modder with fabrication skills, the advantage of such a system is the same. It is *relatively* easy to implement as a mod on a standard ICE.
I searched EM and found mentions of the BAS but no thread devoted to it. I'll come back to this OP to edit it for corrections.
There have apparently been two generations of this system, with the first being launched in 2007 and the second in 2012.
According to a
Hendon Media Group article, a the system has five major components:
1) An electric motor / generator. AC current from the motor / generator is converted to DC current to charge the batteries, and vice versa.
2) A coolant-cooled power electronics that controls the motor / generator and provides 12 volts to the vehicle’s conventional battery.
3) A nickel metal hydride battery pack capable of 10 kW of power.
4) A separate engine-control module with Hybrid Supervisory Software to manage both the gas engine and hybrid system.
5) A different engine accessory drive with a dual tensioner assembly and aramid cord belt. This belt transfers torque to the gas engine from the electric motor for starting and acceleration, and torque from the engine to the motor to generate electricity.
And there is a more detailed and longer description from "
Under Hood Service." Here is a key section describing the functions:
"The BAS alternator’s output is controlled by two modules: the main generator control module, and an auxiliary control module. In normal driving mode, the generator control module converts the alternator’s three-phase, 36-volt alternating current (AC) output to 36 volts direct current (DC) to keep the hybrid battery charged. In start/stop mode, the generator module also converts 36 volts DC from the hybrid battery back into 36 volts AC when the BAS unit requires power to restart the engine, or to provide some extra kick when accelerating."
And then these images and charts from around the internet:
