Fifth Time the Charm for GM Hybrids?

Edward Niedermeyer
by Edward Niedermeyer
fifth time the charm for gm hybrids

Showcased in the Saab 9-X concept at Geneva, GM's unveiled their fifth hybrid powerplant: an evolution of their first-gen Belt-Alternator-Starter system (a.k.a. BAS or "mild hybrid"). The Detroit News says upgrades include a new, Hitachi-sourced lithium-ion battery, a new electric motor, the addition of "brief electric-only propulsion" and improved regenerative braking. At Geneva, GM hybrid guru Steve Poulos said these upgrades do not an American Revolution make. "We took the same [first-gen BAS] system and put it on steroids." GM's next gen system is three times more powerful than the existing BAS unit. That said, Poulos admitted that the new system will improve a BAS-equipped vehicle's fuel efficiency by one to two miles per gallon. CEO Rick Wagoner says this new drivetrain is "important step to make hybrid technology more affordable to a wide variety of consumers." Baby steps indeed. If GM wants to catch-up with Toyota's Synergy drive, they'll have to do better than this.

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  • Jonathon Jonathon on Mar 04, 2008
    You know what would be a cheap solution and save gas, adapting the cylinder deactivation technology we already have to shut down 75% of the engine while stopped or moving less than 5 mph. I'm not sure this is always feasible. GM looked at putting cylinder deactivation on the 3.5 OHV engine, but apparently it created an unacceptable amount of vibration. I'm looking forward to the HCCI engines that GM and others are working on, though. It sounds like very promising technology, especially if paired with a mild or full hybrid system.

  • Joeaverage Joeaverage on Mar 04, 2008

    Not to mention the larger diameter of the flywheel is going to have a better efficiency (leverage) than the little alternator pulley... I say all this drawing on some big conclusions without seeing the Asian flywheel motor/alternator design. Would be nice if there was some way to add a clutch into the flwheel assembly so that it would not be necessary to rotate the engine at all when the electric motor was working. Of course that introduces another level of complexity but I'll bet that clutch would last the life of the car (200K miles) since it would not be mating a 1500+ rpm engine to a stationary transmission input shaft. It would be mating a stationary crankshaft to an electric motor turning a few hundred rpm. Heck, roll the engine over on battery power before you mate the electric motor shaft and the crankshaft... Yep this armchair designed hybrid is getting out of control. Still you could roll the engine over with one of these alternator/motors to match the speed of the flywheel motors before engaging the two shafts. Frankly I'm ready for a full hybrid - a small diesel engine charging batteries based on a throttle position chosen by a computer (which learns the best efficiencies based on a laundry list of data indicators) with electric motors providing all of the vehicle motion. May not be the method best suited for all vehicles but it would certainly be fine for my daily commuter. Best of all I could go full stealth for say 50-75 miles and that would be plenty to get me home where I could recharge. Maybe the DeWalt/Porter-Cable guys will release a full hybrid before the car companies...

  • Jonathon Jonathon on Mar 04, 2008
    What is the cost premium of this system over that of a non-hybrid? The Detroit News article simply says that the cost will be "roughly the same."

  • Brendino Brendino on Mar 05, 2008

    That's the point of BAS - provide some hybrid benefits without all the extra cash. If GM can improve it by 1 or 2 MPG every cycle, hey, more power to em. Ultimately I think it's good not to have all your eggs in one basket. And what was GM's old saying back when there was brand differentiation? "A car for every budget and taste"? Well, maybe they want to have "a hybrid for every budget and taste." And BAS has a better shot of becoming ubiquitous than a full-blown hybrid in the short term.