GM's surprising new hybrid
Posted by: Adam Aston on August 16
After checking out GM’s new entry, I was surprised, practically amazed, and convinced this could be a game changer. The engineering advancements that GM was showing off in the Yukon hybrid GM brought to Manhattan on a recent morning were impressive in their own right — more on that later. Likewise, the scope of GM’s vision to roll out the new system into new models left me more convinced of the company’s commitment to a technology it was dismissive of a few years back. Indeed, GM has been talking about this new so-called “2-mode hybrid” for years. Whether GM could scale it up into full production was a big question, though. The proof sat parked in the guise of an aerodynamically sculpted SUV (that sounds like an oxymoron, I know, but is true) parked outside a restaurant in New York’s art gallery district. It goes on sale later this year.
The new hybrid design is a smart blend, joining a smart, new organization of the gas-electric drive train with GM's existing engine technology that imperceptibly turns off cylinders at cruising speeds. The combination improves mileage in city traffic and also while cruising on highways. GM pledges this approach will deliver a 20-25% mileage boost overall, even on big SUVs and pickups, and without sacrificing the horsepower American car buyers crave. Given GM's offerings in the hybrid market to date -- so-called mild hybrids like the Chevy Silverado with unimpressive mileage gains -- the new technology is a giant leap forward.
First the technical details. If you could dismantle a Toyota or Ford hybrid today, you'd find a chunky electric motor connected up to the motor and drive train. Yet if you disassemble a Yukon, you won't see any electric motor. That's because GM was able to sneak a powerful electric generator into the big case that holds the transmission gears. This has many benefits. It saves space, since the transmission case is no bigger, even with the extra electric bits. The design should also make it easier for GM to adapt hybrid drive trains into other cars. And there may energy efficiency advantages in this approach (compared with the Toyota, Honda, Ford design) because it cuts down on the number and complexity of mechanical linkages necessary to join electric motor to gas engine. (Any mechanical engineers out there want to weigh in?). As an added plus, it frees up precious underbody space for batteries, regenerative braking systems, and the other goodies that make hybrids go.
Source / Continued: http://www.businessweek.com/investin...id_cadill.html