A green Cadillac? GM's surprising new hybrid

Posted by: Adam Aston on August 16, 2007

After checking out GM’s new entry to the green car market, I was very nearly amazed, convinced the new hybrid design could be a game changer. The engineering advancements that GM showed off in the Yukon hybrid company reps drove 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 other models left me more convinced of the company’s commitment to a technology it was dismissive of just a few years back. GM has been talking about this new so-called “2-mode hybrid” for years. Till seeing this demo, however, the question remained whether GM could scale it up into full production. The proof sat parked in the guise of an aerodynamically sculpted SUV (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, combining a 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 at both low speeds in the city and at high speeds 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 that deliver unimpressive mileage gains -- the new technology promises to be 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. The design saves space, since the transmission case is not much bigger, even with the extra electric components. 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 the design 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, this approach frees up precious underbody space for batteries, regenerative braking systems, and the other goodies that make hybrids go.

On a cruise north up 10th Avenue, though about as un-nimble as any big SUV in city traffic, the Yukon was quiet and smoother than its gas-only cousin. This, explained Mark Cieslak, vehicle chief engineer of GM's full size truck hybrids who's been driving an early production hybrid Yukon for months, is because the battery pack and electric motor have enough kick to take this 5,000-lb vehicle up to city road speeds without the 6 liter V-8 gas engine kicking in. When accelerating, or towing loads, the vehicle has all this power at its disposal. But if it's not needed, it stays dormant. At highway speeds, as I saw driving south along the Hudson River, the engine saves gas by deactivating cylinders not needed to maintain a 65-mph clip.

Back to the big view. In debuting the Yukon, GM reps also guided a small group of reporters through their hybrid strategy for years to come. Earlier, I blogged about my skepticism that GM could beat Toyota to a plug-in electric hybrid. But GM's step-by-step vision makes me think they could do it. The hybrid GMC Yukon, and its doppleganger the hybrid Chevy Tahoe, will hit sales lots late this year. Soon there after, the 2-mode hybrid will appear in 2008 models, including a hybrid Cadillac Escalade -- what better way to assuage SUV guilt? -- followed by 2-mode hybrid treatments of the Chevy Silerado/ GMC Sierra pickup, and a similar upgrade to the Saturn Vue Green Line all in 2008. Sure enough, at the end of this road map, in 2009/2010, GM shows two plug-in hybrids: the Saturn Vue Green Line and the Chevrolet Volt.

Oddly, GM won't be deploying this 2-mode system into any sedans, just SUVs and trucks. Given GM's success (at least till $3 gas) with trucks and SUVs, this makes sense: Americans don't necessarily want sedans, they're justing more of them now since they get better mileage. If you can deliver a small SUV with car like mileage, who wouldn't opt for the bigger vehicle? This omission may be because the new all-in-one transmission-plus-electric-motor is too bulky to fit into smaller car forms. Another question, as with all hybrids, is the final pricing. Hybrid buyers, and their critics, tend obsess over the complicated calculation of the time it takes to pay back the premium cost of a hybrid. The more expensive gas is, the quicker this happens. But the bigger the upcharge for hybrid technology, the longer it will take.

Reader Comments

John Herris

August 18, 2007 1:37 AM

I do not own an SUV nor have I owned one, I have a sedan -- but if I did I would certainly NOT feel any "SUV guilt". People buy vehicles that fit their lifestyle needs; no need to feel guilty about that despite the Sierra Club and their fellow travellers hyping "global warming". There has been global warming since the end of the last ice age -- WAY before SUVs -- and thank goodness! An ice age would be a real bummer for growing food, summer recreation, etc. Since water vapor accounts for 98.2% of the greenhouse gas effect, and nature produces 30 times more CO2 than humanity does, CO2 produced by humanity is less than 1/1000 of the greenhouse effect. So what is the problem?

Chad

August 18, 2007 5:50 AM

This is good news. GM needs to change minds with technology and products, not marketing promises. It should be noted that the 2-mode system being attached with the vue is the same FWD V6/tranny that is being put in several of GM more recent sedans - G6, Aura, Malibu ect. So perhaps it is not a constraint of size of the package, but rather a constraint of availability.

BILL DIXON

August 23, 2007 3:27 PM

WHAT ABOUT AVALANCHE?

I HAVE DRIVEN IMPALA RENTALS WITH 6/3 TECHNOLOGY...APPEARS SEAMLESS...

Dano

August 29, 2007 4:26 PM

I have been watching GM for a while - they are a changed company with great products and more on the way. I own a Chevy MAXX and love it. I get 25 MPG average and I can carry anything in it including 2 X 4 X 8s. The interior looks cheap, but and this a big but, it actually rides like a BMW thanks to a very stiff frame. I am a former Altima owner and wouldn't go back

Liz

September 5, 2007 12:31 AM

Why do cars need to weigh 5,000 pounds? Every car, every size, could save potentially quite a large amount fuel or energy in city driving if they weighed less. Given the astounding technologies we have available, I wonder if auto companies are researching new materials in order to 'lighten the load.'

LM

January 28, 2008 1:03 PM

Is there any news on the forefront about Saturn coming out with an Outlook green line? when?

Adam Aston

January 29, 2008 3:16 PM

On LM's question regarding the potential of an Odyssey hybrid, I checked in with BW's Detroit bureau chief, David Welch. He pointed out that Saturn and Chevy are looking to expand the hybrid line with a new version of GM's belt-alternator starter hybrid -- it's first generation mild hybrid technology. The rumor is that the second gen so efficient that it could replace GM's vaunted, and more costly dual-mode hybrid (like the one used in the Caddy hybrid) for many mid-tier and entry-level vehicles. So Saturn and Chevy are both likely to get a crack at it, but not anytime soon.

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BusinessWeek correspondents John Carey and Mark Scott, cover the green scene, keeping on top of the business aspects of energy, the environment and climate change, as well as the technologies, policies, markets and people that are shaping how the earth's resources will be used in the century ahead.

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