GM Ready to Take Next Big Hybrid Leap

Unlike the current mild-hybrid system, the new version is designed to be compatible with any GM vehicle and powertrain – gasoline, diesel, 4-cyl. and V-8 – around the world.

David E. Zoia

March 4, 2008

6 Min Read
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PONTIAC, MI – General Motors Corp. will lay the groundwork to go high volume with hybrids in 2010, when it launches its lithium-ion-based next-generation technology.

GM CEO Rick Wagoner is set to detail plans for the next, aggressive stage in the auto maker’s belt alternator/starter system (BAS) hybrid-electric vehicle technology today at the Geneva auto show.

GM’s current low-cost BAS technology bowed on the Saturn Vue Green Line in 2006 and now is featured on mild-hybrid versions of the Saturn Aura and Chevrolet Malibu – all equipped with GM’s Ecotec 4-cyl. engine and a 4-speed automatic transmission.

Unlike the current system, the new version is designed to be compatible with any GM vehicle and powertrain around the world – from gasoline to diesel and 4-cyl. to V-8, paving the way for the auto maker to seriously crank up the volume, particularly as fuel-economy regulations continue to toughen in the U.S., Europe and elsewhere.

The system is expected to have a bigger impact on improving fuel economy than the current version, because its higher output capability will allow GM to downsize a vehicle’s internal-combustion engine without negatively impacting performance.

GM executives here for a backgrounder on the new system are cautious about predicting volumes, but it’s clear the goal is to begin proliferating the system throughout the auto maker’s global lineup in short order.

“We’re going to debut in North America in 2010, and then, after that, there’s a significant volume growth potential, a lot of potential for applications, and we see this as a real expanding technology,” says Stephen Poulos, global chief engineer-GM hybrid system.

“I think the only thing we’re prepared to say is that you can expect volumes in excess of 100,000,” he says, declining to be more specific. “But this is not something we’re going to just put in a few variants.”

GM won’t say which vehicles will be first to get the new system. It is being shown in Geneva on the Saab 9-X concept, a new entry-level model for the Swedish brand based on the Opel Astra. Insiders say there already are production engineering programs under way involving a wide range of vehicles, from trucks to midsize sedans and small cars.

“I think the strength of the system is that we can use it just about where we choose to, not depending on the engine or the vehicle application or the market,” says spokesman Brian Corbett. “We’ll take it where we need it, where we think it’s best applied.”

Technical details are being kept close to the vest, but GM says the system is three times as powerful as the current BAS technology, thanks to its Li-ion batteries. It also provides more regenerative-braking capability and will improve fuel efficiency beyond the 10%-25% gain offered by the current system, depending on application.

Its design and packaging is similar to the current BAS, though the Li-ion batteries take up about 24% less space, have 40% less mass and provide 33% more power than the nickel-metal-hydride cells they replace.

“We took the same system and put it on steroids,” Poulos says.

The starter-generator, itself, is slightly larger than the current unit but still fits in the same space and employs the same accessory drive system. Poulos declines to provide specific power output numbers but says the unit provides three times the boost of the current 6.7-hp (5-kW) motor.

GM also doesn’t reveal the supplier for the Li-ion battery technology, nor does it disclose details as to the cells’ chemical compound. It would not say whether the chemistry is similar to what will be used for Li-ion batteries for its upcoming Chevrolet Volt or Saturn Vue plug-in hybrids due sometime after 2009.

The Wall Street Journal, citing GM sources, says Japan’s Hitachi Ltd. has landed the first contract to supply the batteries. GM is working with A123Systems Inc., Compact Power Inc. and Continental Automotive Systems on Li-ion batteries for the Volt and Saft Advanced Power Solutions LLC and Cobasys for Li-ion batteries for the Vue plug-in.

Using Li-ion in this application is an easier technical hurdle than in a vehicle such as the Volt, which requires batteries capable of delivering a more extended driving range, Poulos says.

“What we’re doing here, in some ways, I would call it a Li-ion-friendly application,” he says. “Lithium ion is a very high-power capability for its weight and mass, and that’s really a great fit for what we’re doing here.”

Despite the more expensive battery technology and bigger motor, the auto maker says it expects the cost of the system to be similar to today’s, where the Malibu and Aura, both based at $22,790, are among the lowest-priced hybrids offered in the U.S.

Higher volumes and better component integration will help keep costs down, Poulos says.

“Clearly we’re adding more capability, so we’re going after higher-power devices, but we’re also switching to motor technology that is less expensive,” he says.

“The method of integration of the components is something that reduces our cost as well,” Poulos adds. “The big enabler for us is really going to be the volume, though. If we can tread water on the cost of the components with a system that is that more capable, we’re doing well.”

How big an impact the new modular system will have on fuel economy will depend on the application, and whether the vehicle is optimized for fuel economy or performance, Poulos says.

“There’s a wide range of what you’ll see,” he says.

In a straight switch to the new system without additional engineering changes to the powertrain or vehicle, it could improve fuel economy 1-2 mpg (0.4-0.8 km/L), Poulos says.

But it appears likely GM will try to pair the more powerful hybrid system with downsized engines, which could boost the fuel economy gains significantly beyond a couple miles per gallon.

For instance, GM says a 2.4L turbocharged gasoline engine coupled to the second-generation BAS could mimic the torque curve of a 3.6L V-6 with variable valve technology, allowing the auto maker to employ a smaller engine without customers noticing a difference in performance.

GM is the second OE in the past few days to announce near-term plans to use Li-ion batteries in hybrids. Daimler AG said last week it would launch a hybrid version of its Mercedes S-Class flagship that would use Li-ion technology in 2009.

GM says it now has 1,600 engineers working on hybrid-vehicle development in 11 countries worldwide. It will launch its first hybrid for sale outside the U.S., the Buick LaCrosse EcoHybrid, in China later this year. It employs the first-generation BAS system.

GM says the ability to pair the BAS system with bigger engines, including V-8s, will not affect plans for its 2-Mode hybrid system offered on some fullsize SUVs. GM will offer the more premium-priced 2-Mode system in fullsize pickups later this year and launch its first front-drive application in the Saturn Vue in late-2008.

Although the two systems won’t share components, software will be similar in the future, Poulos says.

“That’s a huge driver for us,” he says. “It’s something most people don’t think about; they don’t recognize it. There will be a lot of commonality in what we’re doing in the future, which is different from what we have today. Today there are two different software sets completely.”

The auto maker says it is studying whether to re-name its second-generation hybrid system. “BAS-plus” reportedly is in the running.

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