Powering up GM’s Volt

  • 09-Jan-2009 02:47 EST
Alex Cattelan - GM Volt.JPG
Alex Cattelan works within a pack of “Alpha dogs” and “type-A-squared” personalities on GM’s fast-track Volt program.

“At this stage of the program, there is literally nothing that’s making me think we’re not going to make it,” reported Alex Cattelan, during lunch recently at a restaurant near GM’s Warren, MI, Tech Center. “There are some technology challenges, but not a single one is keeping me awake at night.”

As Powertrain Assistant Chief Engineer on the 2011 Chevrolet Volt, Cattelan may not be losing much sleep, but she’s finding it more difficult to sneak out of the Tech Center for a bite to eat. She’s charged with successfully delivering the car’s extended-range electric vehicle (E-REV) propulsion system featuring a 1.4-L four-cylinder combustion engine, lithium-ion battery pack, and their attendant subsystems on time for the November 2010 production launch.

Volt is the most scrutinized and anticipated passenger vehicle powertrain in decades. And the stakes for GM are as high as the risks of launching an unproven new battery technology. To say Cattelan and her team may be working under the auto industry’s biggest microscope is a vast understatement. But she remains cool, humorous, and optimistic.

"My job is keeping focused on the long-range concerns while the team remains focused on the day-to-day stuff,” she noted. “My greatest challenge is to balance those two responsibilities.”

Volt’s midprogram development milestones are hitting with regular cadence. Last month’s top-level review covered software and calibration—“big measurables for us,” Cattelan noted. While she admits to feeling overworked after long, long days, the word “excited” best describes her view of the job.

“Volt is an awesome project to be working on from a couple perspectives,” she explained. “One is the technology itself—we’re breaking new ground with the E-REV [extended-range electric vehicle] technology. And the challenge of meeting customer needs with it, while delivering the absolute best efficiency for the best price, is fantastic.”

Then there’s Cattelan’s passion for alternative vehicle propulsion, the focus of most of her 13 years at GM engineering.

“To culminate in this application and recognize that society and GM ‘get it’—and knowing Volt is not just a niche product but a game-changer—that’s doubly exciting for me.”

Agents of change within GM

A native of Canada and an enthusiastic Ducati-riding motorcyclist, Cattelan likens the Volt program’s substantial risks to rafting on a daunting river, with little knowledge of the path or turbulence—only knowing exactly when it will reach its destination.

“Dealing with so many unknowns is very hard to do in an engineering organization because by nature we’re conservative—and especially working for an OEM that’s been bitten by mistakes in the past,” she said. “Engineers hate to say this, but we work from the gut and emotion just as much as anybody else.”

However, as what Cattelan calls “the fear of the unknown and risks” has steadily lifted, the powertrain team has become increasingly bold in finding solutions to technical challenges. The team’s total staffing has stabilized, and Cattelan praises the effectiveness of the mostly hand-picked group she laughingly dubs “type-A-squared, Alpha-dog” personalities.

They’re also serving as agents of change within GM’s vehicle engineering organization.

“We’ve taken processes that we’ve known in developing conventional vehicles and started building upon them,” Cattelan noted. “There are a lot of system requirements at GM in the way we document objectives and processes. We’re taking them and either adding to them or rewriting them as necessary. Or, we throw them away,” she explained.

“Some of the team’s choices may have been questioned at first, but I think Volt will become the model for future vehicle programs at GM. We’ll definitely have an influence on rewriting GM’s ‘book of knowledge’ on how to do programs,” she asserted. “It’s a paradigm shift in how we think about program execution.”

Cattelan notes that on her previous assignment (the Saturn Aura hybrid), the hybrid-powertrain team was segregated as an “incubator” away from the conventional Aura’s engineering team. While GM fed many lessons learned in that program back into mainstream vehicle programs, there is no longer a need to separate hybrid from non-hybrid engineering functions on a given vehicle program.

“I have the feeling over time there will be more and more integration of hybrid and EV systems into mainstream programs,” she said. Of Volt, she said, GM will end up mainstreaming the program’s processes so the engineering community at large within GM will understand their effectiveness.

Backup plans

As one example of the new organizational processes being wrought by Volt, Cattelan said those that used to integrate powertrain into the total vehicle have changed “dramatically.” For starters, the Volt powertrain and vehicle-integration teams work as a single unit sharing the same physical area at Warren.

“Sometimes it gets pretty smelly with pizza boxes piled high and everybody working long hours,” she chuckled. “But I’ve got to be able to get into vehicles very regularly with my vehicle-integration counterparts, and with [Volt Chief Engineer] Andrew Farah, and go for drives to see how this thing works.

It’s true that the Volt’s lithium-ion battery pack, developed by LG Chem’s Compact Power group and to be manufactured in the U.S. by GM, is the program’s technology linchpin—and its great hope. The development team is working 24/7 to accelerate battery durability and reliability testing.

The challenge, Cattelan noted, is accurately predicting the 10-year, 150,000-mi (241,000- km) durability bogey within a two-year test window.

“In some cases, I’ve had backup plans backing up my backup plans because if anything goes wrong, I’ve gotta know that I still have tools to develop my product while we fix whatever needs fixing,” she admitted. Rising confidence in the Li-ion chemistry and the general robustness of the packs under severe test have thus far kept the backup plans on the shelf.

Beyond the new battery are a host of technology opportunities being pioneered by Cattelan’s team. They include optimizing an off-the-shelf combustion engine for the series-hybrid type application and leading to development of a new generation of purpose-built power units for the next-generation E-REVs, Cattelan indicated.

New maintenance and service strategies also are in the works, including those to preserve a tankful of fresh gasoline that may be unused for protracted periods due to Volt’s 40-mi (64.3-km) electric-only range. Conversely, how to achieve cold-start emission levels with an ICE that is called upon only infrequently is another issue for which Alex Cattelan’s team has interesting solutions prepared.

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