“We are very, very committed to this,” said GM vice chairman and head of its Global Product Development Bob Lutz, with the pronoun referring to a strategy of mission-specific powertrains that the company is labeling “E-flex.” Under that moniker the corporation will be developing a variety of electric vehicles that deploy electric drives in concert with engines using gasoline, ethanol, diesel, bio-diesel, or hydrogen, or with fuel-cell power.
If GM is the company that “killed” the electric car, then with the E-flex initiative, it could be hailed as the company that is making the electric vehicle viable, affordable, useful, and at some point unremarkable—it will just be a part of the automotive landscape.
According to Lutz, GM had made a “bad decision” when the corporation didn’t pursue hybrid powertrain technology. Consequently, Toyota has taken the lead in public perception, something that he maintains GM is committed to gaining. “Being a technology laggard is not conducive to selling automobiles,” he says, emphasizing, that GM is going to work exceedingly hard “to become the purveyor of technology vehicles.”
Putting some sheet metal behind that statement is a concept vehicle, the Chevrolet Volt, a version of the E-flex architecture. According to Nick Zielinski, chief engineer on the project, who has involvement with both the Sequel and the Equinox fuel cell programs, “the heart of the system” is an electric motor that has 120-kW peak power, about 160 hp. It is used for driving the front wheels. There is a 1-liter, three-cylinder turbocharged engine that is E85 capable. The other key components are a lithium-ion battery pack and a 53-kW generator.
Fundamentally, the electric motor drives the wheels. They’re talking about a 0 to 60 mph time on the order of 8 to 8.5 seconds, and a top speed of 120 mph. Based on a fully charged battery, the Volt is said to be capable of running as a full electric vehicle from 40 to 45 miles. In other words, an owner could plug the Volt into a standard 110-volt outlet for six hours and have a fully charged battery. Beyond that is where the engine comes into play. It is not used for purposes of propulsion. Rather, it is used to run the generator (so it will operate at a steady speed in the range of 1,800 to 3,000 rpm), which then charges the battery pack. Based on a 12-gallon fuel tank, a Volt is said to be capable of a range of 640 miles. Remember that one of the knocks on the EV1—GM’s now-notorious electric vehicle—was that its range was limited to 60 to 90 miles, total, a fraction of the Volt’s range.
One reason that GM is confident about its ability to take a leading position with regard to this architecture is due to its experience with the EV1, as the power electronics and software capabilities developed for that vehicle are transferable to the E-flex.
According to Jon Lauckner, GM vice president, Global Program Management, the element that looms largest on the critical path to mass production is the battery. Elizabeth Lowery, GM vice president, Energy and Environment, notes that GM is part of the U.S. Advanced Battery Consortium (USABC; Ford and DaimlerChrysler are members, as well), which is dedicated to the development of electrochemical energy storage technologies, like lithium-ion batteries. In December 2006, USABC awarded A123Systems (Watertown, MA; www.a123systems.com) with a $15-million contract for the development of lithium ion technology; in January ’07, GM announced that Cobasys, a battery developer who is working in partnership with A123Systems, is one of two companies that GM has signed contracts with for the development of lithium-ion batteries (with the other being Johnson Controls-Saft Advanced Power Solutions; see sidebar: “GM Places Lithium-Ion Bets”).
There are several reasons why lithium-ion batteries are key. One is that compared with the nickel-metal hydride batteries used, for example, in the EV1, they have greater power density, and consequently reduces weight. The battery pack for a Volt weights approximately 400 lb. Another is that they can handle a multitude of change/discharge cycles, which is essential for automotive applications. (If your iPod gives out, that’s one thing. If your car doesn’t work, that’s another.) One of the issues with lithium-ion batteries that needs to be resolved—and this isn’t a need for invention as much as it is, in Zielinski’s words, “more solid engineering”—is dealing with temperature, as the batteries are particularly sensitive to high temperatures.
Says Lauckner—and realize that one of his responsibilities is the platform strategy of GM worldwide, so he’s more aligned with production rather than development—of the E-flex, “We’re committed to doing this fast.”—GSV