GM vows Volt WILL be built in 2010
By Frank Markus
I just returned from another fairly in-depth GM press event updating us on the progress of its plug-in hybr -- sorry, we're not supposed to use the "H" word -- "Extended-Range Electric Vehicle (E-REV)," the Chevy Volt. An entourage of international journalists were given tours of GM's battery-development lab, a virtual-reality Visualization Center, the E-Flex Studio, and the Aerodynamics lab in order to drive home the point that this is not a science project or a micro-volume technology learning exercise, but a production program -- albeit a greatly accelerated one.
Today we basked in the heat generated by equipment that was performing accelerated-life-cycle testing on a pair of lithium-ion battery packs from potential supplier CPI/LG Chemical. The tests charge the 16kW-hr battery packs to their maximum state of charge (estimated at around 80 percent), then they're subjected to discharge at a rate (peaking at 43kW) that simulates a typical federal city fuel economy cycle, followed by the harder-charging US-06 cycle, the highway cycle, and another city cycle. This regimen drops the battery to roughly 30 percent of its capacity in 40 miles, after which the rig simulates range-extending operation with mild charge/discharge cycling from the onboard engine/generator, before "parking it" and recharging (at 25 kW) back up to 80 percent.
Then we peeked inside an environmental cell where batteries supplied by competing supplier A123/Continental were undergoing hot- (176 degrees F) and cold- (-22 degrees F) climate testing. Such testing helps develop the battery pack's thermal management system (they're liquid cooled), and the hot tests accelerate the life-cycle testing. Other labs have subjected the pack to 10 years of in-car shock and vibration. Also on hand in the lab was an EV-1's lead-acid battery pack casing alongside the Volt's. Both contained 16kW-hrs of energy, but the vintage lead-acid pack weighed three times as much and was over twice as large. As yet, GM is not discussing the specific battery chemistry, except to say that it is NOT anything like that used in laptop batteries (and the Tesla).
On a hoist in the battery lab was a 2005 Malibu that has served for six months as an engineering development vehicle (the first of three prototype stages), employing a NiMH battery pack from a 2-mode in place of the li-ion pack but serving to test the many other control systems. (Judging by the wheel-flare extensions on the Malibu, we can assume that the Volt's track will be wider than a 2005 Malibu's.) These early cars will be upgraded to level-2 mule status with installation of the proper battery packs by the end of April. Soft-tooled prototypes that look like Volts will be the final stage. Engineering development teams have been working two six-day shifts per week, at GM's Milford Proving Ground to meet the Volt's aggressive development schedule.
The visualization center involves a huge wide glass screen with twin rear-projection images that, when viewed wearing special electronic 3-D glasses allow you to see all parts of a car as modeled in the computer, from any angle. It's used to check special relationships that could cause problems in assembly (and even to model entire assembly lines), trouble-shoot potential quality problems, etc. without the need for costly prototype parts. An entire car can be assembled in the system from math data in about two weeks. It's said to have slashed the number of physical prototypes required to be built (at roughly $1 million each) by 60 percent.
What we were shown of the new Global Compact architecture indicates this moon-shot tech can be packaged in traditional architecture -- a must to ensure it can be produced economically alongside high-volume mainstream products. A tall center tunnel (about the size of a Cadillac CTS's) houses the battery pack. The small mainstream four-cylinder "Family Zero" engine mounts in its usual spot, and the generator and motor are co-located in a housing that looks like a big transaxle (though there is still NO link between the engine and front wheels).
The brake system is an electro-hydraulic by-wire setup like the Prius's, allowing a computer to interpret the driver's deceleration needs and apportion braking among regeneration and friction brakes as it sees fit. Naturally, the steering assist is electric, but the motor's input is via a secondary pinion on the steering rack. That's different from current GM designs and more like the VW-Audi setups (whose steering feel is superior), but it will likely be rolled out across GM's lineup. The evaporative emissions system is fortified to contain fumes that may accumulate over days or weeks of vehicle operation without engine ignition to burn them off. The cooling module is also far more complex, with the battery cooling unit out in front, then the A/C condenser, a layer shared by the power-electronics and driveline oil coolers, and then the engine's radiator backed by fans powered by ultra-quiet, high-efficiency brushless motors. The front strut suspension is completely typical, the rear uses trailing arms integral with a transverse torsional member. The Volt will get unique, weight-optimized trailing-arm castings (which will likely be shared with a high-performance coupe variant of the architecture), but otherwise the underpinnings look conventional.
During the final Q&A session, we learned a bit more about the forthcoming Volt. No diesel, fuel-cell, or full battery-electric variants have been approved as of yet. The first two range-extenders will be gasoline PZEV and E85 compatible ULEV engines, with a production launch date of November 2010. That's ambitious, and officials admit the launch will be gradual. Not all states and certainly not all dealers will get the Volt immediately, and the initial lot may well be for lease only. The Volt is not expected to generate a profit right out of the chute, either, but it should earn GM a significant return on investment in terms of Green cred and technology leadership -- especially if, as they promise, the 8.5-seconds-to-60 Volt turns out to be a good-looking, no-compromises, fun-to-drive family sedan. Here's hoping.
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