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Tuesday, 12 February 2013

2014 Chevrolet Spark EV Prototype Quick Drive

2014 Chevrolet Spark EV Prototype Quick Drive Chris Twarog, energy and battery integration engineer for General Motors, hit the nail on the head as he talked me through a 2014 Chevrolet Spark EV cutaway demo unit. I'll paraphrase his noteworthy remark: While the plain-Jane, 84-horsepower, 1.2-liter Spark (with rear drum brakes and optional four-speed automatic) isn't the model of a technically advanced car, its battery-electric variant is -- in spades.

2014 Chevrolet Spark EV Prototype Quick Drive

2014 Chevrolet Spark EV Prototype Quick Drive

 2014 Chevrolet Spark EV Prototype Quick Drive

2014 Chevrolet Spark EV Prototype Quick Drive















2014 Chevrolet Spark EV Prototype Quick Drive

You read it right. The A-segment hatchback that moonlights as an Autobot benefits from a wide array of efficiency enhancing technologies during its EV transformation, despite looking more or less the same as its exhaust-emitting sibling. But electrification is the major difference between the Spark and the Spark EV, so let's get the main components out of the way. Down in front, between the drive wheels, lies a permanent-magnet electric motor. At the core level, it incorporates teachings from the Volt and other eAssist and Two-Mode hybrid efforts. Offering motive force through the single-speed reduction transaxle, the motor is preliminarily rated for more than 134 horsepower and around 400 lb-ft of torque. (The latter number will surely be a fun talking point.) E-motor torque and power profiles can be designed for one or the other depending on application - the Spark EV is definitely after torque. Twarog assures the torque curve is very flat, meaning the motor is highly tractable and suitable for a wide range of driving behaviors. For starters, the Spark EV has no trouble getting out of the hole, and the manufacturer-quoted 0-60 mph time of fewer than 8 seconds is a huge leap from the 11.3 seconds we extracted from a Spark gasser with the five-speed manual. We'll likely see the official e-motor outputs (along with a ton of other unreleased information) at the L.A. auto show, where the car will formally debut.
Also lacking final specification is the energy storage system's stated capacity. The ESS is a liquid-cooled lithium-ion battery supplied by A123 Systems, and it's been conditioned to handle multiple high-amperage, high-voltage DC charges on a daily basis. The stored energy figure is said to exceed 20 kW-hrs -- in comparison, the 2013 Volt is rated at 16.5. Considering the dearth of publicly accessible high-power chargers, it'll be fascinating to see how this part of the overall vehicle electrification saga unfolds, and there'll be no shortage of watchdogs monitoring battery health, charge costs, and electrical grid impact if and when widespread DC charging proliferates. The battery will carry an 8-year/100,000-mile warranty. Official range has yet to be certified, but elusive signs picked up from GM staff point to it at least bettering the Nissan Leaf's EPA-quantified 73 miles.
The fast-charge time is the typical (if you've been following EVs) 80 percent in about 20 minutes, assuming the battery's state of charge is pretty low. Larry Nitz, GM executive director of vehicle electrification engineering, gives a more meaningful estimate: a half-charge in 10 minutes. The plug responsible for DC charging is an amendment to the SAE J1772 protocol, so the combination receptacle can accommodate the Level 1 and Level 2 plug and the bigger fast-charging connection. Charge time at 240 volts is under 7 hours; 120-volt household-outlet charging is well into double-digit hours. The Spark EV's charge port is located on the driver's front fender, just like the Volt. Powertrain can't pick up the efficiency slack alone, so the Spark EV has a shrouded upper front grille, lower grille shutters that open and close depending on vehicle speed and load, and a smoothed underbody. We're told leakage around the cracks already does a good job cooling what needs to be cooled.
If the OEM-claimed weight distribution - 50/50 percent front/rear - is confirmed on our scales, the Spark EV must be entertaining to dial in. The 93.5-inch wheelbase is pretty short, and while our previous Spark tester sussed out a 62/38 percent split, going to 50/50 would lower the polar moment of inertia and hypothetically make for a more enjoyable enthusiast driving experience (if future customers care for such details). The battery system contributes 560 pounds to the back end, so a heartier torsion beam was installed. And to further compensate for changes in load, weight, and weight distribution, the hatchback was balanced with rear brake rotors and calipers, stiffer springs, revised shocks, and a staggered tire fitment. A conventional Spark wears a square 185/55-15 setup, but the Spark EV prototype driven had Bridgestone Ecopia EP150s sized 185/55-15 up front and 195/55-15 aft.
A brief spurt around the block reveals a playful demeanor, and because the seating position is expectedly high due to the Spark EV's tall profile, you feel like you're sitting over the car's center of gravity. The steering is accurate on-center at low speeds, but final judgment is reserved until a more comprehensive drive is performed. Torque steer manifests in a relatively smooth, straight line, but there's apparent counteracting damping in place (presumably software-based) as the steering wheel does slow heaves, not twitches. I'm under the impression the electrically assisted steering is still under development.
Volt owners, who have been identified as probable Spark EV early adopters, will recognize certain elements within the cabin. The gauge cluster software is shared, but the smaller Chevy spits out a power number in kilowatts when moving and when the regenerative brakes are working, plus a "confidence meter." Like our 2013 Car of the Year Tesla Model S, a minimum, maximum, and estimated range is shown and adjusts in real-time on the left side of the gauge cluster, determined by gleaning data from the current expedition and past drives. Coincidentally, my car's estimated range read 73 miles. The Spark EV's OnStar-connected (3-year complimentary subscription) center display will also be familiar - color scheme, screen selection, etc. - but have a tailored Spark EV WayPoint program as part of the RemoteLink app. Interior measurements aren't predicted to deviate wildly from the standard Spark. If you thought the Volt's deployment schedule was long, get ready to wait longer for the Spark EV. Sales will commence in select parts of California in summer 2013, but the L.A. show should yield pricing and more on the rollout strategy. (Particulars like home-charger installation assistance are still being decided.) Additional locations will be announced at a later date.
Understandably, GM was asked if the Spark EV was born to satisfy California's zero-emissions mandate. Is it nothing more than a "compliance" vehicle? The answer was no, and the automaker pointed out that customers will be able to purchase them outright. Now recall the Spark EV is the company's first battery-electric vehicle since the immortalized EV1. It's an entirely different game now.