The Volt's been around for about a year now and still no one that I ran into during my week with this high-profile vehicle seemed to understand how it works.
"Don't you have to plug it up?" "Wait, so it's a hybrid?" "I can't drive a car that only goes 40 miles!" These quotes come from automotive enthusiasts, people who I talk cars with regularly. Clearly Chevrolet/GM has some issues with its message.
The confusion probably lies in Chevrolet's unwillingness to call the Volt what it is: a plug-in hybrid. Instead, the automaker prefers the term range-extended electric vehicle (RE-EV). Granted, neither designation is technically wrong, but when people hear the term "hybrid" they immediately understand that there's a gasoline filler somewhere on the vehicle. Instead, every conversation about the Volt has to begin with a long explanation about why you'd put gas into an EV.
It's an EV that's also a hybrid... but not really. Wait, what?
At this point, you're either shaking your head in agreement or scratching your head in confusion, so let's get into the nuts and bolts of what's happening underneath the Volt's sheet metal.
Turning the Volt's front wheels is a 111kW electric engine. In regular, car guy/gal terms, that engine outputs 149 horsepower and 273 pound-feet of torque. Since this is an electric motor that we're talking about, all of that torque is available from zero rpm, so the Volt actually has pretty good get-up-and-go when floored in its Sport mode, but we'll get back to that.
Electricity is first provided by a 16kWh T-shaped lithium ion battery pack that runs the spine of the vehicle, wrapping behind the rear seats. Find a charging station (or have one installed at your home) and plug its 240-volt power into the port on the front driver's-side fender, and the Volt will charge the battery from empty to full in about 4 hours. If you're using a conventional 110V and the included charging cable, you'll see that charging time jump to about 8 to 10 hours. The Volt can be programmed to charge immediately upon plugging in or to wait until off-peak utility pricing to start juicing the battery pack. Chevrolet recommends that you leave the Volt plugged in even when you're not charging to allow the battery conditioning system to keep the lithium ion battery pack at the optimal temperature for retaining its charge.
Once fully charged, the Volt will run for about 35 miles, depending on your driving style, before its battery is depleted. Here's where things get interesting. A 1.4-liter gasoline engine and its 9.3-gallon fuel tank spring to life. However, unlike in, say, the plug-in Prius, the Volt's gasoline engine doesn't take over turning the wheels. Instead, the engine acts as a generator (or range extender), jiggling enough electrons to keep the electric motor turning and to trickle-charge the lithium-ion battery pack. With the range extender running, total range jumps up to about 380 miles.
This is why GM/Chevrolet hesitates to call the Volt a hybrid. Ideally, the gasoline engine never has a physical connection to the wheels: even when it's spinning, the electric motor is running the show. That may seem inefficient, counterintuitive even. However, with this setup the gasoline engine's rpm can be set independently of the vehicle's road speed, theoretically allowing the Volt to get optimum efficiency out of every drop of fuel. Because the bulk of the range extender's energy is going into turning the wheels, there isn't a ton of energy left over to recharge the battery with (although a bit of trickle charging does occur). As a result, the Volt's gasoline engine will never be able fully recharge its own battery the way a conventional hybrid can.
Your mileage has never varied more
The EPA further confuses things by supplying a hodgepodge of fuel economy estimates and equivalents that you, the consumer, must make sense of. Under electric power, the Volt is rated at 94 miles per gallon equivalent (the Chevy's own trip computer claims an eye-roll-inducing 250+ mpge). Under gasoline power, the Volt drops down to 37 mpg. Combine the two and the EPA guesses that you'll average 60 mpg. The catch is that you won't.
Your fuel economy will vary wildly depending not only on your driving habits, but also on your ability to keep the battery pack charged with regular plug-ins. For example, if your daily commute is within the Volt's 35 or so miles of electric range, it's possible to go weeks without using a single gallon of petrol. If you have a 60-or-so-mile round trip, and make use of chargers where you work and where you shop, it's also possible to keep the trip computer above the 100 mpg mark.
However, I'm an apartment dweller. My building doesn't have a charging station or outlets in the parking garage. During my week with the Volt, I was only able to charge the vehicle fully twice (during visits to a movie theater with ChargePoint stations), with an hour or so here and there at various restaurants and shopping centers around town. I also made two long-distance trips from San Francisco to visit friends in and around San Jose (about 100 miles round-trip for each visit). At the end of the week, my trip computer was reading around 52 mpg. That's about on par with what I achieved during my week with the standard Toyota Prius. While it was nice to be able to exceed the Volt's electric-only range and go days without recharging, my week represents a bit of a worst-case scenario for the Volt. Potential owners should definitely have a charger installed in their home to maximize the fuel economy.
One of the most flexible power trains on the road today
For as complex as the power train and fuel economics are, the driving experience of the Volt is surprisingly simple. You get in, hit the start button, shift gears, and drive. The electric power train is amazingly silent when the range extender isn't running, and the power delivery is linear and predictable. The EV's single-speed transmission means that there's also no jerky shifting, no interruption of power as you accelerate, and no waiting for the vehicle to downshift to pass. You push the pedal more and the Volt just thrusts forward. This isn't my first trip around the block in an electric car, but that sort of effortless torque is something that I'm still not used to.
Past the 35-mile mark, the range extender's rumble is both annoyingly audible and tangible, but that annoyance is probably artificially heightened by the stark contrast with the smooth silence of EV mode. Because the gasoline engine's rpm never changes, the engine does tend to drone on a bit, but that's easily drowned out by the audio system and regular road and wind noise. The pros greatly outweigh the cons here and the Volt has been blessed with what is arguably one of the most flexible power trains on the road today.
The Volt features three different drive modes, selectable by a button on the dashboard. Normal mode is the default and Volt's most economical mode. Sport increases throttle responsiveness and power delivery at the expense of a bit of efficiency. The oddly named Mountain mode forces the range extender to power on, even if the battery isn't depleted. This mode is designed to sustain the battery's charge through excessively hilly terrain, but some owners have speculated that by using mountain mode for long cruises above 50 mph (the cap of the electric motor's optimum efficiency) and saving the 35 miles of battery power for the low-speed city segments at the beginning and end of a long trip, the driver can get closer to eking maximum efficiency out of the Volt.
The Volt's handling is inoffensive, its battery pack both increasing the vehicle's weight and lowering the center of gravity, which allows the dampers and springs to be soft enough to soak up bumps without generating terrifying levels of body roll in the bends. The steering is light and responsive enough to make the Volt feel effortless at the low city speeds that it's most comfortable at without feeling ponderous and twitchy at the highway speeds that it's capable of.
If the Volt driving experience has an Achilles' heel, it's the brakes. The balance between the regenerative braking system and the Volt's friction brakes is both out of whack and inconsistent. Applying the same amount of pedal pressure for two subsequent stops would produce noticeably different deceleration rates. This made it difficult to judge stopping distances, which led to more than a few "Holy crap" emergency stops, jostling the vehicle and its passengers. At lower speeds, the brakes were excessively grabby with a digital on/off feel that was difficult to modulate, making the simple act of parallel parking a herky-jerky affair.