WARREN, Michigan – The second-generation Chevrolet Volt will have an all-new extended-range electric powertrain, including a direct-injection 1.5-liter naturally aspirated, high-compression four-cylinder engine that runs on regular unleaded, when it goes on sale next year. General Motors Voltec engineers say the new powertrain in the 2016 Chevy Volt will provide up to 12 percent better efficiency, including the car’s all-electric power range, in a variety of situations.
Voltec customers “want more range, more fuel efficiency from the engine, and more power,” says transmission and electrification executive director Larry Nitz. And they want the transitions to be smooth. “They love that liquid feel,” he says. (The Chevy Volt drivetrain name and a plug used for shipping the engine from its plant to final assembly in Hamtramck, Michigan, will be the only carry-overs.)
There will be no consternation over whether the gas four will occasionally drive the front wheels of the 2016 Chevy Volt. It will. Chevy says owners are more concerned about getting better fuel mileage when the battery charge is depleted and the range-extender becomes necessary, no matter how it’s achieved.
A new two-motor electric power configuration uses three small barrels as internal connectors — the integrated traction-power inverter module — between the transmission and motors to eliminate the bulky, potentially intimidating external high-voltage orange cables found under the hood of the current model. The 52mm stack first motor and 35mm stack second motor are designed to smooth the transitions and torque band, not unlike a twin-scroll turbocharger.
The new aluminum-block 1.5-liter four, which replaces the current Volt’s iron-block 1.4-liter four, has a compression ratio of 12.5:1 (versus 10.5:1 for the same engine used in conventional applications) and weighs about 100 pounds less than the old engine.
While the new Volt’s battery pack looks the same from the outside, it’s all-new inside. It contains 192 cells, down from 288, and has 20 percent more overall storage capacity and an active thermal system. The battery pack’s center of gravity has been lowered about a half-inch and the system weighs nearly 30 pounds less than before, for a total powertrain weight reduction of nearly 130 pounds.
That weight savings will not be offset by more equipment or a heavier body structure, Chevrolet says, so the new car should weigh no more than 3,660 pounds, depending on whether the body also is lighter. But the new car’s range and fuel mileage estimates remain a mystery outside of GM’s deepest bowels, for now. Voltec engineers would not disclose the power of the new battery pack. When GM is ready, the power and efficiency figures will be trumpeted with the sort of exclamation usually reserved for power and torque figures for a muscle car.
“It’s more” than the current Chevy Volt’s 17.1 kilowatt-hours, says battery systems director Bill Wallace, “but I can’t say how much.”
These were the first official details of the Mark II Chevrolet Volt, presented by senior engineers at the GM transmission factory that builds six-speed automatics for most of its high-feature transverse-mounted V-6 models. The plant has expanded about 75,000 square feet to accommodate assembly of the new Volt’s transmission. GM will move production of the 1.5-liter four, which is part of a new engine family, to Flint, Michigan, from Mexico early in the new Volt’s life cycle.
Besides better electric range and higher gasoline fuel mileage, the new Chevy Volt will cost GM less to build when at full production, and a lower sticker price is expected. The 2015 Chevrolet has a pure-electric range of about 35-40 miles on a full charge and is EPA-rated 98 mpge/37 mpg. The list price is $35,170 before tax incentives.
The 2016 Chevy Volt will be unveiled at the North American International Auto Show in Detroit in January. Production of the new transmission is expected to begin late in the first quarter of next year, which means the 2016 Volt should be ready for retail sale about mid-2015.
Chevy has sold about 69,000 Volts since the ’11 model went on sale in very late 2010. It says that, based on data provided by the majority of owners via OnStar, only 45 percent of them charge off a 220-volt home system, though the owners charge on average 1.4 times per day, which means many recharge at work or in public spaces. Owners report they go 80 percent of their mileage on pure electric. The engineers’ goal in redesigning the Voltec powertrain after just five years on the market is to boost that number to 90 percent.