|The new Chevy Volt has a decidedly more sculpted look than its predecessor. Click to enlarge.|
Chevrolet unveiled the second-generation Volt extended range EV at the North American International Auto Show. With a sportier design and an entirely new drive system (earlier post), the 2016 Volt electric car features a higher capacity battery pack and 50 miles of all-electric range (MY 2015 = 38 miles); greater efficiency; and stronger acceleration. GM estimates fuel economy to be 41 mpg combined (MY 2015 = 37 mpg) with 102 mpge (MY 2015 = 98 mpge). The 2016 Volt goes on sale in the second half of 2015.
The new propulsion system will offer a General Motors’-estimated total driving range of some 420 miles and with regular charging, owners are expected to travel more than 1,000 miles on average between gas fill-ups. Currently, drivers of the first-generation Volt are averaging more than 900 miles between fill-ups. Put another way, drivers of the first gen Volt drive electric about 80% of the time, said Andrew Farah, chief vehicle engineer for both generations of the Volt. Farah suggested that the new Volt may be able to boost that figure to nearly 90% in moderate climates.
Volt owners complete more than 80 percent of their trips without using a drop of gasoline and they tell us they love the electric driving experience. Putting that experience at the center of the new Voltec system’s development helped us improve range, while also making the new Volt more fun to drive. We established a precedent when the original Voltec propulsion system debuted and this newest iteration sets the EV technology bar even higher.—Andrew Farah
New 111 kW two-motor drive unit is up to 12 percent more efficient and 100 pounds lighter (45 kg) than the first-generation drive unit.
Two-motor design enables 19 percent stronger zero-to-30 mph acceleration.
Battery capacity has increased to 18.4 kWh using 192 cells (96 fewer than current generation) with weight reduced by more than 20 pounds. It also has a more powerful discharge rate of 120 kW vs the previous 110 kW, which contributes to greater performance.
Regen on Demand feature enables driver control of energy regeneration via a convenient paddle on the back of the steering wheel
New 1.5L range extender, designed to use regular unleaded fuel, offers a combined GM-estimated fuel efficiency of 41 mpg (EPA estimate pending).
Stronger body structure and quieter ride.
New braking system with improved capability and blended Regen feel.
New, five-passenger seating with available rear heated seats.
Location-based charging capability.
120V portable cord set has a simpler, compact design with more convenient storage location.
Available illuminated charge port.
The Voltec propulsion system includes the battery, drive unit, range-extending engine and power electronics.
The 2016 Volt will use an 18.4 kWh battery system (MY 2015 = 17.1 kWh) featuring a tweaked NMC/LMO chemistry developed in partnership with LG; the cells increase storage capacity by 20% volumetrically when compared to the original cell. While overall system storage capacity has increased, the number of cells has decreased from 288 to 192. The battery pack retains the familiar T-shape of the first-generation Volt, but with revised dimensions. The new cells are layered in pairs in each cell group rather than the previous three-layer configuration. The cells are also positioned lower in the pack for an improved (lower) center of gravity and the overall mass of the pack is 21 pounds (9.8 kg) lighter.
The new pack also retains the active thermal management system, but features a simpler controls architecture.
Like the battery system, the next-generation Volt’s two-motor drive unit delivers increased efficiency and performance along with reduced noise and vibration. The drive unit operates up to 12% more efficiently and weighs 100 pounds (45 kg) less than the current system. With 149 hp (111 kW) of motoring power (the same as in Gen 1) and 45 kW generating power, the system delivers 294 lb-ft (399 N·m) of torque, up from 273 lb-ft.
Unlike the first generation Volt, which assigned different roles to its two-different sized motors, the second-generation drive unit uses two motors of the same size which operate together in more driving scenarios, in both EV and extended-range operation. The motors can be used individually or in tandem, effectively delivering two torque paths to make the most of performance and efficiency.
The new Volt can operate on a primary motor at lower speeds such as city driving, split power between the motors at moderate speeds or fully engage both motors for higher-load/higher-speed driving, such as passing on the highway.
As a result, while the four driving modes available to the user—Normal, Sport, Mountain and Hold—are the same across generations, the power flow is quite different. GM will be detailing the new power flow in a coming SAE paper, Farah said.
The ability to use both motors helps deliver a 19% improvement in electric acceleration from zero to 30 mph (2.6 seconds) and a 7% improvement from zero to 60 mph (8.4 seconds). GM engineers designed the Voltec electric motors to use significantly less rare earth materials. One motor uses no rare earth-type magnets.
The Traction Power Inverter Module (TPIM), which manages power flow between the battery and the electric drive motors, has been built into the drive unit to reduce mass, and size, which contributes to greater efficiency.
The new high-efficiency 1.5L naturally aspirated four-cylinder range extender engine is rated at 101 horsepower (75 kW). It features direct injection, a high-compression ratio of 12.5:1, cooled exhaust gas recirculation, wide authority cam phasers and a variable-displacement oil pump to make the most of performance and efficiency. It also features a lightweight aluminum block, compared to the current engine’s iron block.
The new range extender also runs on less-expensive regular unleaded fuel, unlike the Gen 1, which uses premium.
Using real-world experiences of today’s Volt owners, Chevrolet made the charging system in the next-generation Volt more convenient for customers to recharge the battery and to check the charge status. The new and enhanced features include:
GPS location-based charging. Owners will now be able to set their charging preferences exclusively for “home” charging and the vehicle will automatically adjust to that setting when it is at “home” based on GPS data, said Farah, the chief engineer.
This will allow owners to pre-set their 120V charging level (eight amps or 12 amps) and whether they wish to charge immediately, set a departure time for each day of the week, or set a departure time and a utility rate schedule to charge only at off-peak rates. These setting will only have to be programmed once and the Volt will default to them when the vehicle return to its home location.
New, more intuitive charge status indicators. The next-generation Volt makes it easier for owners to confirm their Volt is charging and gauge charge status. The new status system features a specially designed tone that indicates when charging has begun, with additional tones for delayed charging. It will even indicate if the charge port door was left open after unplugging but before entering the vehicle.
With a glance through the windshield, an updated charge status indicator light on the on the top of the instrument panel will show the approximate charge level through a series of flashes. An available illuminated charge port makes it easier to plug in after dark.
Portable cord set enhancements. A new 120V portable cord set has a simpler, compact design with more convenient storage location. The storage bin for the cord is now located on the left side of the Volt’s rear cargo area, above the load floor, for improved accessibility.
Safety and driver assistance systems. The new Chevrolet Volt offers new standard and available safety features that work with an all-new body structure to provide crash-avoidance and passenger protection capability. Highlights include:
Standard rear-vision camera.
Ten standard air bags, including driver and front-passenger knee air bags.
Available active safety features offering lane keep assist with lane departure warning, side blind zone alert with lane change alert, rear cross traffic alert, forward collision alert with following distance indicator, front automatic braking, and advanced park assist with front and rear park assist (semi-automatic parallel parking).
Expanded use of high-strength steel throughout the body structure improves strength and reduces weight.
More effective structural load paths in the frame, along with reinforced rocker panel structures and side structure reinforcements.
The new, active safety technologies and structural enhancements build on the Volt’s legacy of top safety performance, which include a 5-Star overall New Car Assessment Program rating from the National Highway Traffic Safety Administration for the current model.
Design and aerodynamics. Designers had to work with aerodynamic boundaries when crafting the Volt’s new form. One of the key areas where designers paid close attention was the aerodynamic performance of the Volt’s rear end. While a longer, tapered tail generally means better aero performance, it can hamper cargo room and look slightly out of proportion. However, the teams devised a rear end design for the 2016 Volt that incorporates aero-optimized side panels that flow smoothly into a more rounded rear section with pushed-out corners.
With electric vehicles, such as the Volt, aerodynamics play a more important role in efficiency than conventional vehicles. The knowledge we took from the first-generation Volt and other recent Chevrolet cars allowed us greater leverage to work with a more flowing design.—Nina Tortosa, aerodynamics engineer
Additional aerodynamic enhancements and new features include:
A new shutter system behind the grille to manage airflow into the engine compartment, which enabled the designers’ desire for a shorter front overhang and wider grille opening – attributes that would typically add to aerodynamic drag. In typical highway driving when less airflow is required for cooling, the shutters close to block air from entering the engine compartment, reducing drag and enhancing efficiency.
Sculpted tail lamps were shaped in GM’s wind tunnel to minimize airflow disruption that adds drag, based on lessons engineers learned with the Chevrolet Impala.
Interior. The Volt retains its signature dual digital color displays, with larger, eight-inch-diagonal screens—one in front of the driver for the instrument cluster and driver information center, and the other in the center of the instrument panel that controls the Chevrolet MyLink system and other apps.
The center stack is simple and intuitive, reflecting “less of an attempt to be futuristic,” Farah commented. It projects approximately one-third fewer icons, and offering separate climate control knobs. Buttons below the center display offer a clear and convenient operation. Most of the features can be controlled with a single rotary knob and four buttons.
Returning technologies and new amenities include:
OnStar 4G LTE with three years of service and standard built-in Wi-Fi hotspot (with a three-month/three gigabyte data trial)
Siri Eyes Free and text message alerts (requires compatible iPhone)
Bluetooth phone connectivity
Automatic climate control
Keyless access and ignition
Auxiliary 12-volt power outlets and dual USB ports
Leather-wrapped steering wheel
Premium cloth seats and available leather-appointed seating
Available Navigation and Bose premium audio
Heated driver and front passenger cloth seats
Manufacturing GM is investing $435 million in the production of the next-generation Chevrolet Volt at the Detroit-Hamtramck Assembly Plant and at the Brownstown, (Mich.) Battery Assembly Plant, where its lithium-ion battery pack is produced.
The new drive unit will be manufactured at GM’s Powertrain plant in Warren, Mich., and the 1.5L engine will be manufactured at GM’s Toluca, Mexico engine plant for the first year of production, then shift to the Flint, Mich. engine plant.
The next-generation Volt will feature approximately 70% US and Canadian components within its first year of production, a nearly 20-percent increase from the first generation.