The Chevrolet Volt is an electric car with a gasoline range extender generator that was produced by General Motors and marketed by Chevrolet. The first generation of the Chevrolet Volt, it was manufactured at the Detroit facility until it was succeeded by the second and final generation of the Volt in 2015. It is a five-door liftback with a range-extending generator.
In 2006, under the direction of GM Vice President Robert Lutz, General Motors began development of a car to rebuild their "environmentally-friendly, technologically advanced" image following the setback of the unsuccessful EV1 program. The project sought to establish a new family of common powertrain components for electric propulsion, known as the "E-Flex Systems" or "Voltec". This powertrain was versatile enough to accommodate various electricity-generating systems, such as gasoline, diesel, ethanol, or fuel cell-powered engines. A lithium-ion battery pack with a 16 kWh energy storage capacity was selected to provide a target all-electric range of . The Volt concept car became the first application of the E-Flex propulsion system. This drivetrain comprises an electric motor, a lithium-ion battery pack, and a genset with a small combustion engine.
Official series manufacture of the car at the Detroit/Hamtramck Assembly began on November 30, 2010. In place of the "Chevrolet Volt" nameplate, the Australasian markets received the Holden Volt, which was produced between 2012 and 2015. In numerous European markets, the Opel/Vauxhall Ampera was introduced, featuring various visual modifications to differentiate it from the Volt. Nevertheless, the Chevrolet Volt continued to be sold in Europe, albeit in lower volumes.
The Chevrolet Volt functions as a battery electric vehicle until its battery capacity diminishes to a predefined threshold from full charge. At that point, its internal combustion engine activates an electric generator to extend the vehicle's range as necessary. During high-speed operation on gasoline, the engine may be mechanically linked to a generator set through a clutch, improving efficiency by 10% to 15%. The Volt's regenerative braking system also contributes to on-board electricity generation.
Terminology
According to the Society of Automotive Engineers' (SAE) definition of a hybrid vehicle, they are characterized by the presence of "two or more energy storage systems, both of which must provide propulsion power, either together or independently". General Motors has refrained from using the term "hybrid" in reference to its Voltec designs, even following the disclosure that, in certain instances, the combustion engine offers assistance at very high speeds. This contribution from the gas engine is limited to high-speed scenarios, as during normal driving, there is no such facilitation, and the vehicle operates solely on electric power. General Motors instead describes the Volt as an electric vehicle equipped with a "range extender" gasoline-powered internal combustion engine (ICE) functioning as a genset and calls it an "extended range electric vehicle". In a January 2011 interview, Pamela Fletcher, the Global Chief Engineer of the Chevrolet Volt, described it as "an electric car with extended range".
The Society of Automotive Engineers (SAE) states that the Volt qualifies as a plug-in hybrid vehicle due to its combination of an internal combustion engine, two electric motors, and a battery capable of accepting off-board energy. Functioning as a plug-in hybrid, the Volt can operate as a purely electric vehicle for the first in charge-depleting mode. When the battery capacity drops below a pre-established threshold from full charge, the vehicle enters charge-sustaining mode. In this mode, the Volt's control system selects the most efficient combination of its two electric motors—one powered by the propulsion system battery pack reserve and one by the combustion generator—to enhance performance and boost high-speed efficiency.
Design and development Concept vehicle
The Chevrolet Volt concept car debuted at the January 2007 North American International Auto Show. The Volt concept featured a four-door layout with a rear liftgate and seating for four. This design contrasted with the former EV1 which seated two to minimize weight and accommodate its lead-acid battery pack. Top speed was increased on the Volt, from the electronically limited to . Additionally, there was a reduction in battery size, from approximately in volume, to in the Volt.
Led by then-vice-chairman for global product development at General Motors Robert Lutz, the Volt project sought to emulate the success of the Toyota Prius and become a leapfrog product like Apple's iPod. Inspired by the Tesla Roadster sports car and the rapid advances in lithium-ion battery technology, Lutz advocated for the development of a new car after the 2006 Detroit Auto Show despite internal opposition stemming from the billion-dollar loss experienced in the 1990s with the EV1. Lutz's initial idea was to develop an all-electric car. Still, when Jon Lauckner, General Motors vice president for global program management, briefly sketched out the powertrain layout, estimated the vehicle weight and battery requirements, he decided a range extender design was more appropriate. He convinced Lutz that adopting a smaller battery pack and a small combustion engine to drive a generator, serving as a range-extender, would address concerns related to expensive batteries, range anxiety, and the lack of public charging infrastructure, thereby circumventing the limitations observed in the EV1 program.
The majority of the Volt's initial design parameters defined for the development of the concept car then referred to as the "iCar" in homage to the iPod, were kept throughout the process up to the final production version. A major design parameter was a target of for the all-electric range to keep the battery size compact and lower costs. This decision was largely based on research which indicated that 78% of daily commuters in the United States travel 40 miles or less. This target range allows drivers to effectively use its zero-emissions system, assuming that charging takes place at home overnight. To meet these requirements, a lithium-ion battery pack with a 16kWh energy storage capacity was selected. The choice took into account that the battery would be used until the state of charge reached 30%, ensuring operational performance across various conditions and minimizing the battery degradation, achieving a minimum ten-year lifespan. The initial target range for the gasoline engine/generator was set between , and the vehicle had to accommodate four or five passengers, conforming to the standards of a family car.
A major design decision was to develop the concept car based on a new family of common powertrain components for electric propulsion, which initially was called the E-Flex Systems, but was later renamed Voltec drive system. This powertrain was designed to establish a standardized framework for various components within potential future electrically driven vehicles, facilitating the integration of multiple interchangeable electricity-generating systems. The E-Flex powertrain was designed to configure vehicles for battery electric, fuel cell-powered, or alternative energy sources for onboard electricity generation, including engine-generator sets (genset) powered by gasoline, diesel, biodiesel, ethanol fuel (E100), or flex-fuel (E85). The incorporation of regenerative braking further improves the onboard electricity.
In October 2006, General Motors selected the E-Flex powertrain as the new propulsion architecture. They chose the name Volt. The Volt concept car served as the first application of the E-Flex drive system with a combination of an electric motor—similar to that of the one used in the Chevrolet Equinox Fuel Cell—a lithium-ion battery pack with 136kW of peak power, and a genset consisting of a small 1.0L, 3-cylinder turbocharged flex-fuel capable engine linked to a generator. General Motors referred to this genset as an electric vehicle (EV) range extender. The vehicle is synergized by an electric motor with a peak output of delivering of motoring torque. Various advanced materials from GE Automotive Plastics were incorporated, effectively reducing vehicle weight by up to 50%.
With a fuel capacity of , which provides the vehicle with a total driving range of approximately , the car combines a gasoline fuel efficiency of approximately and an all-electric range of . General Motors estimated that a daily drive of , coupled with an overnight recharge to support the first 40 all-electric miles, would result in an effective gasoline fuel economy of . General Motors underscored the potential to further reduce dependence on imported oil by using E85 ethanol instead of gasoline to power the onboard generator engine. General Motors also noted that actual production of the Volt depended on advancements in battery development, as the required rechargeable batteries needed to make the Volt a viable vehicle did not exist in the market and were yet to be developed. The prototype vehicle is propelled by a pair of standard 12-volt conventional car batteries, which provides the vehicle with a sufficient amount of energy to operate at low speeds while stationary. Location 2234 Kindle edition.
Lutz initially claimed that the Volt was expected to sell for around US$30,000, based on the cost of a conventional car of that size with a four-cylinder engine. Additionally, an extra US$8,000 was estimated for the lithium-ion battery. Engineers faced cost escalation when they realized that the Volt could not share components from General Motors' compact car platform such as power steering, power brake, and air-conditioning compressor, each of which was driven by a belt running off the engine. This, coupled with the inclusion of a compact electric motor and specialized microprocessors to control energy flow to the motor, led to a base price of around US$40,000.
Production model
General Motors stated on December 7, 2009, that US$700million would be spent at eight Michigan facilities to prepare the Chevrolet Volt for production. GM officials provided a comprehensive overview of their investment strategy for the Chevrolet Volt during a presentation at the assembly plant situated on the border between Detroit and Hamtramck. The plant underwent a significant upgrade amounting to US$336million, encompassing the installation of new machinery and equipment. GM's investment in Volt-related initiatives extends to several key projects, including the allocation of US$202million for a new plant in Flint dedicated to manufacturing engine generators; US$43million for a plant in the Detroit suburb of Brownstown Township responsible for battery packs; US$37million for the Bay City powertrain plant; and US$27million for the GM Tech Center housing the Volt's battery laboratory.