Chevrolet Volt Review

Chevrolet Volt photos

The Chevrolet Volt is a plug-in hybrid electric vehicle to be produced by the Chevrolet division of General Motors and expected to be launched in November 2010 as a 2011 model. Its propulsion system will be based on GM's new Voltec (formerly known as E-Flex) electric automobile platform, which differs significantly from GM's earlier BAS Hybrid and Two-Mode Hybrid systems. For up to the first 40 miles (64 km), the Volt is powered by electrical energy stored in its on-board lithium-ion batteries which are charged by connection to an electrical power outlet. The car's 16 kW·h (8.8 kW·h usable) lithium-ion battery pack can be fully charged by plugging the car into a 120-240VAC residential electrical outlet using the provided SAE J1772-compliant charging cord. No external charging station will be required.

With fully charged batteries, enough electrical energy will be stored to power the Volt up to 40 miles (64 km). This distance is capable of satisfying the daily commute for 75% of Americans, whose commute is on average 33 miles (53 km). After 40 miles (64 km), a small 4-cylinder gasoline internal combustion engine creates electricity on-board using a 53 kW (71 hp) generator to extend the Volt's range to more than 300 miles (483 km). The electrical power from the generator is sent primarily to the electric motor, with the excess going to the batteries, depending on the state of charge (SoC) of the battery pack and the power demanded at the wheels. The distribution is controlled by the electronic control unit (ECU) of the vehicle. Unlike most current commercially available hybrid electric vehicles, the actual propulsion of the Volt is accomplished exclusively by the electric motor.

The Volt's retail price has yet to be officially announced. Recently the Volt's vehicle line director Tony Posawatz from GM responded to the question of anticipated Volt pricing by stating "the real or effective cost to consumers is easily less than $30,000” which includes the $7,500 U.S. federal tax credit and effective savings in electricity and other benefits.

Development and production of the Volt has been kept on or ahead of schedule, despite GM's Chapter 11 reorganization. The first pre-production test car based on the full Volt design was built in June 2009 in Warren, Michigan and by October 2009, 80 Volts had been built and are being tested under various conditions. On March 31, 2010 the first factory-built Volt was produced at the Detroit Hamtramck Assembly Plant in order to test the production line and for quality control purposes, both of the tooling and the pre-production vehicles that will be produced before regular production begins.

Chevrolet Volt Drivetrain

The 2007 Chevrolet Volt concept vehicle that appeared in the North American International Auto Show introduced the Voltec drive system, which is an attempt to standardize many components of possible future electrically-propelled vehicles, and to allow multiple interchangeable electricity-generating systems. The initial design as envisioned in the Volt combines an electric motor and 16 kW·h (58 MJ) lithium-ion battery plug-in system with a small 1.0 L engine powered by gasoline linked to a 53 kW (71 hp) generator. The vehicle is propelled by an electric motor with a peak output of 120 kW (160 hp). Ordinarily, the vehicle would be charged while at home overnight. According to General Motors a full charge will take approximately eight hours from a standard North American 120 V, 15 A household outlet and less than three hours if using a standard 240 VAC outlet. Charge times will be less if the battery is not fully depleted when charging commences.

Since the electrical drivetrain is not affected by the method used to charge its batteries, several options could be available for an engine. The original prototype specifications for the Volt indicated a turbo-charged 1.0 litre 3-cylinder engine would be used. However the initial production configuration currently specified by GM indicates the use of a naturally aspirated 1.4-liter 4-cylinder gasoline engine (Opel's Family 0). The Volt will be E85 flex-fuel capable about a year after its introduction.

This drivetrain layout is considered a plug-in series hybrid design since mechanical power drives the generator, which in turn either charges the battery pack or provides power to the electric motor. While the ICE has an electrical connection with the electric motor and hence the wheels, there is no mechanical linkage to the wheels (unlike current automobile hybrid vehicles such as the Toyota Prius), allowing optimization of engine rpm for fuel consumption, efficient rate of charge, and low emissions.

GM plans to station charge the lithium-ion battery to a state-of-charge (SoC) range of approx 85%. Then once the battery depletes to a precise low set-point (<25%) the on-board ICE powered generator will maintain the state of charge of the battery between the lower setpoint and an upper set-point above the 30% SoC level.

GM has decided on a new descriptive terminology to distinguish it from traditional hybrids. They are calling the Volt an E-REV, for extended-range electric vehicle, although it still qualifies as a hybrid.

Chevrolet Volt Tax credits

In the U.S. market, the price of the Volt is expected to be around US$40,000 and due to the capacity of the Volt's battery pack it qualifies for the maximum US$7,500 federal tax credit as specified in the Emergency Economic Stabilization Act of 2008. Initially, the former GM vice president Bob Lutz wanted the Volt at about $30,000.

The Volt is being endorsed by Dalton McGuinty and the Ontario government in Canada. The province will provide a $10,000 subsidy, and will purchase 500 Volts for the Ontario Public Service fleet. The subsidies are part of McGuinty's target to have electric vehicles make up 5% of all cars in Ontario by 2020.

Chevrolet Volt battery

Reuters reported in October, 2008 that GM had decided to work exclusively with Compact Power Incorporated (CPI), a Detroit-based unit of South Korea’s LG Chem, to develop the battery systems for the first production version of the Volt. The cells will be produced in Korea and subsequently shipped to the United States, where the battery packs will be assembled at a purpose-built facility in Brownstown Township, Michigan owned and operated by GM.

The Volt's 375 lb (170 kg), 220-cell lithium-ion battery (Li-ion) pack is anticipated to store 16 kW·h of energy, but will be restricted (in software) to use only 8.8 kW·h of this capacity to maximize the life of the pack. It will only be allowed to charge to 85% of full capacity and to discharge only to approximately 30% SoC before the engine cuts in and maintains the charge near the lower level. When the vehicle is plugged into a charger the battery SoC is restored to 85%.

Despite containing near identical energy,(+/- 0.5kWh) the Volt's battery pack is over 70% lighter than the EV1's original 1,310 lb (590 kg), 16.5 kW·h AC Delco lead-acid battery pack, mainly because the Volt will use higher specific energy Li-ion batteries. Li-Ion batteries are expected to become less expensive as economies of scale take effect.

The battery needs a minimum temperature of between 0 °C and 10 °C (32 °F and 50 °F) to be used and when the Volt is plugged in the battery will be kept warm enough so that it can be used immediately when the Volt is unplugged. If the Volt is kept unplugged and the temperature of the battery is below the minimum temperature the gasoline engine will run until the battery warms up. This temperature regulation is done since electro-chemical batteries have degraded performance when they are very cold.

Chevrolet Volt Cost

In 2009, the Presidential Task Force on the Auto Industry said that "GM is at least one generation behind Toyota on advanced, “green” powertrain development. In an attempt to leapfrog Toyota, GM has devoted significant resources to the Chevy Volt." and that "while the Chevy Volt holds promise, it is currently projected to be much more expensive than its gasoline-fueled peers and will likely need substantial reductions in manufacturing cost in order to become commercially viable."

Earlier in June 2008, Bob Lutz admitted the first-generation Volt with a price tag of about US$30–40,000 was not expected to generate a profit for GM. In an April 2009 interview with the president of GM's North American operations, Troy Clark stated he was uncertain if the next generation systems following the Volt would be profitable.

A recent Carnegie Mellon University study indicates that a PHEV-40 will be less cost effective than a HEV or a PHEV-7 in all of the scenarios considered, due to the cost and weight of the battery. Jon Lauckner, a Vice President at GM, responded that the study did not consider the inconvenience of a 7 mile electric range and that the study's cost estimate for the Volt's battery pack was "many hundreds of dollars per kilowatt hour higher" than what it costs to make today.