Chevrolet Volt

Chevrolet Volt Concept

Manufacturer	General Motors
Production	concept - late 2010
Class	Compact car
Body style(s)	4 passenger, 4-door liftback
Layout	FF layout
Platform	Delta/E-Flex
Engine(s)	120kW electric motor, 1.0L turbo 3-cylinder for 53kW generator
Transmission(s)	direct
Length	170 in / 4318 mm
Width	70.5 in / 1791 mm
Height	52.6 in / 1336 mm
Fuel capacity	unknown + 16 kWh
Electric range	40 miles (64.4 km)

The Chevrolet Volt originally was a plug-in hybrid concept car created by General Motors - GM indicates that it is no longer a concept, but a full-fledged production vehicle . However, the company has avoided the use of the term "hybrid," preferring to call it an electric vehicle with a "range extender" due to its design. The vehicle is designed to run purely on electricity from on-board batteries for up to 40 miles (64 km), or about half the range of the GM EV1 — a large enough distance to cover the daily commutes of most Americans, which is around 33 miles (53 km).With use of a small internal combustion engine driving a generator to resupply the batteries, the vehicle's range is potentially increased to 640 miles (1,030 km) on the highway. General Motors Corp. had originally planned to build 60,000 of its Volt electric cars for their inaugural year, however have now scaled back production to 10,000 units.

The Volt concept vehicle was officially unveiled at the North American International Auto Show (NAIAS) on January 7, 2007 in Detroit, Michigan. An updated version was unveiled at the Shanghai Auto Show in April 2007 in Shanghai, China. At the time of unveiling, the Volt project had been in existence for less than a year. The Volt was targeted to cost around $30,000. As of April 2008 Lutz was quoted as saying that the realistic unsubsidised cost had risen to $48K, that he reckoned that $40,000 might be possible, without making any profit, and that only government tax incentives could take the price tag nearer to $30,000. When asked directly GM claimed that this was a misquote, and that Lutz did not know how much it would cost.

GM faces competition from Nissan Motors, which announced its own electric car on May 13, 2008 as well as a number of startup auto manufacturers, some backed by Silicon Valley angel financing.

E-Flex drivetrain

The concept vehicle that appeared in the Detroit Auto Show introduced the E-Flex 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 kWh (58 MJ) lithium-ion battery plug-in system with a small engine (1 liter) powered by gasoline linked to a 53 kW generator. The vehicle is propelled by an electric motor with a peak output of 120 kW (160 horsepower). Ordinarily, the vehicle would be charged while at home overnight (plug-in hybrid). The vehicle has two charging ports for convenience, one on each side. A full charge reportedly takes 6.5 hours from a standard North American 120 V, 15 A household outlet.

Since the electrical drivetrain is not affected by the method used to charge its batteries, several options could be available for an engine. The primary configuration specified in promotional literature uses a turbocharged 1.0-liter engine with three cylinders. It would be a flex-fuel engine capable of running gasoline or E85 (85% ethanol, 15% gasoline). Fuel would be supplied from a "saddle" tank 45 litres (12 US gal) in size.

The second option is the Volt fuel cell vehicle, which appeared in the 2007 Shanghai Auto Show. Due to the high cost of fuel cells compared to newer lower cost lithium batteries, General Motors has publicly suggested that the Volt will not be using fuel cells in any near term production vehicles.

Other options have also been mentioned, such as a pure ethanol (E100) engine, a diesel engine capable of running biodiesel fuel, or even a hydrogen fuel cell, once that technology becomes practical. (The Ford Airstream concept, which debuted at the same show, uses a fuel cell plug-in hybrid design.)

This general layout is considered a plug-in series hybrid design since mechanical power initially drives the generator, which in turn charges the battery pack. Power is then drained from the batteries to run the electrical motors which move the vehicle. The internal combustion engine does not have any mechanical linkage to the wheels (unlike current vehicles such as the Toyota Prius), and can run at a constant speed for both optimal efficiency and mechanical simplicity (i.e., there is no need for a multi-valve, multi- or variable-cam design).

GM plans to keep the lithium-ion battery in a state-of-charge (SOC) range of between 30% and 80%, with the on-board generator starting to recharge the battery at the 30% level.

GM has decided on a new descriptive terminology distinct from calling it a hybrid. They are calling the Volt an E-REV, for "extended-range electric vehicle".

Related and similar vehicles

The concept vehicle has four doors with a rear liftgate, and it is capable of carrying four to five passengers. This is a significant change in design philosophy when compared to the General Motors’ EV1 of the 1990s, which only seated two. The top speed has also been increased on the Volt, from 80 miles per hour (130 km/h) to 120 miles per hour (190 km/h). The battery pack size has also been reduced between the two, from about 300 L in volume in the EV1, to just 100 L in the Volt. The weight of the battery pack in the Volt will also be significantly less, primarily because the Volt will use lithium-ion batteries while the EV1 used heavier lead-acid and nickel metal hydride batteries.

The purely electric range of the Volt will be considerably smaller than that of the EV1, but the overall range will be much higher. However, there was a 1998 prototype version EV1 in series hybrid configuration, that also had four seats and the same all-electric range of 40 miles (60 km) as the Volt, and it featured combined range of 390 miles (630 km), though with a different engine engagement control program. In contrast to the current Volt, this car was actually a running prototype. The turbine could run on many fuels, from gasoline to compressed natural gas.

The Opel Flextreme concept vehicle is based on the same platform and technology, but designed for the European market; it has a diesel engine and a hatchback body.

Production plans

General Motors said it will have the Volt on the market in 2010. To help spur battery research, GM selected two companies to provide advanced lithium-ion batterypacks: Compact Power, which uses manganese oxide based cells made by its parent company, LG Chemical, and Continental Automotive Systems, which uses nanophosphate based cylindrical cells made by A123Systems. However, on August 9, 2007 GM established a more close-knit relationship with A123Systems so that the two companies could co-develop a Volt-specific battery cell. This cell was later unveiled at the EVS23 industry convention in Anaheim, CA. Work with CPI has continued at a rapid pace, and in late 2007 CPI delivered two fully-functional prototype battery packs to GM's testing facilities. On January 31, 2008, A123 and Continental delivered their first prototype to GM's European test facilities. GM will likely use both suppliers for the Volt, although this remains a matter of speculation.

GM executives report that battery technology will have a large impact in determining the success of the car.

GM expects 10 years of life out of the batteries. They have started extensive battery testing and plan to have 10-year battery results in 2 years. They are also placing the batteries in Chevrolet Malibus for further real-world testing.

The initial production run for first year of sales of the Volt is most likely 10,000 vehicles. Lutz has indicated a target retail price of at least $30,000 and more likely something nearer $40,000.

With the outcome of the 2007 UAW-GM contract talks, assembly of the Volt was assigned to Detroit/Hamtramck Assembly.