How it Works: 2007 Chevrolet Volt Concept

General Motors’ 1996-99 EV1 electric car was a brilliant science project but an abject business failure. After investing $1 billion in R&D, GM leased only 900 EV1s to customers in California and Arizona, after which the program was terminated. The EV1 failed because it could transport only two passengers less than 100 miles before needing a lengthy stop for recharging.

The Chevy Volt concept’s mission is to solve those shortcomings. Peeved by Honda and Toyota winning repeated kudos for their green-car strides, GM’s vice chairman and product guru Bob Lutz conceived this project to show that GM knows a thing or two about electric propulsion.

The Volt is a series hybrid with components borrowed from the E-Flex propulsion system that GM engineered for its Sequel fuel-cell concept vehicles. The front wheels are driven solely by a 161-hp (120-kW) electric motor operating through a planetary gear reduction unit. A lithium-ion battery pack located along the car’s spine powers the motor for forty miles. When the batteries’ state of charge falls below 30 percent, a turbocharged and intercooled 1.0-liter three-cylinder engine fires up to spin a 53-kW generator. Current from the generator is routed to both the electric propulsion motor and to the battery pack.

The engine shuts down as soon as the batteries are recharged to 80 percent capacity. Thanks to this series-hybrid approach, there’s enough power to accelerate this 3200-pound vehicle to 60 mph in about 8.5 seconds with no loss of performance as the batteries lose their spunk. (Diesel-electric locomotives, originally developed by GM in the 1930s, are the most common example of a series hybrid.)

Two six-gallon fuel tanks give the Volt a maximum range of 640 miles and an average mileage of more than 50 mpg. According to GM, the internal combustion engine can be configured to run on gasoline, E85, or biodiesel. Two fender connectors allow you to plug in the Volt at home and recharge the batteries in 6.5 hours. Another possibility is the installation of a fuel cell for zero-emissions driving.

When wrapping a body around all that technology, GM designers steered clear of the sensible-shoes look. The project’s design director, Bob Boniface, notes, “The Volt is something one would buy because it’s sporty and athletic looking. The fact that it has the potential to consume little or no gasoline is a bonus.”

But is the Volt real or just a publicity ploy? GM insists it’s the precursor of a production program. Engineers have been working for a year to advance the Volt’s cause, and the Chevrolet badge is meant to signal aspirations of selling the car globally. GM’s next-generation compact, scheduled for introduction in two years, has been configured to accept the Volt’s electrical components. The batteries are the holdup. Suitable lithium-ion technology, which offers two to three times the storage capacity of the nickel-metal hydride batteries that powered the EV1, won’t be ready for at least three years.

Battery technology never caught up with the EV1. If battery-development efforts succeed this time, the Volt could be the first truly viable electric car.