In August last year, General Motors announced something seemingly ludicrous: that its 2011 Chevrolet Volt was likely to get a 230 mpg city rating. That was long before the EPA testing methodology for electric vehicles was set, which caused GM to retract that statement in July this year and to eventually wait for an official EPA rating before shipping Volts to dealers. Now that the EPA rating is set and in the windows, here’s a look at how it was determined.

So, by now you’re all likely familiar with our Automobile of the Year Chevrolet Volt and how its unique series/parallel hybrid powertrain setup works, but if you’re not, here’s a recap and a breakdown of how the driving modes were scored by the EPA.

Initially the Volt has a fully charged battery, giving it a range between 25 and 50 miles depending on how the car is driven. This all-electric range is officially estimated as 35 miles by the EPA. In this mode of driving, the Volt uses no gas whatsoever, potentially allowing owners to only use one tank of gas per year (the Volt senses when gas is going bad and will burn a tank once per year to keep the engine healthy).

The EPA decided to give consumers a figure relating the electrical efficiency to something they understand already, so it converted electrical efficiency to an equivalent gasoline efficiency — Miles Per Gallon equivalent, or MPGe. To obtain a MPGe rating, the EPA determines a miles per kilowatt hour rating and then uses the energy in one gallon of gasoline (roughly 33.7 kWh) to convert this mpkWh figure to MPGe.

After the battery is depleted a gasoline engine kicks on to act as a generator, supplying energy to the drive motor. This is the second MPG figure given by the EPA and is straightforward. When the gasoline engine is running, the Volt is rated at 37 mpg combined.

Of course, most Volt owners will likely use a mix of the two driving modes, which caused the EPA to add a separate addendum. Another portion of the Volt’s EPA sticker provides a relative breakdown of the costs per mile owners can expect under a variety of conditions. The EPA breaks down charging every 30, 45, 60, 75 miles, and never. This new rating system turns something potentially incredibly confusing into something, well, slightly less confusing.

At the 2010 Guangzhou Auto Show last week, General Motors unveiled its new Chevrolet Sail electric concept vehicle.

“GM is committed to delivering a range of advanced propulsion technologies and offering a portfolio of solutions that will allow our customers to choose the vehicle that best meets their needs,” said Kevin Wale, President and Managing Director of the GM China Group. “GM’s expertise in batteries, electric motors and power controls will enable us to provide the best possible choices when it comes to vehicle electrification technologies.”

The Chevrolet Sail electric concept is powered by a lithium-ion battery with an output of 87-hp and 162 lb-ft of torque. The electric Sail has a top speed of 80 mph and can travel up to 93 miles on a single charge. It uses regenerative braking to produce additional energy.

Will it be produced? No word on it yet, but GM has plans to greatly expand its EV offering by 2015.

Chevrolet Sail Electric Concept:

General Motors Participates in Guangzhou Auto Show
Introduces Sail Electric Concept Vehicle

Shanghai – General Motors is participating in the 2010 Guangzhou Auto Show, which began today, through its Shanghai GM joint venture. Under the theme of “Drive to Green and Leading Innovation,” it is showcasing 23 production and concept vehicles. Among the products on display are the Sail electric concept vehicle, which is making its global debut, and the Chevrolet Volt extended-range electric vehicle.

Sail Electric Concept Vehicle

The Sail electric concept vehicle was developed by Shanghai GM and the Pan Asia Technical Automotive Center (PATAC) in Shanghai. Based on the Chevrolet Sail that went on sale at the beginning of the year, it is an environmentally friendly small car that is targeted at ordinary Chinese families.

The Sail electric concept vehicle is powered by a lithium-ion battery with maximum output of 65 kW and maximum torque of 220 Nm. It has a maximum speed of 130 km/h and can go up to 150 kilometers on a single electric charge. It uses regenerative braking to produce additional energy. The Intelligent Charging Assisting System maximizes the energy conversion ratio.

Its simple contemporary design is aerodynamic. Inspiration has come from leaves, and is reflected across the exterior. The Sail electric concept vehicle features a simple yet modern interior along with a range of electronic amenities. It has adopted electric vehicle standards for safety set by SAE and ISO.

Chevrolet Volt Extended-Range Electric Vehicle

The Chevrolet Volt is the world’s first extended-range electric vehicle that provides the benefits of an electric vehicle without the range limitations associated with other electric vehicles on the market. Powered by GM’s revolutionary Voltec propulsion system, it provides maximum torque of 368 Nm, maximum output of 111 kW and a maximum speed of 160 km/h. It can run solely on electric power stored in its 16 kWh lithium-ion battery for up to 80 kilometers without consuming a single drop of petroleum and with zero emissions.

When the battery is depleted, its on-board engine-generator starts producing electricity to drive the Volt another 490 kilometers, giving the Volt a range of up to 570 kilometers. When launched in China in the fourth quarter of 2011, the Volt will be equipped with the OnStar system, which will offer a smart phone application co-developed by Chevrolet and OnStar. Owners will be able to control all vehicle functions and OnStar services on a 24/7 basis.

The Volt has received several awards in North America including Motor Trend 2011 Car of the Year, Automobile Magazine 2011 Car of the Year, 2011 Green Car of the Year from Green Car Journal, and Best Innovation from Popular Mechanics magazine.

“The Sail electric concept vehicle and Chevrolet Volt are examples of industry-leading solutions being developed by GM and our partners globally,” said Wale. “GM is also establishing battery electric vehicle demonstration fleets around the world to better understand driving patterns, battery charging, market needs and customer acceptance of electric vehicles. At the same time, GM is investing in start-up companies with innovative ideas to accelerate next-generation electrification technologies.”

Other Premieres

Among the production vehicles making their debut in Guangzhou is the new Chevrolet Spark, which takes functionality and environmental friendliness to a new level in the mini-car segment. The new Spark is equipped with a 1.0-liter engine. It offers a personalized interior in line with the demands of younger customers and is priced between RMB 77,800 and RMB 88,800.

Another new car that is making its global debut is the Cadillac SLS 2.0T SIDI, which sets a new performance standard for low-emission luxury business cars. It is the first vehicle in Cadillac’s 100-year history to offer a four-cylinder turbocharged engine. It represents the brand’s entrance into the 2.0- to 2.5-liter luxury business car segment. Three variants are priced between RMB 388,800 and RMB 488,800.

Making their maiden appearance in Guangzhou are two new models from Buick. The New Regal GS Sport is the newest member of the upper-medium sedan family. It takes driving excitement to a new level with its 2.0-liter turbocharged SIDI engine that generates maximum power of 190 kW and 400 Nm of torque. It has three different driving modes, including the FlexRide adaptive driving system.

The new Buick GL8 luxury MPV, which will reach the market next month, builds on the heritage of the original GL8, China’s first family of executive wagons. It features seven innovations and 27 technological breakthroughs along with improvements in design, space and safety, technology, power, features and quality for business users. It comes with a choice of a 3.0-liter V-6 SIDI intelligent direct injection engine or a 2.4-liter Ecotec engine with segment-leading fuel efficiency.

GM’s EN-V (Electric Networked-Vehicle) concept, which was a star of the SAIC-GM Pavilion at World Expo 2010 Shanghai, is also appearing on the Shanghai GM stand. EN-V introduces a new automobile DNA based on electrification and connectivity. It represents GM’s vision of future urban transportation in which driving promises to be free from petroleum, free from emissions, free from congestion and free from accidents.