The U.S. government isn't the only one that gives grants and loans to help automakers develop advanced-technology vehicles. The U.K. government's Technology Strategy Board does it as well, for companies that build cars there.

Luxury carmaker Jaguar Land Rover, collaborating with Lotus Engineering and Caparo Vehicle Technologies, has already received several million pounds for its "LimoGreen" project to create a full-size luxury car with CO2 emissions below 120 grams/kilometer.

Now, more details have emerged on what a fully electric Jaguar sedan might be like.

Lotus Range Extender 1.2-liter, three-cylinder engine and generator

Lotus Range Extender 1.2-liter, three-cylinder engine and generator

2011 Jaguar XJL Supercharged Neiman Marcus Edition

2011 Jaguar XJL Supercharged Neiman Marcus Edition

2011 Jaguar XJ

2011 Jaguar XJ

2011 Jaguar XJ

2011 Jaguar XJ

According to Autocar, it would be a vehicle similar to the all-new aluminum-framed 2011 Jaguar XJ, but powered by a 145-kilowatt electric motor, supplied with electricity from a lithium-ion battery pack of unspecified capacity.

And, similar to the upcoming 2011 Chevrolet Volt, it would use a small gasoline engine as a range extender to power a generator that would recharge the battery pack--an arrangement also known as a "series hybrid".

That engine, designed by Lotus specifically for this application, would be a tiny 1.2-liter, three-cylinder running on gasoline and providing either 20 or 47 horsepower. Lotus introduced the engine-generator set at last fall's Frankfurt Motor Show.

It is built as an aluminum "monoblock," meaning the engine block, cylinder head, and even the exhaust manifold are integrated into a single casting. As a result, it weighs just 125 pounds (56 kilograms). It runs at two speeds: 1,500 revolutions per minute, where it produces 20 horsepower (15 kilowatts) of electric power, and 3,500 rpm, for an output of 47 hp (35 kW) at the generator.

The combined powertrain would offer as much as 47 miles per gallon, a top speed of 112 miles per hour, and a range of more than 600 miles. (An alternate design also funded by the British government uses a micro-turbine as the range extender to power a generator.)

And insiders at Jaguar claim the handling and performance of an electric XJ will be surprisingly good, given the weight subtracted when today's 385-hp, 5.0-liter V-8 engine is removed from a car like the 2010 Jaguar XJ.

Industry analysts expect future Range Rover models to be built on adapted versions of the floor and structure of the latest XJ, so it's possible the extended-range electric drivetrain could be offered in future Land Rover models as well.

Why an electric Jaguar? Large cities across the globe may slowly introduce or expand zero-pollution zones, where only vehicles without tailpipe emissions will be allowed to enter.

And even in cities that don't ban emitting cars outright, electric-drive vehicles may be offered free entry or major discounts on access charges, just as electric vehicles pass through London's congestion zone free of charge today.

[Autocar]