European automakers consider the electro-diesel option

FRANKFURT, GERMANY — If you think all hybrid cars are like the Toyota Prius -- mirthless, ugly hair shirts of green conscience -- BMW would like you to meet its Vision: a stealth submarine of a car, lower than a boxing foul, all folded geometry and LED tracer lights. The signature BMW grille glows blue like a reactor cooling pond. The transparent doors open like dragonfly wings.

The all-wheel-drive Vision sport coupe is the Usain Bolt of hybrid cars: zero to 60 mph in under 4.8 seconds, top speed of 155 mph, 356 horsepower, and handling and braking comparable to the company's brain-melting M3 coupe.

Fuel economy: 75 miles per gallon. And you can plug it in.

Santa Monica might never be the same.

The Vision is one of several so-called electro-diesels at the Frankfurt Motor Show that put a typically European spin on Japan's signature eco-tech of hybrids. By combining electric motors and batteries with the huge torque and efficiency of direct-injection turbo- diesels, the European automakers are breeding a species of car that delivers V-8 performance with the fuel economy of mopeds.

Behind the menacing grille of the Vision, there's a small, 1.5-liter, 163-horsepower three-cylinder turbo-diesel engine and a big electric traction motor; arrayed like a capital "I" running down the spine of the car are rows of lithium-polymer batteries. At the rear axle is another electric motor, which gives the car essentially all-wheel drive. Together these components produce a whopping 590 pound-feet of torque, considerably more than your average Lamborghini.

The Vision, which uses batteries developed for Apache attack helicopters, is only an experimental vehicle for now. But "all the components are very realistic," said Philip Koehn, BMW's director of concept vehicle development. The batteries, the diesel components and electric motors are "off the shelf," he said.

Too flashy for you? At the other end of the performance spectrum is Volkswagen's L1 concept, a hyperlight, tandem-seat oil-burner, like a bobsled for the road. Getting its world premiere in Frankfurt, the L1 is powered by a small, two-cylinder turbocharged direct-injection (TDI) diesel engine and a small electric motor.

The L1's marquee number: 170 mpg, or about four times that of a Honda Insight hybrid. If it comes to market as planned in 2013, the VW L1 could claim the title of most fuel efficient passenger car on the road.