Extreme Fuel Efficiency 235 MPG VW

Volkswagen's CEO, Martin Winterkorn, recently confirmed the company is working on a car that will get 235 miles-per-gallon (1 liter-per-100 kilometers) fuel economy. In 2002, VW showed its 1-Liter concept car that achieved 264 mpg (0.89L/100km). The project was cancelled in 2005 but VW has now revived it. How real is this? VW now says a limited production car could be offered by 2010.

A future car that gets this kind of extreme fuel efficiency requires "thinking outside the box." For example, reducing aerodynamic drag is critical. Thus, the VW 1-Liter, developed in a wind tunnel, has a very narrow and very flat body configuration. The body - only 4.1 feet wide - necessitated tandem seating for the two occupants. It is just 11.4 feet long and just over 3 feet tall. The car's drag coefficient is an impressive 0.159 and it has a 75 mph top speed. With its 235 mpg fuel economy, it can travel 400 miles on its 1.7 gallon fuel tank.

Minimum weight is also crucial. The VW 1-liter is made entirely of carbon fiber composites with the outer carbon fiber-reinforced skin tensioned over a spaceframe made of magnesium, which is lighter than aluminum. To further reduce weight the body is unpainted. The car's running gear makes extensive use of lightweight alloys. Low rolling resistance tires are mounted on 16-inch wheels made of extremely lightweight composite materials. The magnesium seat frames feature fabric covers rather than conventional upholstery.

The fuel sipping VW would probably be powered by a tiny single-cylinder diesel engine of 300 cc to 500 cc displacement, made of aluminum, and using the latest direct injection technology. The 1-Liter concept car used a single-cylinder 300 cc diesel engine with an aluminum monobloc crankcase and cylinder head, resulting in a total 8.5 horsepower output. The non-turbocharged direct injection engine uses advanced high-pressure unit injection technology. It's mounted transversely in front of the rear axle and mated to an automated direct shift 6-speed transmission.

With the VW 1-Liter, VW engineers showed that safety doesn't have to be compromised to obtain ultra light weight. The 639 pound car incorporates advanced safety features including a deformable front end, an impact tolerant spaceframe, and racing car-like roll-over protection. It also has anti-lock braking, electronic stability program (ESP), and a driver's airbag. All it needs now, from our perspective, is a quick path to market.