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to learn things about everything from materials to aerodynamics. "Experience we gained from this hybrid will be used on production cars," he said. And he means "mass production" cars, because the XL1 is actually certifed in Europe as a production car. Which allowed Feldhusen to point out that the XL1 has "the world's best drag of a production car"—it has a coeffcient of drag of 0.189—and "the world's best weight for a production car"—1,753 lb. (As a point of reference: the car is 153 in. long, 65.5 in. wide, and 45 in. high.) q The diesel hybrid XL1 is carbon fber-intensive. Its coeffcient of drag is just 0.189. The car seats two, with the passenger seat slightly behind the driver's so as to make the cabin narrow. "It demonstrates what can be done," Feldhusen said. Weight and aerodynamics are key, he explained, to creating a car that achieves remarkable effciency. If you consider what is happening with most cars, there is what he describes as an upward "weight spiral." So the VW engineers went at reducing weight. As 43% of a midsized car's weight, Feldhusen said, is the car's body, they addressed that. Aluminum was a consideration for the XL1 because compared with steel, the traditional body material, it provides a 30% weight save. "But that's not enough," he said. So because the XL1 is an overall "technology spearhead," they use carbon fber reinforced plastic (CFRP), a 50% weight save compared with steel, for the monocoque, which weighs just 197 lb. It serves as the safety cage for the two-person vehicle, as well as a structure onto which the running gear is attached. CFRP is also used for the skin, roll bars, and the seat structures. The wheels are magnesium, as is the cross member behind the natural fber-covered dash. There are carbon fber brake discs. The side windows are polycarbonate. There are aluminum crash beams in the doors and aluminum crash tubes fore and aft for safety. Aluminum is also used to make the wiring for the lightweight electrical system. There are some notable absences that keep the weight down. Like no power steering system. And no sound insulation. Both are evident when driving the XL1. Especially the latter. The parallel hybrid powertrain for the XL1 is based on a 48-hp twocylinder, 0.8-liter common rail turbodiesel, a seven-speed DSG dual-clutch gearbox, and 20-kW (27hp) electric motor. The powertrain is located in the rear of the vehicle. Up front, there is a 60-cell, 5.5kWh lithium-ion battery pack. The vehicle can travel up to 31 miles on electric power alone; the total range is approximately 310 miles. And when that turbodiesel kicks on, approximately behind the driver's and passenger's heads, the stiffness of the carbon fber structure and the lack of sound insulation become exceedingly evident. From an aerodynamic perspective, the car has a comparatively small frontal area and, with a teardrop shape (top view), the rear is narrower than the front. The roof profle is low (the doors are hinged at the A-pillars and on the roof frame; they pivot upwards and slightly forward to provide ingress and egress to the vehicle; given the low height, getting in and out is somewhat tricky). The underbody is fully enclosed, as are the rear tires. There are no sideview mirrors. VW had to get an exemption for replacing the sideview mirrors with cameras; Feldhusen said that the XL1 is "the frst car to drive on the road with e-mirrors": there are high-resolution displays on the inside of doors to provide the rear exterior view. (There is also no rear-view mirror because there is no backlight.) The XL1 is not the future per se. But it is most certainly directional in the approach that VW has taken as regards the materials, the powertrain, and the aerodynamics. 31