GirlDriver, USA

GirlDriver, USA
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Friday, December 13, 2013

VW's XL1--into the Future.

Scissor doors open.
I swear, scissor doors are like catnip to guys.  You wouldn't believe how much attention we got driving VW's XL1 in midtown on December 11th.  Men behind the wheels of their Maximas and Bimmers grinning from ear to ear; workmen jumping out of their trucks to ask about the car.  "How much is that car?,"  one asked.  "$145,000, but for you, $138,000," I quipped (and I hope it is not too egotistical to say I quipped).  My colleague had a bus driver stop his bus in the middle of the street, open the bus door and start asking questions about the car--while he was on his bus route with passengers in the bus!

The XL1 looks like a space ship that was inspired by a mango--in our case a bright white mango.(VW says it's a dolphin.)  The vehicle uses everything in the automotive design and engineering toolbox to get 261 miles out of it's battery/diesel powertrain.  Carbon fiber, no mirrors mounted to the doors--these are replaced by small cameras known as e-mirrors (digital outside mirrors) that send images to two displays inside the vehicle, rear wheels fully covered to prevent turbulence, while airflow around the wheelarches is optimized by small spoilers in front of and behind the wheels.  Polycarbonate side windows weigh about a third less than conventional windows.  This two-seater can drive up to 31 miles as a zero-emissions electric vehicle.

Patrick, who showed me around the car clutching a part made of carbon fiber described the car as a technological guidepost for VW's future.  Interesting then, that it has no Nav system (it uses a Garmin--again to save weight and probably money) and it has roll-up windows.   The XL1 weighs only 1753 pounds, has exceptional aerodynamics, and has a low center of gravity. That allows the XL1 to  cruise at  62 mph using  8.3 horsepower. In all-electric mode, the XL1 requires less than 0.1 kWh to cover more than 0.6 miles.

Take a class on graceful entry and exit before getting in the car.
This is the third generation of Volkswagen’s 1-liter car strategy.   The XL1’s plug-in hybrid system consists of a 48-hp two-cylinder TDI® Clean Diesel engine, a 27-hp electric motor, a seven-speed DSG® dual-clutch automatic transmission, and a lithium-ion battery.
The 5.5kWh lithium-ion battery supplies the electric motor with 220 volts of electrical energy. The electronics system manages the flow of high voltage energy to and from the battery or electric motor and converts direct current to alternating current. Battery regeneration occurs when the car is slowing down and when the car brakes, at which point the electric motor acts as a generator. The XL1’s 12-volt electrical system is supplied via a DC/DC converter and a small auxiliary battery.  The lithium-ion battery can be charged from a conventional household electric outlet.

As well as boosting the TDI engine under hard acceleration, the electric motor can also power the XL1 on its own for a distance of up to 31 miles. The driver can choose to drive the XL1 in pure electric mode, provided that the battery is sufficiently charged, by pressing a button on the instrument panel is pressed.
Restarting the TDI engine is a very smooth process. While driving, the electric motor’s rotor is sped up and is very quickly coupled to the clutch in a process known as “pulse starting”. This accelerates the diesel engine to the required speed and starts it, so the driver hardly notices the transition. In certain operating conditions, the load of the TDI engine can be shifted so that it operates at its most favorable efficiency level. The gears in the DSG transmission are also always selected with the aim of minimizing energy usage.

 It's a two-seater cabin with only one airbag (weight savings again)  The passenger's seat is as far back as it can go so that in case of an accident there would be no chance of hitting the dash or the windshield.  Still, it's a no-no in the U.S. so the car won't be sold here.  Here the XL1 is an idea --it shows the direction VW is headed technologically.  Just 250 XL1s will be produced at the Volkswagen factory in Osnabrück, Germany.

The XL1 utilizes lightweight and extremely strong molded, carbon fiber reinforced polymer (CFRP) construction for the monocoque, meaning the exterior skin provides the main structural support, all exterior body parts, and components such as the anti-roll bars. CFRP parts are as strong as comparable steel or aluminum parts, yet the exterior skin of the XL1 is just 0.05 inches thick.
  A total of 21.3 percent of the new XL1, or 373 lb, consists of CFRP.   Just 23.2 percent (406 lb) of the car being constructed from steel and iron.

In a collision, the extremely strong CFRP monocoque provides an impressive survival cell for the driver and passenger. This is achieved by intelligent design of load paths, including the use of sandwich structures in the monocoque, while the front and rear aluminum crush structures absorb a large share of energy in frontal and rear collisions. The CFRP doors have aluminum impact beams to absorb crash energy and the door frame also minimizes intrusions into the safety cell. A great deal of attention was also paid to extricating occupants in the event of a rollover collision: pyrotechnic separating screws are used to simplify opening of the doors, which ordinarily open upwards.
Compared to manufacturing CFRP in a pre-preg process, the RTM process is more economical—with lower costs at higher volumes—because it can be automated.  Lots of very interesting ideas here for the future.

Fun to drive.  Carbon brakes make noises reminiscent of dentist..
The XL1 uses scissor doors that are reminiscent of a high-end sports car’s. Because they are hinged low on the A-pillars and just above the windshield in the roof frame, they swivel upwards and slightly forwards as well. The doors also extend far into the roof. When they are opened, they create an exceptionally large amount of entry and exit space.  But because the car is low to the ground you better have carbon fiber knees and a sprightly back to enter and exit.  You also need to take a class on entering and exiting the car so that you look really cool instead of old.

Is it a mango or a dophin?  Send your votes.
The design takes an entirely new path at the rear, but the brand values of precision and quality are clearly evident. Four characteristics stand out: First, there is the dolphin body form that narrows towards the rear with highly defined trailing edges, for optimal aerodynamics. Second, there is the coupe-shaped roofline that doesn’t have a rear windshield. Merging into the roofline is the large rear trunklid/hood that covers the drive unit and4.2 cubic feet of luggage space. Third, the strip of red LEDs frames the rear section at the top and on the sides and incorporates the reversing lights, taillights, rear foglamps and brake lights. Fourth, a black diffuser exhibits a near seamless transition to the full underbody.

The car is also designed to reducing rolling resistance, with friction-optimized wheel bearings and drive shafts, as well as ultra-low rolling resistance Michelin tires, sized 115/80 up front and 145/55 R16 at the back. But all this efficiency isn’t at the expense of safety: the XL1 has an anti-lock braking system (ABS) and a stability control program (ESC).

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