The 2014 Volkswagen XL1 looks like a car of the future, but it sounds like a car from the past. A body as streamlined as a fish, tires as thin as a motorbike's, gullwing doors and a tail tapering like a tadpole's give this car an otherworldly look that's as startling as the sound of its engine. But instead of the low hum or jetlike whoosh that you'd expect from a car so dramatic, you hear the lumpy putterings of a lawnmower.
And that's because there's a tiny twin-cylinder diesel engine beneath that insectlike rear end, whose jumpy idle has you wondering whether this car's mechanicals are entirely as they should be. They are, of course. The 47-horsepower 800cc engine is part of an ingenious, lightweight bundle of parts designed with a challenging mission in mind.
The mission is Dr. Ferdinand Piech's. The VW boss challenged his engineers more than a decade ago to develop a practical, everyday 1-liter car for the showroom. In case you're wondering, "1 liter," in this case, has nothing to do with engine displacement. Rather, it refers to a car that can travel 100 kilometers — or 62 miles — on a single liter of fuel. This is how fuel consumption is measured in mainland Europe, with 1 liter equivalent to 0.26 gallon and a spectacular 240-mpg fuel consumption.
The Goal: 261 MPG
After 11 years and two prototypes (including a 639-pound carbon-fiber and magnesium prototype powered by a 1-cylinder diesel engine that Piech famously drove 200 kilometers for the annual shareholders' meeting) the XL1 is ready for prime time.
And it's this car that Volkswagen has put into small-scale production. A probable run of 250 examples will allow a lucky few to drive the most economical car in the world. There's no word on price yet, but there are plenty of mouth-dropping numbers to mull over for now.
The finished item weighs 1,749 pounds. It has a drag coefficient of 0.189. Its 800cc twin-cylinder diesel plug-in hybrid powertrain achieves 261 mpg on the official drive cycle, and puts out just 21g/km of CO2. In electric-only mode it will travel 31 miles, and on electricity and diesel together you can cover 310 miles before plugging in or refueling. The XL1 accelerates to 62 mph in 12.7 seconds and it's electronically governed to 100 mph in the interest of economy.
The numbers are impressive, but not half as arresting as seeing the 2014 Volkswagen XL1 on the road. This is a car that's roughly the same length as a Ford Fiesta, and sits 5 inches lower than a Porsche Boxster. It looks like a cross between a space-age reconnaissance machine and a sports car and also (whisper it) more than a little like a Honda Insight and GM's EV1. That's because the teardrop silhouette common to the three is the cleanest way to cleave the air, but only the VW has gullwing doors and a carbon-fiber monocoque chassis. Weight reduction is the reason for this indulgence, though mass has been chased from every corner of this car.
Of the XL1's featherweight 1,749 pounds, 372 pounds are accounted for by carbon-fiber components, 393 pounds are lightweight metals such as aluminum and magnesium, and only 405 pounds are of iron and steel. The drivetrain weighs 499 pounds including the lithium-ion battery, the running gear accounts for 337 pounds, the electrical system (complex on a hybrid) is 231 pounds and the car's equipment 176 pounds. Weight has driven every aspect of this project.
Half a Diesel
The diesel twin driving the car itself is one half of VW's direct-injection, common-rail 1.6 TDi engines. It produces 47 hp and 89 pound-feet of torque, comes with a balance shaft to calm the twin cylinders' uneven pulses and drives through a seven-speed paddle-shift DSG automatic. Sandwiched between the pair is a 27-hp electric motor providing a stout 103 lb-ft of torque and doubling as a starter-generator. An extra driveline clutch allows the TDI engine to be decoupled from the starter-generator and the transmission so the car coasts unimpeded by engine braking. Obsessing with rolling resistance reduction has yielded low-friction wheel bearings and driveshafts and bizarre-looking front tires only 125mm wide. The rears are fatter but are a still-anemic 155mm.
If you're wondering why the Volkswagen XL1 has no rear window, it's because the drivetrain sits behind the passenger compartment. The rear hatch opens to reveal a trunk walled with carbon fiber and the electric cooling fan that is the reason for the neat little vents in this panel. This arrangement eliminates the need for a rearview mirror and the door mirrors have gone too, replaced by twin door-mounted cameras that project onto screens forward of the door armrests.
All of this adds to the drama of this ultrahigh-grade engineering. So do the gullwing doors, which cut deep into the roof to ease your passage past a fat rocker into a low and economically upholstered seat. The door closes easily with a high-quality thunk. Low volume or not, this VW feels like a quality piece as you're confronted by a wide dash, a flat-bottomed telescoping wheel, twin pedals, paddle shifters and a stalk-mounted infotainment system. But more striking than any of these pieces are the twin screens in the doors, which will shortly be showing you where you've been.
Any thought that you're in an exotic sports car is instantly dispelled by the diesel twin spinning to life, its muffled clatter the stuff of an ancient two-stroke Saab. This car does not sound fast, but it does sound interesting.
Drive it unthinkingly and you can pull the shift lever into Drive, leave it there and score what will undoubtedly be impressive mpg numbers. But there are modes that will take you further on gallon and ampere and an EV button in the center console switches the XL1 to electric-only propulsion at speeds of up to 44 mph for up to 31 miles. Tugging the gear selector engages Sport, which provides more regenerative braking and more throttle-off deceleration. Tug it again, return to normal mode and the diesel decouples when you back off the throttle, allowing the car to coast forever: the pay-off for its low-friction, low-drag engineering. Like all hybrids, this is a car in which you can learn to go farther. You must also learn to use your electronic mirrors, which work well but take time to trust.
Remarkably, the 2014 Volkswagen XL1 has a subtly sporting side to its character. It's not fast, of course, though if you nail it and convert diesel putter to muted throb it will gain pace briskly enough. This is a low-mass car with an even lower center of gravity and a midengine drive layout, so cornering is downright respectable. There's amazingly little roll, and although there wasn't the chance to discover this on the test-drive, it's easy to imagine that part of your fuel-saving technique will involve a minimum of slowing for bends.
The car's feeling of taut connectedness helps, the suspension as firm as the seats and the unassisted steering promising plenty of feel when you push. The odd drumming of bumps and the scrape of brake pads on ceramic rotors tells you that this VW's running gear is bolted to a very robust structure.
That's probably why the aural difference between full EV mode and hybrid mode is more apparent in this car than other hybrids, and why you more easily hear the electric motor winding down to a stop and the diesel's putterings. But while these sounds aren't loud, they're certainly interesting and give this fascinating car great character. They also mask VW's excellent integration of diesel engine and electric motor, their coupling and decoupling as unnoticeable as you'd hope.
The result has to be the most sophisticated and ingeniously entertaining eco-car yet invented. Add in eye-freezing looks, construction worthy of a supercar, charming practicality and the opportunity to top 250 mpg and you have a mighty compelling car. And an expensive one, too. Which is ironic for a car that's about saving. The good news is that much of the content of this ultra-rare VW is destined for models that most of us can afford.
And that, we'd bet, won't bother Dr. Piech one bit.
|Year Make Model:||2014 Volkswagen XL1|
|Vehicle type:||RWD 2dr 2-passenger coupe|
|Assembly location:||Osnabruck, Germany|
|Configuration:||Tranverse, midengine, rear-wheel drive|
|Engine type:||Two-cylinder turbodiesel|
|Horsepower (hp @ rpm):||47|
|Torque (lb-ft @ rpm):||89|
|Hybrid type:||Series-parallel plug-in|
|Electric motor rating (kW):||27|
|Combined horsepower (hp @ rpm):||68|
|Combined torque (lb-ft @ rpm):||103|
|Battery capacity, rated (kW-hr):||5.5|
|Plug-in type (110v/220v):||110-volt|
|Plug-in driving range, mfr. claim (mi.):||31|
|Transmission type:||Seven-speed dual-clutch automated manual|
|Suspension, front:||Independent, double wishbone, coil springs, stabilizer bar|
|Suspension, rear:||Independent, semi-trailing arm, coil springs|
|Curb weight, mfr. claim (lbs.):||1,749|
The manufacturer provided Edmunds this vehicle for the purposes of evaluation.