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Volkswagen XL1 Diesel Plug-In Gets "Just" 120 MPG In Real-World Drive

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While the assembled hoardes drooled over Ferraris, Porsches and McLarens at March's Geneva Motor Show, those of a greener disposition were more interested in another vehicle.

Launched alongside the hybrid hypercars was a true hybrid supercar in its own right--the plug-in diesel hybrid Volkswagen XL1.

Its 261 mpg combined gas mileage figure raised a few eyebrows, but as usual such a higher figure has quickly been disproven--the XL1 "only" gets 120 mpg in real-world driving.

Not that the 120 mpg figure attained by Automobile (via Autoblog Green) is absolutely terrible... really, it's highly impressive.

Okay, so it serves to illustrate how messed-up official fuel consumption figures are for vehicles that use two sources of propulsion on a short, unrepresentative lab-based test. And that in turn shows us why we should be highly skeptical of any such official figure when thrown around at an auto show.

But it also shows just how much more there is to come from vehicles if 120 mpg is possible right now.

The XL1 isn't a "normal" vehicle by any means--you can gather as much from its cigar-shaped body, covered rear wheels and supercar-style doors.

Under the skin it uses an engine that you'd hope would be economical in anything small and light, with just two diesel-fired cylinders and 47 horsepower to its name.

Power is enhanced a little by a 27-horsepower electric motor, but its 12.7-second 0-62 mph time confirms that this is an eco-car first and foremost. Such a sprint would be borderline acceptable in Europe, but less so in the U.S.

Electric range is around 30 miles from the 5.5 kWh lithium-ion battery, though the journalist reports that higher speeds are better served by the (rather noisy) diesel engine than they are by the electric motor.

However, 30 miles should provide the normal plug-in benefits when the small selection of lucky buyers--none of whom will be in the U.S, it seems--get their hands on the car, with enough range for the daily commute. In such a scenario, that unlikely 260 mpg figure might hove closer into view.

And they'll have fun too, if Automobile's review is anything to go by.

In whatever format the XL1's technology eventually reaches full-scale production, it's reassuring to know that regular production cars with 100 mpg capability aren't that far out of reach.

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Comments (22)
  1. Sounds awesome. Something that can beat a 50 MPG Prius by a factor of 2 in the real world, very impressive.

    And as Antony says, and I've said for years now, these corporate produced for press-release MPG numbers are highly suspect.
     
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  2. I coulodn't find specifics on how many miles they drove, speeds and if the battery was charged or not. As we all know, those specifics can make a huge difference in the mpg or mpge achieved.
     
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  3. It should be noted that 120mpg is still somewhat "BS" since it includes the 30 miles or so electric miles and didn't account for the electricity used.

    3 important facts to point out:

    1. It was a 1,800 lb car.
    2. Its 0-60mph time was 12.7 seconds (very slow and limite in power)
    3. Its average speed reaching that 120mpg is slower than your average hwy cruising speed.
     
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  4. Some quotes to point out:

    "In theory, the XL1's 5.5-kWh lithium-ion energy cells provide about thirty miles of electric-only driving. In reality, it is almost impossible to maintain the steady pace required to reach this goal, so it's advisable to switch to hybrid mode as soon as the speed quickens and whenever there are mountains to climb"

    "After 135 miles in test car number three, the trip computer reports the equivalent of 147 mpg, an average speed of 23 mph (which, even for Switzerland, is very slow), and 127 miles of range remaining"


    A Tesla S average 23mph can go almost 400 miles. That is 158mpge.
     
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  5. Having owned one of the original Insights I don't find this very impressive. Considering the little improvement in economy over the Insight there are a lot of compromises car wise. I have actually averaged 103.7 mpg in the insight in normal traffic at speed and regularly averaged 83mpg per tank.
     
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  6. In the VW's defense, it's only fair to point out that the test route appeared to be through a rather hilly region of Switzerland (is there any other kind?...).

    While I'd have to drive the thing to back up my suspicions, I expect a lightweight and aerodynamic two-cylinder diesel would be quite capable of 100 mpg+ tanks on a typical commute, even without those few miles of battery power. If it *isn't* capable of that, there'd be something seriously wrong with it.
     
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  7. Otoh, it uses diesel, a denser fluid, containing more energy per litre. The Honda Insight runs on petrol. The difference is about 12%, so 83 mpg petrol is 93 mpg diesel equivalent.
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  8. [It should be noted that 120mpg is still somewhat "BS" since it includes the 30 miles or so electric miles]

    Don't you use this formulae when extolling the virtues of your Volt.
     
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  9. Yep, it should be called out where-ever it happens. In this case, I missed it. I didn't really it was 120 mpgBS and thought it was 120 mpg.

    As happens too often on GCR (and elsewhere), there is no accountability for reporting on whether or not the value of the electricity is thrown in "for free." It's poor reporting if you ask me.

    Thanks Xiaolong.
     
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  10. I never do. I never claimed that my Volt is at 136mpgbs.

    I have always said that My Volt has over 17,890 miles in 12 months and only has used 132 gallons of gas. I never ever used the word "mpg" in that sense. In fact, the I have repeatly pointed that out over and over again to all plugin owners.
     
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  11. When are we going to call the manufacturers on their obfuscating claims. Using whatever "standard" test you wish -

    An ICE vehicle gets a certain number of miles per gallon. So does a non-plug-in-hybrid.

    An electric vehicle gets a certain number of Wh (out of the wall) per mile, or miles/kWh if you wish.

    A plug-in hybrid can claim miles/kWh when running electric or mpg when running under liquid fuel, but to claim one energy source number while ignoring the other is simply (expletive deleted).

    My Honda Insight with close to 90K miles has now unfortunately dropped its 'lifetime' mileage to 77.0mpg (from a high of 78mpg).

    Sure wish that VW would make that XL1 purely electric.
     
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  12. Car and Driver did an excellent article on the XL1 in the July issue of Car and Driver(ask John Voelker for a copy of the article). VW built this car to persuade (try to) environmentalists that the cost curve for improving MPG is going to get very steep. VW stated that the super high MPG of the XL1 was achieved through exotic materials and fabrication, NOT exotic drivetrains. Green Car Reports breaks out the pom-poms every time some company comes up with a new idea and a usually small improvement in technology. VW used the XL1 as a benchmark in MPG to show that technology, price, and impracticality will get maxed out to get much more improvement in MPG. It is a demonstration of the absurdity required to achieve 120 MPG.
     
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  13. The drivetrain of the XL1 uses an off the shelf Jetta hybrid motor and a Golf diesel motor with the block cut in half to make a 2 cylinder diesel. Not very exotic.
     
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  14. There's probably a little more to it than breaking out the band-saw, Randall ;)
     
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  15. Very unimpressed the more I read on it. Nothing New to see other than a shape and the shape would not be accepted by the mass public. This car is a waste of time and a setback. A more efficient ICE motor needs to be made and for heavens sake try something new in the battery or electric motor department. Sounds like they used off the shelf parts for this one.
     
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  16. You guys finally figured this out. The European drive cycle is 100KM or 62 miles, the vehicle can travel 50KM or 31 miles on electric alone. The figures said the car could travel 100KM on .9 liters of fuel. But it only traveled 31 miles on diesel and used.9 liter or .2377 gallon which is 130.42 MPG. Just can't believe that it took sooooooo long to figure this CF out.
     
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  17. How do you mean "finally", George?

    I don't think we've ("we" being Green Car Reports *and* the green car community as a whole) ever suggested that plug-in hybrid efficiency figures do anything *other* than contain a mix of fossil fuel and electric driving.

    Looking at the bare numbers can be misleading of course, but as any Chevy Volt owner will tell you, they're quite capable of *beating* official figures too (at least on paper), if only electric power is used. Overall efficiency entirely depends on just how much electricity you use, and how often.
     
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  18. Nobody was reporting on how the numbers were determined and it seemed kind of queer to me that this engine consumed only about a quart of fuel for 62 miles traveled, that would be a world record in itself in engine thermal efficiency (almost twice what the record is). I am just saying that the marketing on the product was false and you guys could have exposed it early on, but you didn't.
     
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  19. I have not had a chance to try a 27mph run with the BITW vehicle, however I have done a run at 45mph and achieved 94mpg on a 100 mile run.http://www.motherearthnews.com/green-transportation/100-mpg-speed-kills-gas-mileage.aspx#axzz2VvXpTXSa
     
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  20. Editor: seriously, I think the article should be corrected. If the 120 mpg includes the value of the electricity, is it too much to add a note indicating such?
     
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  21. It is an "industry" trend to do this since it overinflates the "MPG" value of the plugin cars. It is a marketing tool to bring in more buyers...

    Prius Plugin, Energi and Volt all display their so called "MPG" this way. Disappointing.
     
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  22. It is all about $$$$ for me and many EV PHEV.
    Yesterday I drove 53 miles and used 10.8 Kw and a quart of gasoline at speeds 45-65 mph, normal acceleration and speeds.
    Display = 200 mpg
    Cost = (10.8 x .075) +(.25 x 3.69) =$1.73
    That will buy 0.469 gallons of premium gas. 53 miles / 0.469 = 112.9 MPG
    That's the way I look at it.
    CHEVY VOLT
    New rate is ZERO per Kwh. OMG = 212 MPG
     
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