Wednesday 17th July 2013

Volkswagen XL1: the tech

Inspired by penguins says VW - bulls**t says the designer. PH gets to the truth...

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It's a horrible cliche, but knowing where to start with the VW XL1 is real challenge. Therefore you can read some driving impressions separately and here we'll outline the tech of this incredible little car.

Camera replace mirrors on aero grounds

The XL1 represents a decade of development of Ferdinand Piech's vision for a usable car capable of 1l/100km (282mpg). This began with the L1 of 2002; by the time the 2009 L1 was revealed, work was already underway on the production XL1.

This is really an engineer's car, and it's therefore hard to avoid a comparison with original Honda Insight. Both employ a methodical and innovative approach to efficiency, rejecting the conventional dullness of hybrid vehicles to wide acclaim. Whether you will ever be able to buy an XL1 for £3,000 though, is another matter...

Surprisingly, the Porsche 917 is another vehicle the XL1 has ties with. Ferdinand Piech was involved with both projects, and there are links between the two; the Porsche was one of the first cars to use magnesium wheels, as does the XL1. The rear-mounted fans in both are similar and the overall proportions are not dissimilar. Unsurprisingly, the Porsche Le Mans legend isn't mentioned in the press pack...

Body and chassis

Entirely smooth front helps 0.189cD

With around 40 per cent of a car's weight typically accounted for by the body, VW had a project goal of significantly reducing this for the XL1. The carbon fibre reinforced poylmer (CRFP) monocoque is both a safety cell and a supporting structure; its 89.5kg total weight is an important contributor to the XL1's 795kg kerbweight. Aluminium subframes are attached to cradle the battery pack at the front and the electric motor/diesel at the rear. CRFP is again used for the body panels to further reduce mass. Consequently, the XL1's body is now only 29 per cent of the overall weight, at 230kg. The drivetrain contributes another 227kg, the chassis 153kg and the final 185kg is comprised of equipment and electronics. The overall weight distribution is 40:60 front:rear

Dash is clad in carbon film; every little helps!

VW designer Peter Wouda rebukes the official claim that the XL1's appearance is based on a penguin, whose drag coefficient is, according to VW, an amazing 0.03. "That's marketing bulls**t. I was inspired by sharks." That's settled then.

But that does explain the aggressive yet smooth front end and narrow rear, with every surface made as flush as possible. The rear windscreen is steeply raked, the underside flat and the rear wheels covered to boost the XL1's aerodynamics. The overall result is an astonishing drag co-efficient of 0.189.

The windows are made from polycarbonate, which is around a third lighter than glass. On top of the weight saving, the flexibility of polycarbonate gave the designers more freedom with the glasshouse. It also means that side airbags aren't necessary as it will not shatter like regular glass.

The meticulous attention to removing unnecessary weight continues inside. The dash is made from recycled wood pulp, mounted in a magnesium carrier and then trimmed in a carbon film. Driver and passenger both sit in carbon fibre seats without conventional height and backrest adjustment, with each one weighing just 11.6kg.

Wheels, brakes, tyres

Slatted covers cool carbon-ceramic brakes

It's a shock the first time the guys from VW dry-steer the XL1; the 115/85/R15 tyres look to have been sourced from a bike shop. They have also been specifically designed for the XL1 with Michelin. Might be worth phoning Kwik-Fit in advance for a new set...

The magnesium wheels are covered by slatted trims to aid cooling of the carbon-ceramic brakes. They are used to further reduce unsprung mass and each is 280mm in diameter.

Powertrain and transmission
In layman's terms, the XL1's 800cc two-cylinder engine is half of the 1.6-litre diesel found in something like a Golf Bluemotion and produces 50hp. With the electric motor's assistance, total power is 67hp. It is supplied by a lithium-ion battery pack rated at 5.5kW/h, which is water-cooled and cased in the same carbon fibre reinforced polymer as used on the XL1's tub and body. In total, the battery pack weighs 68kg.

Weight saving here? Yep, DSG uses magnesium

The XL1 is a parallel hybrid, meaning it can run on either power source or both. The electric-only range is 50km (31 miles) with a top speed of 70mph. At 1l/100km (282mpg, below the official claimed figure), a range of 1,000km is theoretically possible with a 10-litre tank. Emissions are rated at 21g/km of CO2. A full battery charge takes between 90 and 160 minutes depending on the supply, plus regenerative braking also restores charge.

The DSG is the same as used in other VW group models, but with magnesium components rather than aluminium to save weight.

 

[garypotter]

What the fk is that!!!!!!!

Please VW do not follow BMW into a decade of seriously ugly ducklings, why can they not fit the new tech into exisitng models that a look good and b sell well?

[LaurasOtherHalf]

Absolutely stunning bit of kit, unfortunately us mere mortals will never be able to afford it!

Only surprise is the dsg box as they're surprisingly heavy things-I would have thought some cvt type affair would have been both lighter & more efficient.

[scubadude]

I think it looks rather good.

Obviously these will be overpriced roadgoing concepts but a properly productionized real world example at a real world price would be IMO very popular. I could certainly live with a small 200mpg commuting vehicle- saves fuel, trees and penguins so you can drive a "real" car at the weekend :-)

Frankly it would be nice just to see some sensible weight saving measured applied to current normal cars, its crazy that so called super-mini types weight 1500kgs or more!

[MikeyBoy2000]

Brilliant, brilliant, brilliant...! Well done VW for raising the bar.

Just the question of pricing that will either make it or break it... I can't see VW taking it as a loss leader.

[IN51GHT]

It is a beautiful thing to behold having spent an age looking one on Thursday, shame VW don't take a leaf from Hondas book, allegedly each Insight cost them £50,000 to build, selling for about £18,000 in the UK.

However, I'm astonished looking at the measures they have taken to remove weight that it's only 60KG lighter than my Insight. I'm guessing it's NCAP driven.

[0llie]

I think that looks fascinating. Technology certainly sounds intriguing!

[loudlashadjuster]

The Article said:

"The rear windscreen is steeply raked.."

It is? My understanding of rake means the rear window would be more upright, like a three-box saloon.

Do you mean shallow?

[IN51GHT]

loudlashadjuster said:

It is? My understanding of rake means the rear window would be more upright, like a three-box saloon.

Do you mean shallow?

It doesn't actually even have a rear screen

[another 3 points]

Tie-up with Google driverless car thinking?
Afterall what driver would ever set foot in something that looks like that?

Hell VW,, what a grim future we face.

[timothymcn]

I love this thing. Love it. Never thought I'd be lusting after something with 67 hp.
Now, if they made a mad Audi tdi hypercar version with some of their R18 knowledge sprinkled in, I'd sell my own organs, as well as my future childrens'.

[loudlashadjuster]

IN51GHT said:

It doesn't actually even have a rear screen

Hahaha! Good point!

[71tuscan]

Wonderful idea! More fuel left for real cars!
Hideous looking thing tough...

[renaultgeek]

I like the idea behind it, I just can't help but think it could be done cheaper though and they're using the high tech materials just because they can. Like whats the point in covering the dash in carbon, paint is lighter.

Also, I'd be worried about the polycarbonate windows yellowing.

[anonymous-user]

I'd drive that, and i bet it would get more attention than any Fezza or Lambo !


I'm not sure however that i'd forgo the side airbags just because the windows no longer break? Whilst it is currently trendy to state than some natural item (sharks, penguins, eagles, fish or whatever) was your inspiration, when it comes to aero drag, then all you ultimately want is to pick one of these:




and then do this:




Note the date btw, Nothing really new in aero for a while!

[darkangelv2]

Edit - misread!

[FlossyThePig]

Max_Torque said:

Interesting Stuff!

Cd is great for marketing departments but shouldn't we be considering CdA, which takes the frontal area into account. A less slippery small vehicle can still be better than a more efficient large vehicle.

[MJK 24]

"Side airbags aren't necessary as the windows aren't glass..."

What a load of nonsense. The Euro Ncap pole test and side impact test will illustrate very well the advantages of side airbags and it's nothing to do with protecting occupants from virtually harmless safety glass. Who wrote such nonsense?!

[Gecko1978]

I was looking at the interior and thought of loads of things thery could ditch to save weight in there. the Sat nav thing in the center way not have one screen behind the wheel with display split for side mirrirs etc then make the dash just a pod area for the driver. forget trim on gear gators etc bare bones stuff here. savew a gram here or there and soon enough you have saved a kilo.

[hairykrishna]

garypotter said:

What the fk is that!!!!!!!

Please VW do not follow BMW into a decade of seriously ugly ducklings, why can they not fit the new tech into exisitng models that a look good and b sell well?

It's form following function. It looks like that for aerodynamic reasons.

[Dr G]

hairykrishna said:

garypotter said:

What the fk is that!!!!!!!

Please VW do not follow BMW into a decade of seriously ugly ducklings, why can they not fit the new tech into exisitng models that a look good and b sell well?

It's form following function. It looks like that for aerodynamic reasons.

...and as a direct result to my mind is an incredibly good looking car. Uncorrupted function tends to look very good (see LR Defender).