VW XL1 production version gallery

[wyatt]

Originally Posted by NachtRitter

Anybody have a graphic that shows how the engine cooling works? From the article, it sounds like the cooling comes from underneath and exits at the top of the engine. I realize none of the graphics that I've seen so far show a radiator... (or I missed it).

It's possible that there is no radiator, and it's just an air cooled engine, in the same spirit as the old rear-engine VW Bugs.

[NachtRitter]

Hmmm... possible, but I'd be surprised if that were the case... image of the engine (assuming it is relatively accurate) don't show the cooling fins that (I would expect) would be necessary for an air-cooled engine, and the article indicates the engine is half the 1.6-liter TDI used in the Euro-only Golf, which is not air-cooled. ... unless they are only saying the displacement is half... hmmm

[some_other_dave]

And air-cooled engines do not cool consistently enough to minimize emissions. Plus it is actually harder to get cooling air into all of the places you would want it in an engine. Remember, Porsche didn't go to four-valve heads until they went water-cooled. A few motorcycle engines did go with four-valve air-cooled heads, but motorcycles are not cars and the set of constraints they operate under is different.

-soD

[kah]

It is actually fairly simple, there are two air ducts on the car (parallel to each other and right below the upper rear led brake light), underneath there are on or two electrical fans pushing air down to the radiator.
VW-XL1-Live-25

[NachtRitter]

The article is claiming that the ducts on top are the air exit ducts... and in the photos of the fan, there is no radiator visible under the fan.

But the air coming out of the rear diffuser beneath the bumper isn’t going out, it’s going up. VW managed to channel the air out the splitter, through the engine compartment and then suck it out through a top-mounted fan. It’s a concession to the Gods of aerodynamics that wouldn’t work with massive side ducts like you’d seen on the 911 Turbo.

If the engine is water-cooled, and if the air flow is exiting at the top, then I would expect the radiator to be located at (near) the entrance of the air, toward the bottom of the engine.


It is hard to tell in this pic what the 3 blue-capped reservoirs are for, but if you look between the fan and the blue cap on the bottom left, it looks like there *might* be a radiator way down in there. That, and the shape of the fan blades does seem to indicate that the air flow is coming upwards...

[NachtRitter]

SAE article describing the XL1. It indicates that the diesel alone (without electrical assist) will consume only 2.1L/100km (112mpg).
Hyper-efficient VW XL1 drives to production

[cRiPpLe_rOoStEr]

Originally Posted by some_other_dave

And air-cooled engines do not cool consistently enough to minimize emissions.

Air-cooled Diesel engines are harder to control NOx emissions, and can't get a cooled EGR.

[gone-ot]

Originally Posted by NachtRitter

SAE article describing the XL1. It indicates that the diesel alone (without electrical assist) will consume only 2.1L/100km (112mpg).
Hyper-efficient VW XL1 drives to production

This picture says a lot:

[Frank Lee]

I'll point out one thing that does happen rarely, but happens nonetheless: when the rear track is significantly different from the front track, on a soft dirt road the rear end will hunt from side to side as one rear tire then the other goes into the front tires' ruts. OMG for annoying!

[sendler]

Originally Posted by NachtRitter

SAE article describing the XL1. It indicates that the diesel alone (without electrical assist) will consume only 2.1L/100km (112mpg).

So there is the number I have been wondering about. It seems the 260 mpgUS number that has been promoted is some kind of voodoo number combining unaccounted for wall power like the Chevy volt fans always love to quote. The XL1 will really get only 112 mpgUS on a long trip as the Volt gets 40. A pregen Insight can get 66 with decades old technology and was apparently cheap at less than half the price.