## Volkswagen Concept Car Averages 262 MPG 353 353

coolnumbr12 writes

*"The Volkswagen XL1 averages an amazing 262 mpg, and although it may never hit streets in the United States, the technology behind the car could impact future Volkswagen vehicles. The keys to the incredible mileage in the Volkswagen XL1 were reducing the weight of the vehicle and eliminating wind resistance. The XL1 only weighs 1,753 pounds — that's more than a thousand pounds lighter than the Toyota Prius, which weighs in at 2,921 pounds. The wheels on the Volkswagen XL1 are as thin as road bike's and wrapped in custom Michelin rubber. The XL1 chassis is a single piece of molded carbon-fiber, and has a drag coefficient of only 0.189 – similar to a bumblebee."*
## Re:And what's that in metric? (Score:5, Informative)

Which of the two widely used metric standards do you want? ;-)

If you're from one of the countries that uses the km/L measure (Netherlands, Denmark, Japan, Korea, etc.), then this Volkswagen prototype gets about 110 km/L.

If you're from one of the countries that uses the L/100km measure (Germany, Italy, Australia, etc.), then this prototype uses about 0.90 L/100km.

## Re:We need a new class of 'ultralight' cars (Score:4, Informative)

There's a category of neighborhood electric vehicles [wikipedia.org] that are basically glorified golf carts. They can go about 30 mph, in some states can legally go on roads up to posted speed limits of 45 mph, and don't weigh much.

## Neat, but unsafe. (Score:5, Informative)

Given the drag coefficient, I assume this car exhibits Laminar flow. This can get disrupted by external factors (say getting passed by a buss) and result in localized turbulent flow. This would drastically increase the drag on one part of the car, causing a sudden unexpected side load, likely causing a turn (into the passing bus). An airplane bouncing around is not much of an issue, but when your car moves over 6 feet sideways on the freeway unexpectedly, it can be rather bad.

Generally maximally aerodynamic cars are not safe. They may not have gotten to that point, or may have cleverly worked around the issues, but given the lack of side mirrors, I think mileage was the priority over safety here. Its a neat technical feet, but as mentioned in the article, its dangerous in multiple respects.

## Re:One problem (Score:4, Informative)

The concept car is real wheel drive with rear engine, similar to the origianl VW although it isn't aircooled.

## Re:Not really (Score:4, Informative)

This is nice and all but the cars I drove in my life were about 45 mpg (non hybrid cars from the 1980s and 90s). I find that to be too much fuel use to my liking. It's polluting too much and we can't much reduce GHG emissions by 80% with that. Right now a regular car does 50 mpg. So (ignoring the problem that people will drive longer and more often)

50 MPG regular car = 6 gallons consumed

100 MPG research car = 3 gallons consumed

300 MPG super-car = 1 gallon consumed

3 gallons saved comes from the 50 MPG jump from 50 MPG to 100 MPG.

2 gallons saved comes from the 200 MPG jump from 100 MPG to 300 MPG.

50.0% of the fuel savings comes from the 50-100 MPG jump

33.3% of the fuel savings comes from the 100-300 MPG jump

## Re:One problem (Score:4, Informative)

## Re:Metric Units. (Score:4, Informative)

Yeah... Nothing I enjoyed more than doing conversions of miles, feet, inches,

tenths of inches, pounds, ounces (avoirdupois), gallons, fluid ouncesUmm, you're doing it wrong. Inches are most commonly divided into

eighthsorsixteenths, not tenths. (And, on occasion, even into 32nds or 64ths.) Americans like themore advanced binary systemsof measurement, rather than some stupid 10-based system... [/sarcasm]all the while there were these lovely decimal systems just itching to make everything much easier.

I'm definitely a fan of the metric system, but honestly I don't know if it's "much easier" in the days of calculators and computers that can do conversions easily -- heck, for many years your web browser has even been able to interpret unit names to do the conversion for you, so you don't even have to memorize it.

I'm not saying the old units make a lot of sense, but surely the math isn't

that hard. Carrying a unit like "in." or "ft." or "lb." around with a number is equivalent in complexity to carrying around a pi or e or whatever and then plugging in 3.14 or 2.718 at the end.Few people seem "itching" to make things "much easier" by converting time units to decimal (at least not since the French Revolution), so we live with base 60, base 12 and/or 24, base 7, and a completely irregular month system... why?

Same as GP's answer -- because it is a "working system," even if it's inefficient.

For the average Joe, he almost never has to convert miles to feet or gallons to ounces. About the only unit conversions average Americans ever have to think about on a regular basis are 12 inches = 1 foot and 3 feet = 1 yard. If you're ordering a steak or a hamburger, it might help to know that 16 ounces = 1 pound, and if you're ordering a beer, knowing the size of a pint might be helpful. That's about it for the average American. (Perhaps unfortunately...)

A mile could be 5280 feet or 5000 feet or 5347 feet for all most people care -- the exact amount is pretty irrelevant in everyday life. The units of miles and feet are so different in size that they only tend to occur in completely different contexts for most people. Very few people these days ever use the intermediate units like furlongs, chains, or rods, so complicated length conversions rarely are needed.

And that's true for most units. Different units may exist that are orders of magnitude apart, and from a practical everyday standpoint, you rarely need to know that some big unit converts to 5280 or 128 or 1728 or whatever of some smaller unit. You just use the appropriate unit in the first place. If you happen to be in some business or something where you actually need to convert hogsheads to pints or something on a regular basis, you get your spreadsheet or calculator to do it.

I'd be happy if the U.S. converted to metric, but the only people whose lives would be

significantly easierwould be scientists and engineers, and most of them use metric on an everyday basis already. For average Joe, unit conversions just don't impact his life so much.## Re:And what's that in metric? (Score:5, Informative)

5 gallons per 100 miles traveledwhen you go from a vehicle which gets 10 mpg to one that gets 20 mpg, but you only save2.5 gallons per 100 miles traveledwhen you go from a vehicle that gets 20 mpg to one that gets 40 mpg.Understanding this makes clear how much it is costing us to make ever smaller incremental changes in improvements in gas usage by vehicles. Paying attention to that will allow us to more readily recognize when further improvements in fuel efficiency are not worth the cost. It is called the law of diminishing returns, a law to which we as a society pay too little attention.