2,843 mpg

"I don't quite understand how the 2 solar powered entries used any gas."

It must be the gas used by the supporting vehicles proportionally allotted to each vehicle in relation to the cc of the engines rounded to the next higher value.

Maybe they have a lawnmower engine in there to get them past the difficult spots or they use petrol (gas) to clean tar from the underside to reduce weight.

"Has anyone seen higher mpg than this?"

Yes infinity.

In any case my conspiracy theory has been disposed of with Shell sponsoring the effort.

In SA we use a comma as the decimal point so my first response were "2.8 !! even my 3 litre Camry does better " (even when using imperial gallons)

But agreed it is needed research that should be done and the rules may just as well introduce the competition component.

Uh-oh, time for Ken Fry to re-post his diatribe about MPG calculation.

My hat's off to Shell and the winners. YMMV

People would have to watch their mileage more closely and schedule their oil changes every time they consume one gallon of gas.

Gas companies will not let automobiles go into mass production with this type of gas mileage. They would lobby against it and win or they would buy up the patents and bury it. They would risk losing money over that.

Although 2843 mpg is impressive, the 2003 European Shell Eco Marathon record set by the French car from the Microjoule team is more impressive: 10,705 mpg. We Americans and our 2843 mpg gas (sunlight) guzzlers!!

The Shell Eco Marathon is a great educational challenge, and the students do some really impressive things. Of course, these are not road vehicles, and they are driven at incredibly slow speeds on tracks -- about 15 miles per hour. The average bicyclist can go faster and not use any fuel at all, beyond food.

The solar power consumption is converted to the equivalent joule value of a gallon of gasoline. Although the solar-powered racers start with full batteries, they must nevertheless get all their energy from the sun -- wattage both into and out of the batteries is measured.

The (possibly) more familiar solar racers which race across Australia have several times as much solar panel area, are much heavier (500 lb instead of 100 or less) and are much faster (90 mph possible). The MIT entry has 1200 watts of solar panels, which would support an electric motor of about 1.5 hp continuously in bright sunlight, but the batteries allow temporary peak output of 10 hp.

It is interesting to compare the technology in these cars to cars like those that will be in the Automotive X Prize competition. The electric motors in the solar challenge cars are apt to be 96% efficient, while many in the Auto X prize will be closer to 90% efficient, in the interests of production cost. The batteries used will be very close in terms of power and energy per kilogram. The really dramatic differences will be in weight and aerodynamics. Once the vehicle is large enough to hold two people seated upright enough to be fairly comfortable, then the weight and frontal are have increased a great deal. Compounding the aero problem of larger frontal area is the increase in coefficient of drag: a boxier car that is on realistically sized tires is not as slippery (even for its size) as the solar racers. More weight requires bigger brakes, bigger tires, stronger structure, etc. and things quickly spiral up to the point where 300 MPGe equivalent (on electricity) is about all one can expect from an alternative class vehicle (many of which will be three-wheeled in the X Prize). 300 MPGe is not bad, but it is quite a way from 2843.

Blink -

Very informative and enjoyable reading, as usual. Do you happen to know whether they allow vehicles powered by synthetic muscle tissue or electric eels?

shock me like an electric eel