Eco-Marathon Team Hits 2,843 mpg

At this year's Shell Eco-marathon Americas event the team from Mater Dei High School shattered last year's record by traveling 2,843.4 miles on a single gallon of gasoline. "How did the Evansville, Ind., team come up with its winning airfoil-meets-teardrop design and beat out its largely collegiate competitors? "It comes from trial and error, seeing what works and what doesn't," an unidentified student and team member told a local newscaster Friday. Those top three vehicles, like most in the competition (25 out of 33 total), used internal combustion engines. The goal for all entrants was to travel as far as possible using as little fuel as possible. Vehicles--sans driver--couldn't weigh more than 160 kilograms (352 pounds), while drivers had to weigh at least 50 kilograms."

Comments

Re:OH WOW

[Kozar_The_Malignant]

I don't understand why modern cars get such lousy mileage. Air conditioning, for one thing.

Modern cars get better mileage with the windows rolled up and the AC on than with the with the AC off and the windows rolled down. Of course the best mileage is with the AC off and the windows up, but the passengers might be done to medium-well at the end of the trip.

Re:OH WOW

[Phanatic1a]

Weight.

Crash test standards add weight. Power windows, power-adjustable seating, 6-disc in-dash CD changers, power moonroof, they all add weight.

Colin Chapman, the founder of Lotus, pointed out that "Adding power makes you faster on the straights. Subtracting weight makes you faster everywhere." He was going for speed, but the same thing applies to fuel economy.

Consider a car that's a lot newer than those you mention: the 1985 Honda CRX. It had a 76-horsepower engine, and it had a 9.1-second 0-60, and 32 miles to the gallon. It was able to do that because it only weighed 1860 pounds.

1860's unthinkably light by current standards. I drive a Mustang GT that has a curb weight of something like 3860 pounds, so that's more than two tons with a driver and a tank of gas. You want a performance car that's even close to that 1860lbs, you end up with...a Lotus Exige, which is about 2000 lbs. And costs a hell of a lot more than an '85 CRX.

Re:OH WOW

[Phanatic1a]

Yeah, your guess sucks. Advances in engine technology have been utterly remarkable over the past several decades, to the point where Honda can squeeze well over 200 horsepower out of a naturally-aspirated 2-liter 4-cylinder engine. Specific power has increased by incredible amounts since the cars the poster was referring to.

Cars have gained ridiculous amounts of weight since the 1960s, but that's not because of the engines.

Burn and Coast

[michaelepley]

Also, an essential strategy for achieving high mileage is to burn the engine at optimum efficiency RPMs to quickly get to speed, and then use your mass combined with low aerodynamic and rolling losses to coast as long as possible (frequently almost to the point of stopping). This is why there are required average lap speeds and maximum speeds. Of course, this strategy could hardly be used in production vehicles or in public roads.

Re:Not Eligible

[atommota]

Maybe if you'd RTFA you'd see that only solar cars were excluded from the grand prize (all other fuels were ok including LP, H2, fuel cells, etc) and for a good reason. From the contest rules...

Shell Eco-marathon Americas Grand Prize - $10,000 Awarded to the educational institution or University in honor of the team who completes the farthest distance with the least amount of fuel. Because solar cars do not use "fuel" and the solar energy that is used is limitless and cannot be converted into an equivalent measure to compare to other engine types, solar cars are not eligible for the Grand Prize award. Enough with the Slashdot corporate whining already.

Power, add ons, cat, fuel

[Kupfernigk]

First, the cat wastes power because fuel has to be burned to heat it to operating temperature. My 2007 Diesel is less efficient than my 2001 Diesel for this reason (I monitor the computers and it is clear that the 2007 model has to heat the cat before the fuel consumption goes to its lowest.After about 40 miles the newer model starts to use less fuel than the older one.)

Second, modern cars have bigger engines. Even a tiny town car in Europe often now has a 100BHP engine when 20 years ago it would have been 60. More acceleration, more wasted power, plus the bigger engine just takes more power to turn over. Third, modern fuel has a lower octane rating than older fuel, and so must use a lower compression ratio - which means lower efficiency, as you find out in basic thermodynamics. Finally, air con,power steering, all need power to operate. Even the most basic model of possibly the most basic car in Europe - the Hyundia i10- has air con, power steering, and a 60HP plus engine.

Despite this, the best modern engines are remarkably good because of advances in fuel injection (both Diesel and gas), and because the timing cycles and better valve gear result in less port wastage. The real fuel consumption of that 2007 Diesel is about 80% of my 1990 non-turbo mechanically injected model of the same weight and size, which is pretty good.

RTFA. It didn't go that far on a gallon of gas.

[Darth Muffin]

If you read the article, the top competitor using gasline got 163.5 MPG. It does say they used Internal Combustion Engines, and it doesn't say what they did use but it's not gasoline. It doesn't say whether that 2843 MPG is miles per gallon of some other fuel of if they gave them the engergy equivalent of 1 gas of gasoline in that "some other fuel" and measured how far they went on that. Or maybe it's something else completely. The article is poor on details.

Re:OH WOW

[Tuidjy]

I have a 460hp (modded) car that got 38mpg on a LA-San Diego round trip. At the same time, it gets about 2mpg at full throttle and top speed. There is nothing wrong with modern engines, but if you have a ton of power and habitually use it, you will pay in fuel.

And do not forget, modern cars are heavier because of safety requirements, noise reduction materials, power everything, air conditioners, etc...

Re:OH WOW

[RingDev]

Not really. The EPA tightened the restrictions on diesel emissions last year (2007). The Diesel technology to meet those requirements already existed, but the excessive amount of sulfer in US Diesel prevented those systems from being introduced here.

Also taking place in 2007 was the change over from Low Sulfur Diesel (LSD) to Ultra Low Sulfur Diesel (ULSD). Because of the time line of the USLD conversion you could still buy LSD up until October/November of 2007, and In theory, the tanks could have a LSD/ULSD mix there after if there was still some amount of LSD in the storage tanks when the first ULSD delivery came in.

So basically, due to really crappy timing on the EPA's part (that ironically enough helped the US manufacturers who had no light duty diesel options), there was only 1 light duty diesel that could be sold in the US through 2007.

But now it's 2008. ULSD is the only Diesel now. VW, Mercedes, Jeep, hell even Honda all have new light duty diesels either already out, or coming out in the US this year.

-Rick

Calm Down

[Hubec]

The reporter got it wrong (as usual). The single entry was actually running Liquefied Petroleum Gas (LPG) not as he reports "liquid petroleum gasoline". I believe the "combustion" class of which the winner was a part is plain old gasoline, just as the headline states.

Re:Calm Down

[shiftless]

The single entry was actually running Liquefied Petroleum Gas (LPG) not as he reports "liquid petroleum gasoline".

For those who are unaware, in the United States LPG is basically propane. It is liquefied and stored in a pressure vessel under relatively low pressures, 150 psi or so. The most common (and preferred) variety of LPG in the US is HD-5 which is minimum 95% propane and a maximum 5% "other" gases, such as isobutane. The RON+MON/2 octane rating of HD-5 is 104.

While the energy content is a bit lower per-gallon compared to gasoline, the fuel does have a number of advantages which this team may have found helpful. First, the 104 octane would allow them to run a higher compression ratio than if they were using pump gasoline, which results in a big jump in fuel efficiency. Due to its gaseous nature, it's easier to meter and maintain the proper air:fuel ratio. The fuel delivery components are much simpler (and possibly lighter, depending on how they designed the vehicle) than a gasoline fuel system. Propane also burns more efficiently (mainly thanks to its gaseous nature), which could likely result in a improvement in a small engine. Another advantage is the fact that propane is a refrigerant, and thus absorbs a large amount of heat when it vaporizes from liquid to gas. This could be/could have been used to cool the incoming fuel/air mixture, resulting in a much denser mixture and measurably higher power output.

My old university got 5691 mpg in 1986

[Chirs]

Not sure if the rule have changed or what, but my university (University of Saskatchewan) got 5691 mpg in the Shell Fuelathon back in 1986, and 3086 mpg at the SAE Michigan Super Mileage Competition the same year.

The vehicle weighed 84 lbs and used a 70cc engine.

http://engrwww.usask.ca/affiliation/societies/sae/history.html

2,843 MPG is shabby compared to...

[GPS Pilot]

...12,665 MPG, achived by a Swiss Eco-marathon competitor in 2005. ( http://en.wikipedia.org/wiki/Eco-Marathon )

Gotta love this quote...

Shell points out that "it would be possible for the winning Shell Eco-Marathon UK car to travel three times around the equator on the same amount of fuel that Concorde needed to reach the end of the runway.

Re:OH WOW

[Fozzyuw]

and that passenger has to be 110 lbs or less.

while drivers had to weigh at least 50 kilograms.

From the article, drivers had to weight 110lbs or more, not less.

I hate articles like this

[kcbanner]

Thanks for the results list...but the article doesn't say anything at all about the tech behind the cars. Bah.

More like scam troll

[Chris Burke]

Here's a photo of the winning car (the one on the right, #22), where are these 200 sq ft of solar panels you're talking about? There's also a better angle on the team's homepage here, no solar panels to be seen. Heck, that car doesn't even have 200 sq feet of surface area even if you counted the belly.

Did you know that while solar cars did compete, they were not allowed to win the grand prize?

Yeah, you're full of it. But at least you tricked a mod or two.

Re:Extraordinary, But Over-Engineered for The Mark

[Rei]

Where I live, more than half the cost of electric is in the delivery/line charge.

It doesn't matter how much is in the "delivery line charge"; cost does not equal efficiency. In the US, the average transmission efficiency is 92.8%.

you lose 15% in the charger

AC Propulsion's 20kW charger is 93% efficient, while their 150kW charger is 90% efficient. That's pretty typical for non-inductive chargers.

and another 30% to the lead acid battery.

Lead-acid battery? Lol, what do you think we're talking about here, golf carts? NEVs? Even Firefly lead acid batteries are simply unsuitable for these sort of tasks. Way too short lifespan, way to inefficient, way too low energy density. We're talking about lithium ion variants. Lithium ion batteries are over 99% efficient (that's why they charge and discharge cool).

So while at the power plant rock in efficiency, it doubles in cost getting to my house

Please learn to separate the concepts of "cost" and "efficiency".

My understanding is Gas engine are 70-80% efficient

Try about 20%, give or take.

It's okay to be unfamiliar with this topic. Just educate yourself so you're more informed for future debates and we can talk some more. :)