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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."
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.
Some mornings it's hardly worth chewing through the restraints to get out of bed.
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.
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.
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.
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.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
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.
Real programmers use "copy con program.exe"
A heavier car is less susceptible to wind gusts. And drag isn't effected by weight, so the only downside to adding more weight is the initial cost of getting the thing moving.
Quid festinatio swallonis est aetherfuga inonusti?
Africus aut Europaeus?
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...
No good deed goes unpunished...
My Dad's old Corrolla would get 44mpg. He used to track it in his little notebook every time he filled up. It was carburated, 4-cylinder, seated 4, and ran over 200K miles before he sold it. How the hell do today's manufacturers get away with boasting/advertising 25mpg?
Actually you are incorrect. Diesel cars are allowed in the US: http://www.caranddriver.com/reviews/hot_lists/car_shopping/2008_new_car_reviews/2008_volkswagen_jetta_tdi_first_drive_review And VW has had several of their cars using Diesel here in the US for a while.
unimatrixzer0
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
"Most people in the U.S. wouldn't know they live in a tyrannical state if it walked up and grabbed their junk." - MyFirs
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.
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
In the diesel world fuel is required to burn off trapped hydrocarbons.
On all new 2007+ truck engines a Diesel Particulate Filter is required to trap diesel 'soot'. What happens when this filter gets full is fuel is injected to heat up the the element and burn off the soot.
Also if you run your engine TOO efficiently you create NOx (Oxides of Nitrogen), which is also regulated as an emission. So if you're at a low load condition (say idle) you could get away with burning 0.1 gal/hr. But you'd be spewing NOx, so instead you burn 0.2 gal/hr so that you have 0 NOx (but higher CO2, which is unregulated).
I don't know how it works for gasoline engines.
(Disclaimer, I work for one of the 'big 3' American diesel engine makers)
And drag isn't effected by weight, so the only downside to adding more weight is the initial cost of getting the thing moving.
On a flat Earth I would agree with you. However since the real world outside the lab has hills, I would say that adding more weight has a bit more downside than you think. Oh I agree there are devices that try to "harness" the energy from the downhill runs (and deceleration) via hydraulics or pneumatics, and "boost" the engine when needed (startup, uphill). And all self respecting scientists know that you will never approach 100% efficiency (40% being the theoretical max).
But you can't escape the m part of the F = ma formula.
Seven puppies were harmed during the making of this post.
The catalytic converter, which is an important part of the emissions control systems in a car, sits in between the engine and the tailpipe. It contains a honeycomb structure coated in a catalyst. For it to work at any real effectiveness, the honeycomb must have many densely-packed chambers the exhaust gasses are forced through.
The catalytic converter is therefore an impedance to the flow of exhaust gasses. In a four-stroke engine the exhaust gasses are pushed out by an up-sweep of the piston. If you restrict the exhaust, the piston "feels" the resistance. Imagine plugging the tailpipe entirely - the result isn't what you'd call "efficient."
There are also a few other complexities introduced with catalytic converters, like the fact that it's much harder to burn fuel lean.
...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.
That that is is that that that that is not is not.
From the article, drivers had to weight 110lbs or more, not less.
"The past was erased, the erasure was forgotten, the lie became truth." ~1984 George Orwell
Well, I can't point you to a vehicle a tenth as efficient, but this car due out later this year comes in two models -- the Aptera Typ-1h, which gets 130mpg plus has a 40 mile all-electric range, and the Typ-1e all-electric with a 120 mile range. Since power plants have a higher thermodynamic efficiency from burning fuel than gas engines, while battery, charger, and transmission losses are very small, you're looking at almost 200mpg equivalent for the Typ-1e and for the first 40 miles of the Typ-1h's range. So, you're looking at roughly a 20th as efficient, give or take in either direction. The price is a bit steep for a two seater ($30k for the Typ-1h and $27k for the Typ-1e), but when you're nearly or completely eliminating a couple thousand dollars in money spent on gasoline per year for a hundred dollars spent on electricity, and cutting maintenance (the electric drivetrain only has the following moving parts: three wheels, one drive belt, one sealed brushless electric motor; not even a transmission), you can hit payback pretty quickly, and certainly pay off the difference over a normal car in several years. Not to mention, it's all sorts of crazy neat features like in-seatbelt airbags (like small planes use -- they don't explode toward you, but upwards to be between you and the dash, shielding your whole body), StreetDeck (a nifty nav/entertainment system), camera situational awareness displays, and so on.
They're currently moving into their production facility, and plan to offer test drives and factory tours in 30 to 60 days.
I'll BUILD someone to replace you. Some kind of gamma-powered monster, with a heart as black as coal!
Thanks for the results list...but the article doesn't say anything at all about the tech behind the cars. Bah.
Obligatory blog plug: http://www.caseybanner.ca/
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.
The enemies of Democracy are
Actually, I just looked under my 1996 Oldsmobile Ciera recently and was suprised to see that there is indeed a stainless steel air injection line running into the catalytic converter - at least I'm pretty sure that's what it does, what else could it be?
The back pressure is largely additive: its in addition to the muffler and resonator. EFI does not choke the engine like a carb; it always runs at optimum fuel mix. It just might be more fuel and less air when the engine is cold. It doesn't really "waste" it. Also, the emissions system cannot ADD to gas mileage, so it cannot pay for itself in terms of it. If you take it out, the computer will simply correct the fuel mileage.
My car, when it was new, got 38MPG(actual reading on a trip to Ohio) on the highway and generated 155Hp. You'd be VERY hard pressed to find such mileage results today.
Anyway, YES, EFI cars have far less emission control systems than older carbed cars. Less PCV and vacuum equipment, smaller or nonexistant air pumps - but the catalytic converter will always be there. The reason is that most of the the converter takes care of is not a part of the combustion of fuel- but is rather the result of what happens to the rest of the air (nitrogen and such) in the extreme heat and such. Efficiency cannot affect that - in fact, higher operating temperatures of modern cars have made it worse.
Nitrous oxides, for instance. There's no nitrogen in gasoline.
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.
I'll BUILD someone to replace you. Some kind of gamma-powered monster, with a heart as black as coal!