Slashdot Mirror
Can Your Car Get 1,700 MPG?
Xaroth writes "Given all the hubbub over EPA mileage ratings, I'm a little surprised that this one hasn't come up earlier. SAE apparently holds a contest each year to encourage students to design single-person, fuel-efficient vehicles. This year's winner achieved 1,747.4 MPG, with the press release that tipped me off pointing out that third got a 'measly' 1,194. There are more details on the competition over at SAE's site about the competition. Now, if only they could make these street-legal..." However, even the winner has nothing on top entries we mentioned in Shell's competition a few years back.
So, how much energy can you get from combusting a gallon of gas? If an engine was completely efficient, how far should it push 1ooo pounds?
This article makes me wonder: just how fuel-efficient can an aircraft be?
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
Can increase the efficiency over metal based ones. The temperatures they can withstand are far higher, raising the efficiency substantially over conventional ones.
They're also much lighter, the materials don't expand/contract and can be machined to closer tolerances and they wear out much slower than metal ones.
Government of the people, by corporate executives, for corporate profits.
How about comparing modern day cars, trains, busses, and planes, on a per-passenger basis?
According to Top Gear a few nights ago, trains get worse mileage than the average car, per passenger(I'm trying to find any info about the study online to see if that's based on maximum capacity of each type of vehicle or real-world average passenger counts) and a high speed train gets worse mileage than a jumbo jet! Personally I'm kind of curious about a subway train as well. Both averages(ie based on typical # of people in them) and maximum figures would be interesting for all vehicles.
When they asked the UK "Green Party" for a statement, they said "the best choice is the journey not taken". Um...okay.
Oh, and ever watched a diesel locomotive idling or at speed, belching lots of blue/black smoke? How about a city bus? Here in Boston, they're downright filthy, and in neighborhoods near the bus depots and garages, asthma rates are much higher, and studies have repeatedly shown diesel soot causes both cancer and asthma.
Please help metamoderate.
heh. I just love the way that site claims that 4 wheel drives have better brakes than normal cars... I didn't even get to the part about gas milage before giving up on them as idiots.
I check my gas milage every tank. My truck gets 3 more miles to the gallon towing the boat at 65mph over unloaded at 55mph! (I can't recall a trip at 65 without the boat to check the difference) I've checked this enough to consider it statisticly significant. More people should do this, if not every tank, at least often so they know.
There's a University competition sponsored by Ford and the DOE to build environment-friendly, fuel-efficient vehicles called FutureTruck. The catch? They have to modify Ford Explorers, not create go-cart sized vehicles, maintain existing performance, and remain fairly manufacturable. (In other words, Ford is using college teams for their R&D.)
There've been amazing results: the winning team, from University of Wisconsin Madison, built a hybrid Explorer that got somewhere over 40 mpg. (Different sources disagree as to the exact number.) For reference, stock Explorers are rated at merely 15/19 mpg for city and freeway driving. They also scored well in emissions and made a vehicle which could probably be manufactured and sold for about the same price as a stock vehicle.
So it's not 1700 mpg. It's still pretty darn impressive for an SUV!
"Science is a way of trying not to fool yourself." -Richard Feynman
There's probably a happy medium in there somewhere where aerodynamics aren't as much of an issue, but it's still in a range high enough on the torque curve to get decent mileage.
I drove my old DSM at about 130mph for about 4 hours straight, and I had to stop for gas 4 times (this was back when montana had no speed limit). I was getting about 10mpg, when I normally got around 20. At 130 in 5th, it was definitely approaching or at the top of the torque curve. I assume it was air resistance that was making me get poor mileage.
Need Free Juniper/NetScreen Support? JuniperForum
> Vehicles sold in the US have to meet certain standards of crashworthiness ... This has kept a lot of cars from being imported here
Their are many cars that are safer than anything in the US, not legal because the US requires the cars to be crashed, wont take any computer simulations. So many of the safest (and most expensive) vehicles are precluded since it's to expensive to sacrafice a dozen cars to sell a few dozen.
Actually if you check that link, theres a bit in there that states: "Why was this design not used earlier in autos, see as it has been around since at least 1904?" So a hemi wasn't a new invention, it was just Chrysler that recognized something good and ran with it. AFAIK, Hemi's were popular in airplane engines long before they ever got their start with Chrysler in automobiles.
:)
As for your first question, well, they do! Most every engine I can think of has a hemi shaped (commonly called "pentroof" to get around the trademark) design. From what I know, virtually all automakers use a hemispherical inspired cylinder roof in their engines. They just aren't called "Hemi's" because thats Chryslers thing. And since hemispherical chambers are now commonplace because of their efficiency, no one bothers marketing the feature. Chryslers "rebirth of the Hemi" kick is just a marketing gimmick. "Hemi" has been synonymous with "power" since Chrysler popularized it. The word 'dissapeared' when the gas crisis hit, because "hemi power" used lots of gas in the minds of the public. Instead, we got smaller I4 and V6 engines with "efficient" designs that were still basically a hemi/pentroof cylinder head. Understand that Hemi's just get more power out of the same amount of displacement as other designs do. So a small hemi is "efficient" because you can make the same amount of power with less displacement (which burns less gas), and a big hemi is "powerful" because you can get more power out of it than a similarly sized engine.
Now that we're back into a modern day horsepower race, its cool to have a powerful engine again. Mix with nostalgia, and voila: the Hemi is "back" when really, it never left.