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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.
The formula:
1) Take a highly-efficient small engine.
2) Modify for even more efficiency.
3) Attach to 80 pounds of framework, gas tank, and wheels.
4) Drive 9.6 miles at 15 mph.
5) ???
6) Profit?
"They redundantly repeated themselves over and over again incessantly without end ad infinitum" -- ibid.
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."
The Future Truck competition may or may not meet your requirements, but it tries to do something more practical.
A phrase I heard years ago, though I don't remember where. It was something like... "Sure, we could hundreds of miles per gallon out of todays cars, just as long as you don't care how fast you accelerate or how fast you get there..." Personally, I could deal with a lot less acceleration...
~~ Please keep your arms, legs, and outright stupidity inside the ride at all times. Thank You ~~
Further requirement necessary for the real world: must be able to ascend a 5% slope at 45 MPH.
Don't blame me, I didn't vote for either of them!
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.
I always wondered why recriprocating engines theoretically required more energy to reverse the direction of the parts. I mean, once the piston passes mid stroke and starts slowing down, it is pulling/pushing on the crank, accelerating (imparting energy to) it. After it passes dead center, I would think that the added rotational energy of the crank would be transfered back to the piston. The kinetic energy thus is transfered back and forth between the engine's flywheel and the pistons. Aside from the usual friction in the rings and bearings, I'm not really sure where the loss is.
Unknown host pong.
Nice that Briggs & Stratton sponsors science fair projects like this.
Even nicer though if they could design their products to be repaired with ease.
I just replaced a fuel filter on an late model 8 horse B&S. Now you would think it would be an easy thing, but the line had to be replaced, because a) it had deteriorated at the connection end; and b) the old line was smaller than the nipple and any currently available filter.
I'm really not sure if there is anything I didn't have to take off the engine block to remove the old and useless fuel line. (the carb was in front of the starter, on top of the line.)
I'll take ergonomics and long-usable-life over fuel efficiency any day.
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.
Must be a bitch to take that shiny new 21 inch monitor home from the store.
I'd think that if you're spending ~$500 on a monitor you'd be able to afford a $20 taxi ride to get it home.
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.
The good thing is that hydrogen production can be done using only electricity, which doesnt depend on fossil fuels exclusively. In places like Quebec the vaste majority of electric production is hydro dams (which have their own problems but are about as green as you can get). Don't know much about production in other places.
As for nuclear energy, the problem with the waste is severly overblown. Yes, you have really bad radioactive byproducts that end up being buried but the good thing is that it is manageable and easily controled, which cannot be said for such things as car exhaust. Because you can stuff it in barrels you can restrict environmental damage provided you store in in a highly secure place, which is why geologically inert places such as locations in the canadian shield with no fault zones or groundwater (to prevent seepage) are used. Future solutions for radioactive disposal are inevitable. Maybe space flight will become much cheaper and we can dispose of it in the sun (which is one giant nuclear reactor anyways) or if we are really lucky, someone will invent a star-trek-like matter to energy converter
Which do you think is more efficient:
1. Burning fuel and turning it directly into mechanical power. One step.
2. Burning fuel; converting it into electricity; storing the electrical voltage in a battery (possibly a fuel cell); convert the battery power into mechanical power. Three steps.
Yes, the power plant is more efficient at converting fuel into electrical power than the car engine is at converting fuel into mechanical power. The problem is that you have to store the electricity and then convert it into mechanical power. Even if all the individual steps are more efficient, it would be very hard to replace one step with three and increase overall efficiency.
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.
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> 4 wheel drives have better brakes than normal
of course you are correct the less weight transfer (lower center of gravity, less suspension travel) will make you typical 4x4 stop much worse than your typical 2x4
I maintained slashdot status of not reading the article, but I assume they mean, you do get a touch of ABS effect, in a locking 4wd, with 4WD engaged. in that you can't lock up just one wheel. So you will likely stop quicker in 4x4 mode vs 2x4 on a varying tractive surface, thats assuming you want to stop in a strait line, and the best traction is in that direction (it better, cause thats whats going to happen if your at the braking limit in the engaged 4x4.)
> 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.
Depends on the biker- but I'd guess about 33 miles to the Big Mac (based on a Cycle Oregon website that claims 100 miles per day is not undoable, and based on Big Macs for Breakfast, Lunch, and Dinner). Last I saw, that would come out to just about 12 miles per dollar.
Ok, now given that gas costs $1.89 lately- I get 23 miles per dollar in my car. When you consider I can haul the whole family- the cost savings gets trippled.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
Well, the one you failed to click on (Convection) may have the most promise. It's not geothermal convection, it's a giant tower with a giant greenhouse at the bottom. The hot air flowing up the tower drives turbines. It would potentially power an entire city. Planning work has already begun for a tower to be build in Australia.
LS
There is a fine line between being a cultivated citizen and being someone else's crop. - A. J. Patrick Liszkie