Can Your Car Get 1,700 MPG? 719
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.
My car gets 40 hectares to the hogs head (Score:4, Funny)
(you knew this one was coming)
your calculations are a little screwy (Score:5, Funny)
Re:your calculations are a little screwy (Score:4, Informative)
Re:My car gets 40 hectares to the hogs head (Score:3, Funny)
Re:My car gets 40 hectares to the hogs head (Score:3, Interesting)
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.
Safety Equipment? (Score:4, Insightful)
Re:Safety Equipment? (Score:3, Insightful)
Re:Safety Equipment? (Score:5, Insightful)
Fuel efficiency is a difficult thing to deal with - engines have the highest efficiency (power out/fuel in) basically at the minimum point in the power band. Yes: this means that a common engine is getting terrible gas mileage if you're moving along at ~15 mph normally. This is why a car's maximum fuel efficient speed is complicated (and is rarely 55 mph, regardless of what hundreds of websites with terrible math will tell you!) and depends very strongly on the car's gearing. Many cars with overdrive will actually have a "two hump" fuel efficiency curve - that is, they'll be most efficient at about 30 mph or so if you're in 3rd gear, but also have another efficiency peak at 65-70 mph that's lower than the first (but still higher than going 55 mph in the overdrive gear).
The way to get good fuel efficiency with a standard design engine is twofold - make the car light, make the engine underpowered, and go slow. If the engine is always struggling, it's always in the power band, and always efficient. Hence the reason that a Geo Metro gets great gas efficiency.
Note the details of these cars - slow speed (15 mph), massively underpowered engine (3-4 hp), and very light chassis.
Here [viragotech.com] is a very good explanation.
(As an aside, most websites are crap at explaning this. See here [davidsuzuki.org], where they state that going from 100 kph to 120 kph increases the fuel consumption by 20%. Since you're moving 20% faster, a 20% increased fuel consumption means exactly the same gas mileage.)
Re:Safety Equipment? (Score:4, Interesting)
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.
Re:Safety Equipment? (Score:3, Informative)
I didn't look at that site, but Trucks do have better brakes then cars in the sense they are much bigger and more powerful.
Re:Safety Equipment? (Score:3, Informative)
The way to get good fuel efficiency with a standard design engine is twofold - make the car light, make the engine underpowered, and go slow. If the engine is always struggling, it's always in the power band, and always efficient. Hence the reason that a Geo Metro gets great gas efficiency.
That's exactly opposite to what i've always heard. My recollection is that maximal efficiency is roughly at torque peak (ignoring such things as aerodynamics and gearing), and that underpowering a car kills the mileage
Re:Safety Equipment? (Score:3, Informative)
The problem is that this is measured at full throttle, and cars don't need full throttle power at the torque peak to cruise at speed. Small throttle openings are less efficient because of pumping losses with the intake restriction (diesels don't have this problem). A single
Comment removed (Score:4, Interesting)
Re:Safety Equipment? (Score:3, Informative)
At 130 mph??? Holy bleep yes! At 130 mph probably something like 80-90% of your power output was going to fight the aerodynamics. You want to be at the point where 50% of the power is going to aerodynamics, 50% to rolling resistance. More or less, that's about good.
The point I'm trying to make is that if you then attempt to go 60 mph in 5th, you'll get lower gas mileage than if you go 60 mph in 4th (assuming that in 4th it's in the 3000
Re:Safety Equipment? (Score:5, Informative)
That's exactly what I said - though actually, efficiency is pretty constant in the power band, so maximum fuel efficiency is at the lowest point in the power band.
(Except for the last part, but that's addressed later...)
Case in point: a particular truck is offered in an economy V6 and a V8 trim. The V8 got better mileage because the V6 was always running full throttle (above the powerband).
Woah, woah - you're talking about two different situations here. Most cars are way overpowered for going at the speed where aerodynamic losses equal total residual losses - this is about 35 or 40 mph for most cars. So when I said underpower the engine, I meant underpower it compared to most cars, not underpower it compared to its needs.
You're exactly correct that a car that's running full throttle will have crap efficiency, but that's because it's past it's torque peak. You want to be at the torque peak, not above it (full throttle) or below it (going slow).
In your case, the aerodynamics and rolling resistance are so high because the weight is so high that the car is now not overpowered to go the speed that's efficient for aerodynamics. The V6 would get better gas mileage than the V8 if it went slower.
Your Geo may get good mileage, but it's crap, and I won't drive one. I have an MR2 that gets 30 MPG and handles nicely, so I don't have to.
I don't own a Geo. It is however a good example of a car that uses standard design principles to get high gas mileage. Small engine, light weight.
Re:Safety Equipment? (Score:5, Informative)
Also, you almost made a full connection there: horsepower will almost always rise with engine RPM as HP = (tq*RPM)/5252. The almost meaning if the torque band falls off dramatically, the HP may go down. Looking again at a Dynamometer readout, you will always see torque and HP cross at 5252. This is why even though a Honda may have 240HP and my car has a paltry 225HP, my 310ft/lbs+ of torque will "own" most any Honda (except the S2000, because that car weighs almost half of mine, but it still would be a pretty good race).
New hummer? (Score:5, Funny)
The winner is... (Score:4, Funny)
Fred Flinstone, with infinite miles to the gallon.
Haha (Score:4, Insightful)
Laugh if you will, but we'd all be a lot healthier if we followed Fred's example and ran to and from the office, instead of hit cruise control after rolling drive-thru.
Re:Haha (Score:5, Funny)
I suspect the cardio vascular benefits of using your legs to power your car would be dwarfed in comparison to the damaged caused by eating one of those ribs that toppled said car.
Re:Haha (Score:3, Insightful)
For example, my drive is about 25 km.
but I bet if you had to run to work everyday, you wouldn't be living 25km away...
Re:Haha (Score:3, Insightful)
Re:Haha (Score:4, Funny)
Dunno 'bout him, but the one I get to talk to on occasion comes up with gems like:
"SUV's should be ILLEGAL!" (what about people who haul heavy/large loads, i.e. construction workers?)
"Well, then people should have to prove they need them then!" (How?)
"Compulsory state licensing for construction workers!"
"Nobody should be allowed on the freeway without at least two people in the car!"
"Nobody should be allowed to drive more than 15 miles to work!" (how do they get to work?)
"Public transit!" (This is Los Angeles. Public transit is already inadequate to meet the meager current need)
"Tax gasoline a couple more bucks a gallon to pay for more buses!"
They're the ones who usually posit absurd solutions to in a tone of voice that makes every sentence sound like it should end with "..and the consequences be damned!" Plenty of self-righteous outrage and no common sense.
Infinite MPG (Score:3, Insightful)
I win.
Re:Infinite MPG (Score:3, Insightful)
Re:Infinite MPG (Score:2)
Re:Infinite MPG (Score:3, Funny)
Re:Infinite MPG (Score:3, Insightful)
A more realistic challenge (Score:5, Insightful)
Than watch those MPG numbers plummet. Add to that must have respectable performance numbers (ie it must not be so slow accelerating as to cause a hazard on public roads)
That's a real contest.
Re:A more realistic challenge (Score:5, Insightful)
Re:A more realistic challenge (Score:5, Insightful)
A little optimistic when it comes to the better ideas winning. You ever read any books whatsoever? Heard of Tesla and Edision? How about the old steam engine wars? Why not look at the history of automobiles in general? The history of suppression of good ideas goes back as far as history itself. In a world of patents, copyright, reputation, various intellectual property laws, egoism, and other factors, the better idea doesn't always triumph. In fact, the opposite is true for the most part. It will take more than an idea to improve the automobile, there are plenty of those to go around. The technology exists to make automobiles many times more efficient. It is obvious that there are many factors that are not allowing these "ideas" to be used. The question is not what the next technological solution is, but what is the solution to bring out the tech that already exists without collapsing the economy and convincing/forcing/etc. the rich and powerful to go along with it. It will also take some education of the general population, which the wealthy and powerful don't care to do. The people have a say in this as well, but in general we appear to be happy for now.
Re:fuel economy is not a selling point (Score:3, Funny)
It's all chrome plated plastics now...
engine noise from the exhaust pipe
with the right resonator configuration, a 1.3L 4cyl can sound like an awfully big engine.
dangerously tinted windows
We're geeks, aren't we? I burn too easily
aggressive stance (too high to be stable)
Wrong Wrong Wrong... agressive == low and fast (with lots of stickers).
loose spinning reflectors on the wheels!!! Hate those.
jacked-up suspension, with angled drive train
those are the air bags. w
Re:A more realistic challenge (Score:3, Interesting)
how about cars vs. trains vs. planes (Score:5, Interesting)
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.
Re:how about cars vs. trains vs. planes (Score:3, Insightful)
Re:how about cars vs. trains vs. planes (Score:5, Informative)
For freight there's no doubt that diesel locomotives are the winner. Diesel locomotives are hybrid vehicles: a 2-stroke diesel generator, but electric motors. They are very efficient at moving large loads, not so good at light loads due to the weight of the loco itself (something like 135 tons). That's why passenger trains tend to be purely electric - to keep the huge weight of the generator off the train.
Here are some links:
HowStuffWorks article [howstuffworks.com] on diesel locomotives.
A CN Railroad page [www.cn.ca] claiming a diesel locomotive can travel 3.5 times further than a truck on a gallon of fuel (presumably pulling equivalent loads).
A BNSF Railroad page [bnsf.com] claiming fuel efficiency of approx. 750 GTM (gross ton miles) per gallon. Most high efficiency cars would probably weight a ton or less so a 50 MPG Prius would be about 50 GTM per gallon.
Re:how about cars vs. trains vs. planes (Score:3, Informative)
Re:how about cars vs. trains vs. planes (Score:3, Informative)
Diesel locos are basically power plants on wheels, which is very useful for vast stretches of land that they need to cover. It'd be almost useless to run electric lines across the US to power trains, as the transmission losses would be huge.
"Diesel" locos (Score:3, Informative)
Interestingly, here in Ireland, our newest diesel-electrics are required to supply three-phase 220v a/c to the carriages from the head-end power (HEP) unit. Being US locos (GM-EMD), it seems they were merely retrofitted for this. We now have ten-year old locos that are more unreliable than 40 year old ones (also GM-EMD)! In addition, due to the engine overload, three
Re:A more realistic challenge (Score:4, Insightful)
realistic is a 2 seater subcompact used as a commuter vehicle. wher 90% of fuel is used by the consumer.
There are some GREAT efficient cars that are tiny overseas made by ford and others that get damn near 50mpg but they flat out REFUSE to sell them here.
I hate to break it to you, but you do not need a 8 passenger, 107 cu foot cargo area 6 wheel drive with 57 inches of ground clearance and 1.5 lanes wide vehicle to drive to work on the interstate.
I know it's a shocker but it is true.
I drove a 2 seater sports car that outperformed most sports cars on the road and still got 55Mpg in college. I built it from plans I got from here [rqriley.com]
instead of using a goldwing I used a different honda motorcycle (magnum)
if someone from basic plans and no real engineering background can build a commuter car that outperforms nearly all efficient cars on the road today from cast-away and old parts, then engineering students and firms can certianly do better.
Yes, I met all state and federal safety requirements, I had to before it would get licensed.
and it was licesned as a car not a motorcycle.
I sold it for 4 times what it cost me to make after I put almost 50,000 miles on it. still wish I never would have sold it though, in high school / college you have all the time in the world to do such things.
The formula (Score:2, Interesting)
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?
High Mileage Cars (Score:5, Informative)
Re:High Mileage Cars (Score:5, Informative)
Re:High Mileage Cars (Score:3, Insightful)
<rant>
Fuel cells are only batteries. The theoritical best is getting back what you put in them. Even assumming a 99% efficiency you'll still be running off how efficient the original power source was.
Although hydrogen is essentially everywhere, you can't just dig it out of the ground. I can think of two ways (I'm sure there are more) to get usable hydrogen, electricity (split the atom off from an exis
Fuel cell != Hydrogen fuel cell (Score:5, Informative)
However, you seemed to have invoked shades of a strawman - the grandparant did _not_ make any reference to a hydrogen fuel cell. It is, in principle possible to make a fuel cell that will convert fuels other than pure hydrogen into electricty (+ wastes).
That's not to say that they exist - most 'methonal' fuel cells are reformation style, where the carbon -> CO2 converstion is not used to produce power, but just to free up the hydrogen.
In principle, however, there is no theoretical barrier to a gasoline fuel cell, with high efficency (just a huge, _huge_, long list of practical ones). There _is_ a theoretical barrier to raising the efficency of an internal combustion engine.
Re:High Mileage Cars (Score:3, Insightful)
Very true, but they do provide an easier means of transition once better energy generation comes on line. It is a lot easier to just convert over/build new electricity generation plants and use that electricity to charge all the fuel cell powered g
Re:High Mileage Cars (Score:3, Insightful)
Another path is to have a better (different) means of storing el
Re:High Mileage Cars (Score:5, Informative)
But, since you are on that topic, there are a number of avenues besides fossil fuel for generating the electricity or heat or whatever for creating hydrogen:
Bacteria [tu-berlin.de]. Some scientist at UCLA did some calculations, and determined that a decent sized canyon in the Mojave desert covered 2 feet of water and a sheet to collect the hydrogen produced by the bacteria would be enough for all of Southern California.
Geothermal [geothermal.org]
Photovoltaics [energy.gov]
Tidal [wavelengthsjournal.com]
Convection [wired.com]
Fission [iclei.org]
Fusion [iclei.org]
Biomass Fuels [fao.org]
Solar Thermal [sandia.gov]
Wind [awea.org]
Hydroelectric [green-trust.org]
So, who are you swinging your fists at? Certainly not the original poster?
LS
Re:High Mileage Cars (Score:3, Interesting)
LS
Re:High Mileage Cars (Score:3, Interesting)
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 i
Re:High Mileage Cars (Score:5, Informative)
2. Burning fuel; converting it into electricity (40% at a power plant); storing the electrical voltage in a battery (possibly a fuel cell) (90%); convert the battery power into mechanical power (72%).
It's close. One thing's for certain: fossil fuel cars are inseperably tied to oil. I'm for fuel cell cars, because that would mean more options for the consumer, and more competion.
reference [howstuffworks.com]
Re:High Mileage Cars (Score:5, Informative)
This is simply not true. There is a bit of variation between the different types and grades of diesel and gasoline but it pretty much comes down to they are fairly equal in the amount of energy that each fuel contains. If you look at this web site [ornl.gov] you will see the following numbers:Diesel has a bit more energy than gasoline but by no means does it have twice the energy!
fuel energy contents? (Score:3, Informative)
Re:High Mileage Cars (Score:3, Informative)
Clue: The people of the earth consumed 28 billion barrels of in one year while discovering only 8.5 billion barrels of oil to replace it [peakoil.net].
Nobody's going to stop any coal fired plants from being opened.
Looking at it a different way, the human race is about two million years old [cnn.com] give or take. In the early 1800s there were only about 800 million people alive. Now we are a
Ceramic engines (Score:5, Interesting)
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.
Re:Ceramic engines (Score:5, Insightful)
I'm a machinist, and I've dealt with automotive engine blocks before. I think the big problem is going to be manufacturing costs. When machining a ceramic, it tends to chip very easily, which could raise costs due to high waste, and special manufacturing procedures that hamper productivity. However, since it's non-ferrous, you can use diamond tooling instead of the traditional carbide tooling, which will save a fortune on tooling costs
Ceramics are also very abrasive, which might drive up maintenance costs due to the need to frequently replace piston rings. The engine block itself should wear much more slowly than a normal cast iron block, however.
Ceramics can be pretty resilient even when faced with temperature stresses, but I don't know how well a car that needs to be running one moment, and parked the next would fare. I doubt people would put up with the need for a 5 minute warm up period, especially if failure to do so would destroy their car.
Another issue is that a ceramic block would be impossible to repair, and would probably be a good deal larger than a regular cast iron engine to provide strength at every location on the block that feels stresses. But, if it's possible to build ceramic handguns, I'm sure it's possible to build a durable ceramic engine block.
I doubt there's very many manufacturing experts who read slashdot, but I would be very curious to see solid numbers on the costs of ceramics manufacturing compared to traditional cast iron. I haven't done much work with ceramics, so much of the above is just educated speculation. Treat it as such.
Re:High Mileage Cars (Score:5, Insightful)
The actual efficiency is 1-Tc/Th. From wikipedia [wikipedia.org].
In this equation, Tc is the temperature of the heat sink, and Th is the temperature of the engine's heat source. For a 40% efficient engine, your hot engine gases have to be about 1.75 times hotter than the atmosphere that you discharge your exhaust into.
That doesn't sound like much - but remember you have to use absolute temperature. Room temperature is about 300K. So you need a 500K heat source - which is 230C, which is actually fairly hot. And of course you have all kinds of non-idealities in a real engine.
The only way to get anywhere near 100% efficiency is to get the hot part really hot and the cold part really cold. That is why metal-cooled reactors are fairly efficient - you have liquid sodium metal (very hot) coupled with river water (reliably cold).
If you run the math backwards it tells you what the maximum efficiency of an air conditioner is as well. As the temperature difference between hot and cold grows the efficiency drops accordingly. Of course, in real life you also have to deal with the fact that as delta-T grows your walls also start leaking heat like a sieve...
Re:High Mileage Cars (Score:3, Interesting)
Re:High Mileage Cars (Score:5, Funny)
640 MPG should be enough for anybody. (sorry, couldn't resist)
upper limits? (Score:3, Interesting)
Re:upper limits? (Score:4, Informative)
Unless you're one of those people who figures in friction from air resistance, rolling resistance, etc.
Re:upper limits? (Score:3, Informative)
With a Carnot engine, that means you get half of that, max, assuming perfect cooling (which doesn't really exist).
By the way, 114,000 btu == 33.41 kWh
Re:upper limits? (Score:3, Informative)
This isn't an easy question to answer.
What sort of assumptions are you making on wind resistance? At 55 mph, most of the output of an engine goes into fighting wind resistance.
Which "completely efficient" are you asking about? A heat engine has a maximum potential efficiency that varies based on operating temperature, and is always (for reasonable conditions) much
Re:upper limits? (Score:4, Informative)
Gasoline that has not been oxygenated with MTBE or ethanol holds about 115,000 BTUs of energy per gallon, give or take depending on environmental conditions and a few things about the blend. Oxygenates typically reduce that value by about 3% or so.
street legal? (Score:2)
I think street legality is mostly related to things like bumpers and lights, as well as emissions.
Btw, didn't they have a 10,000MPG vehicle a while ago? I think driven by a tiny 12 year old girl
Re:street legal? (Score:5, Insightful)
Re:street legal? (Score:3, Insightful)
The most compelling argument for buying an SUV is that in one you are most likely to survive a crash with an SUV. However, that's also a pretty compelling argument for banning the whole bloody lot.
We even give t [americanfinancialtax.com]
Re:street legal? (Score:3, Interesting)
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.
People could do this hundreds of years ago (Score:5, Funny)
Re:People could do this hundreds of years ago (Score:3, Funny)
Drive that sucker... (Score:2, Insightful)
driving technique (Score:3, Informative)
Comment removed (Score:5, Interesting)
Re:What about aircraft? (Score:2)
When you generate lift, you generate drag. Most cars try to generate as little drag as possible, and they depend on gravity to hold them down. Airplanes have to generate lift to fight gravity. Or, in other words, this is not at all congruous.
However, most airplanes are not very fuel efficient, and most props are fixed (where props are applicable) which is not as efficient as having variable pitch, so certainly some aircraft could be made significantly more efficient.
Re:What about aircraft? (Score:5, Insightful)
Also, planes can use propulsion systems much more exotic than a reciprocating mechanical engine.
Driving Styles (Score:5, Insightful)
Re:Driving Styles (Score:4, Funny)
Re:Driving Styles (Score:3, Insightful)
G
No, but hows about 370 miles per charge? (Score:3, Informative)
And that was in 1997 with old NiMH batteries. Current LiONs would double that to around 700 miles and next generation Li-Ss should pretty much double that again to around 1,300 miles.
I'm sure it's just what we need. (Score:2)
That would be great. Then we could all put around in our aluminum frame, 1" ground clearance, back breaking go carts [rose-hulman.edu]. He's probably wincing and holding his right hand near his head because he just sliced off a few fingers in the wheel spokes. Oops.
-Adam
As far as acutal street legal vehicles go (Score:5, Informative)
Some thoughts for you (Score:5, Insightful)
There's one catch. Nitrogen is very stable. Almost any chemical reaction will take more energy than it releases. When it comes to engine efficiency, this is Not Good.
Ideally, what you'd want to do is separate the oxygen and nitrogen, so that the oxygen ratio in the engine is much higher. Since you're losing less energy through the nitrogen, you would (by implication) get more useful energy out.
Ok, so how to do this, without reducing the energy you're getting from the oxygen at the same time?
That's tough. However, it may be possible. Nitrogen, as mentioned, doesn't react easily. The electrons in the outer shell are tough to displace. With oxygen, the reverse is true. Oxygen reacts very easily, and electrons are displaced with considerably less effort.
You can certainly use this to separate oxygen and nitrogen. Just set up an electrically charged grid, such that the charge will convert O2 into O2+, but leave nitrogen (N2) electrically neutral. Set up a second grid, with the reverse charge. The oxygen will be attracted towards it, the nitrogen won't.
If you picture the first grid at the entrance to a y-shaped tube, and the second grid at the fork splitting off of the long section of tube, you can see how the nitrogen will travel straight on, whilst the oxygen will be diverted.
Now, here's the tricky bit. The oxygen is one electron short (it's charged), and you've got to put quite a bit of energy into a device like this to charge the grids up enough. Will you get a net gain in efficiency?
That part, I can't answer.
Would it be worth doing anyway? Maybe. Well, it'll cut out a major air pollutant. The oxides of nitrogen that you get off will react with water to produce nitric acid. Not really something I want to be breathing in, if I don't have to.
Are there better solutions? Not using a conventional piston engine. We're almost at the limits for those, given a standard air mix. A rotary engine might get you a better theoretical limit (you don't have to keep reversing mechanical devices), but they're costly to make (they develop far higher pressures) and you have to develop one that's large enough that the increased surface area to volume is no longer a factor.
For ultimate fuel efficiency, I suggest a small fusion reactor. Though you may need to wait a while for them to be approved for use in cars.
rotary engine (Score:3, Interesting)
Re:Hemi Power (Score:4, Interesting)
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.
4 cylinder engine (Score:5, Insightful)
Also, since the peak horsepower of a car is rarely needed except in rapid acceleration, I would think that the key to reducing engine size, and thus, improving efficiency would be to use a small engine with some kind of storage system. Since batteries are bad for the environment, maybe two flywheels rotating in opposite directions (to cancel out precession) under the floor can be used, along with an electric motor/generator to transfer power to/from them. Extra power generated by the engines, as well as from braking, can be used to accelerate the flywheels. This would also improve handling because the gyroscopic effects would keep the car perfectly level on fast turns.
Also, I would think that the car would be cheaper to engineer and produce if you could eliminate most of the mechanical parts. How about a gasoline fired generator, a flywheel battery, and an electric motor on each axle?
Comment removed (Score:5, Informative)
Sheesh, tough crowd (Score:5, Insightful)
Urm, note the headline (Score:4, Insightful)
If it was something like "SAE contestents achieve 1,700 MPG" then I would think that these comments would be much less.
I don't think these vehicles would impress chicks. (Score:3, Funny)
Something a little more practical... (Score:5, Interesting)
There's a University competition sponsored by Ford and the DOE to build environment-friendly, fuel-efficient vehicles called FutureTruck [futuretruck.org]. 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!
lame (Score:3, Insightful)
Yeah, they made neat toys. Wahoo.
Re:Funny, I get more each day. (Score:5, Insightful)
When I can buy a car with that kind of effencieny I'll look into it, but until then, a walkin' I a' go.
Must be a bitch to take that shiny new 21 inch monitor home from the store.
Re:Funny, I get more each day. (Score:3, Informative)
If you're serious about riding as a way of life, get a Yak [bobtrailers.com] trailer. Light, easy to park, very little drag, and carries a lot more than they should.
Re:Funny, I get more each day. (Score:3, Interesting)
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.
Re:Funny, I get more each day. (Score:3, Insightful)
Hell, when was the last time that you bought anything besides a cable or adapter at a brick-and-mortar computer store?
Re:Funny, I get more each day. (Score:2)
Re:Funny, I get more each day. (Score:2)
Yea, easy to say if you are in prison...
Re:Funny, I get more each day. (Score:2)
However, you will have burnt off calories that you otherwise would not have needed to ingest in the first place.
Along the way from solar energy to your feet, a lot of energy is lost. For example, aots are only 1% effective at converting sunlight for use in growing. And that's not even counting all of the farming going on, tr
Re:Funny, I get more each day. (Score:3, Informative)
Checking some classnotes there is approx 686 kcal/mol in glucose which gets converted to 219 kcal/mol of potential energy in ATP. Which means only 32% efficiency for converting glucose to the energy form used by about every cell operation inside a cell.
Now there is also inefficiency in getting glucose to those cells (and not all of it of course gets to them). Plus ATP isn't completely itself efficiently used so 10
Re:I Can Hear Gas Company Execs Shouting..... (Score:3, Funny)