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Students Build 2752 MPG Hypermiling Vehicle
MikeChino sends along this awe-inspiring excerpt: "Think claims of electric vehicles that get over 200 MPG are impressive? Try this on for size: a group of mechanical engineering students at Cal Poly have developed a vehicle that can get up to 2752.3 MPG — and it doesn't even use batteries. The Cal Poly Supermileage Team's wondercar, dubbed the Black Widow, has been under construction since 2005. The 96 pound car has three wheels, a drag coefficient of 0.12, a top speed of 30 MPH, and a modified 3 horsepower Honda 50cc four-stroke engine. It originally clocked in at 861 MPG and has been continuously tweaked to achieve the mileage we see today." It's not quite as street-worthy, though, as Volkswagen's 235 MPG One-Liter concept. Updated 20:01 GMT: The Cal Poly car's earlier incarnation achieved 861 MPG, not MPH; corrected above.
Yeah, I could make a car that went 861 MPH and got 2k+ MPG if I dropped it out of a plane, too.
I'm not that impressed. I mean, while the figure mentioned seems impressive, how is this 'research' helpful? I mean, we already have *known* for a very long time that if you made a super small, lightweight vehicle with excellent aerodynamics, very low top-speed, and very low torque/accelleration, you can get much more mileage than the typical car. But, nobody wants a vehicle like that. People want vehicles very much like what they already have. . . enough mass around them to provide protections in an accident, enough space and power to haul 4 - 8 people plus cargo/luggage, and decent speed and accelleration - I think most of us have had driving experiences where we really needed to accellerate *right now* in order to avoid getting run over by a truck or bus or whatever.
I honestly think these 'toy car' concepts, while they might be great learning exercises for engineering students, aren't very impressive. I'd be much more impressed by the 80-100 MPG 4-door sedan.
Hypermiling is interesting, but totally useless. It's not even that interesting from an engineering standpoint because it's the answer to a question that nobody has asked: "How do I get amazing mileage in a way that is completely and totally infeasible to actually implement?" Now, if they were doing aeronautic hypermiling, that would be interesting, because the vehicles in question need not interfere with other vehicles. But hypermiling techniques involve acceleration and coasting, and every vehicle would need its own road to take advantage of them without screwing up everyone else's mileage and decreasing everyone's safety. Even typical hybrid drivers create a road hazard by paying too much attention to their MPG readout; not due to their inattention to the road, but because they are slowing down excessively while going up hills, causing drivers behind them to have to leave their powerband and downshift to a less-efficient gear ratio to maintain it. Every time I see a Prius I pass it at the earliest opportunity so as not to be stuck behind it and have to suffer their inconsideration, often consuming additional fuel in the process. A hybrid might get better mileage, but as they are typically driven, they cause worse mileage; and they provably consume more energy over the course of their lifetime than a comparable vehicle with a small diesel engine and no batteries which gets the same or even superior mileage.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Not to steal their thunder (and this mpg result is old news), but according to their own blog, Universite Laval got 2757 mpg in that race. And Mater Dei High School hold the record with 2,843.4 mpg.
Banu
quote from the rtfa: "It originally clocked in at 861 MPG and has been continuously tweaked to achieve the mileage we see today."
Arash Partow's Philosophy: Be a person who knows what they don't know, and not a person who doesn't know.
This car used to do even more mpg, but wasnt very fast.
MPG is backwards. It tells you how much further you can go on a single gallon, not how much less fuel it'll take to cover a fixed distance. In practical terms, the latter is much more relevant to how people drive. If you buy a car which gets twice the MPG, you do not suddenly start driving twice as far every day. Your miles driven each day will probably remain fixed, so fuel saved is based on the inverse of MPG.
A consequence of this is that MPG exaggerates the benefit of highly fuel-efficient vehicles. 2752 MPG sounds like a lot. But switching from a 25 MPG vehicle to a 50 MPG vehicle saves you more gas than switching from a 50 MPG vehicle to a 2752 MPG vehicle. To cover a distance of 50 miles, the 25 MPG vehicle would consume 2 gallons. The 50 MPG vehicle would consume 1 gallon, for a savings of 1 gallon. The 2752 MPG vehicle would consume 0.018 gallons, for a savings of 0.982 gallons. This is less improvement than the switch from 25 MPG to 50 MPG. Because MPG is inverted, a 10 MPG improvement on a 25 MPG vehicle saves a lot more fuel than a 10 MPG improvement on a 2000 MPG vehicle.
Consequently, the most important thing for reducing overall fuel consumption is to get people out of gas guzzlers and into more fuel efficient vehicles. Stuff like hypermiling vehicles getting >2000 MPG are interesting from an engineering and design standpoint, but they serve little practical use. Even if you could develop a real car which got 2000 MPG, getting a single SUV driver to switch to a Prius would save 3.5x as much fuel as getting a single Prius driver to switch to this new ultra-high MPG vehicle.
This is why most of the rest of the world measures fuel efficiency in liters/100 km. It makes the amount of fuel your car will use for a typical drive pretty obvious, and makes it dirt simple to compare how much fuel you'll save switching to a different vehicle (just subtract the two numbers):
SUV = 16 liters/100 km
sedan = 9.4 liters/100 km
Prius = 4.7 liters/100 km
vehicle in article = 0.085 liters/100 km