Students Build 2752 MPG Hypermiling Vehicle 233
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.
861 MPH!!!!!!! (Score:2, Interesting)
It originally clocked in at 861 MPH and has been continuously tweaked to achieve the mileage we see today.
Not only eco-friendly, it leaves some fighter aircraft in the dust! How do they prevent the sonic boom?
not getting it here (Score:3, Interesting)
Think claims of electric vehicles that get over 200 MPG are impressive?
How about infinite miles per gallon? Electric cars don't consume gas.
hypermiling is useless.y v (Score:5, Interesting)
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.
Mail carriers (Score:2, Interesting)
Re:2752 MPG ? (Score:1, Interesting)
My analysis indicates that it is theoretically infeasible.
The Calorific value of Gasoline is 45 MJ / kg.
Burning a gallon of Gas would yield us 45 MJ/kg * 0.77 kg/l * 3.76 liters = 118 MJ
Assuming an 4 Stroke Engine efficiency of 25% [ http://en.wikipedia.org/wiki/Thermal_efficiency] , the total useful mechanical work that can be created is 29.5 MJ
Neglecting Drag, work done = Frictional Force * Distance. Using 29.5 MJ as the work done, we can calculate the frictional force to be 6.7 N.
For a 96lb car, the coefficient of rolling friction required to achieve 6.7N of frictional force is 0.015.
For the whole thing to hang together, the surface coefficient of rolling friction needs to be smaller than 0.015.
The coefficient of rolling friction for concrete roads 1.0!!!
Re:So what? (Score:4, Interesting)
Current vehicles aren't anywhere near fully optimized, mass-wise or aerodynamics-wised. They're still largely built out of steel (composites can be as much as nearly an order of magnitude better in terms of passenger protection per unit mass -- plus, they can't pin you in). We *still* don't generally shroud the tires (and many cars have overly large wheel wells to boot). Most cars have a sharp kink between the windshield and the hood, as well as around the A-pillars. The hood is too long and the rear end too short. There's not *nearly* enough rear taper. We do all sorts of un-aerodynamic ridiculous grill styling, when most of the air for the engine of a modern car comes from underneath anyway. Most cars still don't have aero belly pans. Many include stupid things like fake (or even worse, real) spoilers. Most cars still use *way* overweight wiring harnesses, rather than an aircraft-style networked communication system. The rear wheels are spaced way too far apart (optimum is a single rear wheel). I could go on and on. Heck, only a small fraction of cars are even hybrids.
With current tech, we could make a reasonably affordable 5-person sedan that gets ~70mpg, four-person that gets ~90, three-person that gets ~110, two-person side-by-side that gets ~130, and two-person tandem that gets ~150+, with all of the normal car comfort and safety features. But it'd mean having to first redo our production infrastructure for composites and throw our conventions of what cars *should* look like out the window.