Interesting articles from Autospeed on Power vs Torque: Part 1: http://autospeed.drive.com.au/cms/A_108647/article.html Part 2: http://autospeed.drive.com.au/cms/A_108648/article.html Nice top speed calculator too (if you're into that sort of thing!): Top Speed The top speed of a vehicle has almost nothing to do with the mass of the vehicle (apart from bearing friction and tyre losses which, in terms of power consumed at top speed, are minimal). The two major factors are power and aerodynamic drag. The equation to get a pretty good approximation of top speed of a vehicle is that relating power to drag:- where P is the power in Watts, r is air density (1.3), CD is the coefficient of drag, A is the frontal area in square metres, and v is the velocity in m/s. To see how well this works, lets take, for example, a modern Falcon XR6 and an old 4.1 Cortina. The XR6 produces about 110kW at the wheels, has a CD of 0.31, and a frontal area of about 2.4 square metres. In the case of the Cortina, the numbers are 60kW, 0.48 and 2.2. To get top speed: For the XR6, this equates to 66.6m/s or 239km/h. The XR6 has been tested at over 230km/h, so this seems pretty reasonable. For the Cortina, the speed is 48.4m/s, or 174km/h, which is pretty lineball with the tests for the car. An interesting exercise would be to test the numbers for your own favourite car, remembering to use power at the driven wheels, not at the flywheel. And again, note here that it is peak power, not peak torque, which is the important engine performance variable.
nice work love the equations. I'm waiting for electric cars to be readily available, max torque at min speed is going to be so much fun! Theres a small hybrid electric, nissan prius or something, with over 400nm torque in a shopping basket, awesome.
F*** the Prius, go the Tesla Roadster. 0-100kph in four seconds, batteries included. There's an all-electric drag racing series in the US too. All your torque are belong to them
Is that the one that kills a ferrari 355 over the quarter? I know theres an electric car that does, saw a video of the drag couldnt believe it
no way! Its good to know theyre getting some power out of the things but they just dont sound the same. If they make one that beats the veyron ill spew
Drag racing is easy for electric cars The hard part is making them go hard for a long period of time, mainly because of battery power I think. and maybe heat-soak during extended peak loading too. The torque in an electrical motor comes directly from pushing amps, but the heating of the electrics is proportional to the amps squared. Twice the output power will mean four times the heat generated. I wonder how they cool them?
Interesting developmet From TreeHugger.com... "Yesterday, Zap announced that it will pursue a long-range, high-performance electric car based on Lotus' lightweight APX concept design. Zap will display the concept, which it is calling the Zap-X, at the upcoming North American Dealers Association (NADA) annual meeting in Las Vegas. Zap plans to use Lotus Engineering's APX (Aluminum Performance Crossover) concept design as a platform for a revolutionary breed of electric car. Zap claims this project will lay the basis for a "production-ready electric all-wheel drive crossover high performance vehicle for ZAP in the USA market." The battery system for the vehicle (details have yet to be disclosed) boasts a 350 mile range between charges and a 10 minute recharge time. Four in-wheel motors will give the Zap-X a total of 644 horsepower and a top speed of 155 mph." But in response: "Announcements like the one you found come out every few months or so from somebody and have been appearing for many years now. I read about a car just like that in Popular Mechanics back in the 70's. The missing link all this time has been the energy storage system (battery). There are dozens of electric cars on the market. I have test driven some. They cost a lot for what you get (poor performance), and their poor performance is primarily because they use lead acid batteries, which have unacceptable weight to energy ratios, charge slowly, and have limited recharge life. Now that battery technology has finally turned a corner for weight, charge cycles and charge time, the only thing left is cost. The only reason we don't have cars like that one is cost and the only expensive thing about an electric car is its energy storage system (batteries). The batteries I use on my electric bike are solid evidence that we will see plug-in and finally all electric cars before long that are affordable to the middle class. My hope is that the first one out will kick off a consumer frenzy that will drive costs down like it has for cell phones, computers, and digital cameras." Original transcript/discussion here: http://gristmill.grist.org/story/2007/2/1/125742/0649 Also some interesting thoughts on using the roofs of parking lots to host solar panels to harvest energy and recharge solar vehicles.
It was an electric Wrightspeed X-1, beat a 360 Spyder & Carrera GT over the quarter. "The minimalist X-1 is the product of Wrightspeed, Inc., Ian Wright's Silicon Valley startup "using clean technology to make very energy efficient cars that are also very fast." The X-1 prototype is a U.K.-built Ariel Atom, modified to use an electric power system from AC Propulsion instead of the Ariel's Honda iVTEC 4-cylinder powerplant." ...but I'd still take the Carrera GT anytime!!!
you know your stuff yeah motors in the wheels is the way to go, electrical transmission is more effective and reliable. Those batteries tho. Wheres a genius scientist when you need one? Maybe if we have another damn good world war the technology will leap forwards?
LOL yeti re World Wars! I guess every cloud has a silver lining... Regarding battery development: Currently, the advanced lithium-ion battery is basking in the manufacturers' hype. However, some are already questioning whether there is enough inexpensively obtained lithium in the world to make batteries for hundreds of millions of cars. Should this be the case, then perhaps the carbon foam battery, while not quite up to advanced lithium-ion batteries in performance, may end up as the inexpensive battery technology of choice. Finally we have the ultra capacitor, which a secretive little company down in Texas claims to have developed and will soon release to the world. Capacitors are not batteries in the common sense, but are devices that are capable of holding static electric charges. They have been around for a century in all forms of electronic equipment, but were only capable of holding tiny amounts of electricity by car-powering or house-running standards. If the little company in Texas is to be believed, all this is about to change, for they claim to have invented a way to store large amounts of high voltage electricity, initially 17 kilowatt hours, in a compact device. Although this technology has yet to be subjected to independent verification, the company says its device will have a specific energy of about 280 watt hours per kilogram, compared with around 120 watt hours per kilogram for lithium-ion and 32 watt hours per kilogram for lead-acid gel batteries. If all this turns out to be true, we will have a technology that will be right up there with the electric light bulb and the transistor. Such a device would be invaluable for storing intermittent wind, wave, and photovoltaic produced energy. It would open up a whole new era. Be it a Ford, a Chevy, or an Asian econobox, 2007 just might turn out to be the birth year for practical electric cars. Complete article: http://www.fcnp.com/index.php?option=com_content&task=view&id=817&Itemid=33
Ahh, wisdom beyond your years yes, lets make war, so we can have better mobile phones, electric cars and most importantly a vibrator that doesnt run out of "puff" at the crucial time.... hahaha
Supercaps are used on PCB's now. But yep bigger ones would do the trick. of course any regenerative braking is gonna help too. An electric 300zx r32 would be a great project car!
oh, nup thats it you ruined it... there is no substitute for tha aural extacy that is a petrol engine at high rpm, with boost even better. -1 for tree hugging-ness-ness attitude ;p
Getting the battery to charge quickly, retain efficiency and produce reasonable power output is the big problem. Some more ideas: You would need a heatsink, but it can be self-powered off the Diode output. More immediate problem would be circuit (eventually) draining the battery if power's off. Hence the LED's for indicators. All in all, a good system. http://www.aaroncake.net/circuits/charger2.asp Taken from "Charging An Electric Car" April 2007: http://www.evconvert.com/article/charging-an-electric-car
yeah I know gimme fuel gimme fire... but what if the fuel cost $3 per liter huh? Youd be in the same position as people with old US tanks designed for 25c per gallon glory days. and if you can hear the engine over the stereo well some people would find that unacceptable.
Yes, we have to remember where the electric car's fuel actually comes from - coal. Hence the push for hydrogen, though the safe distribution of hydrogen at mass filling outlets and personal home booths lends itself towards a tendency of fear in comparison to the supposed 'safe' distribution of electricity. What makes you think you would hear the engine enough to interrupt listening to the radio? Some alarmists looking for an angle against electric/hybrid cars actually discuss the sensory detachment that would occur when losing the sound of the petrol motor. Personally I think this is redundant, as a significant amount of travel noise in modern cars comes from the tyres, not the motor at low cruising revs.
Theyll do something like ricer BOVs Where they make cool noises for no other reason than to sound cool. like baffled cooling fan noise or something.
