Appeal For Commuter GPS Logs To Aid Electric Cars 144
holy_calamity writes "A team at Carnegie Mellon University has begun a project seeking to design a kit to cheaply convert secondhand cars into cheap, electric ones suitable for commuting, if little else. They hope to rely heavily on smart management software to extract as much efficiency as possible from regenerative braking, and knowledge of terrain from GPS tracking. But they are hampered by a lack of public data on how commuters actually drive. Their solution is to appeal to GPS users to upload .gpx log files of their commute to the team's site. The data is plugged into a simulator that reveals how much cheaper an electric car could do your journey, and an anonymized public dataset will be created. A programming contest will award a production electric car to the coder who designs the best management algorithm using it."
Regenerative breaking? (Score:5, Funny)
I am Car of Borg. You will be assimilated.
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Is that where they break, and then fix themselves?
No, it is a series of electricity saving dance steps from the streets.
Regenerative Breaking 2 - Electric Boogaloo.
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While you were jesting, you actually aren't too far from the truth. To over simplify what it does, all of that excess energy created while braking, it dumps that energy back into the battery (or fuel storage device) to help keep it charged. I honestly don't know how much of an effect it has on the batteries to help keeping them charged, but it does do a little charging. I guess the more efficient the system, the more impact it has.
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In a NiMH hybrid, it regens about 1/3rd of the energy. On a li-ion EV, it's about 2/3rds.
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Don't they dump the power into capacitors first then send it to the battery in controlled doses?
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The problem is dumping that much power into a battery quickly.
I don't think that is a problem, most batteries that are not fully charged can withstand huge dumps of energy for short periods. In fact, the current produced during braking is probably less than that required during acceleration. The general problem is that the voltage coming from the electric motor is equal to (best case), or below the voltage of the batteries. So the voltage needs to be boosted above that of the battery before any regenerative charging takes place. Thus, taking significant extra electron
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I remember reading about buses that captured braking energy by compressing nitrogen gas and then using it immediately to help get rolling again.
Its called a pneumatic actuator [wikipedia.org] and it is not a new idea. One of the major disadvantages of these pneumatic actuators is the release of compressed gases back into the atmosphere and the associated staccato noise. If you want to have an idea of how that sounds then just remember the last time you heard a pneumatic jackhammer being used or a jake brake [wikipedia.org] engaged by a trucker on a downhill grade. There is also the additional weight and mechanical complexity of having this system and connecting it to the drive sh
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The french have a hydraulic system that could do this.
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But regenerative breaking
is an incredible energy saving technology.
Homophone Fail.
And I believe a WHOOSH too.
When the car brakes the electromagnetics are turned on, and the generator starts converting the momentum of the car, back into electrical energy.
RIGHT.
Regenerative breaking makes the difference between eletric automobiles being a pipe dream, and an efficient inner city car.
WRONG.
It's not funny if you have to explain it.
TomTom (Score:2, Informative)
TomTom has been collecting this data for years for their IQ Routes:
http://www.tomtom.com/page/iq-routes
Did CMU ask them ?
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It's probably a lot more sensible to use the data over at OpenStreetMap, actually...
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exactly. http://www.openstreetmap.org/ [openstreetmap.org] project has massive amounts of gpx tracks uploaded from all over the world, and i think that would be a wonderful source of information for these people.
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Yes, but if they'd gone straight to http://www.openstreetmap.org/traces [openstreetmap.org] or http://www.openstreetmap.org/traces/tag/drive [openstreetmap.org] they wouldn't have got any press coverage about what they're trying to do with the data...
My experience (Score:4, Insightful)
From what I see here in rush hour, you only need boolean control: Full throttle or hard braking. When I coast towards a red light, there'll always be someone next to me who steps on it and cuts in front of me.
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Yeah I wrote travel time algorithms for freeway travel in my last job. The travel time was pretty much directly related to the length of the queue at the end of the freeway.
Re:My experience (Score:4, Funny)
Yeah I wrote time travel algorithms for freeway travel in my last job. The queue travel was pretty much directly related to the length of the freeway at the end of time.
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I love the people who tailgate using boolean throttle techniques; they constantly alternate between slamming on the accelerator then the brakes to maintain a constant average speed. It's only slightly better than driving at a constant speed while simultaneously applying the brakes and the accelerator but it clearly projects to drivers around them that they're morons...which I assume is the idea because I can think of no other reason why they do it.
I think every new car should have a system that calculates h
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Ha, you don't know how good dealers are at taking trades away from people for nothing and then reselling them for $10K. In fact, dealers probably make more on 3 year old trade-ins than they do on the new car itself!
Braking (Score:5, Informative)
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I wonder if electric cars will start to sacrifice power to brake without using friction. The benefit would be longer service intervals, at the cost of some power. I wouldn't be surprised if electric cars in a decade or so have a single friction brake for emergencies and parking with brake pads which last the life of the car.
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Another nice feature of the Tesla is that the regen is triggered merely by lifting off the accelerator, so you can
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That's why the friction brakes on my Tesla still squeak; because the regenerative deceleration is enough 98% of the time, and I rarely need to use the friction brakes.
I think his point is if you actively burned battery power you could probably eliminate that last 2%, making for an even lighter, faster, higher performance car. I've got years of experience driving a hybrid with regen braking, and it is not nearly powerful enough to trigger the anti-lock brakes. Perhaps a Tesla can regen brake hard enough to feel it in your eyeballs, don't know, would be fun to find out...
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Actually that should be 85 to 95 percent efficiency. Then charging/discharging each take a cut and final conversion back to mechanical energy takes a cut. But raw regen-braking to DC should be 90 percent efficient or better. OTOH, your Tesla has an induction motor which is inherently less efficient than PM motors, and the 70% may be including some of those other losses as well.
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Re:Braking (Score:5, Interesting)
What do you mean sacrifice power? The prius' regenerative braking already has this kind of effect. It doesn't completely eliminate pad wear, but it fantastically extends the life of the pads. There are ones out there with over 100k miles still using the factory pads.
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I mean don't (or hardly use) brakes at all. Have a simple brake which can stop you in an emergency and keep you parked. Use the traction motor to bring the car to a stop.
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If I understand you correctly, the Prius has done this for a decade. One of my Priuses is at well over 100,000 miles, and still has its original brake pads. The only time the Prius' friction braking system is activated is during very slow speed stops (when there's not enough counter EMF from the generator to get significant regenerative braking), and during emergency stops (when maximum deceleration is requested by the driver). The rest of the time the car uses regenerative braking.
What do you mean by sa
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The only time the Prius' friction braking system is activated
When the car is completely quiet (no ventilation, no screaming kids, no music) I can hear them activate, if I'm actively listening for it an paying attention. Not even a sound so much as a change in road feel as the friction kicks in. Now the anti-lock, that is a different issue and its impressively loud.
What do you mean by sacrificing power? Regenerative braking returns some of the vehicle's kinetic energy to the battery, making the car more efficient.
Think slamming it in reverse at full throttle instantaneously, up to and including breaking the tires loose and smoking them. With current technology (electric "current" get it?) that would probably roas
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Exactly right.
?? I don't understand your point. What does slamming it in reverse at full throttle have to do with rege
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Think slamming it in reverse at full throttle instantaneously, up to and including breaking the tires loose and smoking them. With current technology (electric "current" get it?) that would probably roast the controller and the motor.
Current regenerative braking systems are far more advanced than this.
Today's electric cars use AC induction motors driven by variable frequency inverters. Throttling the motor from acceleration to deceleration is done by varying the motor's drive frequency from slightly higher then the motor's speed (positive slip) to slightly lower (negative slip). This speed/frequency difference can be controlled very precisely, thereby controlling the amount of torque and power into or out of the motor. So, like accelera
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What do you mean by sacrificing power?
I mean that instead of using the brakes at very low speeds where regenerative braking doesn't work it will just run the traction motor backwards. You lose power that way but you lose complexity as well, and save on maintenance. I can imagine cheap cars being totally fly by wire with more electrical and electronic components. Maybe shock absorbers will be electric. Steering may be totally fly by wire. At most they may have a one shot last ditch friction brake.
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> At most they may have a one shot last ditch friction brake.
You're not going to lose much complexity if you still keep a friction brake. I'm not even sure that a "one shot last ditch" friction brake is going to be simpler than normal friction brakes.
Stopping a 1000kg car travelling at 100kph within 3 seconds means dumping/transferring 128 kilowatts. The faster the stop the more energy has to be dumped. Until they start to be able to take in th
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The friction brakes on my Tesla still squeak after 12,000 miles of driving.
I find the brakes on my Tesla Roadster also squeak - mostly due to non-use. The brake dust gathers on the rotor and doesn't get wiped away since I mostly use regen to slow the car. This causes the brakes to squeak when I do try and use them. When this happens, I can make the squeak go away by braking hard once to remove the brake dust. I find an empty residential street and bring the car up to 15 or 20 miles per hour, and then stomp hard on the brakes to come to a complete stop. No more squeak for anoth
Anonymized Travel Data (Score:3, Insightful)
Ok, so maybe someone can help me out here, but how exactly do you anonymize travel data?
I mean sure, psuedo anonymized could be fairly easily done, just take the raw data, match with topographical data, and output the combined result devoid of geographic representations.
But even that wouldn't be anonymized to anyone who's looking for info on a specific area, since the data would all be similar and it wouldn't be hard to detect a route that goes through a given set of terrain, especially if the start or stop points (someone's house/parking garage) is known.
So someone who's more in-the-know with anonymizing data sets of this or similar nature able to shed some light on this?
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I think they answer this on their site: http://chargecar.org/privacy [chargecar.org]
Two passages jump out:
"To further ensure your privacy, the first and last tenth of a mile of every commute is automatically removed before it is saved to our servers, and no data from those omitted portions is retained."
and
"ChargeCar will also not disclose your position data to anyone and it will be used strictly for research purposes. Search capabilities are only as low as the city level. The only information that ChargeCar will share are
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I would still be wary of having a GPS log my position and speed over time. It takes one traffic officer to realise the proof of speeding infractions is stored on ones own nice phone.
I would like to know if the data on ones own device could be used to be convicted of speeding. Until I get the assurances then I would be careful with having the tracking turned on.
However I really like the approach to data collection. I am going to try to help.
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Just deleting start and end of each trip is not good enough. Especially not if they just delete .1 of a mile at each end. Doing that still allows someone with sufficient access to the data to combine "likely trip combinations" and derive hidden information. To do it properly they'd need to cut all trips into anonymous pieces at fixed way points such that an onlooker cannot know whether any given car that came from A-Ville went on to B-Village or C-City. The level of granularity at which this needs to be don
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You don't really need details of left and right to analyze driving style (so the data can be simplified down to velocity and change in elevation).
Over a short commute the details of the hills are probably important, but for a longer commute, I doubt they matter much (and the same thinking likely applies to road choice and whatnot).
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*remove the end points of the journey and use the data between the end points.
*separate the movement data from other data; they don't need to connect a car to its data as it probably isn't needed to determine general commuter habits. If they somehow need to connect a car to its journey they can generalize to its model or assign a randomised alphanumerical tag to it instead of someone's name etc..
Re:Anonymized Travel Data (Score:4, Insightful)
Ok, so maybe someone can help me out here, but how exactly do you anonymize travel data?
You have a table of GPS tracks. And you have a table of cars. And the two tables have no columns in-common that could be used to join the data.
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And here we see a completely anonymous GPS track starting at 47 Washington Ave, Charleston, California*, stopping for 30 minutes just outside "Bobbie's Big Bargain Bisexual Brothel" before continuing to parking space 15 at the Word Of God radio station. We have no idea what car it was.
(P.S. others have pointed that this scenario will not happen, because they delete the first and last .1 mile of the trip.)
* All parts of this address except 'California' were made up by me. Any resemblance to the address of an
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You haven't really thought this through, have you? Don't feel too bad; most people take to glib over-simplifications about data deidentification.
Maybe this [arstechnica.com] will help.
Re:Anonymized Travel Data (Score:4, Interesting)
So someone who's more in-the-know with anonymizing data sets of this or similar nature able to shed some light on this?
Much like social networking sites, the best solution is not to upload anything you don't want your name on. Since they're trying to build a "commuter car" as opposed to a "adult video shopping excursion car", the best solution is to only upload the drive to and from work, unless your work happens to be "professional adult video shopper".
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A guess: you start out with a long list of personal data - driver ID, car make and model and year, and a longass list of coordinates with timestamps (from which the speed and braking and all that can be derived).
Throw away all the names, so that you only have the car make/model and the path. Then throw away the first and last two minutes of driving of every trip. Cut all the trips into random five minute slices. Convert their timestamps from absolute time to relative time (the trip starts at 0 and each fram
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On reflection, I realized I left part out:
After you have those random five minute paths, you can also change coordinates from absolute to relative - the path starts at (0,0) and proceeds onward. Then rotate the path a random number of degrees, around a random point along the path. If you also have z-coordinates (possible, if the GPS unit's map had altitude data), then pick another random point along the path and shift the entire path such that that point is at sea level.
My initial version was pretty anonymo
Good in theory (Score:1, Interesting)
In theory, this is a good idea, but I do not think it will work that way. I have yet to see a specialized, 35+ mph, 10+ year lifespan (important for resale value) car that will cost under $10K. A basic, 30+ mpg car can be had under $12K. A basic plug in hybrid (Prius?) will likely go under $25K (without extra batteries), and get pretty good mileage as is.
I expect in the near future, there will be plug in hybrids with a variable amount of batteries. People will go to a car dealer and buy (or rent) the plug i
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First, lets see any domestic car manufacturer make any car of any technology with those specs:
35+ mph ... 10+ year lifespan ... under $10K.
I mean before going all star trek with complicated stuff, can they even build a "model T" or VW-bug-alike that meets just those basic specs, even if it only seats one and gets two miles per gallon, etc, before trying to install new high tech with amazing performance (and probably, amazing costs)?
the buyer will buy the amount of kwh in batteries they feel they need
I do agree that "marketing-miles" will become the new "cupholder count" in car advertising. Perhaps, instead of advertis
Wow, look at that: (Score:4, Insightful)
Do they really expect anyone who isn't already driving a hybrid or electric and/or driving super-energy conscious will be interested in helping a project like this and send in Data? How people really commute: They drive 10-20 miles over the speed limit on highways, and 5-15 miles over the speed limit on city streets. They speed up to get in front of a slower (but still over the speed limit) car, just in time to brake hard for the stoplight. The data they collect will say regenerative braking is pointless, but the common-knowledge data will say that regenerative braking is the bee's knees.
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I love the speed limit argument, let me play too! :)
Speed limits, and the optimal speed varies by vehicle!!!!!
Every engine has an optimal speed. That's generally 1700 to 2200 RPM.
In my car, optimal cruise RPM is 2200 RPM.
I tested at identical RPM (2k RPM) in 5th and 6th gear. 6th gear was more fuel efficient.
I tested at identical speeds (The speed limit, 70mph), in 5th and 6th gear. 6th gear was more fuel efficient.
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Complete off-topic for the original story but this is exactly why I'm hoping more cars get CVTs as the technology matures. I have a Subaru Legacy with a CVT and it is great for MPG. The car can always run the engine at the optimal RPM for the combination of speed, load and acceleration demand. When cruising on the highway its fun to watch the RPMs vary slightly to compensate for hills but having the speed never budge. I think in this case the Legacy with the CVT gets ~5mpg better than the same care with an
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Problem is efficiency is a combination of engine speed, and intake restriction (assuming we run at stochkometry). Since your gas pedal is actually just decreasing the intake restriction. as you push the gas, at every rpm the more efficient your engine will run (assuming manual trans*, with EFI, no boost.) Generally with peak efficiency at same rpm as peak torque, wide open. So ideally you need a small enough engine that it can run wide open at this RPM the majority of the time, but since this is usuall
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The whole point of a overdrive 5th or 6th gear was that it was a highway cruising gear for optimal economy, because the old 'top gear' 4th in cars was the one where maximum horsepower arrived at top speed.
Actually, there are vehicles with only three speeds which have an overdrive gear, and there are vehicles with six speeds and no overdrive gear (double under, tow package). An overdrive is an overdrive, and the point of having more gears is to have closer ratios. You can always double-shift. Even modern automatics can do it.
Yet many small cars these days scream at 3500rpm or more on the open road, because the manurfacturers seem to have sacrificed economy for close ratios, and once again, peak hp at terminal speed.
Fail. Higher RPMs doesn't necessarily mean lower efficiency. Given a specific engine design, the engine makes peak power at a specific RPM and load combination, and peak efficiency at ano
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Don't be too sure about that. I have almost 400hp, and a 0.32 coefficient of drag.
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So data that runs counter to 'what everyone knows' is pointless? It seems the rejection of science that so many characterize as being typical of America has at last come to Slashdot.
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Data is useless for extrapolating to a population if sampling was HIGHLY biased (as in this case, it probably would be). So yes, common-knowledge may represent the population better.
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Of course, someone who bothered to read the article would know the sample is biased by design. They're examining the design of a commuter car, so the data they seek is biased towards commuters.
Duh.
Not all 'biased' data is bad.
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the data they seek is biased towards commuters.
But the data they will get will be biased to a tiny subset of commuters (fuel-gaugers), not a heterogeneous cross section. You sound like the type of twit that never learned math and is sure that his calculator is always correct. Science needs common sense to question stupid results. Or even better: A &*^%ing better method of selecting a sample set.
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That represents an assumption, not a fact. Somebody who presumes to lecture another on science should be able to tell the difference between the two. Furthermore, someone who knows anything about data analysis should know that this type of driving will stick out like a statistical sore thumb when the data is analyzed.
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Well, they could expect at least one person to send in Data (two if you count when he went back in time and left his head in a cave). Wait, what were we talking about again?
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I'm just not going to because my "commute" consists of me bringing my coffee upstairs to my office.
So retrofitting batteries... (Score:1)
I'm having a hard time believing that, but I suppose it depends how much you drive.
Hell, wouldn't it be cheaper to buy a new electric than to retrofit it?
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and the whole electric drive-train, is going to be cheaper than paying for gas?
Hell, wouldn't it be cheaper to buy a new electric than to retrofit it?
I know you're just trolling, but its an interesting topic anyway.
Most conversion stories seem to begin with "remove burned out IC engine and leaky transmission". You'd be surprised how expensive a new gas drivetrain plus installation costs compared to the new parts for a small electric drivetrain. So, drivetrain is usually mentally justified as a repair cost.
Then justify the purchase price of just enough small lead acid deep cycle batteries to just barely work, because you've got leftover money from the d
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I go through $80 of gas every second week; so roughly $2k a year.
So going by the other reply, of $6k in parts, that's 3 years just for parts - not counting the cost of charging the batteries, or the labour to install the kit. Throw that all in, and I'm thinking we're looking at 6+ years to break even, vs. just buying gas.
I just don't see electric as feasible, especially in my (-40 for several months) climate. Diesel or booze are the only feasible options I see for
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I'm thinking we're looking at 6+ years to break even
There's a few electric conversion cars in my neighbourhood - A minivan, an old Ford Fiesta etc. For most of the guys who have done this it's not for the cost savings (although here in BC with cheap hydro there is certainly a piece of that) - It's largely a hobby for them, in the same way some people like playing around with computers, messing about with toy trains or 'tuning' their Hondas. To be honest, this sort of project appeals to me as a hobby pro
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What's wrong with six years to break even, with the money spent raising the value of the vehicle?
If you were given an low-risk option for your 401k wherein you'd earn the amount of money you put into the fund in only six years, and continue earning from there on out, wouldn't you leap at the opportunity? That's a 12% rate of return.
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Even if that were the case, you lost nothing. But if it's a li-ion conversion, you'll get more than 6 years out of it. And by going electric, you'll skip most other vehicle maintenance -- no more oil changes, no transmission failures, no belts, pulleys, blah blah blah... EV drivetrains have a tenth as many moving parts.
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One problem with the idea is that used cars aren't worth shit by the time the drivetrain is worn out.
Another is shoehorning a replacement drivetrain and battery pack into a car not designed for it in a crashworthy manner. There is no reason to put a "new" drivetrain in most used cars, typical practice is to install a used drivetrain out of a wreck.
As a mechanic, I'd have to say the project will be fun with someone else paying for it but is a waste of time.
Slightly related, open source electric cars (Score:3, Interesting)
I've been following the progress of a Finnish electric car project:
Quote:
"we are offering the open source blueprints of the electric conversion kits globally and leave the manufacturing of the kits to the markets"
http://www.sahkoautot.fi/eng [sahkoautot.fi]
http://ecars-now.wikidot.com/ [wikidot.com]
Requires Cheap Batteries First (Score:5, Interesting)
According to http://www.sahkoautot.fi/eng:faq#toc3 [sahkoautot.fi], lithium batteries will last for about 125,000 miles. What nobody wants to talk about is the price of replacing them. They just want to talk about how "cheap" it is to charge them. Articles just assume that by the time you need to replace them, surely cheaper and better batteries will be available. I've heard estimates of about $10,000 for replacing the batteries in an electric vehicle. So that's 8 cents per mile times 30 miles per gallon that conventional engines get for the same size vehicle which is $2.40. So pretty much zero savings.
My Versa gets around 36mpg which bumps the cost per gallon of the electric up to $2.88 which is about 30 cents more than fuel in my area. And that doesn't include the cost of electricity needed to charge the batteries.
Electric cars simply cannot beat the economics of a small commuter car. Until they get the price and performance of rechargeable batteries well below the cost of regular gas there's no financial incentive to buy an electric car. They need to do far better than 8 cents per mile for electric. I'm not going to spend $20,000+ on a car just to have electric when I'm saving no money per mile and could have spent $10,000 less on standard car AND saved money on getting where I want to go.
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Electric cars simply cannot beat the economics of a small commuter car. Until they get the price and performance of rechargeable batteries well below the cost of regular gas there's no financial incentive to buy an electric car.
They just need to stop using Lithium-based batteries. Lithium-ion is a horrible battery technology, manufacturers like Apple love it because they can use it to force the upgrade cycle and planned obsolescence.
The only way they should use lithium ion is for small-scale projects where before recycling 18650's and ipod batteries they shove them into car battery sized modules for a few years to make sure they are well and truly worn out before melting them down.
Ultracapacitors FTW. once they make them wi
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So what you are saying is that everybody in Europe, where gasoline prices are multiple times what they are in the US, are likely to see huge savings ?
Second question, how long do you think gasoline prices in the US will stay where they are ?
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Second question, how long do you think gasoline prices in the US will stay where they are?
Perhaps longer than you might otherwise believe. There are costs associated with owning a private vehicle, above and beyond the price of gasoline, that put such ownership out of reach for substantial numbers of people living outside the United States; especially in developing nations where such personal non-work vehicles remain a luxury. In Europe, where high taxes and extensive regulations are the rule rather than the exception, private vehicle ownership and its attendant fuel use is also discouraged. The
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Did you know that by adding carbon nanotubes to the graphite electrode of Li+, you can drastically increase the number of recharge cycles? Adding 20% wt of CNTs will in fact enable them to be recharged an infinite amount of times. The company that has the patent and makes these batteries, is not interested in adding 20% wt of CNTs however - they add only 10%, so the number of cycles is larger than with the ordinary Li+, but still not unlimited.
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So that the battery won't be indefinitely re-chargeable, but rather only longer-lasting-than-competition. If it lasted an infinite amount of recharge cycles, customers would stop buying new batteries quicker than new customers would be found (this is what I am guessing their logic should have been).
The part of the story you're missing... (Score:2)
If you've got a halfway modern Garmin GPS, you have already been collecting the very data that this project is working for. What? Your GPS is logging you without permission? Yes. (Garmin probably got some legalese somewhere to cover their tracks.)
The Garmin GPS has a facility to show/hide your 'trail' (which is based on a time/location log of your travel). I believe it also has an option to reset that log. (Or, at the very least, you could USB mount its storage device and clean out the log file.) But even i
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I would suspect that this varies depending on the model. My Garmin 60csx has the ability to disable track logging. There have been numerous times where I've wanted it to record the track, but it had turned off track logging... Sounds like a good time to say "YMMV". :^)
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Wow. Lots of poo-pooing. But partially my fault.
A clarification (since there are so many Garmin models): the Garmin Nuvi line is what I had in mind. That would be the line that is aimed at automotive market (which related to the topic). Sample models would be 260, 265, 780, 255, 200, 205, and all the widescreen variants.
There is no way to turn of tracking on these standard automobile models. Someone mentioned the 60csx, which is a handheld unit and not aimed at the automotive market. Same with the GPSmap60c
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Support from Garmin support:
--- On Tue, 2/10/09, Product.Support@garmin.com wrote:
From: Product.Support@garmin.com
Subject: Re: Disable tracklog RECORDING feature in Garmin Nuvi 255w (KMMxxxxx)
Dear [AtariDatacenter],
Thank you for contacting Garmin International. Unfortunately you will have to clear the trip log manually.
With Best Regards,
Jonathan P
Product Support Specialist
2nd shift-OCC
Garmin International
913-397-8200
800-800-1020
913-440-8280 (fax) Att: Jonathan P
www.garmin.com
Original Message Follows:
Form
Their biggest bang (Score:2)
Those have demonstrated much more energy recovery from regen braking.
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Wheel motors aren't the greatest because it means there's a lot more unsprung weight (not on your suspension). Also, while 4 small engines may or may not be as efficient overall as one big engine and some transmission, they're almost certainly more expensive.
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Wheel motors though could lead to a lot easier conversion project. Trade offs.
As spoken by someone who has no idea what they're talking about. Like the GP said, wheel motors lead to shitty handling. That's why they're used only in special-purpose vehicles going very slow. Having one motor per wheel is a good idea, having one motor in every wheel is a crap one. Speaking as someone who reads the specifications for tires for his sports cars (one at a time, thanks) you're full of shit. Going from stock 21 lb wheels on my 240SX to 9lb wheels resulted in a bent wheel (I couldn't afford for
A little real influence? (Score:2)
So if enough people upload a commute including hard braking, hard acceration, high-G turns, and sections well over 100mph, will that cause them to design an electric car with some serious power?
Fundamental flaw in Carnegie Mellon approach (Score:2)
What real world data will reveal (Score:2)
This is what makes regenerative braking work out for most people. However, I used to regularly commute 46 miles touching my brakes only once: when parking in the lot at my destination. How much would regenerative braking have helped me?
Regenerative braking only works when you drive like an ass. A
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Ah, truth, justice and the american way. How refreshing
Damn straight. If you are so hot to trot for people to work for free, then you should work for free for me.
Re:CMU can pay for it. (Score:4, Insightful)
Well, once would have to wonder if CMU produces any IP as a result of this free data, would they release all copyrights and patents for free?
Or is that different?
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And the whole stupidity of driving 22 miles to do the modest job that I do?
Yes, that is stupid. But the blame can be shared between businesses and employees. I have known a ton of people who could all but eliminate the car if they just lived closer to work, and they'd save the difference or even more by just not having to maintain a car all the time. The problem with this idea is that in most cities, you're a non-person without one. What are you going to do when you're not working? Sit at home and wistfully dream of functional public transportation? And the car companies deliberat
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