Metro aerodynamics

[The Toecutter]

Hmm, that does give me an idea for another topic, but such a competition outlined here would never get any substantial backing anyway.

[Mighty Mira]

Originally Posted by The Toecutter

Hmm, that does give me an idea for another topic, but such a competition outlined here would never get any substantial backing anyway.

Yes, the more I look at it the more I understand the problem.

Look at the "futurecar" competition:

Best Use of Alternative Fuels Open to alternative fueled vehicle (E85, CNG, LPG, H2, and DME) -- it is based on the sum of the scores for Emissions, Energy Economy, and Vehicle Design Inspection Event
Where the hell is electricity as provided by power stations? It ain't there!

Who is it funded by?

The FutureCar Challenge is part of the larger Partnership for a New Generation of Vehicles (PNGV), the national public-private research program begun in late 1993 to develop super fuel-efficient vehicles. This ambitious collaborative effort is making progress in many technical areas including advanced materials, manufacturing processes, and energy conversion and storage devices. PNGV also recognized the need and importance of a competitive educational component like the FutureCar Challenge. There is much at stake in this competition. As part of the PNGV effort, the FutureCar Challenge is connected to the larger, nationwide effort that is already leading to energy, environmental and economic benefits to the nation. The U.S. Department of Energy and the American auto industry, through the United States Council for Automotive Research (USCAR), are principal sponsors of this program. USCAR is an umbrella organization created by Chrysler, Ford and General Motors to do pre-competitive research in variety of advanced automotive technologies.

[Mighty Mira]

Originally Posted by The Toecutter

Hmm, that does give me an idea for another topic, but such a competition outlined here would never get any substantial backing anyway.

Why don't you outline it anyway?

What is really desired?

Minimize total cost of ownership over, say 10 years, while maintaining:
-minimum number of highway and city miles per year.
-minimum acceleration
-minimum range per trip
-minimum range per day with maximum stopping period
-minimum number of passengers
-minimum visibility considerations
-minimum luggage considerations

Off the top of my head.

[The Toecutter]

Pretty much. It would be a performance and luxury oriented hyper-efficient car with one of its key design criteria being affordability, under $10k.

say,

*0-60 mph under 7 seconds
*120+ mph top speed
*must be designed to accomodate multiple fuels, specifically E100/gasoline, B100/diesel, or electricity, not necessarily in the same car. For instance, it could be one platform that will come in a model that runs on ethanol, another might run on diesel, another might run on electricity
*40+ mpg city, 70+ mpg highway if powered by gasoline, ethanol, or diesel, < 150 Wh/mile at 65 mph if powered by electricity
*capability to seat 4 adults 6'5", 200 pounds each
*professional finish, must *look* expensive
*200 miles range or more
*under $10k pricetag for IC/diesel versions, under $20k pricetag for EV
*for IC versions, minimum of 300,000 mile engine life with no powertrain repairs at 95% confidence interval, for EV minimum of 1 million mile motor life and 250,000 mile battery life at 95% confidence interval
*capability to sustain 120+ mph collision with no severe damage to occupants(ie. roll cage, safety harnesses, ect.)
*500W+ premium sound system
*leather interior
*exterior body must be built with replacable modules. Get into a fender bender, pop one off, snap on another, for cheap. The roll cage should be rigid enough to make the car difficult to total, even at racing speeds, but crumple zones adequate enough to keep occupants safe during impact.


We certainly have the technology to do it. Might be difficult to do the EV because that would require NiMH batteries, which Chevron Texaco has the patent of.

It would essentially be a people's car of the 21st century. It would blow away everythnig else on the market.

I imagine such a car would look like a very aerodynamic version of the 60s VW Beetle, longer and much more powerful. Or perhaps an updated Tarta T77a. It would be cheap to make, it would be designed to look as much like a luxury car as possible, it would be designed to be as low maintenance as possible and as cheap to operate as possible, and it would have to be fuel efficient and able to use alternatives where available.

Such a car would be light, weighing ~1,600-1,800 pounds unloaded. The roll cage and properly designed crumple zones would keep it sufficiently safe to allow such a low weight without use of composite materials to keep cost down.

The gas IC version would have to be able to use any combination of gasoline or ethanol including 100% of either, the diesel would need to be able to use any combination of petrol diesel and biodiesel including 100% of either.


How willing do you think the auto industry would be to see something like this made? Don't answer... lol...

[Mighty Mira]

Originally Posted by The Toecutter

Pretty much. It would be a performance and luxury oriented hyper-efficient car with one of its key design criteria being affordability, under $10k.

Interesting.

Why do you keep coming back to NiMH batteries? Are they better than Li-Ion or Li-Poly?

[The Toecutter]

1,750 cycles to 100% depth of discharge for the Ovonics according to UC Davis, and a shelf life that's like NiCds. They basically don't wear out.

Even Chevron Texaco puts them at a conservative 1200 cycles to 80% DoD. With 200 miles range, do the math on battery life... Since not everyone drives 200 miles per trip, and since batteries last much longer with shallower discharge, you can see the advantage.

In contrast, lithium batteries degrade ~4% per year, sometimes faster.

Also, mass production of Ovonic NiMH batteries was estimated at $150/kWh according to ECD chairman Robert Stemple in the 90s. Today, the more conservative estimates provided by UC Davis' Team Fate range from $200/kWh to $300/kWh. For 200 miles range, we need at least a 30 kWh pack for an efficient car that uses 150 Wh/mile.

Too bad the oil industry has the patent.

Take the projected cycle life of these batteries and prokected cost in mass production, and you get a battery cost on the order of $.02-.04/mile. This is extremely cheap given an electric motor needs no maintenance and given electricity for such a car is around $.015-.02/mile. So cheap, that even if the gasoline for most gas cars were given away for free, the electric car would still cost less to operate.

As for real world figures, Southern California Edison put like 3 million miles on their EV fleet with NiMH batteries. They only had 6 battery module failures. Each Toyota RAV4 has like 24 battery modules. The RAV4s that have been in use the longest have approached 150,000 miles on the same pack, no degredation in range or power yet, the others with less miles show no degredation either. Toyota conservatively rated the packs at 100,000 miles, but no one really knows how long they will last in real world use. In theory, these batteries will last at least 170,000 miles before they only deliver 80% of their range in the RAV4 EVs(although these RAV4s aren't being discharged to 100% all the time, so actually longer than that, in theory). These RAV4s only have 100 miles range. Imagine an EV with 200 miles range.

The amount of car battery packs that can be made from the world's nickel reserves far outnumbers the amount that can be done from the world's lithium reserves as well.

5,000,000,000 kg of nickel is produced each year.

The Toyota Prius hybrid has 1.3 kWh battery pack from that 10 kg of nickel. So basically, for every kWh of battery, you'd need 7.69 kg of nickel.

A midsize EV with attention paid to aerodynamics(~22 square foot frontal area, .18 Cd) and about 2,800 pounds curb weight would need 180 Wh/mile at 70 mph. So, for 200 miles real highway range, that's a 36 kWh battery pack with 277 kg of nickel in it. This battery pack would also allow for roughly 180 horsepower to be delivered to the motor for a 0-60 mph time of roughly 7 seconds and top speed in excess of 160 mph.


But nickel production could be ramped up. The known commercial reserves are 62,000,000,000 kg(USGS), so that is enough for 224 million electric cars. Or, if we can miraculously access that 160 million tonnes estimated to be all through the Earth, enough for 578 million EVs!

So, that is enough nickel for 18 million new EVs each year. And this is only one battery chemistry.

We didn't include lithium, we didn't include lead acid(ie. Firefly batteries). The world's readily accessable lithium reserves are enough for about 100 million EVs of the type outlined above with 200 mile range packs.

We do have to be cafeful though. What's good about battery material is that it's recyclable. But getting that material can be an environmental disaster. We must be careful not to turn this planet into a giant strip mine.

But again, the oil industry has the battery patent, and is sitting on it. It is viable, it is plentiful.

[Mighty Mira]

Originally Posted by The Toecutter

Long informative post snipped

Thanks for the excellent post!!!

I'm glad that someone who isn't a vested interest has done the research on this for me. Kudos.

So, basically it comes down to life cycle... they don't wear out.

I don't suppose these batteries can be manufactured in your backyard...

I suppose that relegates us to using lead acid in the meantime, correct? Stick one in Phil Knox's CRX, I wonder what sort of highway range it would have?

[The Toecutter]

I suppose that relegates us to using lead acid in the meantime, correct?

Indeed.

Stick one in Phil Knox's CRX, I wonder what sort of highway range it would have?

This is pure guess, but I'd say a 1,125 pound pack of Optima Yellowtops for 300V nominal would give 130 miles range at 65 mph.

If you want to get 200+ miles range with lead acid, you're going to need a lightweight tubeframe chassis and a lightweight/aerodynamic body to place on it, that can contain both the weight and volume needed for that range. You're looking 200 miles range with a 2,000 pound battery pack if the car can be kept aerodynamic enough and has LRR tires and such. This car would need to attain ~150 Wh/mile efficiency at 65 mph or so, and this is a car that would weigh around 3,200-3,500 pounds loaded with 2,000 pounds of batteries. An electric musclecar could perhaps be designed around such a concept. It would not be easy. A vehicle with a 23 square foot frontal area would need a drag coefficient of ~.16-.18 to do this.

To actually do this with a conversion instead of a custom built vehicle, your only option is a small pickup truck, loaded with about 2,400 pounds of batteries, and with extensive aeromods.(See Phil Knox's gas powered Toyota T100 pickup. Aeromods got it over a 30% improvement in highway mileage. Roughly the same will apply to eelctric car range.)

There are electric pickups that got 120 miles highway range using a large amount of lead acid batteries. They had no LRR tires and no aeromods.

With aeromods, I have no doubt they'd get at minimum 150 miles highway range, perhaps 200 miles. I don't know anyone who has been crazy enough to try this yet. If I had the cash, I'd be glad to.

See the following:

http://www.austinev.org/evalbum/37

http://www.austinev.org/evalbum/185

Note: "Red Beastie" was unfortunately destroyed about a week ago. The owner was gone from home and a dumptruck parked uphill blocks away began rolling after its parking brake had failed. It crashed into the owner's home and caught fire, destroying the home, his Indian motorcycle collection, and both his electric vehicles, including "Red Beastie", one of the 100+ mile range electric trucks linked above.

[Mighty Mira]

Originally Posted by The Toecutter

If you want to get 200+ miles range with lead acid, you're going to need a lightweight tubeframe chassis and a lightweight/aerodynamic body to place on it, that can contain both the weight and volume needed for that range. You're looking 200 miles range with a 2,000 pound battery pack if the car can be kept aerodynamic enough and has LRR tires and such. This car would need to attain ~150 Wh/mile efficiency at 65 mph or so, and this is a car that would weigh around 3,200-3,500 pounds loaded with 2,000 pounds of batteries. An electric musclecar could perhaps be designed around such a concept. It would not be easy. A vehicle with a 23 square foot frontal area would need a drag coefficient of ~.16-.18 to do this.

As I said in PM, I think that the ideal shape for this sort of thing is long and thin. Thin to minimize frontal area/Cd, and long both to fit in more batteries and to increase Cd. It can afford to be thin because all the weight is hardly higher than the tyres. Kind of like a longer, aerodynamic and wider version of the Tango.

[MetroMPG]

For those who are interested, I have updated my site with a page about the XFi Aero Car that was posted in this thread in June.

I sent the builder/owner some additional questions, and he wrote back with more detail about himself and the car. I posted the Q & A at MetroMPG.com, and his son also put up a new page on his site with my questions. So, if you'd like to know a bit more about this project, you can find out at either:

http://metrompg.com/posts/xfi-aero-car.htm

and/or

http://www.1989geometro.com/ - in "questions asked"