[dontworryaboutpeakoil]

Copyright 2004 dontworryaboutpeakoil

Here's my idea.

Have an air car with two air tanks, and on board air compressor, and an electric generator at the brakes.

Use one air tank while driving and refuel the other air tank using the air compressor powered by the electricity gained from the brakes.

Having an onboard air compressor will extend the range of the Air Car to limitless miles.

What do you guys think?

[Licho]

Well, umm, this syustem (regaining energy by braking) is already implemented in standard air car design, but even with this, it can onyl drive 100km at very low speed

[dontworryaboutpeakoil]

Well, umm, this syustem (regaining energy by braking) is already implemented in standard air car design, but even with this, it can onyl drive 100km at very low speed

Why only 100km? If you refill the air tank with the energy from braking, shouldn't the air tank be full and your range is extended?

[Licho]

No ) Not at all.. You cannot "refill it" you can only recover part of energy lost by brakling. But you cannot gain energy that was used to actually move a car..

See other thread about electricity made from turning wheels
http://www.peakoil.com/fortopic2636.html

[Kingcoal]

Go ahead and build it, but you are correct in calling it a dumb idea. You might want to read up on some things first:

http://www.fact-index.com/t/th/thermodynamics.html#The%20Laws%20of%20Thermodynamics

The problem is very simple and explainable with high school physics. You have to go up a hill to use the brakes coming down the other side (unless this is a one way vehicle.) Supposing you use 50% of your air pressure to get up a hill, how much will you recover braking your way down the other side? Less than 50%. Friction and therefore heat, the enemy of any closed system is produced and radiated into the air increasing entropy. The heat loss is produced while coaxing the vehicle up the hill and also coming down the other side.

Thermal Dynamics is the much hated science that explains why perpetual motion, these days called free energy devices don't work.

[dontworryaboutpeakoil]

Go ahead and build it, but you are correct in calling it a dumb idea. You might want to read up on some things first:

http://www.fact-index.com/t/th/thermodynamics.html#The%20Laws%20of%20Thermodynamics

The problem is very simple and explainable with high school physics. You have to go up a hill to use the brakes coming down the other side (unless this is a one way vehicle.) Supposing you use 50% of your air pressure to get up a hill, how much will you recover braking your way down the other side? Less than 50%. Friction and therefore heat, the enemy of any closed system is produced and radiated into the air increasing entropy. The heat loss is produced while coaxing the vehicle up the hill and also coming down the other side.

Thermal Dynamics is the much hated science that explains why perpetual motion, these days called free energy devices don't work.

Going uphill won't use 50% of the air pressure! Say an air tank can provide 60KM range, and we have 2 air tanks onboard for a total of 120KM range.

Whenever the brakes are used, the air tanks will be continuously refilled by this energy. Since it takes only 2 minutes to refill an airtank, the range of the air car can be continuously extended. The range won't be limitless but my guess is it will be comparable to the range of a conventional car.

When the Air car arrives home, you simply plug it in the wall and recharge both air tanks for tomorrow.

[dontworryaboutpeakoil]

I want to get started on this project. Does anyone want to help me develop the subsystems?

I need someone who can design an air tank that can hold enough air for 60Km and is totally safe.

I regenerative brakes powering a Lithium battery much like the ones in today's Hybrids.

I a 2 or 4 piston engine that uses air pressure to generate sufficent torque and horsepower to move 2,000lbs at up to 90MPH.

I need a lightweight electric air pump.

[djd]

... an air tank that can hold enough air for 60Km and is totally safe.

Safety is in the eye of the beholder. High pressure tanks are always dangerous when full; then again, so are gasoline tanks. Vehicles carrying high pressure tanks have been on the roads for many years, although very few of them are air cars.

The MDI Air Cars (a group of commercial products) use "90 cubic metres of air compressed to 300 bars" for a range of 200-300 km. They weigh 1650 pounds, can carry (most models) 1100 pounds, and have a top speed of 65 mph. They feature regenerative braking and can refill their air tanks if supplied with electricity. Alternatively they can be directly charged with air at an "air station".

Using regenerative braking does extend the range, but how much is dependent on the fraction of the energy which is lost to rolling "friction" and air resistance, as well as the efficiency of the regnerative braking system. Since air resistance is roughly dependent on speed cubed, regnerative braking will be more effective the slower you go.

Refilling an air tank in "2 minutes" is very difficult. The power required runs to hundreds of horsepower, or hundreds of kilowatts if you prefer. The MDI cars take hours to refill when connected to 240V power.

In summary, building an air car with performance anywhere near that of a more traditional car is as much of an engineering challenge as the traditional car, and is in practice harder as there is less prior work to draw upon.

[djd]

... an air tank that can hold enough air for 60Km and is totally safe.

I should have mentioned that MDI (http://www.theaircar.com/) is using carbon fiber tanks similar to those used for compressed natural gas powered vehicles, so perhaps CNG tanks could be used in a homebuilt air car? Certainly they would be cheaper than a custom-made set of equivalent quality.

[deconstructionist]

I want to get started on this project. Does anyone want to help me develop the subsystems?

sure i'll help you, i'll just need a few million dollars to get things underway... just wire it to my account in the cayman islands and i'll keep you posted on my progress...

[pilferage]

Not a bad idea, the question is, will there be enough energy gained through having the regenerative breaking system provide power for an onboard air compressor?
I'm thinking you'll get maybe 10% more range (30% from the braking system, anyone know what the efficiency of the compressor would be?) from a system like this if you're lucky, but in an air car the extra weight might be prohibitive...
a better appraoch would be to have the compressor essentially brake for the system (with the conventional friction brake there for emergencies) and take the kinetic energy directly. If we ever figure out fusion this system would be viable...

[Cash]

Hey, how about adding a windmill to the top of the car to help recharge the batteries as you're driving down the street!

Nice tongue-in-cheek idea, BTW. Two air tanks, onboard compressor with battery, heh heh heh. Good one.

Cash

[clv101]

Going uphill won't use 50% of the air pressure! Say an air tank can provide 60KM range, and we have 2 air tanks onboard for a total of 120KM range.

Whenever the brakes are used, the air tanks will be continuously refilled by this energy. Since it takes only 2 minutes to refill an airtank, the range of the air car can be continuously extended. The range won't be limitless

by your logic why not?

but my guess is it will be comparable to the range of a conventional car.

why comparable not half, twice or 10 times?

When the Air car arrives home, you simply plug it in the wall and recharge both air tanks for tomorrow.

The single point you are missing is that only a small fraction of the energy used to get the car up to 30 mph can be regained by breaking from 30 mph down to nothing. When you look at how much energy you can get from breaking you'll find it's not enough to run the on-board compressor to refill the air tanks.

[Madpaddy]

This thread is great. I was having a bad day but I'm really cheered up now.

Thanks everyone.

ROFLMAO

[WebHubbleTelescope]

I want to get started on this project. Does anyone want to help me develop the subsystems?

I need someone who can design an air tank that can hold enough air for 60Km and is totally safe.

I regenerative brakes powering a Lithium battery much like the ones in today's Hybrids.

I a 2 or 4 piston engine that uses air pressure to generate sufficent torque and horsepower to move 2,000lbs at up to 90MPH.

I need a lightweight electric air pump.

"help me develop the subsystems?"

State your name, address, engineering qualifications. I will send the info along to Mark Cuban. I heard that he is a benefactor.

swish

[mortifiedpenguin]

Heh. Mr. "dontworryaboutpeakoil" never ceases to amaze me.

[dontworryaboutpeakoil]

The same guys who laughed off Fuel Cells with numerous gloom and doom excuses are the same guys who are laughing at my Air Car idea. I sincerely believe my idea can work. If you haven't noticed, fuel cells can now achieve 1800MPG, something these pessimists here never imagined was possible. If the platinum issue can be resolved using other materials (and it will), Fuel Cells can definitely solve the transportation component of Peak Oil problem.

The Air Car IMHO is superior to Fuel Cells since no hydrogen fuel is needed. Only compressed air and the power to compress it is needed. If not enough energy can be recaptured from braking alone, why not install a 2-3 gallon bio-diesel tank? Use the fuel to power the on-board compressor motor to refill the air tanks in about 2 minutes. Doing this several times should extend the range of the Air Car to several hundred to a thousand Kilometers which is comparable to the standard cars of today. I don't think this idea is implemented in the Air Car.

I wish Mark Cuban were reading these boards. I would gladly donate my time and ideas to solve peak oil. I know we all have quite a few ideas in our brains and though we're not engineers, I think our ideas are doable. We definitely do need a few billionaires like Mr Cuban, or a Bill Gates to finance some of our ideas. It would only cost a few million, a mere pittance to these billionaires.

Even an Air powered motorcycle would be great. Imagine a tri-wheeled motorcycle vehicle capable of going 60MPH powered by air. It would probably be much more effiicent than the Air Car due to lighter weight. On one small tank, it could probably go 500 miles, and it could have a small trunk in the back to haul your things. Perfect for city dwellers.

I know some of my ideas sound outlandish but I honestly feel they are doable.

[Itch]

Well, dontworryaboutpeakoil, if you do inted to market your idea to potential investors, don't refer to your idea as a "dumb idea." There is already no way that people who actually know something about engineering will invest resources in your idea, so it's especially important to appear confident to people who are swayed by emotion emotion rather than logic, because they are your most likely source of capital.

Also, when you say that you can "feel" that it will work, it implies emotion instead of logic. I don't think the eco-consumers will accept this, so you might just want to show them the glossy side and have them wrongfully draw the conclusion that your idea is coherent.

If you are actually trying to convince people that your idea is valid, you should try somewhere else; people on this board have an understanding of basic physics and engineering.

I humbly suggest that you learn from the information that others have already posted. If you ignore this opportunity to do so, you are only choosing to ignore facts that would negate your emotional ideas, and, furthermore, being intellectually dishonest with yourself.

[clv101]

The Air Car IMHO is superior to Fuel Cells since no hydrogen fuel is needed. Only compressed air and the power to compress it is needed. If not enough energy can be recaptured from braking alone, why not install a 2-3 gallon bio-diesel tank? Use the fuel to power the on-board compressor motor to refill the air tanks in about 2 minutes. Doing this several times should extend the range of the Air Car to several hundred to a thousand Kilometers which is comparable to the standard cars of today. I don't think this idea is implemented in the Air Car.

What makes you think that 2-3 gallons of diesel will take you further is it is used to compress air then the compressed air is used to drive wheels rather than just used to drive wheels directly!

There is a finite amount of energy in a gallon of diesel, the most efficient way to use that finite amount of energy is in an internal combustion engine directly driving wheels. Adding the 2nd stage (compressed air) will reduce the overall efficiency.

It takes a certain amount of energy to compress air, as the compressed air is 'used' only a fraction of that original energy is released. It's a inefficient way of storing energy. No more, no less.

[clv101]

Oh and forget the "2 minutes" you keep mentioning. It doesn't take a fixed amount of time to fill the tank, it takes a fixed amount of energy.

On second thoughts, do you actually know what ENERGY is?