A New Alterntive Fuel Source For Cars

[TheDude]

We Use Air to power cars. There will be air vents on the side of the car that pulls air in while your driving.

The air will go into a small air turbine which will generate electricity.

[swansont]

How will this work? What "pulls the air in" and drives the turbine in when you're not moving, to get you going in the first place?

[InigoMontoya]

The 2nd Law of Thermodynamics. You should look into it.

[chilled_fluorine]

We Use Air to power cars. There will be air vents on the side of the car that pulls air in while your driving.

The air will go into a small air turbine which will generate electricity.

 

"While your driving"... And what, exactly, starts the car moving in the first place?Any power gained from the moving air will make the car proportionally harder to move, plus energy "lost" through inefficiencies. Your idea is therefore worse than useless... No hard feelings though, right?

[Dekan]

"While your driving"... And what, exactly, starts the car moving in the first place?Any power gained from the moving air will make the car proportionally harder to move, plus energy "lost" through inefficiencies. Your idea is therefore worse than useless... No hard feelings though, right?

 

What about "ramjet" engines - don't they work on similar lines to what TheDude suggested in post #1?

[Greg H.]

What about "ramjet" engines - don't they work on similar lines to what TheDude suggested in post #1?

 

Ramjets have the same issue illustrated above. They can't produce thrust while they aren't moving, so how do you start the vehicle moving in the first place?

 

Also, ramjets tend to need to be going above the speed of sound to operate with any kind of efficiency, which isn't really conducive to normal highway speeds for a car.

 

See Wiki - Ramjet for more details.

[Dekan]

Ramjets have the same issue illustrated above. They can't produce thrust while they aren't moving, so how do you start the vehicle moving in the first place?

 

Also, ramjets tend to need to be going above the speed of sound to operate with any kind of efficiency, which isn't really conducive to normal highway speeds for a car.

 

See Wiki - Ramjet for more details.

 

Thanks Greg H, I appreciate the link, which I've studied with interest. It shows that even sub-sonic ramjets are possible! Even if not very efficient. I hadn't realised that before - I'd thought they had to go at Mach 3 + Thanks for enlarging my understanding of the subject!

 

However, may I just go back to InigoMontoya's post #3. It seems to suggest that ramjet engines contravene the Second Law of Thermodynamics.

 

That can't be right surely?

[Greg H.]

Thanks Greg H, I appreciate the link, which I've studied with interest. It shows that even sub-sonic ramjets are possible! Even if not very efficient. I hadn't realised that before - I'd thought they had to go at Mach 3 + Thanks for enlarging my understanding of the subject!

 

However, may I just go back to InigoMontoya's post #3. It seems to suggest that ramjet engines contravene the Second Law of Thermodynamics.

 

That can't be right surely?

 

 

While I admit Inigo's message was a bit terse, I don't think that was what he was implying, since Ramjets obviously work just fine (the first was flown on a working aircraft in the 1950s).

[JMJones0424]

However, may I just go back to InigoMontoya's post #3. It seems to suggest that ramjet engines contravene the Second Law of Thermodynamics.

 

That can't be right surely?

 

Notice the difference between a ramjet, which uses the velocity of the air the craft is moving through and the unique shape of the air inlet to compress air for combustion of fuel, and the proposed air turbine in the opening post. The Dude's air turbine is powered solely by the craft moving through air. The energy generated by this turbine cannot be more than the drag caused by the turbine. In practice, due to inefficiencies, it will actually be significantly less. So unless there is another energy source available, The Dude's proposal will not work.

[InigoMontoya]

While I admit Inigo's message was a bit terse, I don't think that was what he was implying, since Ramjets obviously work just fine (the first was flown on a working aircraft in the 1950s).

 

Ramjets extract their energy from fuel; typically JP-8. There's no violation of the 2nd Law. As presented in the OP, the car in question does not have an energy source other than it's own drag (if you consider drag an energy source).

[Dekan]

Ramjets extract their energy from fuel; typically JP-8. There's no violation of the 2nd Law. As presented in the OP, the car in question does not have an energy source other than it's own drag (if you consider drag an energy source).

 

Thanks Inigo - of course you're right - ramjets need some kind of independent fuel injected into them, to energise them. The ambient air by itself, won't do.

 

Mind you, sailing-ships manage to go along with just air-power. Obviously that's because the air is blowing on the ships, in the form of wind.

 

And suppose this wind was blowing on a car fitted with sails - oughtn't it make the car go along similarly. So I wonder why we don't have wind-powered cars. Is it because the car wheels, as they roll round, make too much friction with the ground? But ships must also make friction, with the water. In fact, shouldn't they make a lot more friction than car-wheels. I reason like this:

 

1. With a ship, the entire length of the ship's hull at the waterline (perhaps hundreds of feet), rubs and drags against the water - hence, much friction.

 

2. With a car-wheel, only the few square inches at the bottom of the tire, rub against the ground - hence, less friction.

 

Is my reasoning wrong?

Edited August 27, 2012 by Dekan

[JMJones0424]

So I wonder why we don't have wind-powered cars.

 

We do, though land sailing is more of an eccentric sport than a practical means of transportation. The biggest difference between sailing on open water and driving a land vehicle is that land vehicles need to be able to navigate through particularly constricted areas at many different angles of attack relative to the wind. Using the wind as a primary source of power for a land vehicle is therefore not practical, but perfectly possible.

[J.C.MacSwell]

Thanks Inigo - of course you're right - ramjets need some kind of independent fuel injected into them, to energise them. The ambient air by itself, won't do.

 

Mind you, sailing-ships manage to go along with just air-power. Obviously that's because the air is blowing on the ships, in the form of wind.

 

And suppose this wind was blowing on a car fitted with sails - oughtn't it make the car go along similarly. So I wonder why we don't have wind-powered cars. Is it because the car wheels, as they roll round, make too much friction with the ground? But ships must also make friction, with the water. In fact, shouldn't they make a lot more friction than car-wheels. I reason like this:

 

1. With a ship, the entire length of the ship's hull at the waterline (perhaps hundreds of feet), rubs and drags against the water - hence, much friction.

 

2. With a car-wheel, only the few square inches at the bottom of the tire, rub against the ground - hence, less friction.

 

Is my reasoning wrong?

 

Regardless of how little friction the system has, it has some. There must be air movement with respect to the water or road, not just the vehicle, to maintain or increase speed.

[Externet]

As the air car project is highly unlikely to work, you can always dream of sitting the car on air instead of propel it with air :

 

Enjoy----> http://www.flixxy.com/volkswagen-levitating-car.htm#.UDznb3I_dt0

[swansont]

The 2nd Law of Thermodynamics. You should look into it.

It's not only a good idea … it's the LAW!

[mississippichem]

It's not only a good idea … it's the LAW!

 

There is a punishment for violations the second law too.

 

Run a process that doesn't increase the entropy of the universe...nature still keeps the books and you'll have a loy of pent up entropy coming your way in the near future *(not something you want).

 

*statement not strictly true, consume for humor value and not scientific insight.

[swansont]

There is a punishment for violations the second law too.

 

Run a process that doesn't increase the entropy of the universe...nature still keeps the books and you'll have a loy of pent up entropy coming your way in the near future *(not something you want).

 

*statement not strictly true, consume for humor value and not scientific insight.

This is known as pentropy.

[Daedalus]

This is known as pentropy.

I thought pentropy was this:

 

pentropy (pen-tro-pee) n. The tendency for the ballpoint pens at rest to suddenly and surreptitiously take flight or disappear, until none remain. (Once thought to be the result of filching co-workers, now believed attributable to the inexorable contraction of the universe.)

 

pentropic (pen-tro-pik) adj. Having the property of pentropy.

Edited August 29, 2012 by Daedalus

[chilled_fluorine]

Ramjets have the same issue illustrated above. They can't produce thrust while they aren't moving, so how do you start the vehicle moving in the first place?

 

Also, ramjets tend to need to be going above the speed of sound to operate with any kind of efficiency, which isn't really conducive to normal highway speeds for a car.

 

See Wiki - Ramjet for more details.

Thanks for answering for me. It saved a few seconds of my life.

 

We Use Air to power cars. There will be air vents on the side of the car that pulls air in while your driving.

The air will go into a small air turbine which will generate electricity.

 

When you said you use air to power cars, was that a joke? If not, please stop lying to us, not cool.