electric car, can use as much power as your house

Turning the fan would consume energy and retard the motion of the car. The only time there would be benefit is when you wanted to slow the car.

Or going down a big hill...
You can not create energy from nothing...
It has to come from somewhere...
Wind energy comes in part from the solar energy hitting the earth...
Coal is really just stored solar energy...
The ultimate in green power...

Adamiscold wrote:I wonder why there has yet to be some type of box connected to an electric car that has a setup inside it much like a wind mill does where the air flowing from the car moving would turn the fan's blades and charge the cars batteries so the car would virtually be powering it's self.

AKA, a perpetual motion machine, which is not possible. But, why not capture the excess HEAT generated by the internal combustion engine, currently disposed of (i.e., wasted) by the radiator and by the exhaust system's exposure to the air? There must be ways of converting the heat to electricity, which obviously would be useful for a hybrid car. Maybe it's too complicated or expensive to do the heat-to-electricity conversion?

rberq wrote:

Adamiscold wrote:I wonder why there has yet to be some type of box connected to an electric car that has a setup inside it much like a wind mill does where the air flowing from the car moving would turn the fan's blades and charge the cars batteries so the car would virtually be powering it's self.

AKA, a perpetual motion machine, which is not possible. But, why not capture the excess HEAT generated by the internal combustion engine, currently disposed of (i.e., wasted) by the radiator and by the exhaust system's exposure to the air? There must be ways of converting the heat to electricity, which obviously would be useful for a hybrid car. Maybe it's too complicated or expensive to do the heat-to-electricity conversion?

It's not that it's to expensive or complicated, it's not practical because there is so little energy in the engine waste heat because the temperature difference is not very great. For example a simple device that works on heat difference is the thermocouple. You would only get milli-volts, even less that a typical gas appliance thermocouple, because the temperature difference is less. Yes, you could dream up series and parallel thermocouple combinations but so what? It's still not much power. Think of it another way. In winter when you are using the heater. How big of an electric heater might be needed to produce the same heat. Couple of KW? 10's of KW? Not really much power.

Yanche wrote:

rberq wrote:... why not capture the excess HEAT generated by the internal combustion engine ... converting the heat to electricity

It's not that it's to expensive or complicated, it's not practical because there is so little energy in the engine waste heat because the temperature difference is not very great.

The temperature difference may be low (maybe 100 degrees?), but isn't there a LOT of heat, therefore a LOT of energy? For every gallon of gasoline burned, isn't more than half the energy lost as waste heat? You must be right, because if it were practical to do it would have been done by now. But I can't quite grasp WHY it is not practical.

franco b wrote:Turning the fan would consume energy and retard the motion of the car. The only time there would be benefit is when you wanted to slow the car.

rberq wrote:

Adamiscold wrote:I wonder why there has yet to be some type of box connected to an electric car that has a setup inside it much like a wind mill does where the air flowing from the car moving would turn the fan's blades and charge the cars batteries so the car would virtually be powering it's self.

AKA, a perpetual motion machine, which is not possible.

How would a fan only turning by the air moving past the car consume energy?

But if the fan didn't supply an indefinitely amount of energy to run the car completely on it's own wouldn't it be feasible for the fan to run and extend the range of the car? You are basically only using the free air that surrounds any car now when it is in motion, so you're only using something that you have to create anyways in order for a vehicle to move.

Adamiscold wrote:How would a fan only turning by the air moving past the car consume energy?

I'm sure you have stuck your arm out the window of a moving car, and felt how the air pushed your hand and arm back. Now pretend you are holding a fan/generator in your hand, and stick it out the window. The fan will spin, but your hand and arm will be pushed back even harder than before. The fan pushes your arm back, your arm pushes YOU back, your body pushes back against the car seat, the car seat pushes back on the car, and the car slows down. To keep the car going the same speed, the driver presses down a little more on the gas pedal, and the engine consumes more gasoline (energy).

So, yes, the fan would spin and would make electricity. But to make electricity, more gasoline is used. And due to friction and heat losses in the fan and generator, the energy produced (electricity) is less than the additional energy consumed (gasoline). The bottom line is, you are better off to skip the fan entirely.

I hear your point and you did a very good job in explaining it and I thank you for it.

But my thoughts on it are something like this;

The whole fan wouldn't be exposed to the air only part of the blade needs to make contact with the air in order to get it to spin. A horizontal fan located in the back of the vehicle where the least amount of drag exists. You ever watch those air tunnels with the smoke that flows over the car you see once the air gets past the trunk of the car it doesn't just drop but continues for a little ways. It's in the sweet spot where another car needs to be in order to drag off of the first car. I would think that it would really only need to just get a small piece of air in order to make it turn? Even if it did create a little drag on the car if the fan is below the trunk level then and such drag would go back up over the fan but it would already be past the vehicle. A fan motor would seem to weight a lot less then having extra batteries to extend the mileage.

Something of a design off of this.



To question the drag on a vehicle how much more drag would it create? Would a new 2011 car with a fan on it create more drag then a car from 1970?

Adamiscold wrote:... A horizontal fan located in the back of the vehicle where the least amount of drag exists ...

I think another way to ask your question is this: The car moving through the air creates turbulence; can that turbulence be converted to electricity in a way that doesn't increase the drag on the car? If the conversion device (fan) is attached to the car, I think the answer is no. If the conversion device is independent of the car, for example sitting beside the road, I think the answer is yes. But it's making my brain hurt.

Just FYI:

In an internal combustion engine (from my notes, which cost me about $20K ... so thank me later ... :

35% of the energy is used to make POWER

35% leaves with exhaust gasses

30% leaves as heat, removed by cooling system

I'm a big fan of the 2-stroke engine. I believe the 2-stroke is superior in every way to any other design ... but the treehuggers cry about the emissions from it.

If treehuggers have their way, & the electric car fails, we can look forward to THIS: THE 6 STROKE ENGINE!! http://en.wikipedia.org/wiki/Six-stroke_engine

Exactly. A 2-stroke has no cams, no rockers, no pushrods & no valves. Less friction. Cheaper to rebuild, easier to work on, lighter, & more horsepower than an equivalent sized 4-stroke. Yet, manufacturers have forsaken it in response to the "green" movement. Are we progressing ... or are we progressing BACKWARDS ???? Outboard marine 2-strokes are the most advanced 2-strokes ever produced. My father's boat has a V6 150HP 2-stroke. It uses a tank of 2 -stroke oil (2.5 gallons) after 4 tanks of fuel (105 gallons each!! ). At some point the treehuggers have to give it a rest, & be happy with what we have today!! After they bury the economy, how many new advances in engine technology do you think we'll see? We're alot closer to that scenario than many think ....

I don't know if anyone has mentioned this, but; there is this little thing called the Laws Of Physics. One of the biggest is the second law ( I believe it is the second law, correct me if I am wrong) of Thermodynamics which is called Entropy. It applies in this case that no system can return as much or more energy than was put in to it. In other words, you can't have a device that produces more energy than it uses. Everything in the Universe is moving from order to disorder and the only way to slow it down is to put more energy in to the system than it takes to hold it together. Left to itself everything rots, rusts, decays or wears out unless more energy is put into it that exceeds the rate of Entropy.

rberq wrote:

Adamiscold wrote:... A horizontal fan located in the back of the vehicle where the least amount of drag exists ...

I think another way to ask your question is this: The car moving through the air creates turbulence; can that turbulence be converted to electricity in a way that doesn't increase the drag on the car? If the conversion device (fan) is attached to the car, I think the answer is no. If the conversion device is independent of the car, for example sitting beside the road, I think the answer is yes. But it's making my brain hurt.

Turbulence was once a major problem for submarines but with enough hard work at it they have just about over come the problem completely. I guess the question would be where at want point on the car would such turbulence be created? In the air just above the end of the vehicle? How much would that really effect it?

Plus everyone is assuming that this goes on a gas engine, take that out and you've lowered the weight of the vehicle a lot. It doesn't have to create enough energy to power the whole car even if it's just enough to cut the time down greatly that you would need to have it plugged in to charge would be a great improvement on lessening the load of the power grid.

SMITTY wrote:If treehuggers have their way, & the electric car fails, we can look forward to THIS: THE 6 STROKE ENGINE!! http://en.wikipedia.org/wiki/Six-stroke_engine

Smitty that's part of the problem! There's no reason why both can not exist at that same time giving people another way to help cut their dependability on oil. Engines will be around for another ten plus years or so. I found it greatly disappointing that you compare a vehicle ten years ago to the same type now and the weight of the vehicle has gone down but the mileage hasn't gone up. My 2002 ford explorer xlt 4x4 gets 20 miles to the gallon while a brand new one doesn't get out of the teens.