use the air we drive through
 

i was thinking if i have to let air in to cool my radiator why not put that air to use.
i have included a rough drawing to help illustrate my idea

i know we talk about solar to help top off batteries and to help in those who have performed an alternator delete but the other abundant reusable resource besides water ,which is not good for your car, is air or wind. not since the air blowing by your car is going at least as fast as you are moving then there is no shortage of wind when driving. so why not use a small scale wind generator (like this one i found on ebay, 12VDC 2400RPM MINI WIND GENERATOR TURBINE PROJECT MOTOR - eBay (item 250603606228 end time Oct-20-10 16:47:13 PDT) )

my thoughts was to make an inlet in the bumper for air possiblly an air intake velocity funnel ( Air intake velocity funnel image by almc2242 on Photobucket ) these can increase the amount of air taken in by up to 20 percent but it also does not increase the frontal area of the aerodynamics of drilling a 20 percent bigger hole. from this tubing which cold be intake tubing or just pvc pipe would be run to the radiator. inside the tubing i would place the mini wind turbine generator so it would look like a jet engine. the wind in the intake would create 12 volts in my experimental idea. which could be used to top off a battery if you had a voltage regulator ( Solar Charger Regulator Contoller LCD Panel 20A 12V/24V - eBay (item 270643685984 end time Oct-05-10 02:19:39 PDT) ) or could be used for other things i guess.

so what do you guys think would this idea create alot of drag or are there any down sides to an approach like this

Hi TallDude,

Sometimes for the sake of description, I like to take an example of an approach and size it large to an extreme, to see if the idea is worth pursuing or not.

In your example, we are using air that is passing by our vehicle to move another object, namely a fan blade.

Let's take this example to an extreme....

Picture a wind turbine mounted on top of our vehicle. We are moving through the air at let's say, 50 mph. The wind turbine on the top of our vehicle has three blades that are each 5 feet long, and will catch quite a bit of air while moving at this speed.

The blades will generate quite a bit of electricity for some type of use on our car, and this is the good part. However, those same blades will tend to make our motor in the car, work harder and use more gas to move the car forward.

Since we have not invented perpetual motion machines yet, the turbine mounted on the roof will always take more energy in, in the form of air drag, than it gives back out, in the form of electric energy.

Now we should mention that stationary wind generators that are mounted to the earth are useful, because even though they are not 100% energy efficient, they still take the free wind and convert some of that energy into electricity for our use later on.

Mounting this same wind generator on our car however does not give the same results that we are looking for in this case.

Thus we are better off making the air flow paths through and around our moving car bodies, as clean and efficient as possible.

Maybe you take some of your fan idea, and apply that to the free heat that is already in the engine compartment, and use that to propel the vehicle forward. And as you know, anytime there is excess heat, there is also expanded air that be used to make this happen. Just a thought for your next invention.

Jim.

i am not talking about diverting air anywhere i was talking about the front grill openings. there are already holes and air flowing through so that dynamic does not change it is just the addition of a small wind turbine. i am trying to make sure if i go alternator less that my battery stays charged. solar works only in the sun, and would forget to plug in a charger so i had this idea. would a wind turbine mounted in front of the radiator be more efficient than an alternator

I think another question we can ask ourselves is this....

Why is there air entering into this area in the first place?

- Is it by design?
- Was this something overlooked by the manufacturer?
- Does this extra air serve a purpose?
- Can we simply shut off this air source and not let it be a form of drag on our moving vehicle?

Jim.

I can assure you, sir, there would be only a time or two that you would forget to plug in the charger.

I'm not sure about that, I've forgotten to turn off my headlights quite a few times (mostly because by the time I park, the sun comes out and I can't tell they're on).


My thoughts on this are like electric superchargers- You're not going to produce enough energy from it to make a difference.

I do like your enthusiasm about how to make extra energy work to propel our vehicles.

Do not give up too easily on just how to extract extra energy out of the fuel we use to move our cars.

Since the engine does create extra heat in areas that need to be cooled, such as the exhaust system, there is free lunch here concerning excess energy can can be harnessed in some way.

Using a turbine in this area to generate electricity would indeed provide a net gain in energy efficiency.

Just don't try to harness this energy from the cooler, moving air. The goal to high efficiency here, is to present the air with the least amount of drag as possible, and this includes turning fan blades.

Jim.

I think that you might be able to gain a few watts from this idea if you changed it so that the turbines were in the airflow after the radiator. This air has already been heated by the radiator and if you expand it properly you might be able to recover some of that energy that would have been dumped overboard.

You can't get energy for free, as noted by others above.

That said, you can save some energy otherwise wasted. I don't know if you'd have a net improvement or not, but suspect not.

That said, let's look at tweaking your idea: Instead of using intake air from off to the sides, how about using intake air where it's best, i.e., at the highest pressure stagnation point of flow at the nose centerline. Now, let's release that air back into the slipstream where pressure is lowest, i.e., maybe 1' back from the nose on the forward surface of the hood, or at the known low pressure zones on the sides just forward of the front wheels. Look at any fast fish mouth and gill placement, and you'll get the idea--inflow at highest pressure point and outflow at lowest pressure points. So, take a tuna and lie it on its side, add faired wheels, and now you have probably the world's most streamlined car.

Back to your ducted windmill idea: If you put the ducted windmill in an efficient duct that goes from highest pressure nose stagnation point to lowest pressure hood or fender or undertray point, then you can extract the most through-flow energy to turn the fan. Whether this makes more electrical juice at less cost than running the belt-driven alternator remains to be seen. Maybe, using little fans like in computers and installing them in the ducting, you'd get trickle flow of juice to top off the battery. Or not.

Popular Science did a very small writeup circa 1999 - 2000 on a company that was experimenting with a large fan mounted horizontally on the roof of a van. As the van moved forward through the air, the blades would turn and charge the batteries. ( it was an EV )
What made it all work, was that the fan blades were geared to fold flush past a certain point. This reduced the drag that the blades would normally cause.
I don't have the magazine anymore, but if you were wondering, it had a story titled " Detroits new 80 mph cars ".
Much like the ' new 80mpg' cars, I never heard anything from that experimental van .

If you only need to go downwind, you could build yourself one of these: http://www.youtube.com/watch?v=aDzWh...e=mfu_in_order

That might really annoy the folks waiting behind you at the light... :p The guy otter have a manual boost to get the machine going! (pedals or Flintstone slots or some such)

I have to disagree with many people here about this.

The common philosophy is to go alternatorless will save buckets of energy. My question is, if an alternator is drawing no power, how much gas does it consume? The answer is very little in comparison to the gas usage of the vehicle needing to move down the road. If a 100 amp alternator is drawing full power, how much gas does it consume?

@100 amps output, we could assume 50% efficiency, which make 200 amps effective draw from the crank.
750 watts=55.6 amps @13.5 volts
13.5 volts (roughly the voltage of a running alternator) times 200 amps = 2700 watts
2700 watts divided by 750 watts (or 746 for those who are particular) = 3.6 hp.

At cruise the Scanguage calculates I am creating 50 hp from the gas I burn. So 7.2 percent of gas burned at cruise goes to the alternator ASSUMING the battery is dead and requires a recharge, which would require all the alternator has to give. However, generally speaking, with a topped off battery and a healthy alternator, it would be a fraction of that draw. Lets say half that, I'm sure it's less, but half makes easy math.

7.2 hp required divided in half = 3.6% required from my 50 hp output at cruise. At cruise I can easily exceed 30 mpg, so we'll stick with 30 mpg. So if I delete the alternator and ignore any possible side effects from a lower voltage requiring more amperage to components (higher amps = more heat) I'll save 3.6% of 30 mpg which equals 1.08 mpg and a nearly dead battery after a healthy drive.

Where's the benefit when I can allow the alternator to efficiently create electricity on the fly and hardly if ever open the hood to recharge a nearly flat battery?

Hi ShadeTree,

I like what you said above, but I do question the 50 hp at cruise. Of course this does depend on what speed you are going.

Cycle magazine used to use a third wheel to measure various factors such as acceleration, braking, hp at 60 and so on.

Back then the motorcycles of the day used to use something like 6 hp to go 60 mph. Of course a motorcycle has less frontal area and less weight, but a much higher Cd.

Based on this, your car should use something around 20 hp to go sixty. That 50 number sounds too high if you are really going 60 mph at the time.

EDIT: If your driving the van, well, then maybe the 50 hp might be accurate.

As fuel becomes more scarce, I believe the 3% increase in fuel mileage will become more important to all of us. And I still like your analysis.

Jim.

Smokey Yunick modified his Daytona car when he found that the under hood pressure was making the fuel injection system go super rich. He added two relief flaps in the floorboards that allowed the high pressure air to escape the engine compartment.

Good for an additional 20 MPH on the Daytona Beach qualifying. Qualifying in 1957 was a max speed run down the beach with the fastest car getting pole position.

This was before fuel injection was illegal.

regards
Mech

Wind generators are not efficient. Only a fraction of the kinetic energy of wind can be captured mechanically. Converting to electricity is lossy: alternators and wires heat up. Storing energy electrically is lossy: batteries leak due to internal resistance. Far better to forgo the weight, expense and complexity and focus on reducing drag. That will pay dividends ALWAYS and the return on investment increases with speed! :)

I installed a digital amp meter on the battery of my truck. Cranking the engine over saturates the draw above 200A for a second or two. The initial (peak) recharge rate is around 50A initially. That drops quickly and exponentially to 10A within a minute and 1A (steady state) within an hour. When you integrate the area under the curve the total energy to recharge the battery after a start is low. Parasitic power to do the deed is high fruit. Pick it last IMHO once your Cd is under 0.2 for example.

Cheers
KB

so squash using mini wind generators to produce electricity sounds like, well not to be discouraged that easily i will research using the numbers you guys gave me and see if wind is usable numerically and if it can be combined with solar to ease my mind.

...anything you "hang" out in the breeze is gonna effectively become an "air-brake" because the lowest air resistance is to have NOTHING hanging in the air.

I used to have a tachometer on my car that was also an hour meter, I made note of the odometer reading at time of install and a few times a year check to see what my average speed was, turns out it was about 28mph, after I bought my electric car and started using that for 90% of my shorter trips my average went up to 32mph.
I know that there are figures for how much energy is in a given area of wind at a given speed but I couldn't the specs that I have once seen, I did however do some quick math from wind turbine out puts at 25mph and figured you get about 10-12 watts per square foot of rotor area, the ECU for my car uses around 60 watts, then add to that the fuel pump, radio, lights and you need closer to 250 watts or more.

I don't think drilling an exta hole is a good plan, however if you already have an opening for cooling air that goes through the radiator you could use any energy left in the radiator exit flow to drive a mini air tubine then duct the exit air from the mini turbine to a low pressure area it might work. The experament is well worth a try. If nothing else you will find out what doesn't work. The process will teach you a whole lot of other stuff that may become useful in some other experament.

You'd probably not get much out of it because the flow is low to moderate, but there's somewhere where you want air to be flowing- what about in the airstream to the cabin air feed? There's a fan in there already (albeit usually a radial-bladed squirrel-cage fan) but most of the time I like having some sort of airflow through the cabin, and this occurs even with the fan off, with the vehicle in motion.

Not sure how much energy would be in that gas flow though. Probably not much as the route to exit into the cabin is usually convoluted and the gearing on the fan is 1:1...

--Phil

Everyone is forgetting about ducting that does not affect aero, or at least will not add drag. NACA ducts, the type used in racing, are designed to extract air from the stream without adding drag. Granted these ducts will not realize the same amount of air as a open duct in the grill, but will have the benefit of not adding to frontal area or drag. The upside is that there will be air coming in that does have velocity and pressure. You may not be able to generate a ton of power, but it may be enough to trickle charge a battery. Just some thoughts. This is actually a thought i had some time ago, but I am just now starting to get a better idea of generators. I think a BLDC would be better than the standard alternator. BLDCs realize higher efficeincy ratings.

...ah, but NACA ducts "trade-off" velocity for pressure.

you can't have it all, I am just offering an alternative idea. Just trying to offer some help in seeing a project realized. If you do want to reclaim some pressure you can always add a divergent zone in front of the blades to increase the pressure. It all depends on how much space you want to take up with it.

Old Tele man -

Could the wheelwell be used to "pull" the air out?!?!?! :

http://ecomodder.com/forum/member-cf...-wheelwell.jpg

PS - In the above, I say "fan", but I really mean mini-windmill-turbine-thingy.

CarloSW2

talldudenumber5 -

Here are the specs on that motor :

Mabuchi EG-530AD-2F
It's rated at 0.073 Amps. I think I would want at least 1 Amp, but maybe that's asking too much?!?!?!

CarloSW2

I think Dyson has beat me to the punch.
 

I've heard the British vacuum maven has filed a patent for an electric car. His design may even work! My attempt, the jury is still out.

i found this model ( Small Alternator, Mini Generator (YAF-54) ) that may get me the amps i need especially if i do 2 of them plus i could do 2 solar panels like this to trickle charge what the wind does not and they would fit into my sun roof and still allow me to use it. ( 1.5 Watt 12V 90mA MINI SOLAR PANEL for CHARGING BATTERY - eBay (item 130436312637 end time Oct-03-10 20:45:07 PDT) )
i have decided to do a fan behind the radiator since being after the radiator i have nothing to lose in drag or cfm in air moving in to cool the radiator / engine. plus when the fans kick on turbo boost to compensate for them coming on

this idea is very feasible and could replace an alternator it would not be good for a vehicle with heavy electrical load ( bass systems, lots plugged into the cig lighter, lots of lights, etc.)or for alot of turning the engine on then off but for a hypermiling vehicle that neutral coasts instead of EOC this could replace the alternator with out worry of dead battery.

also side note: the solar would trickle charge the battery to keep it topped off which would help the battery last longer and reduce the amount you have to replace those expensive batteries

If you're serious about no alternator, headlights would ruin your plan. Just avoid dark. Change brake lights to LED. If that unbalances the blinker circuitry, that too can be fixed. Seems like a lot of fuss over high fruit IMHO but squeezing the stone...

The project promises to be educational for sure. I hope to read all about it. :)

Cheers
KB

KamperBob -

Maybe talldudenumber5 is a giraffe, so high-fruit is easier to get at, ;) .

CarloSW2

You can't get enough air flow to produce a noticeable amount of power, if you use "math" (fully of theories, so not everyone believes in it) you will find that you will get 18 watts per square foot, I would say you would need a "fan" the size of the entire front of the vehicle.
Wind Turbine Power Calculator

Ryland -

Thanks for the perspective and the URL. I wonder what the effective wind speed is behind the radiator.

CarloSW2

Well I am 6 foot 6 so yes

This makes no sense. Let's say you have a grill that's 2 square feet. So you put a turbine in, and because of the restriction and energy sapped away by the wind generator, it's now effectively 1 square foot.

You'd be better off making a fairing to restrict the hole to 1 square foot aerodynamically.

You can't get something for nothing.

talldudenumber5 -

Woo hoo!

Here are other threads that have asked this question :

http://ecomodder.com/forum/showthrea...air-12453.html
http://ecomodder.com/forum/showthrea...ator-6196.html
http://ecomodder.com/forum/showthrea...tor-12076.html ... that points to ... Wind Generators

CarloSW2

This sounds like an idea I would conjure up some random late night my freshman year in college studying engineering, when the world is full of unexplored possibilities and blah blah...

1. this idea probably will be a net loss in time and money.

2. Aerodynamic losses are incurred when you use your vehicle to move air (or heat up air, but that's negligible for cars).

Say the vorteces you leave behind you have an average velocity of Xmph, when your car passes, you've just taken all the stationary air and accelerated it to Xmph.

the logical extreme would be a car that takes all the air it hits to the same speed the vehicle is traveling. So this free air that you're going to slow down via turbines: think of it as using your proposed turbine-generators to accelerate the amount of air they "use" in the direction your car is traveling at a less than 100% efficiency.

But if I'm wrong and this idea does work, I'd love to compare the payback period on it to the aerocivic's bodywork...

Where is the math that says it might work? if you were in an airplane and traveling at 100+mph then yes, you would have enough air flow to make it work, but you don't have the air flow nor the area to make it work, 18 watts per square foot is enough to power your radio, but your ECU and fuel pump draw closer to 80 watts.

Let me take a step back for a second: This idea can't work, I was just saying, look at what low-hanging fruit aerodynamic improvements are. The aerocivic has paid for itself many times over.

I would submit not even this would work. Any increase in drag (WHICH IS HOW IT'S POWERED) created by the wind turbine would need to be overcome by the propulsion system on said vehicle... ...And I don't think anything out there runs on a carnot cycle...........

http://www.basicaircraft.com/turbo-a...tor-bpe-14.asp

Wind generator for a Piper Cub