The beginning of the end of oil?

[vorticon]

Vort,

Now you're talking about a hybrid, and we already have that answer.  There are several smallish cars that get around on anywhere from 1 to 2 liter engines.  The "breakthrough" for hybrids in the US will be when we get decent diesel gas and a couple of nice modern small turbodiesels.  A prius using a modern high efficiency diesel ought to get another 50% improvement in fuel efficiency with no additional emissions or reduction in drivability.  What that'll do to the price of diesel is another story of course, and we'll see the price of both diesel and regular consumer goods go up when diesel becomes more popular because truck shipping expenses will skyrocket.  Independent truckers are already feeling the pinch, and it's only a matter of time before the effects trickle down to prices at wal-mart.

not so much a hybrid, as those still use the gas engine to directly drive the wheels at some points.   

i'm talking about a small engine running full time to recharge the batteries to increase the range of the car, used from the point where the added range of the gas generator provides better efficiency than simply adding more batteries.

[Maverick]

Vorticon,

Those types of vehicles already exist. They are trains and the large trucks used in mining.

While the idea sounds really neat you need to have a fair sized engine to be able to run the rather large generator. There is a lot of resistance when you put a load on the generator. Someone who is an electrical engineer should be able to tell you how many HP a certain number of amps will supply from a motor. They can also tell you how many HP will be needed to supply a given number of amps from the generator based on the size of the motor.

[eagl]

Vort,

The tradeoff as Maverick implies is in how much power you can get at one time out of the batteries, and how many batteries you must carry.  A diesel-electric train doesn't need a whole lot of acceleration, so it can get away with a steady stream of power coming from the generators.  Getting more than about 50hp from a bank of batteries in a car means you must have a whole lot of batteries and they must be capable of high discharge rates.  So then you need a big motor, lots of batteries, and a hefty generator to recharge those batteries.  Not too efficient in a little car due to the surge requirements during normal driving.

I think they'll be able to work on making everything more efficient in the future but I think pure electric motive power with onboard electricity generation is not very efficient in personal vehicles due to the surge power requirements.  You end up needing huge motors and either a lot of batteries or a fewer amount of very expensive batteries that get really hot while charging and discharging and which may fail in spectacular fashion (kablooi!).

[vorticon]

Vorticon,

Those types of vehicles already exist. They are trains and the large trucks used in mining.

While the idea sounds really neat you need to have a fair sized engine to be able to run the rather large generator. There is a lot of resistance when you put a load on the generator. Someone who is an electrical engineer should be able to tell you how many HP a certain number of amps will supply from a motor. They can also tell you how many HP will be needed to supply a given number of amps from the generator based on the size of the motor.

okay. good enough answer for now...

if someone on the board has enough knowledge of electrical engineering to run the numbers and elaborate, it would be interesting.

"

The tradeoff as Maverick implies is in how much power you can get at one time out of the batteries, and how many batteries you must carry.  A diesel-electric train doesn't need a whole lot of acceleration, so it can get away with a steady stream of power coming from the generators.  Getting more than about 50hp from a bank of batteries in a car means you must have a whole lot of batteries and they must be capable of high discharge rates.  So then you need a big motor, lots of batteries, and a hefty generator to recharge those batteries.  Not too efficient in a little car due to the surge requirements during normal driving."


okay, i knew that there would be issues like that but wasnt sure how much of a requirement there would be. 

would it be feasible to have the gas motor kick in for steady rate highway driving, and recharge fast enough to get, say, an additional 60 miles...while burning less than a gallon of fuel?  while remaining lighter than the equivalent in batteries required?

 thats seems to be the biggest problem with electric vehicles. range. if your doing a lot of acceleration/deceleration, chances are your in the city or on the track. as long as you have enough range to get to and from work its not that big of a deal.

[eagl]

I used to be able to do the math, but that was back in 1994

It's not impossible to do electric only, but there are severe tradeoffs due to energy density and our ability to turn electricity into mechanical energy.  I'm sure one day they'll produce a battery that has as much or more energy density than gasoline (and which doesn't explode if you jiggle it too much or poke a hole through it with a stick) but right now electric only loses out due to the sheer mass/weight of the components required to meet consumer expectations.

That said, a modern electric golf cart goes faster, farther, and can carry a larger payload more reliably than an old model T.  A golf cart isn't too useful as a household vehicle for most people, but even 80 years ago people would be overjoyed to own a modern golf cart.  Instead of gas stations, you'd be able to simply swap out a discharged battery for a full one, for a suitable charge fee of course.  That tells me we're only a generation or two away from the next big thing in consumer vehicle technology.

Heck, the first coal powered steamships were slower and less reliable than the big sailing ships of the day.  The coalers were derided as being too slow, too heavy, not efficient, etc.  Just like electrics are scoffed at today.  Things change as the technology matures however.  The problem is that while nature has provided us with relatively safe and dense power sources in coal and petroleum, the next big thing will be man-made and so far anything we make that has the same power density of gasoline tends to be really twitchy and dangerous.  Early gas or diesel boilers tended to blow up too, so again I think we'll see the technology mature eventually.

Those looking for an electric car TODAY however... dream on.  It's about as likely as asking Henry Ford to make a Roush Mustang or Orville/Wilbur Wright to come up with a concorde, and then blaming it on the govt when they fail even after shoveling an infinate amount of money at them.  The technology just wasn't there for the Wrights to make a concord back in the 1930s, and the technology isn't there to make a really useable pure electric car today no matter how much people stomp their feet and blame the oil industry or greedy politicians for not funding whatever line of research is popular today.

[Holden McGroin]

I used to be able to do the math, but that was back in 1994

It's not impossible to do electric only, but there are severe tradeoffs due to energy density and our ability to turn electricity into mechanical energy. 

So you take the Tesla system as a start, use a motor of 75 hp, put it in a lightweight econobox and you have a VW rabbit size car that does 0-60 fast enough to enter the freeway, can cruise at 70, and can go 250 mi range.  Good enough for 90% of us.  I mean if we were realistic.

[Hornet33]

I guess the idea that's running around in my head is this.

You have your car. The car has a battery pack, and a drive motor. Now add a very efficient alternator or 2 to the car and have it/them connected to the drive wheels. Now I know an alternator will not generate enough electricity unless the rotor is turning at a certain speed so clutch the things and have the clutch controlled by the onboard computer so they don't engage until the car hits, say 45mph.

So while driving in town and stuff, your simply running on the battery pack, regenerative braking is used to send some power back into the system. But when the car is on the highway and running over 45mph, the alternators kick in providing a steady charge to the battery pack while the car is moving. Again I'm not an electrical engineer, but something like that should increase available power and range without adding a bunch of weight to the car, and again if the alternators are capable of generating more power than the single drive motor is using to move the car down the road, then they can provide 100% drive power, diverting the rest back into the battery pack to recharge it.

What I'm describing is not a perpetual motion machine. I know power is going to be lost due to heat. That's not my concern. I'm just thinking there should be a way to harness the energy of the cars physical movement, i.e. the wheels rotation, and use that to generate additional power. If the drive motor is using 250amps of power to drive the car at 55mph down the highway, and you have a 150amp alternator connected to both rear wheels of the car, then they would be generating 300amps of power. Use 250amps of that power to drive the motor at 55mph and send the other 50amps to the battery pack to recharge it.

Even if that's not possible, if you could generate 50% of the power your using to drive the car and channel that back into the batteries, you'd almost double your range before needing to plug in and recharge.

[Nashwan]

So you take the Tesla system as a start, use a motor of 75 hp, put it in a lightweight econobox and you have a VW rabbit size car that does 0-60 fast enough to enter the freeway, can cruise at 70, and can go 250 mi range.  Good enough for 90% of us.  I mean if we were realistic.

I'm not sure 75 hp would be enough, after all the Tesla weighs 2700 lbs empty (about 1000 lbs of that is the battery). If you want a 4 seater car with the same battery, it's going to be heavier.

And what you end up with is a small, heavy car with not enough power, that costs far more than a comparable petrol car.

No one is saying electric cars won't work, it's just that they cannot compete with petrol or diesel vehicles, even when the price of petrol or diesel is $8 a gallon.

What I'm describing is not a perpetual motion machine. I know power is going to be lost due to heat. That's not my concern. I'm just thinking there should be a way to harness the energy of the cars physical movement, i.e. the wheels rotation, and use that to generate additional power.

But that slows down the car.

If the drive motor is using 250amps of power to drive the car at 55mph down the highway,

Right, it's using 250 amps, without powering the alternator. The car is going a steady 55 mph.

and you have a 150amp alternator connected to both rear wheels of the car, then they would be generating 300amps of power.

Which comes from where? The car going 55 mph has considerable kinetic energy, but if you start taking that to power the alternator, then the car has less kinetic energy, ie it slows down.

The only way to keep the car travelling 55 mph and power the alternator is to increase the power to the drive motor, by at least as much as the alternator is drawing (if you have perfect efficiency) or by more than the alternator is generating (in the real world where efficiency is less than 100%).

Even if that's not possible, if you could generate 50% of the power your using to drive the car and channel that back into the batteries, you'd almost double your range before needing to plug in and recharge.

Generating 50% of the power you use will require more than 50% extra power from the battery. You will have a net loss.

There is no way to do this and end up with more energy. A similar idea would be to mount a wind generator on the roof of the car, the faster you go the more electricity it would generate. Of course, it would greatly increase drag, meaning you would have to use more power to go the same speed, and the windmill would generate less energy than the amount required to overcome the extra drag.

[Hornet33]

It doesn't take that much power to turn an alternator. Geez I can spin one with my bare hands and produce a voltage reading on a multi meter. An alternator DOES NOT load up a system the faster it spins. The stators free spin inside an stationary induction coil producing electricity. So if a car is running 250amps to drive at 55mph, 2 alternators would not require twice a much energy for the drive motor to keep the car going at 55mph.

[Maverick]

Using an alternator means you are only using half of the sine wave from it and it means you will need to change it to DC. Using a generator provides direct current and that is what your battery really needs. A load on an alternator WILL cause it to require more power to turn it and produce voltage. When I say load I do not mean a radio or a single small light, I mean a load like trying push a 4,000 lb car down the road.

Like everything else, there is no such thing as a free lunch. Power to do work means you have to do work to provide power.

[Hornet33]

Right, that's why you have a bridge rectifier inline with the alternator output to produce DC power. I'm not an electrical engineer but I am an Electronics Technician. I know how power works. You guys just don't seem to grasp the idea I have, and how simple it is.

Screw it, I might just have to build myself a prototype and do some testing. Might start out with a bike cart. I have a buddy who's into stuff like that. Who knows, maybe Marty and I will be the next generation of car builders. He gets it.

[dmf]

Lol, where do those dumb idiots think electricity comes from?  Here on the East Coast, we tear up the forests in the mountains to mine for coal.  Then we burn the coal, releasing all kinds of mercury (dont eat too much fish now) and CO2 so we can heat water to turn steam turbines.

Well if they can make the thing recharge itself then they could figure out how to make a house work like that we wouldn't need the coal to make electricity now would we? And trees would still be there for you to hunt deer in, and live in .

[crockett]

Perhaps the log jamb is beginning to break...

Come up with a commuter for 30K or so and the Prius is a gas hog.

http://www.teslamotors.com/media/press_room.php?id=841

Actually there might be a total reversal and gas maybe the thing of the future..There are several new companies that have been started by groups of scientists whom are working on making a clean reproducible fuel oil out of bacteria. In fact they have already done it, it's just the matter of figuring out how to do it in mass production.

So in short, we would be self sufficient for our fuel needs (assuming they don't ship the production off to China) and we could continue to drive the same cars we do today, but would be a clean fuel. They expect to have a bio-diesel and a jet fuel out within the next 5 years.

here is a quick link on the subject, but not the article I read. (what I read was in the popular science magazine)  http://www.technologyreview.com/read_article.aspx?ch=specialsections&sc=biofuels&id=19128&a=

[Holden McGroin]

Lol, where do those dumb idiots think electricity comes from?  Here on the East Coast, we tear up the forests in the mountains to mine for coal.  Then we burn the coal, releasing all kinds of mercury (dont eat too much fish now) and CO2 so we can heat water to turn steam turbines.

We also use Hydropower: Much of NY state is powered by HydroQuebec.

We also use Nuclear

We now have wind coming on strong.

And Coal plants are on the order of 35% heat efficiency, which is better than most cars, as the coal plant is run at peak efficiency as much as possible, while your car idles at a stoplight.

Electric cars are an option for a future of diverse power sources.

Gasoline and diesel is not diverse, unless you want to go to F-T, which requires us tear up the forests in the mountains to mine for coal.  Or we can get it from shale, which requires us tear up the forests in the mountains to mine for shale.

[lazs2]

The little generator that was on older cars took about 6 hp to run.   try to spin one.   If you hook up a generator to the wheels it will cause drag.. that is why most electric and hybrids use the charging system as brakes.

lazs