Performance Electric cars

[steveB]

I didn't say from nothing.

But you said PSI can spin a generator and you made an analogy to PSI in tires holding up a car. However, PSI holding a car up does no work, and so requires no energy, while spinning a generator requires work, and hence the PSI will decrease and then needs to be replenished. This replenishing of PSI requires work/energy. So you seem to be saying that you can do this without energy input for free, which is basically saying "from nothing". That is, no energy and no cost.

If it is something else you are saying, then you are free to explain it.

 

[Nigel Goodwin]

I didn't say from nothing.

So perhaps you would care to inform us where the energy would be coming from? - I'll give you a clue, I've already mentioned it earlier!.

 

[rc3po]

But you said PSI can spin a generator and you made an analogy to PSI in tires holding up a car. However, PSI holding a car up does no work, and so requires no energy, while spinning a generator requires work, and hence the PSI will decrease and then needs to be replenished. This replenishing of PSI requires work/energy. So you seem to be saying that you can do this without energy input for free, which is basically saying "from nothing". That is, no energy and no cost.

If it is something else you are saying, then you are free to explain it.

Hi Steve.
We can use a driveshaft to turn a differential to turn the axles and push a car, why can't we reverse the process in a different way?
Why can't we take some of the energy of the rolling wheels when the car is moving and transfer it into energy to drive a simple hydraulic system to spin a generator?
We know that a hydraulic system outputs much more power than it takes to pressurize the fluid. I don't know the mathematics and how to calculate it but it seems to me that it wouldn't take much pressure. I mean, I'm not talking about a bulldozer here, just a simple system to turn a generator.

 

[skimask87]

How much energy does it take to spin a generator?
Ever go to a science museum and hop on the old bicycle/generator and your friends started turning on things...a light bulb, the TV, the fan, etc. Got really hard to pedal really quick. And that's only a couple hundred watts at most. Far less than one horsepower.
I, along with everybody else, could go on and on why this wouldn't work, but I'll leave that for somebody else to cut-and-paste out of a Physics 101 book from somewhere.

 

[rc3po]

How much energy does it take to spin a generator?
Ever go to a science museum and hop on the old bicycle/generator and your friends started turning on things...a light bulb, the TV, the fan, etc. Got really hard to pedal really quick. And that's only a couple hundred watts at most. Far less than one horsepower.
I, along with everybody else, could go on and on why this wouldn't work, but I'll leave that for somebody else to cut-and-paste out of a Physics 101 book from somewhere.

Well, since you mentioned it: EFFov = (HPout/ HPin)X 100.
Overall Efficiency = Output Horsepower/ Input Horsepower x 100.
....you were saying?

 

[cowboybob]

... We know that a hydraulic system outputs much more power than it takes to pressurize the fluid. ...

Are you suggesting that there is more power produced than that used to produce it?

 

[skimask87]

Well, since you mentioned it: EFFov = (HPout/ HPin)X 100.
Overall Efficiency = Output Horsepower/ Input Horsepower x 100.
....you were saying?

My point was that spinning a generator isn't effortless.
Take that same "equation" you just threw up and apply it to your hydraulic imagination. You're going to come up way behind the power curve...literally...

 

[rc3po]

But it was just an i

Are you suggesting that there is more power produced than that used to produce it?

Well I don't know about that, I'm not a mathematician. But I do know that a hydraulic system has a mechanical advantage. I just proposed an idea that maybe that advantage could be used in that application.
Maybe I'm wrong. It was just an idea. I really don't understand the fuss. Some people seem to get over-emotional about these things.

 

[rc3po]

My point was that spinning a generator isn't effortless.
Take that same "equation" you just threw up and apply it to your hydraulic imagination. You're going to come up way behind the power curve...literally...

Where do you think I got that equation? It's a Fluid Motor Power formula.

 

[rc3po]

My point was that spinning a generator isn't effortless.
Take that same "equation" you just threw up and apply it to your hydraulic imagination. You're going to come up way behind the power curve...literally...

I never said it was effortless. I wish you would learn how to read and not put words in my mouth.

 

[skimask87]

I never said it was effortless. I wish you would learn how to read and not put words in my mouth.

I wish you would read Physics 101.

 

[rc3po]

I wish you would read Physics 101.

I wish you would grow up. Did you skip school today?

 

[Nigel Goodwin]

But I do know that a hydraulic system has a mechanical advantage. I just proposed an idea that maybe that advantage could be used in that application.

Except your entire premise is wrong, hydraulic systems don't have a 'mechanical advantage' - it's simply a kind of gearing system, just as with a lever you can get a small high powered movement from a large low powered movement, and with the associated losses of course.

 

[rc3po]

Except your entire premise is wrong, hydraulic systems don't have a 'mechanical advantage' - it's simply a kind of gearing system, just as with a lever you can get a small high powered movement from a large low powered movement, and with the associated losses of course.

Lol! I'm still scratching my head trying to figure out how you became a Super Moderator...

 

[skimask87]

I wish you would grow up. Did you skip school today?

Nope, skipped work though...oh wait, I'm self-employed.
I couldn't make it to work anyways. My foot cranked hydraulic pump and motor driven bicycle wouldn't go fast enough with me on it. Funny how it really moved fast without any mass to move.

 

[Nigel Goodwin]

Lol! I'm still scratching my head trying to figure out how you became a Super Moderator...

By understanding simple principles, which you seem incapable of?

 

[rc3po]

By understanding simple principles, which you seem incapable of?

At least I know that hydraulics isn't a gear/lever system. It's a fluid pressure system to turn fluid pressure into linear mechanical motion.

 

[Nigel Goodwin]

At least I know that hydraulics isn't a gear/lever system. It's a fluid pressure system to turn fluid pressure into linear mechanical motion.

Apparently you don't know it at all, it's the exact same principle - essentially just altering the ratios of speed and distance.

 

[skimask87]

At least I know that hydraulics isn't a gear/lever system. It's a fluid pressure system to turn fluid pressure into linear mechanical motion.

And it's basically the same thing...
Hydraulic pumps/motors, mechanical arms/levers, electric motors/generators, all basically interchangeable.
Turn a hydraulic pump to turn a hydraulic motor to move X mass Y distance takes Z energy input.
Pump a mechanical arm (eg. connecting rod) to turn a wheel to move X mass Y distance takes Z energy input.
Spin an electric generator to spin an electric motor to move X mass Y distance takes Z energy input.

Deplete a battery to turn a wheel to move X mass Y distance takes Z energy input. Now sap some of the Z energy input and use it to turn a hydraulic motor to spin an electric generator to recharge earlier mentioned battery.
You've just incurred a bunch of parasitic losses in the transformation of energy from linear to rotary to hydraulic to electrical to chemical, back to electrical, back to rotary, back to linear, which is your so-called energy recovery system. Not to mention the extra mass of hauling that extra motor/generator pair along for the ride.

Just.....doesn't.....work....

Physics 101.

EDIT: Let me rephrase "Just doesn't work" to "Just.....doesn't......add.....up"

 

[steveB]

Why can't we take some of the energy of the rolling wheels when the car is moving and transfer it into energy to drive a simple hydraulic system to spin a generator?
We know that a hydraulic system outputs much more power than it takes to pressurize the fluid. I don't know the mathematics and how to calculate it but it seems to me that it wouldn't take much pressure. I mean, I'm not talking about a bulldozer here, just a simple system to turn a generator.

You can do that, but we have the law of conservation of energy to deal with. So, when you do it, you slow down the car faster by applying a decellerating force on the car. Mechanical advantage, while very useful, doesn't circumvent the law of conservation of energy. It only allows you to make better use of the energy you have.

So previously we were talking about regenerative energy which comes from breaking and downhill runs. In those cases wasted energy can be utilized to give better overall efficiency. This works because we are identifying the energy sources as kinetic energy of the car motion, or potential energy of the car as it goes from higher elevation to lower elevation. The old ways tend to waste this energy (unless you drive in a very smart, and perhaps dangerous, way), while the new systems can recapture some of this wasted energy.