Probably a stupid car question...

[Taem]

...but when I was having my alternator fixed the other day, I got to thinking about how a car makes its electricity. My father-in-law told me he could take the battery out of his older car and it would run fine without a battery because the car generated its own charge. This got me thinking as to what was generating the electricity! I know the raw kinetic energy outputted from a car is from the gasoline entering the engine block, then being exposed to a spark causing an explosion pushing out the pistons generating momentum, but what about the electricity? I checked online and found out, "it is possible to get electricity from the kinetic energy of a car," but nothing more... Sooo... what devise on a car turns all that kinetic energy into electricity? Any gear-heads here know? I figured it was similar to those wind-up flashlights, the two metal types grinding against each-other generating a static charge that can be temporarily held in the flashlights crappy [hand-wound] rechargeable battery. Concept would be the same for cars, but I never heard of this type of devise in a car before.

[Ruvanal]

http://en.wikipedia.org/wiki/Alternator

[Taem]

Wow, guess it was a stupid question, lol! It was the alternator the entire time... I thought the alternator just regulated where the power went in the car, power it was receiving in current form already. I never guessed the alternator is what made the electricity also. Thanks for the link!

[kandrathe]

... that is until we more fully perfect the naquadah reactor.

[--Pete]

Hi,

... that is until we more fully perfect the naquadah reactor.

Yeah, their present tendency to go unstable and wipe out a whole city leaves a little to be desired.

--Pete

[kandrathe]

Yeah, their present tendency to go unstable and wipe out a whole city leaves a little to be desired.

And, the glass is still half full.

But... it is kind of true that we have the technology to create millions of small scale power reactors that would be emissions free, however, the powers that be don't want to allow such devastating power into the hands of consumers, even if it were affordable. If they were designed to be modular and portable, they would survive multiple vehicle shells before running out of power.

[Rhydderch Hael]

... that is until we more fully perfect the naquadah reactor.

Forget that— what about a good ol' fashioned Asgard neutron ion reactor?

[--Pete]

Hi,

Forget that— what about a good ol' fashioned Asgard neutron ion reactor?

Thor said we couldn't have any more. Something or other about the knowledge eating up our brains. We should start a campaign, ZPMs for all. Of course, that would be ZedPMs north of 49°.

--Pete

[Lissa]

Yeah, their present tendency to go unstable and wipe out a whole city leaves a little to be desired.

And, the glass is still half full.

But... it is kind of true that we have the technology to create millions of small scale power reactors that would be emissions free, however, the powers that be don't want to allow such devastating power into the hands of consumers, even if it were affordable. If they were designed to be modular and portable, they would survive multiple vehicle shells before running out of power.

The problem isn't so much minaturizing, it's shielding. To give you an idea, the TRIGA that the University of Arizona had (the decommissioned and pulled it out this year) used 20 feet of water to shield people from the radiation. While in a shutdown state, the radioactivity in the reactor room was at background levels, but when the reactor was powered up, you were still taking about 10 mRem/hr.

So, in order to properly shield a reactor core, you would need a dense material for the gammas (tungsten, lead, uranium - yes, it's a great gamma shielder) and something loaded with hydrogen (water, parafin wax) for the neutrons. This so called minature reactor would actually be about the size of the car itself with the power transformation equipment (turbines, generators, pumps/compressor depending on the cooling fluid for the reactor) in order to properly shield it from the gamma rays and neutrons it was producing.

[kandrathe]

Yeah, their present tendency to go unstable and wipe out a whole city leaves a little to be desired.

And, the glass is still half full.

But... it is kind of true that we have the technology to create millions of small scale power reactors that would be emissions free, however, the powers that be don't want to allow such devastating power into the hands of consumers, even if it were affordable. If they were designed to be modular and portable, they would survive multiple vehicle shells before running out of power.

The problem isn't so much minaturizing, it's shielding. To give you an idea, the TRIGA that the University of Arizona had (the decommissioned and pulled it out this year) used 20 feet of water to shield people from the radiation. While in a shutdown state, the radioactivity in the reactor room was at background levels, but when the reactor was powered up, you were still taking about 10 mRem/hr.

So, in order to properly shield a reactor core, you would need a dense material for the gammas (tungsten, lead, uranium - yes, it's a great gamma shielder) and something loaded with hydrogen (water, parafin wax) for the neutrons. This so called minature reactor would actually be about the size of the car itself with the power transformation equipment (turbines, generators, pumps/compressor depending on the cooling fluid for the reactor) in order to properly shield it from the gamma rays and neutrons it was producing.

Miniaturization in a different form. Since not many people are designing mobile reactors, there are not any rapid advances in the technology. Most mobile applications (US navy) can accommodate devoting a large engine room for the comparatively large power required to move an aircraft carrier or a submarine. Scaling it down to 200 to 225 Kilowatts, would require core modifications to augment critical mass. The problems I see are that we currently simply create a fissile pile, then ameliorate the consequences with shielding and cooling. Heat is transformed into power the old fashioned way. It would be better to find fissile materials with fewer negative effects, and create a mechanism for better conversion and control of the power output.

Ford Nucleon

[Lissa]

Yeah, their present tendency to go unstable and wipe out a whole city leaves a little to be desired.

And, the glass is still half full.

But... it is kind of true that we have the technology to create millions of small scale power reactors that would be emissions free, however, the powers that be don't want to allow such devastating power into the hands of consumers, even if it were affordable. If they were designed to be modular and portable, they would survive multiple vehicle shells before running out of power.

The problem isn't so much minaturizing, it's shielding. To give you an idea, the TRIGA that the University of Arizona had (the decommissioned and pulled it out this year) used 20 feet of water to shield people from the radiation. While in a shutdown state, the radioactivity in the reactor room was at background levels, but when the reactor was powered up, you were still taking about 10 mRem/hr.

So, in order to properly shield a reactor core, you would need a dense material for the gammas (tungsten, lead, uranium - yes, it's a great gamma shielder) and something loaded with hydrogen (water, parafin wax) for the neutrons. This so called minature reactor would actually be about the size of the car itself with the power transformation equipment (turbines, generators, pumps/compressor depending on the cooling fluid for the reactor) in order to properly shield it from the gamma rays and neutrons it was producing.

Miniaturization in a different form. Since not many people are designing mobile reactors, there are not any rapid advances in the technology. Most mobile applications (US navy) can accommodate devoting a large engine room for the comparatively large power required to move an aircraft carrier or a submarine. Scaling it down to 200 to 225 Kilowatts, would require core modifications to augment critical mass. The problems I see are that we currently simply create a fissile pile, then ameliorate the consequences with shielding and cooling. Heat is transformed into power the old fashioned way. It would be better to find fissile materials with fewer negative effects, and create a mechanism for better conversion and control of the power output.

Ford Nucleon

Incorrect, the TRIGA was 100 kW and required that 20 feet of water for shielding while powered. Radiation has to be attenuated which requires material between the radiation source and the object(s) being shielded. There is a known amount of distance of certain materials required to cut down on the radiation. To cut the radiation for a gamma source in half requires 40 feet of air, with other materials it can be less than an inch to a foot (believe it or not, in the event of a nuclear detonation, 6 feet of earth will cut the radiation to near 0 levels if you're not in the pressure/temperature killzone).

To give you an idea of what needs to be done, the first landers on the moon used the SNAP (Space Nuclear Auxilary Power) reactors that made their power by interactions from alpha particles against a film. One of the things most people don't know, and what Neil Armstrong did first thing after exiting the lunar lander, was to take a Plutonium rod from one of the lander legs (I've been able to identify where it was on the lander after seeing a lander mock-up at the Smithsonian's Air and Space museum) and place it into the SNAP to begin producing power. The reason the rod was placed on the leg and not in the compartment with the astronauts was to protect them using the lander's shielding from the gamma rays that are emitted from Plutonium (yes, it's primarly an alpha emitter, but when emitting alphas, there is a likelihood of releasing gamma rays as well to reduce excess energy in the decay process). So, you have to have shielding of some kind and you have to have a given amount for it to cut down on the radiation.

[kandrathe]

... So, you have to have shielding of some kind and you have to have a given amount for it to cut down on the radiation.

I think you misunderstood me. I'm not saying that shielding is unnecessary, I'm saying that by choosing better nuclear reactions you can minimize the amount of harmful radiation emitted, and by choosing better shielding materials you can minimize the size and mass of the shielding. Water, concrete, earth, or lead are abundant and cheap, which is why for terrestrial uses or even in large vehicles (like aircraft carriers, or submarines) bulk is still not an issue.

Another point I'm trying to make is that while there have been some advances in making nuclear power smaller and safer, essentially a simple critical mass nuclear reaction is still used to generate steam power. That is a fairly archaic and inefficient way to transfer the power of the strong nuclear force into motive or electrical power. Given more attention and less political antipathy, quantum chromodynamics might have progressed much further than it has. For example, allowing for the direct conversion of the strong force into the electroweak force thereby eliminating waste altogether.

[Lissa]

... So, you have to have shielding of some kind and you have to have a given amount for it to cut down on the radiation.

I think you misunderstood me. I'm not saying that shielding is unnecessary, I'm saying that by choosing better nuclear reactions you can minimize the amount of harmful radiation emitted, and by choosing better shielding materials you can minimize the size and mass of the shielding. Water, concrete, earth, or lead are abundant and cheap, which is why for terrestrial uses or even in large vehicles (like aircraft carriers, or submarines) bulk is still not an issue.

Another point I'm trying to make is that while there have been some advances in making nuclear power smaller and safer, essentially a simple critical mass nuclear reaction is still used to generate steam power. That is a fairly archaic and inefficient way to transfer the power of the strong nuclear force into motive or electrical power. Given more attention and less political antipathy, quantum chromodynamics might have progressed much further than it has. For example, allowing for the direct conversion of the strong force into the electroweak force thereby eliminating waste altogether.

No, I'm understanding quite perfectly, what you're not understanding is how much materials are needed and what type. Radiation, depending on type and energy level, will be stopped by some amount of shielding, the higher the energy of the incident radiation, the more shielding required. It's not simply getting better reactions or smaller masses or using different methods to gather energy from standard radioactive decay (which is what the SNAPs do), it's stopping the various radiations that are difficult to stop (externally to humans, gammas and neutrons). We know quite a bit about radiation interaction from both Gamma Rays and Neutrons, and we know that we have to have certain materials with certain thicknesses to limit the exposure of these types of radiation. It's not as simple as you think it is to outright block radiation exposures, you have to have the right materials and those materials have to be the right thickness to limit exposure.

[--Pete]

Hi,

I'm saying that by choosing better nuclear reactions you can minimize the amount of harmful radiation emitted, and by choosing better shielding materials you can minimize the size and mass of the shielding.

... the higher the energy of the incident radiation, the more shielding required. It's not simply getting better reactions or smaller masses or using different methods to gather energy from standard radioactive decay ...

I agree with Lissa on this point. One can say "choose a better nuclear reaction", but nature really doesn't offer one. You can say "choose better shielding materials" but even the best possible still take pretty good thicknesses to work.

The Catch-22 is that if you use low energy reactions, you don't need as much shielding but then the pile has to be much larger to get a sustained reaction. If you use high energy reactions, you can make the pile smaller, but you then need more shielding. Optimizing just for weight, you still end up with something more suitable for railroad engines than cars or trucks. And that optimization involves using some nasty materials and insufficient containment for purely mechanical accidents.

Another point I'm trying to make is that while there have been some advances in making nuclear power smaller and safer, essentially a simple critical mass nuclear reaction is still used to generate steam power. That is a fairly archaic and inefficient way to transfer the power of the strong nuclear force into motive or electrical power. Given more attention and less political antipathy, quantum chromodynamics might have progressed much further than it has. For example, allowing for the direct conversion of the strong force into the electroweak force thereby eliminating waste altogether.

OK, here we're back to naquadah generators (i.e., science fiction). Do you have anything beyond imagination to indicate that the strong force can be re-coupled to the electro-weak in anything other than the conditions immediately after the Big Bang? I suspect that if undoing of the symmetry breaking is possible at all, the energy available will be many orders of magnitude smaller than the energy required. I suspect that that technology will be contemporary with the space warping FTL drive.

--Pete

[kandrathe]

I agree with Lissa on this point. One can say "choose a better nuclear reaction", but nature really doesn't offer one. You can say "choose better shielding materials" but even the best possible still take pretty good thicknesses to work.

The Catch-22 is that if you use low energy reactions, you don't need as much shielding but then the pile has to be much larger to get a sustained reaction. If you use high energy reactions, you can make the pile smaller, but you then need more shielding. Optimizing just for weight, you still end up with something more suitable for railroad engines than cars or trucks. And that optimization involves using some nasty materials and insufficient containment for purely mechanical accidents.

There has been recent work showing that fission product of 235U induced by thermal neutrons show points where fission results in almost stable isotopes. What we do now is a mostly uncontrolled reaction where we need to deal with a potpourri of fractured unstable byproducts, where most of the dangerous stuff (highly energetic) decays within days to weeks. The challenge is to create a fission reactor that results in controlled more stable "waste", and you will greatly reduce the need for shielding.

Another point I'm trying to make is that while there have been some advances in making nuclear power smaller and safer, essentially a simple critical mass nuclear reaction is still used to generate steam power. That is a fairly archaic and inefficient way to transfer the power of the strong nuclear force into motive or electrical power. Given more attention and less political antipathy, quantum chromodynamics might have progressed much further than it has. For example, allowing for the direct conversion of the strong force into the electroweak force thereby eliminating waste altogether.

OK, here we're back to naquadah generators (i.e., science fiction). Do you have anything beyond imagination to indicate that the strong force can be re-coupled to the electro-weak in anything other than the conditions immediately after the Big Bang? I suspect that if undoing of the symmetry breaking is possible at all, the energy available will be many orders of magnitude smaller than the energy required. I suspect that that technology will be contemporary with the space warping FTL drive.

If I outlined how to do that, I'd be in contention for the Nobel at least. It's one thing to learn enough to theorize the feasibility, another to work out the theory, and quite another to put it into practical reality. Look what has been achieved in your brief lifespan? You are almost older than the entire field of quantum physics.

From Wikipedia... "As of 2011 the quest for unifying the fundamental forces through quantum mechanics is still ongoing. Quantum electrodynamics (or "quantum electromagnetism"), which is currently (in the perturbative regime at least) the most accurately tested physical theory,[35] has been successfully merged with the weak nuclear force into the electroweak force and work is currently being done to merge the electroweak and strong force into the electrostrong force. Current predictions state that at around 10^14 GeV the three aforementioned forces are fused into a single unified field,[36] Beyond this "grand unification," it is speculated that it may be possible to merge gravity with the other three gauge symmetries, expected to occur at roughly 10^19 GeV. However — and while special relativity is parsimoniously incorporated into quantum electrodynamics — the expanded general relativity, currently the best theory describing the gravitation force, has not been fully incorporated into quantum theory."

[Lissa]

I agree with Lissa on this point. One can say "choose a better nuclear reaction", but nature really doesn't offer one. You can say "choose better shielding materials" but even the best possible still take pretty good thicknesses to work.

The Catch-22 is that if you use low energy reactions, you don't need as much shielding but then the pile has to be much larger to get a sustained reaction. If you use high energy reactions, you can make the pile smaller, but you then need more shielding. Optimizing just for weight, you still end up with something more suitable for railroad engines than cars or trucks. And that optimization involves using some nasty materials and insufficient containment for purely mechanical accidents.

There has been recent work showing that fission product of 235U induced by thermal neutrons show points where fission results in almost stable isotopes. What we do now is a mostly uncontrolled reaction where we need to deal with a potpourri of fractured unstable byproducts, where most of the dangerous stuff (highly energetic) decays within days to weeks. The challenge is to create a fission reactor that results in controlled more stable "waste", and you will greatly reduce the need for shielding.

Your fission fragments are a crap shoot on what you get from the reaction, likewise, you are going to get neutrons and gammas that are lost to the system (we always look at getting ~2.3 neutrons per fission, you need 1 neutron to continue the chain reaction at steady state, that other 1.3 is typically "lost"). And a thermal neutron is a neutron moving with a velocity around 2 km/s (2200 m/s, but close enough for this). A fast neutron (which is what breeders and weapons use), is typically moving at slightly relativistic speed, several 10s Mm/s. In order to get neutrons from fast (cause they're born fast from the fission) to thermal, they have to bounce off a variety of other, typically lightweight atoms - best being Hydrogen preferably the Protium isotope, until they drop from those near relativistic speeds to around 2 km/s (and best lose is going to 1/2 per interaction, so it's going to take a number of interactions to finally drop by a factor of 1000). In order to get that number of interactions, you have to have quite a lot of moderating materials (this is why we typically use water or carbon in burner style reactors, the typical power generating kind). So, size is going to be an issue no matter what, the difference is how much of a neutron flux you're going to need and at what power level your reaction is going to be at.

[NuurAbSaal]

Ah well, this is all quite a bit over my head. However, I feel compelled to throw another towel on my DIY basement reactor and maybe add some cardboard shielding, just to be on the safe side. That shielding concept sounds like you might be on to something, so I'm going with it (for now).



take care
Tarabulus

P.S.:

You are almost older than the entire field of quantum physics.

Cheap shot!

P.P.S.: Probably a stupid car question: The fuel consumption estimate shown in my girlfriend's VW, how trustworthy would it be? (horribly phrased, I know)

[Lissa]

P.P.S.: Probably a stupid car question: The fuel consumption estimate shown in my girlfriend's VW, how trustworthy would it be? (horribly phrased, I know)

Typically that's under ideal conditions, so highway assumes a constant speed of about 55 MPH/~90 KPH. You can push this higher under the right conditions, but more often it is lower.

When I moved across country a couple years back, I got an unheard of 32 MPG Highway in my Mustang because I was travelling behind my parents motorhome (typical highway for a Mustang is 28). Being in their slipstream assisted the aerodynamics of the Mustang and let it get even better mileage than normal.

[Rhydderch Hael]

... the higher the energy of the incident radiation, the more shielding required. It's not simply getting better reactions or smaller masses or using different methods to gather energy from standard radioactive decay ...

I agree with Lissa on this point. One can say "choose a better nuclear reaction", but nature really doesn't offer one. You can say "choose better shielding materials" but even the best possible still take pretty good thicknesses to work.

The Catch-22 is that if you use low energy reactions, you don't need as much shielding but then the pile has to be much larger to get a sustained reaction. If you use high energy reactions, you can make the pile smaller, but you then need more shielding. Optimizing just for weight, you still end up with something more suitable for railroad engines than cars or trucks. And that optimization involves using some nasty materials and insufficient containment for purely mechanical accidents.

On a (slightly) unrelated note, just how dense does the shielding have to be to impart Bremsstrahlung from Nitrogen-16 decay? I mean, just how energetic is that beta particle event?

---------------------------------------------------------------------

Drifting back to the original topic, really old gasoline engines could have this problem called 'dieselling', where some hot carbon deposit in the combustion chamber caused any residual fuel in the cylinder to burn, forcing the crankshaft around for yet another burn cycle in the engine. Bottom line— you'd turn off the ignition, but the engine continued to run for a few seconds because the hot carbon deposit acted as a sort of glow-plug that provided another source of ignition separate from the sparkplug.

This happened in old cars with carburetors because they usually had a mechanical fuel pump driven by an eccentric on the camshaft. So long as the engine continued to turn, more fuel was drawn into the engine. Modern engines use electric fuel pumps— turn off the key, and you turn off the fuel pump. No dieselling happens there because the carbon deposits have no more fuel to ignite.

[Alram]

...but when I was having my alternator fixed the other day, I got to thinking about how a car makes its electricity. My father-in-law told me he could take the battery out of his older car and it would run fine without a battery because the car generated its own charge.

How would he start the car without the battery?