MH's ideal coil and voltage question

[tinman]

For starters, you are going to have to have the intellectual capacity to make a distinction between "motor shop talk resonance" and the resonance we have been discussing this whole time.  So this sentence, "the way i define resonance is exactly how the resonant systems around the ICE work" is an absolute non-starter.

Like it or not, resonance is the exchange of energy back and forth in a system between two forms.  Typical examples would be between a capacitor and an an inductor, or a moving mass and a spring.  Of course, what I just said is something you are currently completely blind to for some strange and inexplicable reason.  You want to insist that resonance is just the observation of an increased response of a resonant system to an external stimulus at the resonant frequency.  That is an acceptable second definition for resonance, but to claim that it is the only definition like you are insisting is completely and totally ridiculous.

And now it would seem you want to "squeeze in" a new definition for resonance, which is some kind of "motor shop talk resonance" which has nothing to do with an energy exchange back and forth between two components like a moving mass and a spring, and that simply will not fly and is totally unacceptable.

NO, when there is an explosion in the cylinder, that impulse of energy sets up a resonant standing wave pattern inside the cylinder cavity that is deemed undesirable, and so a secondary resonant cavity is set up in the cylinder to counteract that.  That standing wave resonance will happen at its own unique frequency.  That is in no way, shape or form, "resonating at the same frequency of the explosion."

No resonance is not an interaction between the two.  The explosion initiates a separate and distinct resonant standing wave in the cylinder cavity.  The resonance is the resonance in the cavity itself, and not the explosion.

Moving on to the Helmholtz resonators, they just respond to an impulse stimulus and that's it.  The frequency of the stimulus is irrelevant.  The "resonance like" effect in the Helmholtz resonator is that gasses rush into the resonator chamber, and that is a moving mass.  Then the chamber itself acts like a spring.  That is the resonance - moving air as a moving mass and air in the chamber acting like a spring.  That has nothing whatsoever to do with the impulse that initiated the event or the frequency of the impulse that initiated the event.

Note also that there is not really any cycling back and forth of the same energy as you have in true resonance.  It's a one-shot process, kinetic energy goes in, gets stored temporally as potential energy, and then the air leaves, and then new air rushes into the Helmholtz resonator chamber.  Even though the same energy and same mass is not cycling back and forth like there is in true resonance, the principles at play are essentially the same.

So when you mistakenly talk about the air inlet and the exhaust gas outlet being "in resonance" with the cylinder explosions, then what is it really?  It's certainly not resonance even if the boys in the shop call it "resonance" in their own "shop talk" language.  With respect to the cylinder explosions and the input and output ports, there is no cycling of energy back and forth between two forms so it is not resonance.

Here is what it really is: There is a nice synchronicity between the cylinder explosions and the Helmholtz resonators pushing air into the cylinder and then also sucking exhaust gasses out of the cylinder.  The fact that the cycle times for the Helmholtz resonators line up with the cylinder timing to make gas move into and out of the cylinder more efficiently is great but it is not resonance.  The resonance is in the Helmholtz resonators themselves.  What it really is is the Helmholtz resonators act as timing elements in the operation of the engine to ensure that the engine runs synchronously.

Here is the synchronous operation of the engine as a sequence of timing events one after the other:  1) push air into the cylinder, 2) explosion, 3) suck exhaust gasses out of the cylinder.  This is a nice advantageous synchronous operation facilitated by the actions of the Helmholtz resonators that makes the engine run better but it is not resonance.  There is no resonant cycling of energy back and forth in two forms in steps 1, 2, and 3 which is the true signature for resonance.

All that being said, if you would just accept that a tuning fork resonates, then you could accept that the Helmholtz resonators resonate all by themselves without having anything to do with the cylinder explosions and then you would be fine.

MileHigh

It's like i said MH--you need to further your understanding on how the resonant systems around an ICE work.
The 2 stroke engine is your best starting point.

I see from one of your comments that  you do not understand that some of the charge expended into the exhaust resonant chamber,actually returns back into the cylinder.

You do need to brush up on ICEs MH.


Brad

[MileHigh]

I am not going to undertake to learn seriously about ICE's but I am reasonably certain that what I said is quite sound and makes sense.  I am assuming that you had no idea how resonance actually works in a Helmholtz resonator until I stated it.  I think your refusal to engage says something right there.  And your "motor shop talk" definition of "resonance" is a no-go.  It must be resonance in the form of energy cycling back and forth between two distinct and complimentary forms.  There will never be movement on that issue because that's what resonance really is.

Ultimately you are still stuck, you think a struck tuning fork or a struck bell is not resonating.  It's almost unbelievable but knowing you it is believable.

[Magluvin]

I am not going to look anything up, but I think in some engines they simply change the length of the exhaust expansion chamber to match the engine RPM.  That's to ensure a synchronicity between the piston pulse rate to empty the exhaust gasses and the tuned expansion chamber helping suck the exhaust gasses out of the cylinder, but it is not resonance.  It might be called a tuned exhaust port or a variable tuned exhaust port or something like that but it is not resonance.

I know what you are trying to say but it's still bloody annoying because we are primarily discussing electronics and inductors do not resonate all by themselves.

" inductors do not resonate all by themselves."

Actually they do.  Inductors do have capacitance no matter how small. Ive done these tests along with bifi comparisons where the increased capacitance lowers the freq of resonance compared to a normal wound inductor.

Mags

[MileHigh]

I agree but it's really all about good commonsense practices when discussing electronics.  An inductor resonating because of its own inherent self-capacitance is really just a curiosity and Brad's statement could easily be misinterpreted.  The right thing to do would have been to talk about the resonant frequency of an LC resonator changing because you change the permeability of the core material in the inductor.

Original:

If you change the density of the magnetic material of the core of an inductor,while maintaining the physical size of that inductor,will the resonant frequency of that inductor change?

Modified using good practices:

If you change the permeability of the magnetic material of the core of an inductor, while maintaining the physical size of that inductor, will the resonant frequency of an LC circuit made with that inductor change?

[verpies]

If you change the density of the magnetic material of the core of an inductor,while maintaining the physical size of that inductor,will the resonant frequency of that inductor change?

Modified using good practices:

If you change the permeability of the magnetic material of the core of an inductor, while maintaining the physical size of that inductor, will the resonant frequency of an LC circuit made with that inductor change?

Interestingly, actually increasing the density of the core (e.g. by compressing it with sound waves) changes the permeability of the core.  This is known as the Villari effect.