The Old Standard Ignition System. Battery. Coil. Points. And Condenser....

[Magluvin]

I have been fishing around online.  Now I am going to sort of play devil's advocate.

http://classicmechanic.blogspot.ca/2011/03/ignition.html

Here is a comment from somebody:

<<< Bingo! The condenser is connected across the points. When the points closs, the condenser voltage is clamped at zero, and current from the battery "charges" (via a building magnetic field), the primary side of the coil. When this is complete, the current flowing through the coil is now constant. When the points close ((MH:  He means open)), the condenser has two functions. One is to shunt the current which because of the collapsing primary coil sides magnetic field, wants to continue to flow, and would otherwise arc and quickly ruin the points. This probably wouldn't be a danger, because without the condenser, the ignition won't work. The condenser is charged up (voltage wise), by the current flowing from the coil because of the energy stored in the now collapsing magnetic field. This current flow quickly charges the capacitor, and then the capacitor then sends current back to the coil. This continues with each back and forth current swing being smaller. This is called wringing  ((MH: ringing)). The first cycle or longer (at a certain frequency), is what induces a corresponding (but higher) voltage and current that creates the spark at the spark plus. So the condenser protects the points from arcing, and allows a rapid and oscillating discharge of the primary coil, and that is necessary for generating a strong spark. Without the condenser, the spark would be weak or not even there. F on the schematic, F on the explanation.  >>

So, he thinks there is resonance and is basically confirming what you are saying.  So let's examine this more closely.

Would you agree that it's the core of the ignition coil that is the main energy storage component and the capacitor is not a major player in the energy storage?  You have made references to the "tiny capacitor" so I think that you would.

This guy says the cap charges up, and then rings down with the primary and you get a more robust spark.  If this is true then with your plasma sensor loop connected to your scope channel you would have to see a decaying oscillation.  This assumes the plasma stays "lit" the whole time as you get the ring-down that sustains the spark.  In other words, the ringing has to be fast enough such that the plasma stays lit the whole time.  If the plasma goes off and then on, that represents sharp on-off switching of the current and you should see a series of "ticks" on the plasma sensor loop.  Let's assume either way is perfecty viable.

Now here is the problem:  If there is a sustained but decreasing level of magnetic energy in the core then any ringing doesn't make sense.  The reason I am saying this is as follows:  Okay, the cap is charged to it's maximum voltage and it's time to change direction of the current flow.  Well, when the cap discharges into the primary, you will simply get magnetic flux cancellation inside the core with "north" annihilating "south."  So the capacitor would simply "magnetically short itself out" when it tried to reverse the direction of the current flow and discharge.  You would simply reduce the magnetic energy in the core by a chunk.

So what are we left with?  The only thing we are left with is that the capacitor can only reverse the current direction and "swing back" after the initial plasma burn is done and the core has been completely drained of magnetic energy.  And now you face a problem if you assume that the magnetic core of the ignition coil can store way way more energy than the capacitor, even when the capacitor is charged to 300 volts.  And note on the first "swing back" the capacitor has to do several things, 1) pump power into the core that is immediately burned off in the plasma burn, and 2) recharge the battery.  It really sounds like it's not going to fly.

So the conundrum is that the capacitor is "tiny" and is only really there to protect the points.  It's not supposed to be a big energy storage device to sustain three or five or ten "resonance cycles."

Here is a thought that occurred to me:  Is it possible that without the capacitor a hell of a lot of energy is burnt off in the points sparking when they open?  And then when you add the capacitor the elimination of the point sparking means you have more magnetic energy in the core and that's the reason you get a bigger spark?  I view that as a long-shot but you never know.

I still say the fat spark has to get its extra energy from the battery and that could be confirmed through measurements.

Again - there are lots of problems with the supposed resonance mechanism when you examine it.  And right now I am doing the thinking work that you are supposed to be doing.  I don't think you are thinking things through.

If you use a nice spring-loaded SPST switch like I said and then get nice consistent small sparks without the cap and nice consistent big fat sparks with the cap, then you can use the sensor coil near the HV output like I said.  If you get a decaying sinusoid during the fat sparks, or a series of fast ticks during the fat sparks, that would tell you right away that resonance is in play.  If you get a single "on tick" and a single "off tick" that would tell you that the plasma burn is a single unidirectional pulse of current.  One more time, you should be thinking of this stuff by yourself.

Will get back to the rest of this post tonight, but looking at the page link you have provided, I have serious issues with the circuit they present...

First off, they have a conductor shorting the capacitor.   And the cap is not across the switch!! lol  like I said before, possibly in PM and not here yet, there are a lot of ign circuits that are totally incorrect online. And this is just 1 example of such...

Mags

[Magluvin]

Just approved your 3 new posts MH.  Brad will just do it anyway soo.... Whatever..

Go ahead and post freely.  Ive accomplished my point here and I may not be able to go over them all or even reply to them if it is going to be tons of them. 

But go ahead and fill the pages as you like and all of the important stuff will be left behind in the beginning pages.. That was the big reason I wanted to moderate these threads from the beginning. But now you have brad to set you free and do what you do so well... 

I will talk to Stefan about a new topic where I have moderation privileges alone once Im ready to show what we really can do with resonance... Just to keep the real important stuff threads clean.

Mags

[MileHigh]

I don't really have much more to say.  I don't believe there is resonance like you believe and it's up to you if you want to do my suggested tests or do tests of your own to prove your case.  And I am hinting at some simple tests at the end in the form of a pop quiz.  Can you develop some simple tests to answer some basic questions?

And you may be making a classic mistake where you call reduced losses in the circuit a "gain."

[Magluvin]

I don't really have much more to say.  I don't believe there is resonance like you believe and it's up to you if you want to do my suggested tests or do tests of your own to prove your case.  And I am hinting at some simple tests at the end in the form of a pop quiz.  Can you develop some simple tests to answer some basic questions?

And you may be making a classic mistake where you call reduced losses in the circuit a "gain."

Lol   Bah, your suggested tests?  After you put together your imaginary full of garbage explanation of the circuit post(first one I approve for you in this thread), you think I should follow your lead in a test??

Im not going to waste my time on a test that is padded and loaded to block any resonance that could be had.  Just as you did in your full explanation of the circuit.

If you want to call it a reduced loss, Im fine with that.  It is still a gain by way of reducing the loss. The inherent loses  of the circuit without the cap are what they are. Losses .  lol. Your words are a treasure for me to use against you.

I wont block any of your posts here. You now are officially back in the forum..  But now you will have to msg brad to approve your posts from here on in. I will not moderate this thread, one way or another any longer. Im now just waiting for brads description of how the circuit works. I want to see where he goes with it... If he is on the same page as you, then I will reply with due diligence..

Congratulations, you have the stage. Happy mucking. 

Mags

[tinman]

The main point of the thread, stated in the first sentence of the first post, was to talk about how resonance in this circuit can give a gain.

But hey, why wait to explain your knowledge.  As Tesla said, there is no better time than now.

Maybe I havnt put it all in order of operation, and is spread out among posts, but there was a reason for that in my arguments as I go along. If MH has his version that is suppose to be correct and my reasons are not, then why give him all there is to know on my end, when he says I dont know at all what is going on? The end result is the cap increases the coils efficiency without a cap in place where it should be.. See MH first thought that the system didnt have a cap at all, and that I added it as a modification. So I let him ride with that. So initially I could tell he knew nothing about them. But then he applied his thoughts to it and came up with a page of things that had to be argued as it was bad in many places.


So please give us your version.  It would be on topic. If you think I dont know for sure how the process works then please correct me. if you have read it all then you should know my version. I dont think it will change the fact that the cap oscillating with the primary after the switch is open helps us get a much better spark in all aspects by way of resonance.  Resonance doesnt give us anything more MH is claiming, and he further tried to deny that resonance even exists in the circuit in his theory, and even ignored the inductance effects in the whole of his explanation other than there is transformer action and thats it, let alone also ignoring the fact that when the switch is open that the primary due to its own field collapes currents will charge the cap to possibly over 100v( some ign systems from around the world have differing results on that) to initiate the LC ring. Thats why I had said the resonance is initiated by the primary otherwise how would the cap get it high potential to begin with.

Mags

Mags

In regards to your comment that i would only approve MHs comments anyway-->only if his comment was on topic,and of a descent nature.
I hardly ever get on the forums anymore anyway.

Ok,regarding the topic at hand.

The condenser serves many purposes,and here is one to think about.

We all know that if we remove the condenser ,we get very erratic engine running--back firing through the carby-and all sorts.
But how could the timing be that advanced that it would backfire through the carby?..

First thing to do,would to be to look at the ignition coil,which is just a transformer--what is it's rated output voltage?
Most are between 30,000-40,000 volt's
So,the average supply voltage(battery voltage) when an engine is running,is around 14.4 volts.
Lets say our coil is one of the 30,000 volt one's.
The average turn ratio in an ignition coil is around 100:1

So in a transformer sense,100 x 14.4 would give us a voltage of 1440v at the secondary when the points close.-->Remember,we are talking about normal transformer voltage produced here,and not flyback voltage produced across the secondary--which is where the 30,000 volts comes from.

Most plug gaps are between 1 and 1.2mm
It takes 1000v per mm to form an arc within the environment of the engine cylinder 

What roll dose the condenser play here in this one example?.


Brad