Spark plug tech question?

[JustJason]

Re: Spark plug tech question?

haha... Okay i'll bite.

basically you're saying the laws of electricity don't apply here?

Which Law are you talking about?

 

[v1_0]

Re: Spark plug tech question?

But nobody has proved, or can prove that the spark jumps from the center electrode to the side electrode, in a negative ground system.
.

Would you accept basic electric theory? Perhaps this can help clarify:

(1) Voltage is measured from positive to negative. I guess this is done due to convention (from before there was a better understanding of what is actually going on) and because this way voltage can be a positive number.

(2) The electrical charge of an electron is negative.

(3) There are more electrons (a surplus "source") at the '-' side of a battery, or the '-' output of the alternator.

(4) There are less electrons (a deficit "sink") at the '+' side of the battery (or alternator "+" post).

(5) It is the electrons that actually 'flow' through the wire.

(It's really closer to say a new electron in one end of the wire pushes the next one, which pushes the next one, and so on until one comes out the end.... But its easier to conceptuallize this as a 'flow' similar to water).

(6) Since it is the electrons flowing, the current actually moves from negative (where there is a surplus of electrons) to the positive (where there is a deficit of electrons).

Since that is what is going on, the spark is actually jumping from the side of the sparkplug that is connected to the "-" portion of the circuit to the side that is connected to the "+" side.

If you don't see that, or need more clarification, then just go back to the particular points (1-6) that you have an issue with, quote them, and we can discuss your question...

A spark plug with it's copper, or exotic metal core would appear to fire better, stronger, more consistantly, if it were to fire this way, rather then through it's ordinary steel (negative) body, to the exotic (positive) metal core.

I can't answer this question definitively - that's beyond my understanding of what happens to materials when a spark jumps between them.

However, it seems to me that you are making the assumption that the electrons "push" material along with them when they jump. It could be that the electrons actually "pull" the material to them before they jump. Or, more likely still - the center electrode would wear the same in either case (positive or negative ground) because we are talking about areas here. Here's the points on that:

(1) The steel body and center electrode handle exactly the same number of sparks.

(2) The area of the steel body that "arcs" to the center electrode is much larger than the center electrode.

Therefore, the center electrode has a higher "arc per area" proportion than the steel body causing it to wear out at a higher rate than the steel body.

 

[v1_0]

Re: Spark plug tech question?

Isn't that the theory of AC current? Alternating continually from plus, to minus, not DC (direct current)?

DC current flows from - to + always.

AC changes direction - it flows from one terminal to the other (a -> b), then reverses and flows the other way (b -> a). There is actually a time when there is zero flow (in the middle of switching).


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

 

[bruceb58]

Re: Spark plug tech question?

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

Good explanation. Basically, DC current flow opposite that of electron flow.

 

[MikDee]

Re: Spark plug tech question?

Would you accept basic electric theory? Perhaps this can help clarify:

(1) Voltage is measured from positive to negative. I guess this is done due to convention (from before there was a better understanding of what is actually going on) and because this way voltage can be a positive number.

(2) The electrical charge of an electron is negative.

(3) There are more electrons (a surplus "source") at the '-' side of a battery, or the '-' output of the alternator.

(4) There are less electrons (a deficit "sink") at the '+' side of the battery (or alternator "+" post).

(5) It is the electrons that actually 'flow' through the wire.

(It's really closer to say a new electron in one end of the wire pushes the next one, which pushes the next one, and so on until one comes out the end.... But its easier to conceptuallize this as a 'flow' similar to water).

(6) Since it is the electrons flowing, the current actually moves from negative (where there is a surplus of electrons) to the positive (where there is a deficit of electrons).

Since that is what is going on, the spark is actually jumping from the side of the sparkplug that is connected to the "-" portion of the circuit to the side that is connected to the "+" side.

If you don't see that, or need more clarification, then just go back to the particular points (1-6) that you have an issue with, quote them, and we can discuss your question...



I can't answer this question definitively - that's beyond my understanding of what happens to materials when a spark jumps between them.

However, it seems to me that you are making the assumption that the electrons "push" material along with them when they jump. It could be that the electrons actually "pull" the material to them before they jump. Or, more likely still - the center electrode would wear the same in either case (positive or negative ground) because we are talking about areas here. Here's the points on that:

(1) The steel body and center electrode handle exactly the same number of sparks.

(2) The area of the steel body that "arcs" to the center electrode is much larger than the center electrode.

Therefore, the center electrode has a higher "arc per area" proportion than the steel body causing it to wear out at a higher rate than the steel body.

Then you agree v1_0, This then proves my theory that the spark fires (originates) from the negative (side electrode), to the positive (center electrode)

My next theory is that a better spark would be produced if it orginates from the center electrode. Hence positive ground.

 

[v1_0]

Re: Spark plug tech question?

Then you agree v1_0, This then proves my theory that the spark fires (originates) from the negative (side electrode), to the positive (center electrode)

Yes.

My next theory is that a better spark would be produced if it orginates from the center electrode. Hence positive ground.

Why should there be a better spark in one direction than the other - unless there is a property in the material (such as with doped silicon)?

 

[JustJason]

Re: Spark plug tech question?

man o man you guys are over thinking this......

and spark still starts at the center electrode... no ifs ands or buts.

 

[MikDee]

Re: Spark plug tech question?

man o man you guys are over thinking this......

and spark still starts at the center electrode... no ifs ands or buts.

Jason, you've had a chance to prove it, and you haven't. v1_0's statement seems to leave no shadow of a doubt!

Now moving on, In theory then, with a Positive ground if the electron's natural flow is through the wires to the spark plug, to ground, it would encounter less resistance along the way (especially with copper plus, or exotic metals, and, or, a precision tip, spark plug), rather then in a Negative ground system when going from a battery ground, to the engine block, to the spark plugs.

Furthermore, I bet if you put a meter on the spark plug base, and read resistance, it would be higher then if you put the meter on the spark plug center electrode. This, plus the natural flow of electrons, flowing through the center electrode, should develop a better, hotter, stronger, more consistent spark, leading to better combustion, more efficiency, with also less of a chance of fouling, which we all strive for!

 

[JustJason]

Re: Spark plug tech question?

Jason, you've had a chance to prove it, and you haven't.

I thought I did. In the post about what part of the plug wears.

I don't know what you mean by putting a meter on the plugs... the only thing that's going to do is blow up a meter.

Theres 1 major reason everything is negative ground. Electrolosys. And electrolosys leads to corrosion... especially in a boat.

If it were the other way around, then the entire block, and everything connected to it, would transfer both voltage and current.

Now if you have 2 dissimilar metals, an electrolyte (saltwater) you create a battery, albeit a small one. But you can get a measurable reading from it.

Now if you pass an electrical current(as in amps... not voltage alone) through that. You speed up that process of electrolosys that's making that small electrical charge. The end result is everything thats on the inside of a used D Cell battery... and that stuff (usually sulfates) causes corrosion... bad bad corrosion.

Every notice how positive battery cables tend to rot out quickly compared to negative cables... same thing is going on there.

With negative ground systems, The block does carry a return voltage back to the battery, but it does not carry current. Your way means the block has to carry both.

If ya don't believe me by all means call in Don s, bondo or rodbolt...

 

[v1_0]

Re: Spark plug tech question?

Now moving on, In theory then, with a Positive ground if the electron's natural flow is through the wires to the spark plug, to ground, it would encounter less resistance along the way (especially with copper plus, or exotic metals, and, or, a precision tip, spark plug), rather then in a Negative ground system when going from a battery ground, to the engine block, to the spark plugs.

How so? You are saying that the materials have different resistance based on the flow of the current! Stated otherwise: the resistance of the component changes when the direction of the current changes. This can easily be tested with a volt ohmeter. Test it with the red (+) side on the 'cap' end of the plug and the black (-) on the core. Then reverse. Note also that the air gap between the body of the plug and the core /tip doesn't change based on current flow - so it will keep the same value of resistance.

I assert that the copper core will have the same resistance going one way or the other, just as a wire would have.

Now:

The current of a sequential circuit is based on the resistance of the overall circuit. (Ohms law). The overall circuit being alternator, body of car, sparkplug core, air gap, sparkplug body, wire. We sum that up.

The current that goes through each of these components has to be exactly the same (note I said current, not voltage).

The voltage drop accross each component can also be calculated with Ohms law. It's based on current through each component (the value will be exactly the value that we have for the overall circuit), and the component's individual resistance.

Again, since the current is the same and the resistance is the same - the voltage drop across the component will be the same. The cumulative voltage drop may be different - that is based on the order that the components occur in the circuit. However, that has no effect on the components themselves. It would only have effect if you connected a component directly from that point to the 'ground' - effectively creating another leg in the circuit. Then we have a parallel circuit, and the voltage is the same accross that.

 

[v1_0]

Re: Spark plug tech question?

The overall circuit being alternator, body of car, sparkplug core, air gap, sparkplug body, wire. We sum that up.

Ah, was a bit rushed when I typed this - it should be the coil, body of car, sparkplug body, sparkplug core, wire, back to coil.

 

[puddle jumper]

Re: Spark plug tech question?

OK i bite how does the spark get energized from the negative side. Does the coil suck the spark up from the ground side of the spark plug. Ive been pulling wrenches for 20 years and have never seen a spark jump from the block to the coil wire. Its always jumps from the coil wire to the block. And yes if you look closely you can see the direction the spark is traveling.

 

[QC]

Re: Spark plug tech question?

Just buy a diesel and forget it . . .

 

[bruceb58]

Re: Spark plug tech question?

With negative ground systems, The block does carry a return voltage back to the battery, but it does not carry current. Your way means the block has to carry both.

Jason...give it up. This statement is just so wrong...and this is just one!

Go read some articles on electrical theory so you know what you are talkng about. You can find them all over the internet.

 

[MikDee]

Re: Spark plug tech question?

Well finally I'm able to get back online, after giving up from waiting forever this morning And, it seems that v1_0 has confirmed what I thought, about the direction of flow, of electricity. If it works better with a positive ground? That's another story, and I don't even want to bother to get into that now.

And Jason, you're just spinning your props, as usual

 

[aborgman]

Re: Spark plug tech question?

With negative ground systems, The block does carry a return voltage back to the battery, but it does not carry current.

Yes, it absolutely does... and the current it carries would be no different in a positive or negative ground situation, the only difference would be direction of flow.

--
aborgman (Electrical Engineer)

 

[aborgman]

Re: Spark plug tech question?

OK i bite how does the spark get energized from the negative side.

The same way that any circuit (with a pseudo-open in it) does. Negatively charged electrons pile up on the point of the ground, positive charge piles up on the electrode, until attraction between the charges are great enough to cause electrons to jump the air gap between the objects.

Once a few electrons start to move across the gap, they heat up the air, such that more and more will jump across the gap. This heats the air even more. It all happens very fast, and the air gets so hot that it glows for a short time. That is a spark.

It is also ionization. When air is ionized, it conducts. It also becomes somewhat of a "soup" of positively and negatively(electron) charge particles - with the electrons moving from ground toward the electrode and the positively charge ions moving from electrode to ground.

So the spark is started by a small flow of electrons from ground to electrode - but the "spark" itself really flows in both directions.

--
aborgman (Electrical Engineer)

 

[JustJason]

Re: Spark plug tech question?

Yes, it absolutely does... and the current it carries would be no different in a positive or negative ground situation, the only difference would be direction of flow.

--
aborgman (Electrical Engineer)

So in a negative ground system. Where as the block is often a common grounding point, after whatever load in whatever circuit. Your saying current is flowing through the block (even being after the load)???

 

[Pascal]

Re: Spark plug tech question?

So in a negative ground system. Where as the block is often a common grounding point, after whatever load in whatever circuit. Your saying current is flowing through the block (even being after the load)???

That is right.

The engine block carries the amperage draw of the starter when cranking and the frame carries the amperage of all the working lights and accessories used in making the vehicle safe and comfortable.

Doesn't matter which side of the load you place the ammeter in series with the series circuit, you will still get the same reading.

You can do a starter draw test with an inductive pickup on the positive or the negative battery cable at the battery and have an accurate result.

The secondary ignition circuit is the same thing - just lower amps and higher volts.


On the old points and coil systems you could hook up the primary side of the coil backwards and have the spark polarity reversed = weaker spark if wrong. The test often used was called the pencil test like Here..........

It also has a good explanation of center and side electrode polarity and wear in relation to the temperatures that exist.....

 

[bruceb58]

Re: Spark plug tech question?

So in a negative ground system. Where as the block is often a common grounding point, after whatever load in whatever circuit. Your saying current is flowing through the block (even being after the load)???

The block just looks like a big fat wire. It is between the load and the battery.