2002 150txra Ignition Coil Test

[boscoe99]

why would you need to pump it up that high?
cylinder compression is not that high when spark is ignited.
back in the 70s we had spark plug testers and just used shop air, so way less that 200

Back in the day when points and plugs were serviced and replaced. Now most throw out perfectly good plugs on a whim.

[boscoe99]

Remember the air powered grit blasters used to clean plugs?

[zenoahphobic]

why would you need to pump it up that high?
cylinder compression is not that high when spark is ignited.
back in the 70s we had spark plug testers and just used shop air, so way less that 200

To get the density ie to simulate what charge (atoms/molecules) might offer in the way of conductivity (resistance to arching). And the spark does continue after the explosion when the pressure gets up to that. Some might say the spark keeps the fire going for quite awhile although ignition has already commenced.
You could ofcourse use the real thing: one part gas to 13? air at 100 or more Psi and watch the flames. That will require additional equipment to bring to the bench. Maybe even just set up a small engine but then we might as well test on the actual engine and be none the wiser!
Note: a pressure sensor will tell a lot about how the ignition is progressing, but I guess the engine needs to be actually running

[99yam40]

To get the density ie to simulate what charge (atoms/molecules) might offer in the way of conductivity (resistance to arching). And the spark does continue after the explosion when the pressure gets up to that. Some might say the spark keeps the fire going for quite awhile although ignition has already commenced.
You could ofcourse use the real thing: one part gas to 13? air at 100 or more Psi and watch the flames. That will require additional equipment to bring to the bench. Maybe even just set up a small engine but then we might as well test on the actual engine and be none the wiser!
Note: a pressure sensor will tell a lot about how the ignition is progressing, but I guess the engine needs to be actually running

so you have seen and used some device like you mentioned before?

It has been my understanding that once a spark ignites the gas mixture, the flame front just runs through. no need to give more sparks.
plus those old points and condensers did not charge and discharge multiple times for each cylinder

as I mentioned we used shop air, and the tester had clear a window to watch the spark as you induced the air.
I have seen brand new plugs fail the testing.
my thoughts are that the higher resistance to the spark under pressure causes higher voltage build up and the spark finds a better path.

Back in them days I could grab a screwdriver stuck into a plugwire of a running motor and touch someone near me leaning against the vehicle to shock them
a good solid grip on the sparking item did not let the voltage build up as high as it could with a large gap

[zenoahphobic]

Only in science classes. Where they study ionisation of various gases.
A spark is simply (not really simple) where an electrical field is strong enough to force not normally conductive gases to ionise and become conductive sending free electrons that create an exponential increase in the creation of many more free electrons. We see as bright light and hear cracking sound, but it is the heat that is produced that is used for ignition.
A spark event takes time it is not instantaneous. Ignition systems have evolved ranging from low voltage (Kettering) to higher voltage (CDI) to very high secondary conversions. Multi spark and dual spark plug systems with ********g timing.
As you say by finding paths of least resistance, a sufficiently strong spark is difficult to control.

[99yam40]

Only in science classes. Where they study ionisation of various gases.
A spark is simply (not really simple) where an electrical field is strong enough to force not normally conductive gases to ionise and become conductive sending free electrons that create an exponential increase in the creation of many more free electrons. We see as bright light and hear cracking sound, but it is the heat that is produced that is used for ignition.
A spark event takes time it is not instantaneous. Ignition systems have evolved ranging from low voltage (Kettering) to higher voltage (CDI) to very high secondary conversions. Multi spark and dual spark plug systems with ********g timing.
As you say by finding paths of least resistance, a sufficiently strong spark is difficult to control.

Just thinking about this,
I would think that when you compress a gas mixture you push/stack the molecules closer together making it easier for the electricity to flow thru that mixture.
but that is not the case, and I do not really understand that

[boscoe99]

Air is an insulator of sorts. The higher the pressure the greater the insulation properties.

In aviation, where piston motors are flown at high altitudes using super chargers, the magneto's are pressurized to prevent internal sparking.

[zenoahphobic]

Just thinking about this,
I would think that when you compress a gas mixture you push/stack the molecules closer together making it easier for the electricity to flow thru that mixture.
but that is not the case, and I do not really understand that

Just think happy little vegemites like to stick together : the more the merrier. One lonely vegemite will tend to go and find another.

Or just think when you rarerify air, or lower pressure, the things that makeup matter has less force holding it together, so it is easier for an electron to escape. It’s the escaping of the electron that sets off a spark, and in engine it relies on ionisation to travel a great (relative) distance.

Remember conservation of energy. You cannot make it or loose it. You can only move it around. In this case you are using a strong electric field to “split” a molecule to ions, the process is “exothermic” if you like, producing heat......creating another transfer of energy (expansion of gas to mechanical leverage).

[99yam40]

Just think happy little vegemites like to stick together : the more the merrier. One lonely vegemite will tend to go and find another.

Or just think when you rarerify air, or lower pressure, the things that makeup matter has less force holding it together, so it is easier for an electron to escape. It’s the escaping of the electron that sets off a spark, and in engine it relies on ionisation to travel a great (relative) distance.

Remember conservation of energy. You cannot make it or loose it. You can only move it around. In this case you are using a strong electric field to “split” a molecule to ions, the process is “exothermic” if you like, producing heat......creating another transfer of energy (expansion of gas to mechanical leverage).

I just thought more molecules means more electrons to be moved around or be bumped out of place

[zenoahphobic]

I just thought more molecules means more electrons to be moved around or be bumped out of place

One would think that in a normal conductor. A spark is not about how many electrons but the nature of the gases and the conditions imposed.
Want to be totally enlightened (I warn you, this is far from simple) google Paschen’s Law