Spark Color

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maybe he meant ultra violeNt?

disrupting air molecules like nothing else on earth :)

:giggle:
 
I think the cap recharge idea would be useful mostly for engines revving over 12K rpm since there is normally plenty of time for the stator coil to charge that cap. But I like the idea of not wasting energy.
 
somehow generating a spark so powerful that it's capable of denaturing physics.

happens approximately 100 times a second, worldwide. lightning :)


now we delve into the realms of tesla again... and that weird one...quantum physics :)
 
check out the ignition overview at www.daytona-twintec.com/tech_ignition.html


Overview of Ignition Technology

The Stages of a Spark Discharge

The ignition process is key to the operation of internal combustion engines. Four-cycle engines require external combustion, and this is accomplished by discharging electrical energy through a spark gap. Heat transfer and gas ionization (splitting apart of gas molecules) caused by the spark discharge initiate a flame kernel. The flame kernel then grows into a flame front that spreads through the combustion chamber. The stages of a spark discharge include breakdown, arc, and glow discharges.

Break Down

Most engines require nearly 12,000 volts to fire the spark gap. When this voltage level is reached, a very high current flows for several hundred nanoseconds, an almost inconceivably short period of time, as energy stored in the capacitance of the coil, secondary wiring, and spark plug is rapidly discharged. Because the break down phase is so short, it accounts for only a small percentage of the total ignition energy. To better put this into perspective, at 6,000 RPM the crankshaft rotates less than 1/100 of a degree in 200 nanoseconds!

Arc Discharge
The break down phase is followed by an arc discharge. An arc discharge requires a considerable current flowing in the gap, usually on the order of several hundred milliamps. During the arc phase, the voltage across the gap drops to about one hundred volts. An arc discharge is very visible and high levels of energy are transferred to the flame kernel near the center of the spark gap. The duration of the arc discharge for a conventional ignition is usually no more than a few microseconds. Again, to put this into perspective, at 6,000 RPM the crankshaft rotates through less than 1/10 of a degree in 2 microseconds!

Glow Discharge
A glow discharge is less intense and the sustaining voltage across the gap is higher. A neon light is a good example of a glow discharge. It looks nice, but it doesn't generate a lot of heat. Much of the energy in the glow discharge is lost heating the electrodes or ionized gas near the electrodes. Conventional ignition systems have a short arc phase (some microseconds) after the initial breakdown followed by a glow discharge that lasts 1-2 milliseconds. At 6000 RPM, the crankshaft rotates through 36 degrees in one millisecond.

Capacitive Discharge

Capacitive discharge (CD) ignition systems are widely used in automotive racing applications with high RPM requirements. A special high voltage power supply charges a capacitor to 450 volts or more. Energy is stored in the electrostatic field within the capacitor and is proportional to capacitance times the square of the applied voltage. An electronic switch discharges this stored energy into the coil primary. A high voltage pulse then appears across the secondary windings and fires the spark gap.

Spark Plug Wires

Three types of spark plug wires are commonly available: original equipment style carbon core suppression, low resistance spiral core, and solid core. Carbon core suppression wires cause some energy loss due to their high resistance (about 5,000 ohms/foot). Replacing carbon core suppression wires with low resistance spiral core wires only increases spark energy by about 10%. Contrary to any claims, you will not see a performance improvement by changing spark plug wires. On the other hand, carbon core wires can deteriorate over time and any wires more than a few years old are candidates for replacement. If you are going to install new spark plug wires, buy a set of low resistance spiral core wires. Most are less than 500 ohms/foot. At that point, almost no energy is lost in the wire. There are some new versions with very low resistance (50 ohms/foot), but the advantage is insignificant for the short lengths encountered in motorcycle applications.
 
Laser ignition - hmmm, now let me be a little theatrical; throwing on my Dr Evil suit.

As part of my new (evil) plan for world domination, my bike has been fitted with a Jaguar Laser Ignition, which is pretty fricking awesome.
 
OK I finished my testing. Settled on .66ohms which reduced the peak electrical current to half, and I assume increased the spark duration to twice as much. Testing it on the bench both ways generated enough spark at 6000 rpm for the spark to jump from the center electrode all the way over to the side. (because the ground electrode was bent completely away from the center electrode.)
Real life testing though showed no performance difference except when taking off from a start with a very gradual opening of the throttle. In that case there was some misfires with the resistance in place (between the CDI and HV coil primary).
Maybe if a manufacturer makes an economy minded street bike with a lean air/fuel ratio then that may be of some use, but on a bike correctly tuned and jetted the best spark is strong and fast.
 
Concerning spark duration, this is what Kawasaki did:
On their street version of their KDX enduro bike they put a 1.5uf charge capacitor in the CDI. But in their dirt-only version of the KDX they put a 1uf in it. Larger capacitance yields a longer capacitance discharge time so that the 1.5uf discharged 50% longer than the 1uf. The drawback though was that at top rpm it charged up less than the 1uf and so gave a weaker spark at high rpm and less engine performance up there.
How this relates to the Jaguar CDI:
It comes with a 1uf capacitor which from real life testing is correct if the engine revs up to around 8000rpm. If the engine isn't ported and still maxes out at 5500rpm then the capacitor could be 1.5uf for a 50% longer spark duration for amateurs that aren't good at jetting, or for stubborn people that stick with the horrible stock carburetor.
I could make this "amateur" version but really my whole goal was to help people maximize the power output, not keep it stock. If you have a Jaguar CDI and haven't increased compression, put on a good carburetor, and ported it then shame on you.
But if that's you and you want a longer spark without reducing spark current (which happens when resistance is added in the capacitors discharge path) then you can solder this .47uf cap parallel (end-to-end) to the large 1uf cap: 871-B32652A3474J from Mouser Electronics online.
ps- don't anyone request a video to hold your hand while doing this. Any retard can find the largest part on my CDI and solder another capacitor to it.
Online soldering tutorials for beginners:
http://www.epemag.wimborne.co.uk/solderfaq.htm#howto
http://www.epemag.wimborne.co.uk/desolderpix.htm
http://www.epemag.wimborne.co.uk/solderpix.htm
http://www.appliancepartspros.com/how-to-solder.aspx

For a soldering iron I recommend a dual output (20/40 watt) one, # 64-2184, for $23 from Radio Shack. A good cheap .05" diameter solder is available from Radio Shack (locally or online at www.radioshack.com, #64-015) for $3.
 
Now that's the Jaguar CDI option that i wanted - the 1.5uf for a 50% longer spark duration. To hell with 8,000 rpm, because i never rev my engine over 4,800 rpm. I want a brilliant blazing, long duration spark (like an arc welder electrode) when the engine is down on it's knees at 2,300 rpm.

Can the Jaguar CDI be built with switchable capacitance, so the user can select either the 1uf or the 1.5uf capacitor, dependent on their ignition requirements?
 
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