CDI ignition

[kmpillai]

Dear friends,
What is CDI ignition system and what is the advantage of using this system?
Where I can get more information about that?
Advance Thanks for your help
KMP

 

[Metalguy]

Very fast voltage-rise time, which minimizes voltage bleed-off along the center electrode insulator (nose). Do a Google on it.

 

[enginesrus]

Capacitive Discharge Ignition

 

[pulsewidth]

CDI stores the ignition energy in an electric field of a capacitor, Inductive ignition stores the energy in the magnetic field of an inductor (coil). The CDI can switch a large current through a low inductance/resistance pulse transformer very quickly so it is suitable for extreme spark rates.
Inductive ignition needs time (dwell) to fill the coil with energy and time to discharge that energy hence the longer spark duration of the inductive system. A coil that is optimised for CDI system will not work properly with an Inductive System and vice-versa. Commercially available CDI systems can reliably push 150 amps at 450 volts or more through the primary windings of a CD pulse transformer but do so in tens of microseconds.

 

[oab]

An Inductive ignition system generates the voltage as the magnetic field collapses. The CDI generates it as the field is rising.

Harvey.

 

[BrianR]

Putting a slightly different spin on what pulsewidth said, storeing the energy for the spark in a magentic field takes time, typically 10-20ms due to the time constant of the coil primary. A 6 cyl engine doing 3000rpm has a spark every 6.7ms and so there is never a full energy charge available. It gets worse at higher revs.

A CDI stores the energy in a capacitor which can be charged in microsecs so it works much better at high revs.

 

[Sonnyj]

Helo All
I have an old engine that uses a magneto with breaker points.I would like to convert to CDI can this be done without the use of a battry?If so is there a diagram too follow?
Thanx in advance Sonny

 

[patprimmer]

Sonnyj

This is a new question

It would be better if you started a new thread on you specific subject

Regards
pat pprimmer@acay.com.au
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