Philip questioned my statement about CDI :-
}
} > A CDI system is similar to TAI, except that it stores energy
} >in a high voltage capacitor which is discharged into the coil. This results
} >in a much more powerfull spark. Initially, the systems dumped too much
} >energy into the coil, which resulted in the spark firing in more than one
} >of the plugs at once.
}
} Since this system still uses the distributor cap and rotor, I don't see
} how this is possible.
}
These things used to have an initial peak voltage in the order of 10
times standard (i.e. 100kV instead of 10kV). The phenomenon described was
called crossfiring. It could happen due to arcing in a dirty distributor
cap, or due to capacitive loading between sparc plug leads where the leads
run parallel and close for a decent length.
The problem was more often observed in 6 or 8 cylinder engines than
others. The latest systems slowly increase the energy discharge from the
capacitor to the coil, instead of dumping the lot at once. Lower initial
peak voltage, but the same high energy (i.e. longer spark).
--
Nigel Pearson, research dog's-body @ University of Technology, Sydney.
AARNet: nigel@socs.uts.edu.au Talk: (Sydney) 330 1799 or 330 1816
Hardcopy: Nigel Pearson, SOCS, UTS, PO Box 123, BROADWAY, Australia, 2007
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