>Have you run across any systems which allow two ignition coils to feed into
one spark plug?<
I am not familiar with this type of ignition. I presume you are looking for
redundency. Current practice in 4 stroke technology is one coil per plug or
per two plugs, and no distributor.
That said, I did some checking, and may have found what you are refering to.
In 1992, a paper was presented at the Society of Automotive Engineers (SAE)
annual meeting, describing a two coil ignition system. The goal was to
increase ignition energy. This is often a problem in extremely stratified
(lean) engines, as the fuel/air charge is difficult to light off. The system
used a standard ignition coil wired in parallel with a low voltage, high
current coil. A stack of high voltage diodes in series with the high current
coil and in parallel with the ignition coil prevented the ignition coil from
opposing the high current cycle.
Both coils were triggered at the same time. The ignition coil broke down the
air gap and started current flow. The high current from the other
transformer then flowed through the spark gap.
Delivered energy was allegedly increased, but there was a major problem. The
high current EATS spark plugs. Erosion occurred very rapidly. They developed
an exotic spark plug, but I doubt it did much good. This system never went
anywhere.
I read the paper, and I think their approach had several flaws due to
inexperience. Todays systems use advanced magnetic materials to get increased
spark duration. Multi-strike ignition also has its place. Two stroke
systems, of course, are another matter altogether.
If I find anything else, I'll post it.
Jim Hull
A016 - The Windy City
|