TeGGeR® wrote:
> jim beam > wrote in news_-dnS91tZMHfzHfRVn-
> :
>
>
wrote:
>>
>>>TeGGeR® wrote:
>>>
>>>http://www.tegger.com/hondafaq/ignit...ion/index.html
>>>
>>>Hopefully this is correct now.
>>>
>>>Thanks to all for their help, especially Jim Yanik.
>>>
>>>--
>>>TeGGeR®
>>>
>>>The Unofficial Honda/Acura FAQ
>>>www.tegger.com/hondafaq/
>>>--------------------------------------
>>>I think in the 1990 Honda Civic, the igniter also provides
>>>for for some PWM control.
>
>
>
> "PWM" control?
>
>
>
>>It senses the back EMF and
>>
>>>kills the coil drive at the correct momment to insure a
>>>hot spark.
>
>
>
> Do you know the mechanism by which it sees the back EMF?

as the magnetic field decays inducing a current into the secondary [high
voltage] coil, the same is going on with the primary coil, but smaller.
just need to measure it. presumably the chips we see in graham's
photos either have a map or even calculate "dwell" based on what they
measure. but i'm guessing, i don't know for sure.

>
>
>
>
>>>I played with an ignitor and couldn't get it
>>>to because correctly until I connected to to a Honda
>>>igntion coil. As I varied the frequency of the drive pulses,
>>> all the same width, the output created wider pulse at higher
>>>"RPM".
>>>
>>>Terry
>>>
>>
>>interesting! i'd read that they did that, but just haven't had the time
>>to sit down & test for it. thanks for the confirmation!
>>
>>
>
>
>
> So how come my news server has this message, but not Terry's?

ah! news servers! fickle things.

>
> And yes, that's one of the very nice features about electronic ignition
> versus Kettering. With Kettering, the very moments you need a fat spark are
> the very moments you get a weaker and weaker spark since the system has no
> way of increasing dwell time to compensate for RPM.
>
which is why people used to experiment with dual plugs and dual ignition
systems occasionally. total pains in the rear and highly unreliable,
but it was a stab in the right direction. but you're right, once
electronic ignition came in, and it wasn't unreliable or expensive,
suddenly, it was ok to go electronic with everything. and that's been a
good thing up until recently. i don't see current chip technology
physically having the longevity we've been so far used to. and of
course, with increasing reliance on mysterious black box electronic
componentry, how do you know whether a manufacturer caves in to the
temptation to program in an end of life? that already happens with ink
jet cartridges, regardless of their fill state.