[Diy_efi] Use O2 sensor on motorcycle?

[David Gravereaux]

If heat dissipation using a linear output drive (transistor) is a problem,
with a bit of design work and using the direct (unfiltered and rectified)
alternator output, you can use an SCR for the drive part.  It dissipates
almost no heat...  well, almost, maybe 5-10 watts.  I made a 15 amp 12v
battery charger this way.  It worked like a charm.  I can get you a gif of
a schematic, if you're interested?

Basically, you generate a triangle wave from the periods of the input
waveform -- start at zero, end high, repeat.  Feed this into a comparator
along with the out of an opamp (linear) comparing a 6 volt reference to
the output divided by 2.  The feedback resistor is the gain around the
drive point.  My recall is kinda fuzzy, but the idea is to fire the scr
earlier in the triangle wave to output more current.  Because an SCR is
either on or off, the only heat it develops is it's forward drop --
chopper style or Class-D as it's also called but with a 4-layer diode
instead of a linear device.
--
David Gravereaux <davygrvy at pobox.com>
[species: human; planet: earth,milkyway,alpha sector]
Please be aware of the 7.5 year ping times when placing a call from alpha centari

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