K
kell
- Jan 1, 1970
- 0
My antique bike has a points plate with fixed timing, no weights or
springs like a modern breaker. You set the timing to 35 degrees
advance (by viewing a mark on the flywheel) and leave it there when
riding, it fires there -- at all rpm. I have already replaced the
points with hall effect sensors (one for each cylinder), magnets and
shutter disc, with igbts to run the coil, in a setup of my own design.
Now I would like to create an advance curve electronically. With the
breaker set to full advance as per usual, the circuit has to delay the
spark (in practical terms this will likely involve simply extending
dwell time) a varying amount depending on engine speed, more delay at
low rpm, with the delay dropping out entirely at 2000 rpm so that the
ignition goes to full advance. So you could say the circuit will
actually have to create a retard curve.
I have built astable and monostable multivibrators of discrete
components and used 555 timers. I have enough experience as a ham,
and knowledge as an engineering school dropout, to build something,
but could use a little jump-start with the design, even if only
conceptual. Suggested topologies, helpful web site links and such are
much appreciated.
springs like a modern breaker. You set the timing to 35 degrees
advance (by viewing a mark on the flywheel) and leave it there when
riding, it fires there -- at all rpm. I have already replaced the
points with hall effect sensors (one for each cylinder), magnets and
shutter disc, with igbts to run the coil, in a setup of my own design.
Now I would like to create an advance curve electronically. With the
breaker set to full advance as per usual, the circuit has to delay the
spark (in practical terms this will likely involve simply extending
dwell time) a varying amount depending on engine speed, more delay at
low rpm, with the delay dropping out entirely at 2000 rpm so that the
ignition goes to full advance. So you could say the circuit will
actually have to create a retard curve.
I have built astable and monostable multivibrators of discrete
components and used 555 timers. I have enough experience as a ham,
and knowledge as an engineering school dropout, to build something,
but could use a little jump-start with the design, even if only
conceptual. Suggested topologies, helpful web site links and such are
much appreciated.
