variable advance for crankshaft sensor?

[todi]

hi, i've got a test engine in my school that needs a variable advance for ignition. triggering is by a crankshaft sensor. does anyone know how to build a circuit for mating with the crankshaft sensor to provide a variable advance for the ignition. I'm not too sure but a delay might work also as 350 degrees delay is the same as 10 degrees advance?<br>
Thanks

 

[werdnaid]

There are some of those ign boves, MSD, Mallory, Crane, etc, that have adjustable timing modules or features. If it is just the ign timing you want to vary you could get one of these.

Something that I would look into is some of these single board micro controllers that program in Basic. They have IO ports & some have A/D ports. I think you could hook up a pot to the A/D port & make its value a variable to multiply you advance or retard by. This way you could adjust with a knob.

You probably need to check your signal from the crank sensor with a scope & get a controller capable of mimicking it. You would want one that could time input pulses and then make the next output pulse the same time + or - your time change.

 

[NickB]

If you move the sensor so the trigger angle is around 50 degrees BTDC, then it will only be a delay of 10-40 degrees, and not 350.