Electronic ignition

[Vootele Aer]

Hi
I want to build an electronic ignition for two-stroke engine, that revs
high (up to 12.000 rpm). So far I have traditional capacitor discharge
circuit with mechanical points. The problem is, that those points tend
to break up.
So - what I have for electronic ignition is 6volt motorcycle battery,
magnetic rotor and inductive sensor and a 6volt ignition coil.
http://www.ema.edu.ee/ems/vootele/ignition.jpg
Red line resembles signal on sensor, when rotor moves.
I thought using this IGBT:
http://www.fairchildsemi.com/ds/HG/HGTP14N40F3VL.pdf

However, I don't know much about electronic.
So, can anyone help me designin all the electronic stuff?

Vootele

 

[Vootele Aer]

BTW, I have Parallax Basic Stamp 2 microcontroller, is it possible to
use it to do ignition timing and those kind of things?

 

[kell]

Hi
I want to build an electronic ignition for two-stroke engine, that revs
high (up to 12.000 rpm). So far I have traditional capacitor discharge
circuit with mechanical points. The problem is, that those points tend
to break up.
So - what I have for electronic ignition is 6volt motorcycle battery,
magnetic rotor and inductive sensor and a 6volt ignition coil.
http://www.ema.edu.ee/ems/vootele/ignition.jpg
Red line resembles signal on sensor, when rotor moves.
I thought using this IGBT:
http://www.fairchildsemi.com/ds/HG/HGTP14N40F3VL.pdf

However, I don't know much about electronic.
So, can anyone help me designin all the electronic stuff?

Vootele

I built an electronic ignition using the very same fairchild IGBT you
mentioned. I used a traditional dwell scheme, not CDI. I have an old
bike that ran on points, so I took out the points and put in hall
sensors, magnets and a vane. In this setup the hall unit sinks current
during a part of the crank cycle, just like the points did, but the
difference between the hall effect device and points is that the hall
device can only sink a very small current. I used that current to
control the HGTP14N40F3VL turning the coil current on and off, making a
spark when the coil current turns off (the usual).

You say you "have" a magnetic rotor and inductive sensor. Does "have"
mean that you have intalled them on the bike, that they are in your
possession but you haven't done anything with them yet, or that this
inductive sensor is just an idea you have? I can say this, an
inductive pickup like that has a signal completely different than the
signal points give. It means that if you went with that pickup, you
would have to change the rest of your ignition system. Easier to use a
hall effect sensor, which sends the same kind of "square" signal points
do; you would not have to change anything else on the bike: replace the
points with hall effect, leave the rest of the ignition system
untouched and be done with it... probably. There is a chance that you
would have to amplify the signal from the hall effect (not all that
difficult), but it is very likely indeed that even that would be
unnecessary.

Well, think about what I've said and get back. I'll try to help you
make the new ignition for your motorcycle.