MoTeC Global Forum

Hello,

I was wondering whether it is possible and relatively safe to power ignition IGBTs with a PDM and directly drive/send trigger signals from the ignition outputs of M400 like the attached drawing? (Apologies for the crude diagram).



For instance, Fairchild Semiconductor ISL9V5045ST or International Rectifier IRGS14C40L? Never really used other ignition systems other than CDI + coil-on-plug.

Thanks you
Eric.

Might help if you explain what you're trying to achieve ?

stevieturbo wrote:Might help if you explain what you're trying to achieve ?

To simply put, the objective is to replace a CDI unit with ignition IGBTs; like attached diagram above.

I'm not sure whether directly connecting M400's ignition outputs pins (IGN1-4) to gate of ignition IGBTs is safe, despite some logic-level ignition IGBTs are designed to be used with ECUs directly.

eric_s wrote:

stevieturbo wrote:Might help if you explain what you're trying to achieve ?

To simply put, the objective is to replace a CDI unit with ignition IGBTs; like attached diagram above.

I'm not sure whether directly connecting M400's ignition outputs pins (IGN1-4) to gate of ignition IGBTs is safe, despite some logic-level ignition IGBTs are designed to be used with ECUs directly.

If the coils have built in ignitors, then you can trigger these directly off the Motec. 1 wire per coil

The coil will receive a ground and 12v supply from the vehicle wiring as normal.

if the coils are older inductive coils, then you will need an external amplifier first, then to the coils. Still nothing complicated, and certainly no need for a PDM or anything like it.

Those SCR looking things actually sink the current to ground. Bosch makes an (Amp) unit that does this. If I could find it... wow I did.

Ignition Module, part # 0 227 100 211, cost $162.72 plus shipping is available.

This ignition module does not come from Bosch with the heat sink paste and installation screws and washers. We have a kit containing these items sufficient for 1 module, your cost $1.15. (part # B 227 003 035).

We also have available the heat sink, part # B 221 040 009, your cost $19.74.

Those Ecospark IGBT's should be able to drive a std inductive coil just fine with the gate being operated by the Mx00 ign output. You'll have to heatsink and electrically isolate the collector tab though. For a DIY inductive ign transistor setup using IGBT's its usually easier to use TO220 form units.

Scott@FP wrote:Those Ecospark IGBT's should be able to drive a std inductive coil just fine with the gate being operated by the Mx00 ign output. You'll have to heatsink and electrically isolate the collector tab though. For a DIY inductive ign transistor setup using IGBT's its usually easier to use TO220 form units.

Would wiring in a Bosch type unit would be more dependable than the average DiY solution ?

Do the coils get wired to have 12V to them when the ignition is on? and the ECU sinks the ground when the dwell starts and opens the circuit when the sparks should happen?

If so then the original picture should probably have the black lines changed to be red, and the green lines should be black??

I didn't take that pic to be a wiring diagram more like a flow chart, but for inductive coils you would supply the coil primary + with a relay activated B+ on one end and ground the coil - thru the transistor. When the ECU 0v-5v ign output to the gate goes high it starts charging by grounding the coil -, when it goes low spark occurs. Problem with OEM units is they commonly have internal trickery going on such as current limiting or temp limiting and do things like fire the coil prematurely if current is maxed. Pick an IGBT or other type automotive specific ignition transistor with 3x-4x higher capacity than the coil and no problems getting all the energy possible out of the coil, and burning up coils becomes possible as well. Reliable as OEM just a bit larger footprint for multiple IGBT's their heatsinks and a small enclosure.