f4i homebrew ignition

[Analogue]

I'm looking to control stock F4i COP coils with my own hardware.

The relatively new ignition IGBTs on the market have a breakdown voltage of 330-430 volts. Is this excessive for a stock coil?

The F4i manual says the "minimum" voltage is 100V. They don't state a max, this minimum only tells you if the flyback circuit is dead.

This is inductive type ignition, 12V on one side of the coil, and ground the low side through IGBT. When the IGBT is turned off, the ignition fires.

Basically, do I need to clamp ignition voltage to something smaller than the 330V to 430V of typical COP IGBTs, or can the stock coils handle this kind of clamping voltage?

[Analogue]

I'm looking to control stock F4i COP coils with my own hardware.

The relatively new ignition IGBTs on the market have a breakdown voltage of 330-430 volts. Is this excessive for a stock coil?

The F4i manual says the "minimum" voltage is 100V. They don't state a max, this minimum only tells you if the flyback circuit is dead.

This is inductive type ignition, 12V on one side of the coil, and ground the low side through IGBT. When the IGBT is turned off, the ignition fires.

Basically, do I need to clamp ignition voltage to something smaller than the 330V to 430V of typical COP IGBTs, or can the stock coils handle this kind of clamping voltage?

[Jon @ Electromotive, Inc.]

400V should work about right. Don't forget, your switching an inductor, it will cause very high voltages on the primary side when you trigger the spark event by turning the IGBT off. If the voltage clamp is too low, no spark event will occur or the spark will be very weak.

[B Lewis @ PE Engine Management]

Send me an email offline and I can point you in the right direction for driveing these coils successfully. We have been driving these directly in our ECUs for years now.

[raska]

I'd be interested in hearing about it if you're willing to discuss this online.

[B Lewis @ PE Engine Management]

Hi Martin,

We use an automotive grade IGBT for driving the ignition. Currently, we use a part from Internatioal Rectifier (IRGS14C40L) that works well. There are a couple of thinks to be aware of, though. 1) The ignition drivers will create alot of electrostatic noise 2) You must control the dwell of the coils to avoid overheating the drivers.

Good luck. Let me know if you have any questions.