Ignition Coil Driver Questions

[WHONOES]

Your build looks good. Nice and neat. If required, you could reduce the pulse width by reducing the value of R3 to 12 or 10K. But if the pulse width is OK as is then I would leave it alone. I don't know if the actual pulse width has any effect on the apparent ignition timing. If the timing is taken from the leading edge of the pulse, which seems most likely, then within reason, the pulse width is not very important so long as it is not so long that it turns into a continuous pulse at high RPM.

 

[WHONOES]

Just remembered that I should have said earlier that you must add a 10μf decoupling capacitor directly across the supply pins on the 40106. Also, connect the inputs of any unused gates to 0V.

 

[QMESAR]

Just remembered that I should have said earlier that you must add a 10μf decoupling capacitor directly across the supply pins on the 40106. Also, connect the inputs of any unused gates to 0V.

I have added 100nF decoupling over the 40106 supply pins but will add a 10uF also,

If required, you could reduce the pulse width by reducing the value of R3 to 12 or 10K. But if the pulse width is OK as is then I would leave it alone. I don't know if the actual pulse width has any effect on the apparent ignition timing. If the timing is taken from the leading edge of the pulse, which seems most likely, then within reason, the pulse width is not very important so long as it is not so long that it turns into a continuous pulse at high RPM.

The duration is not that important as I also think it is triggered from the leading edge,It also does have no effect on Ignition Timing point it is purely for the ECU to know that the engine is Cranking/running and it should (1) switch the fuel pump relay ON (2) inject fuel and the amount depends on Engine ,Air Temp ,throttle position and the main parameter the MAP sensor Signal(Manifold absolute pressure )

I will get the MJE transistors may be in 1 week time then I will complete the build.

 

[WHONOES]

Ok. I've learnt some stuff as well.
You could use some alternative high voltage transistors instead if you have any in you bits box. I chose the MJE's because a) I use them in my audio power amp circuits so am very familiar with them. b) They are rated at 350V so have a fair bit of head room and should not fail from excess volts. c) They come in a TO126 package which allows some heatsinking if needed without being to large. This might be important at higher pulse rates as the average power dissipation will be greater. d) For a high voltage device, they have a respectable Hfe in the range of 30 to 240.

 

[QMESAR]

Thank you for the advise .I have no High Voltage Transistor with me,mine is around 60V max,
I have them on order will get them soon
Have nice weekend

 

[WHONOES]

Ok. Just thought I'd mention it in case you might have something that would do the job.

 

[QMESAR]

Hi All.
Just an update I have completed the circuit on bread board and It is working fine ,then connected an ECU it is triggering just fine
and no interference problems I can measure the ECU out put very well,

This brings me to thank WHONOES for his excellent help and patience with me,Dear WONHOES I do not now how to thank you words is simple not enough !!!, with out your help this was not possible at all for me .a Million Thank you's to you.
Then I also would like to thank hevans for your very interesting and helpful comments.It was very helpful thank you too .
Duke37 Thank you for your help on my initial circuit you put me on track and help me to get it to work in a way that I at elast have something running ,Thank you very much

I will be back on the circuits in sort while, I have two question to ask which is not clear to me and would lie to understand that. I will also place a photo of the running ecu system

Best Regards
QMESAR

 

[WHONOES]

I look forward to your questions.
Glad you have had a successful expedition and that it is working as you wanted.