Maker Pro
Maker Pro

Multiple Spark CDIS Project

Rleo6965

Jan 22, 2012
585
Joined
Jan 22, 2012
Messages
585
After reading and analyzing post here in Electronics Point. I able to solved electrical noise problem that cause misfiring of my Multiple Spark Project.




Here's the video of my project.

 

twister

Feb 12, 2012
172
Joined
Feb 12, 2012
Messages
172
So what was the problem and how did you solve it?

How many volts does that put out?
 

Rleo6965

Jan 22, 2012
585
Joined
Jan 22, 2012
Messages
585
How many volts does that put out?

30KV spark voltage.:)

Noise on +12 DC supply can’t be avoided. This was caused by charging on CDI Charging Capacitor which was also in series with the ignition coil. I thought 0.5V noise was caused by intermittent turning on or delay of turning off of the 2 switching mosfet on h-drive circuit. ( GonzoEngineer mentioned about mosfet fast turning on and off ) I able to isolate that h-drive and mosfet circuit was working properly. I disconnect the ignition coil from charging capacitor and scope signal on mosfet. Signals were very clean.

Noise on +dc can’t be avoided due to charging of Charging Capacitor.. But this +12V was supplying transistor collector and base of trigger transistor which affect triggering of H-drive circuit.

I remember the reply post of *steve* that use a zener diode to input of LM7805. So, I placed a 7.5V zener before the base resistor of trigger transistor. This is to clip off 0.5 volt noise riding on the trigger signal. This solved the false triggering or not triggering of H-drive circuit.

But I don’t know if 0.5V noise on +12V DC supply will cause problem in my car radio or other electronics add on project into my car. I’m still looking for the filter choke that I removed from the +12V DC circuit of my CDI. This might help reduce the “ 0.5V noise”.

Here's the picture of 0.5V noise on dc supply at high rpm. There were 4 going low pulse created by multiple firing of CDI at high rpm. Initially there were 6 trigger pulse at 800 rpm.

cdinoise.jpg
 
Last edited:

twister

Feb 12, 2012
172
Joined
Feb 12, 2012
Messages
172
30KV spark voltage.:)

Noise on +12 DC supply can’t be avoided. This was caused by charging on CDI Charging Capacitor which was also in series with the ignition coil. I thought 0.5V noise was caused by intermittent turning on or delay of turning off of the 2 switching mosfet on h-drive circuit. ( GonzoEngineer mentioned about mosfet fast turning on and off ) I able to isolate that h-drive and mosfet circuit was working properly. I disconnect the ignition coil from charging capacitor and scope signal on mosfet. Signals were very clean.

Noise on +dc can’t be avoided due to charging of Charging Capacitor.. But this +12V was supplying transistor collector and base of trigger transistor which affect triggering of H-drive circuit.

I remember the reply post of *steve* that use a zener diode to input of LM7805. So, I placed a 7.5V zener before the base resistor of trigger transistor. This is to clip off 0.5 volt noise riding on the trigger signal. This solved the false triggering or not triggering of H-drive circuit.

But I don’t know if 0.5V noise on +12V DC supply will cause problem in my car radio or other electronics add on project into my car. I’m still looking for the filter choke that I removed from the +12V DC circuit of my CDI. This might help reduce the “ 0.5V noise”.

Here's the picture of 0.5V noise on dc supply at high rpm. There were 4 going low pulse created by multiple firing of CDI at high rpm. Initially there were 6 trigger pulse at 800 rpm.

cdinoise.jpg

30kV!!!! That should light your fire! And if the first one misses, you have three more chances.
How many volts are on the primary? I had 300 on mine and I got at least 9000 volts, maybe more. How do you measure the volts? I used a volt tester for electric fences but maybe you know of a better way.
I guess I should try that zener diode next time.
I have noise in my car radio too with just a stock ignition. The funny thing is, when I floor the gas pedal it goes away, or maybe the opposite, I can't remember. I wonder why that is? I don't know if it's coming from the 12V side or the high voltage spark. I suppose resistor plugs or a choke would help.
I liked your video, amp meter, volt meter, frequency meter and a scope. That's the way to work!
So what are you using to trigger the spark?
 

Rleo6965

Jan 22, 2012
585
Joined
Jan 22, 2012
Messages
585
I use NE555 astable oscillator circuit.with separate power supply. Tried before that generator shared dc supply. But the square wave generator becomes inaccurate. It double or triple its output frequency due to "noise". So, I have to use separate power supply and plug it far from CDI.
 

twister

Feb 12, 2012
172
Joined
Feb 12, 2012
Messages
172
I use NE555 astable oscillator circuit.with separate power supply. Tried before that generator shared dc supply. But the square wave generator becomes inaccurate. It double or triple its output frequency due to "noise". So, I have to use separate power supply and plug it far from CDI.

I am still curious to know how you measure the voltage, or is that an estimate?
 

Rleo6965

Jan 22, 2012
585
Joined
Jan 22, 2012
Messages
585
Yes, it's an estimate. I have 300V charging voltage and my ignition coil have a turns ratio of 100:1. So. 300*100=30,000.
 

duke37

Jan 9, 2011
5,364
Joined
Jan 9, 2011
Messages
5,364
The Tesla addicts use 3000V/mm, this seems to agree with my electric fence voltmeter.
An ignition coil may have a spark gap to limit the voltage.
 

Rleo6965

Jan 22, 2012
585
Joined
Jan 22, 2012
Messages
585
Here's the comparison of color of spark of spark plug using Single Spark of Mitsubishi Lancer EL distributor with Exciter IC. Note. spark was color orange, while multiple spark have bluish spark color or hotter spark . Distributor type also consumes more current. notice voltage dropping everytime spark was triggered.

Video of Mitsubishi Lancer with Distributor w/ built-in Ignition coil using Exciter IC or Transistorized Ignition System.

 

twister

Feb 12, 2012
172
Joined
Feb 12, 2012
Messages
172
I see that I'm not the only one that uses a electric fence tester. I would like to build one that would test 30,000 volts, but I don't really understand how they figured the resistors. Here is the value of the resistors if one of you guys wants to build one. They just have a neon lite across each resistor. This goes to 9,000 volts.
1. Top resistor is 150K, ten watts with no neon
2.1.3k
3. 1.5k
4. 2k
5. 3.6k
6. 5.6k
7. 15k
8. 39k
9. 92k
So maybe someone can explain what values I would need to go to 30,000 volts. Did they get the values by experiment?
 

jackorocko

Apr 4, 2010
1,284
Joined
Apr 4, 2010
Messages
1,284
No way, they make an electric fence tester? I just always used a piece of wet grass. *zzzzap* yep, it's working! :D
 
Top