DC CDI module

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MS2tester
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DC CDI module

Post by MS2tester »

i had an idea about a a DC cdi module
but since i am not an electronics engineer i could use some feedback
the design is based on that of sportdevices
it would work in a per cylinder unit so if one fails you should be able to limp home
maybe such a design could also be adapted to drive piezo injectors
dontz125
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Re: DC CDI module

Post by dontz125 »

I've looked at that afew times, but never built one. If you do a Google search on this design, you'll find mixed reviews - some have had great success, others can't get the weakest spark. There's something funky about it that catches some folks, and I'm not sure what it is.
QuadraMAP Sensor Module -- PWM-to-Stepper Controller -- Dual Coil Driver
Coming soon: OctoMAP Sensor Module
TTR Ignition Systems
MS2tester
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Re: DC CDI module

Post by MS2tester »

i have working module based on a different IC with a 100KHz switch limit
it gave a good spark to about 3000 rpm then it would not build up fast enough
now i had a mercury outboard coil which is designed for 400 volt
yamaha and johson/evinrude coils seem to have a lower initial voltage
the IC in the schematic has a 400 KHz switch limit
i was hoping there would be more people on the megasquirt board with a similar interest preferably with an electronics background
but i guess this is not the case :(
thank you for your response anyway ;)
CTMBol
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Re: DC CDI module

Post by CTMBol »

A little late... but i'm develop and build my own discharge ignition systems so i can tell you something about it. The problem with the switching devices as shown above is always the switching frequencie that is to low or the energie storage capacity of the coil is to low. The coil is the most difficult part to develop. The funky part of it: the ionisation voltage is much higher then an inductive system. So rich mixtures are no problem anymore. Also old cars with a 6 volt system have a lot benefit of it. The down side is the spark duration. Its a lot shorter then from a inductive system. So i build systems that is a combination of both. Inductive and capacitive as one system. I don't use a multiple charge system. The coil i use charge in one cycle a capacitor to max. 600 volt. Up to 1 Khz. So rpm's to 15000 with a v8 are possible. The secret is the coil. :-) greetings Marcel

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MS2tester
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Re: DC CDI module

Post by MS2tester »

so could you post a schematic then of your system?
and what size are we talking about
my preference would be a single system per cylinder so that if one breaks
you should be able to limp home or park nearby
in my case go to the nearest harbor
CTMBol
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Re: DC CDI module

Post by CTMBol »

Hello MS2 tester,

I don't know if its tolerated to speak with another language on this Forum but i see in your profile your Dutch to, so if my explanation is not clear please ask me in Dutch.

First i want to say something about the pictures you have posted in May. You can clearly see the problem on the second picture. I think you are measure the voltage over the capacitor there? Your switching speed is 100kHz so one single shot takes 10 microseconds. It takes almost 90 milliseconds to charge the capacitor to, lets say 250Volts. That means the coil is charged for 9000 times!? So your coil has the wrong dimensions and electrical characteristics or the charge time is to short so you don't get any energie in the coil. And 250Volts is to litle, you want a minimum of 400Volts if you use a 1uF capacitor to get a reasonable spark. Switching speed, coil characteristics, capacitor choice, batteryvoltage has to match perfect to make it a good system.

The coil i use is a own design and custom made. Charging time is about 1 ms, the coil contains enough energie to charge a 1 uF capacitor in a single shot. The combination capacitive an inductive in one system gives a sparkduration of 2,5ms even when the voltage drops to 3 Volts the system still gives enough energie to burn the air/fuel mixture.
I cannot give you a schematic of it, it would be useless because you cannot get the right coil. And its a part where i earn money with ;-)
primair.jpg
I don't know what you want exactly but this system works with a normal inductive ignitioncoil and a distributor. I have a smd version who is lxbxh 65mmx75mmx45mm. I have made custom solutions like a microcontrolled ignition with this principle.
Incap20.jpg
The Original first one is a tht version
original.jpg
Greetings Marcel
MS2tester
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Re: DC CDI module

Post by MS2tester »

wat kind of price range are we talking about
and wat kind of signal does the unit expect?

i started this project after i successfully build with the help of thierry from transmic.net a unit to use the original ac cdi from my outboard
running with a megasquirt
https://plus.google.com/100635361637834520148
the later mercury outboards after 2000 had inductive ignition
so i was trying to come up with a way to add CDI without removing the original charging system
you would just have to install the older CDI coils and the DC CDI unit,s
at the moment i am in contact with somebody who want,s to install an MS3 pro on a engine capable of running 11000+ rpm two stroke V6
and he is worried the IGN-1A coils won,t hold up as they are not suppose to go over a 50% duty cycle or for a very short time
so your units would be something to bring to his attention
ronald
CTMBol
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Re: DC CDI module

Post by CTMBol »

Hello Ronald,

The price range depends on what you want, the regular module, like the last picture with logic input (0-5Volt) costs between 150 - 200 euro ex. VAT. But this is a system for a single coil with a distributer. I have sold some people a double set for a dual ignition system. That way you can serve 4 cilinders. I have no experience with boat engines but if the V6 mercury have a six coil setup you need six of these modules....

Theoretical one coil can do it for the V6 that spins 11000 rpm. But i have then made a custom design for your with one coil. It's doable but it would be nice if i can sell some more than just one.
Maybe its interrest to talk with that friend of yours...

The system works only with normal ignitioncoils from a inductive ignition. The electronics can do 2 - 20 Amps for the inductive site (charging the normal igniton coil) The capacitive site can deliver 30000 spark/min. With a good ignitioncoil the total output can get around the 200mJ. For your view the capacitive site delivers only 50 - 70 mJ , That is almost the same as a traditianol inductive system. In case of the V6 engine with a coil for every cilinder: if the dwell of the standard coils is for example 3 ms and max duty cycle is 50 % than you can get to 10000 rpm. after that you have to shorten the dwell. Thats the point the capacitive site shows his benefits.

So far i know two people have build a system that combines a inductive system with a capacitive system. I am one of them. Al the system you can buy are capacitive or inductive. I sell al lot to people who have an oldtimer who runs on a 6 volt battery or running on alternative fuels. That's the reason i made it for a single coil setup.
image370.jpg

This kind of cars :-)
traction.jpg
Greetings Marcel.
LAV1000
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Re: DC CDI module

Post by LAV1000 »

@CMTBol

This system combines the high voltage discharge of a capacitive system and the duration of an inductive system.
Is this the reason for using such a relative big coil on the pcb ?
I also spot a small antenna pcb, is this unit remote programmable ?
Also like the way you used the coil as an cooling aid.
Or is it a hall sensor and used to measure the magnetic field ?
And no I don't need one just curious.
CTMBol
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Re: DC CDI module

Post by CTMBol »

Hello LAV1000.
You don't have to buy one :-) Curiosity makes people interesting. The relative big coil has two reasons. First reason: it charge a 1uF capacitor to 420 volts within 1 ms after it has discharged. Therefore it has to storage a relative high amount of energy. It don't need any kind of oscillating circuit for multicharging, that makes it more reliable. Second reason: it can provide a constant amount of capacitive energy to max. revolution of the engine. The transistor that use the coil as heatsink is the transistor who switch the primairy current of the coil. Peakcurrent is about 23 amps. So a littlebit cooling is necessary. The capacitive site doesn't have any digital circuits, switching time, voltage regulation its pure analog. The version with the pcb antenne is a custom desing for a customer. Its programmable with bluetooth. It has a map sensor, digital ignition timing and a voltageregulating circuit to make it useable from 2 Volts to 18 Volts. So i said in early posts i have developed this system for single coil applications with a distributor but with a couple of modifications it can drive 2 or 4 single ignition coils. Its fast enough.
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