I'll go one step farther, it seems enormously flexible and looks like it could be very useful for all of us. Useful on many kinds of model engine.
Model Engine Ignitions
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Would this work on a v-8 (hall effect)?
Are you talking about the Hall-effect that GM uses with it's window dizzy? If so, I don't see why not so long as the signal-in meets the voltage requirement.
- The CD4047B needs an input signal of at least 3.5 volts when running on 5 volts. 7 volt input signal when running on 10 volts and 11 volt input when running on 15 volts. This would be either positive or negative going.
Ray
I just got a bunch of parts in to make ignitions and parts for testing. I have a few 2 stroke engines I can play with including batteries from 4.7 to 12.5 volt. I'll post my results here. But I have one job to finish first, a automotive 2 relay & 4 relay programmable cooling controller.
Ray
Ray
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Ray:
LED1 is never going to light
The voltage at the base of the transistor will never go above 0.7v. The led will require at least a couple of volts. Unless you have something going on with a negative supply at VSS (-) on the led cathode? But I don't see it on the schematic.
LED1 is never going to light
The voltage at the base of the transistor will never go above 0.7v. The led will require at least a couple of volts. Unless you have something going on with a negative supply at VSS (-) on the led cathode? But I don't see it on the schematic.
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Ray:
If you simply choose to use the Q(not) output of the chip (instead of the Q output) the transistor (and coil) will be energized most of the time instead of off most of the time. (sort of an inverted dwell scenerio). That's going to be an awful load on the transistor and coil and a waste of power for no reason. Maybe I'm not getting your reason for that option.
If you simply choose to use the Q(not) output of the chip (instead of the Q output) the transistor (and coil) will be energized most of the time instead of off most of the time. (sort of an inverted dwell scenerio). That's going to be an awful load on the transistor and coil and a waste of power for no reason. Maybe I'm not getting your reason for that option.
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Ray:
You show an option for an IGBT transistor for Q2. I don't see a Q2 in the schematic. Same for TR2.
I assume they are replacements for Q1 and TR1?
TR1(2) being ignition coils I assume.
You show an option for an IGBT transistor for Q2. I don't see a Q2 in the schematic. Same for TR2.
I assume they are replacements for Q1 and TR1?
TR1(2) being ignition coils I assume.
No, a model V-8 Think Lil Demon V-8.
Your right I missed that one my bad. I'll fix it up.
I haven't chosen a PNP yet but as I stated in the write up I still have testing to do and will let people know what I find. Including the parts I have tested.
Yup, my software wants to sequentially number everything a PITA. I can make things like part 1.1, 1.2 etc. so I'm just going to delete the part reference and use a text box.
I'll post the corrections, thanx dsage.
Ray
Yes but how are you going to direct the spark? are you going to use a dizzy? A crank trigger?
On my race car I'm going to use both a crank trigger to fire and a dizzy to distribute spark at first. From this I while end up using a shift register to use coil near plug and 8 coils along with a Ford 302 cam sensor.
Ray
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Ray:
Q1 only has a dc current gain (hfe) of 8 at 5 amps collector current. Therefore it's going to require about 600ma of base drive current to properly drive the coil.
The CD4047 at best will supply only 6ma. You're going to need at least a couple of pre-drive transistors.
How about this:
As you suggested. Go back and re-design your circuit, test it thoroughly and THEN present it. And make us a video of it working.
Q1 only has a dc current gain (hfe) of 8 at 5 amps collector current. Therefore it's going to require about 600ma of base drive current to properly drive the coil.
The CD4047 at best will supply only 6ma. You're going to need at least a couple of pre-drive transistors.
How about this:
As you suggested. Go back and re-design your circuit, test it thoroughly and THEN present it. And make us a video of it working.
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That's not what I'm trying to accomplish here. What I'm trying to show is the problems one would encounter if they tried to make an ignition on their own with using basic tools like just a multi-meter. I could very easily simulate a circuit using a spice program and get very close to a fully working ignition. If people here want to see that then I could do that also. But what would they learn? Advanced skills? I like this web site because there are people who show their trials and tribulations as they learn to create things from metal, working engines. There are also master machinist here with more knowledge of machining metal than I could possibly learn on my own. I believe "it's not the destination that matters, it's the journey that matters". Show me a completed engine and what did I learn, nothing, what did someone teach me, nothing.
Yes I will go back and redesign my circuit but, I will not finish a working example and display it here. I'll lay it all out for everyone to see as I trip and stumble.
Now the transistor I first decided to use will not work properly. I had a bunch left over from repairing an LED scoreboard and decided what the heck I'll give them a try. Well the CS4047 can put out a signal strong enough to turn on the PHE13007,127 but not fully but, why?
It turns out that the little power supply that I was using has output current overload protection and as soon as the transistor tried to turn on, the power supply turned off. My proper or good power supply decided to show it's age and needs repair. So I got out a 11.7 volt lithium battery 20C and tried that with no protection, well that cooked the coil I was using, LOL. I just went through the transistor to the coil. It's the old Ohms law kicking in. Voltage(E) / Resistance(R) = Current(A) let's make that magic smoke with 20 amps, LOL.
The CD4047 is working just as I predicted which, was nice. As for a transistor, IGBT, or MOSFET I'll have to see what I have and that is a lot. As I check what I have I'll check the specs and update my new inventory database.
R&D (Research & Destruction)
Cheers
Ray
I would like to point out that desage is correct about the PHE13007,127 transistor and the base current. It takes .550 amps to fully turn it on, not good. I'll have to see what else I have.
I'm waiting for parts to arrive from China so I have some time to kill so I'll do some tech writing.
Also I have been following another thread model-engine-cdi-easy-and-cheap, and it works. The cheapest setup, sort of setup, cost US $12.32 with free shipping to Canada. This includes a 4 pin 12 volt DC CDI box and an ignition coil to go with it. I also ordered a GY6 ignition coil. My orders should arrive early September to November 12, ah nuts. Because it is so cheap to make work for most engines used here I decided to either drop or redevelop some of my ignitions. The ignition coils I had made are for CDI ignitions only, need 100 volts pulsed DC to work.
Coils:
My next problem; Almost all the ignition coils I have are for CDI setups and for hi-performance automotive use, 10 amps and up. The coils used with these ignition boxes range in price between $100 to $200 each. I do have 2 Accel coils but they are old 12 volt type, mainly for points use and 1 Mallory magneto (transformer) coil. So this brings me to "what is the difference between a CDI coil and a regular coil ?"
Well CDI coils come wound in 2 ways, usually. They are what I call the stacked approach and the laminate co-wound coil with 1 layer on top of the other. My coils have 6 stacks.
Then there are the laminate co-wound coils. Notice the stacks of secondary windings! non-CDI.
Now some coils depending on how they are wound can work for both CDI and IDI (Inductive discharge ignition). but generally not recommended. Those Accel coils I have, have a low resistance primary (0.7 ohms) for points and are notorious for burning out points as would any true CDI coil with points. So why do CDI ignitions use such a low primary resistance coil? Well it has to do with the C, L, R time constants. Capacitance, Inductance, and Resistance time constants. Basically it means that the voltage leads the current in a purely inductive circuit by 90 degrees. But the wire resistance will slow down the charging and discharging of the coil, so the lower the resistance the faster the capacitor can discharge through the coil creating a current surge. But you can't have it too low of inductance or the magnetic field (flux) will be too small. Capacitors have ESR resistance that will change it's time constant. The capacitance is from the coil windings and of coarse the charge cap, each laminated coil winding also creates a capacitor. The capacitance has 2 effects, the first is the time constant for the charge cap which has a charge and discharge time constant. Too big of charge capacitor and it will not fully charge between ignition firings, use to small of cap and you won't get enough energy stored. It is usually quicker to charge a cap than it is to discharge it through a coil. The second effect has to do with resonance and impedance. At resonance the CLR circuit will have the least amount of impedance at a certain frequency, on GM's big 4 wire HEI distributor this occurs between 2,400 rpm and 3,00 rpm on my test bench.. At max impedance the circuit will have the most resistance to current flow. With GM's big 4 wire HEI distributor this occurs between 5,500 rpm and 5,800 rpm on my test bench. This is a well know problem with GM performance people.
So what else is different with the 2, well CDI usually almost all the time have less inductance on their primaries but, both can have the same secondary inductance. I find that the Chinese small motorbike coils and such can work with both CDI & IDI ignitions. You'll also find both coils can have the same primary to secondary coil winding ratios 100:1! The difference between the 2 is the CDI charges the primary with usually between 220 - 350 volts and MSD charges to 540-560 volts. I charge mine to 1,100 volts! So why does a IDI put out between 35K & 45K volts and with most CDI putting out @ 55K. Shouldn't the CDI put out a lot more? Considering they can have the same winding ratio and the CDI having such high voltage on the primaries.
Well yes it should but, ignition coils don't work like that. If I can find it I will post a research paper on 'ignition in a IC engine'. Anyway the gist of it says and I agree with it, that you need high voltage to create an arc to break down the resistance of the gases and vapors from the ground to the electrode. Once this occurs the resistance from the ground to the electrode becomes a short across the secondary winding. Now when this happens the energy can't be destroyed so it gets turned into current, just what we need to burn something between the ground and the electrode. So the CDI does putout more energy for a single spark. Which is why they usually rate them in joules of energy.
Which coil to use for general usage?
For Inductive Discharge:
For points and transistor and not CDI:
Example generally; Primary 0.7 - 1.5 ohm & 4 - 16mH, Secondary 8 - 12.5K ohm, 37 - 50H & 70:1 to 100:1 ratio.
For CDI ignitions:
Problem with CD ignitions is at idle they have their highest voltage across the primaries, as the RPM goes up there is less time to charge the capacitor and the output voltage starts to drop. Remember the whole idea of a CDI is high voltage output that gets converted to current. I have found that most CDIs quit sparking when the primary voltage is between 100 to 120 volts DC across the primary.
Example generally; Primary 0.1 - 0.4 ohm & 0.112mH - 1.540mH, Secondary 771.0 ohm - 3.80K ohms generally below 1k ohm & 0.922H - 6.64H.
As you can see, the primaries are pretty close to being the same but, the secondary can vary quite a bit.
NOTE: Inductive coils can work with CD ignition boxes but, CDI coils should not be used with an inductive discharge ignition box, something will make magic smoke. If you want to make your own coil here is a pretty good tutorial DIY Ignition Coil. You can also search the web for others. There are programs on the internet that will make the calculations for voltage, current, wire size, and induction but, most are for just transformers which is what an ignition coil is anyway.
I should also note that some ignition boxes will not work with non-resistance plug wires or plugs, too much EMI noise. One needs to test their ignition box.
Well that's about it.
Ray
I'm waiting for parts to arrive from China so I have some time to kill so I'll do some tech writing.
Also I have been following another thread model-engine-cdi-easy-and-cheap, and it works. The cheapest setup, sort of setup, cost US $12.32 with free shipping to Canada. This includes a 4 pin 12 volt DC CDI box and an ignition coil to go with it. I also ordered a GY6 ignition coil. My orders should arrive early September to November 12, ah nuts. Because it is so cheap to make work for most engines used here I decided to either drop or redevelop some of my ignitions. The ignition coils I had made are for CDI ignitions only, need 100 volts pulsed DC to work.
Coils:
My next problem; Almost all the ignition coils I have are for CDI setups and for hi-performance automotive use, 10 amps and up. The coils used with these ignition boxes range in price between $100 to $200 each. I do have 2 Accel coils but they are old 12 volt type, mainly for points use and 1 Mallory magneto (transformer) coil. So this brings me to "what is the difference between a CDI coil and a regular coil ?"
Well CDI coils come wound in 2 ways, usually. They are what I call the stacked approach and the laminate co-wound coil with 1 layer on top of the other. My coils have 6 stacks.
Then there are the laminate co-wound coils. Notice the stacks of secondary windings! non-CDI.
Now some coils depending on how they are wound can work for both CDI and IDI (Inductive discharge ignition). but generally not recommended. Those Accel coils I have, have a low resistance primary (0.7 ohms) for points and are notorious for burning out points as would any true CDI coil with points. So why do CDI ignitions use such a low primary resistance coil? Well it has to do with the C, L, R time constants. Capacitance, Inductance, and Resistance time constants. Basically it means that the voltage leads the current in a purely inductive circuit by 90 degrees. But the wire resistance will slow down the charging and discharging of the coil, so the lower the resistance the faster the capacitor can discharge through the coil creating a current surge. But you can't have it too low of inductance or the magnetic field (flux) will be too small. Capacitors have ESR resistance that will change it's time constant. The capacitance is from the coil windings and of coarse the charge cap, each laminated coil winding also creates a capacitor. The capacitance has 2 effects, the first is the time constant for the charge cap which has a charge and discharge time constant. Too big of charge capacitor and it will not fully charge between ignition firings, use to small of cap and you won't get enough energy stored. It is usually quicker to charge a cap than it is to discharge it through a coil. The second effect has to do with resonance and impedance. At resonance the CLR circuit will have the least amount of impedance at a certain frequency, on GM's big 4 wire HEI distributor this occurs between 2,400 rpm and 3,00 rpm on my test bench.. At max impedance the circuit will have the most resistance to current flow. With GM's big 4 wire HEI distributor this occurs between 5,500 rpm and 5,800 rpm on my test bench. This is a well know problem with GM performance people.
So what else is different with the 2, well CDI usually almost all the time have less inductance on their primaries but, both can have the same secondary inductance. I find that the Chinese small motorbike coils and such can work with both CDI & IDI ignitions. You'll also find both coils can have the same primary to secondary coil winding ratios 100:1! The difference between the 2 is the CDI charges the primary with usually between 220 - 350 volts and MSD charges to 540-560 volts. I charge mine to 1,100 volts! So why does a IDI put out between 35K & 45K volts and with most CDI putting out @ 55K. Shouldn't the CDI put out a lot more? Considering they can have the same winding ratio and the CDI having such high voltage on the primaries.
Well yes it should but, ignition coils don't work like that. If I can find it I will post a research paper on 'ignition in a IC engine'. Anyway the gist of it says and I agree with it, that you need high voltage to create an arc to break down the resistance of the gases and vapors from the ground to the electrode. Once this occurs the resistance from the ground to the electrode becomes a short across the secondary winding. Now when this happens the energy can't be destroyed so it gets turned into current, just what we need to burn something between the ground and the electrode. So the CDI does putout more energy for a single spark. Which is why they usually rate them in joules of energy.
Which coil to use for general usage?
For Inductive Discharge:
For points and transistor and not CDI:
Example generally; Primary 0.7 - 1.5 ohm & 4 - 16mH, Secondary 8 - 12.5K ohm, 37 - 50H & 70:1 to 100:1 ratio.
For CDI ignitions:
Problem with CD ignitions is at idle they have their highest voltage across the primaries, as the RPM goes up there is less time to charge the capacitor and the output voltage starts to drop. Remember the whole idea of a CDI is high voltage output that gets converted to current. I have found that most CDIs quit sparking when the primary voltage is between 100 to 120 volts DC across the primary.
Example generally; Primary 0.1 - 0.4 ohm & 0.112mH - 1.540mH, Secondary 771.0 ohm - 3.80K ohms generally below 1k ohm & 0.922H - 6.64H.
As you can see, the primaries are pretty close to being the same but, the secondary can vary quite a bit.
NOTE: Inductive coils can work with CD ignition boxes but, CDI coils should not be used with an inductive discharge ignition box, something will make magic smoke. If you want to make your own coil here is a pretty good tutorial DIY Ignition Coil. You can also search the web for others. There are programs on the internet that will make the calculations for voltage, current, wire size, and induction but, most are for just transformers which is what an ignition coil is anyway.
I should also note that some ignition boxes will not work with non-resistance plug wires or plugs, too much EMI noise. One needs to test their ignition box.
Well that's about it.
Ray
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Thanks for all that ray. I will need to read it a few more times before it sinks in. Thanks for posting. Much appreciated.
willray
Well-Known Member
I'm sure it's just a typo but, that's backwards.... Current lags voltage by 90deg in a purely inductive circuit. Current leads voltage in a purely capacitive circuit...
Thank you
Yup, thanks for pointing that out and I will correct. More on this below.
Because "ELI the ICE man" ELI - Voltage(E) leads Current(I) by 90 degrees in a purely Inductive circuit. ICE Current(I) leads Voltage(E) by 90 degrees in a purely Capacitive circuit. When you think about it on a coil (inductor) what are you creating/storing? - Magnet flux, which can only be created by current flowing through a wire, so your storing current where as a capacitor is storing voltage. Don't forget your dealing with wire and with very little resistance so the max voltage is there pretty much right away. Forget about impedance for now. The magnetic flux wants to collapse all the time, this is the resistance to the current building up a magnetic field. So long as there is constant current flow the field will eventually build. How big it builds is dependent on the number of coil, wire size, voltage pushing that current, and the amount of current available. In a capacitor it takes time to build up the voltage but the max current is right there and as the voltage builds up the current flow decreases. There are ways to calculate these functions by way of time constants, how fast the coil & capacitor can charge and discharge. Also the best way I can think of to illustrate this is a AC induction motor with a starting capacitor. motor-starting-capacitor
Here are some links about "ELI the ICE man".
Phase Difference
www.electrical4u.com
Ray
