# V8 Ignition



## stevehuckss396 (Aug 28, 2010)

I have been considering what to use for an ignition system for the small V8. Roy's module will only yield 12,000 sparks per minute.

(12,000 X 2) / 8 = 3000RPM

Unless my math is wrong, it will only support 3000 RPM on a V8 engine. Using the same math I think I need.

(8000 X eight) / 2 = 32,000 Sparks per minute. 

Is there another module out there that will supply spark at that rate, or am I going to have to build my own. I have a drawing of a TIM type ignition that my pal Louis designed that might work. I won't need alot of energy (CDI) because the plugs will be so small.

This circuit will drive an automotive coil.


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## Lakc (Aug 28, 2010)

Yes, there is, but I have not finished designing it yet. 

Frankly, I am not sure where your limitations come from, even the most basic of ignition circuits like you pictured should be capable of greater then 3k rpm on an 8 cyl. Perhaps your math is half off because there are only 4 sparks per rev of a 4 stroke 8 cyl.


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## Blogwitch (Aug 28, 2010)

Steve,

I don't know if this will help

http://www.5bears.com/tim4.htm

Maybe the TIM7 unit. I used to use the TIM6, and it performed faultlessly once I started to pot the hall sensor up to keep it away from any stray whatsits that could short it out. I was not quite up to your RPM, but I do know the model V8 lads were using the same sort of system a few years back by using a distributor and a steel interrupter plate. I used to make my own TIM boards up, but the last one I used was the generally available kit ones, and that seemed to work just as good as the others.

It is also worth rooting through the 5 bears site, as a few interesting things are going on there in the oldish stuff.


Bogs


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## stevehuckss396 (Aug 28, 2010)

Lakc  said:
			
		

> Yes, there is, but I have not finished designing it yet.
> 
> Perhaps your math is half off because there are only 4 sparks per rev of a 4 stroke 8 cyl.



4 X 8000rpm = 32,000


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## stevehuckss396 (Aug 28, 2010)

Lakc  said:
			
		

> Frankly, I am not sure where your limitations come from



Not my limitations, Roy posted on his site that his CDI will only deliver 12,000 per minute. Being too lazy to build my own, I was hoping someone makes a module that delivers what i need. If I have to, I'll build the circuit that was posted.


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## gbritnell (Aug 28, 2010)

Hi Steve,

 When I sorted out the problems with my 302 ignition I pondered the same questions as you regarding Roy's ignition versus Jerry Howell's ignition. I have several of each type.

 My 302 will rev to 7200 rpm so that's 28,800 sparks per minute. Not that I have held it there for any amount of time. I am currently running it on the Howell style ignition (TIM-6). I have switched over to Roy's and it seems to run fine but I have never taken it up to maximum rpm as I did with the other ignition installed. Once I found out how high it would rev I was satisfied and don't press the limits anymore. I don't need a box full of bent and broken pieces. 

 I had gone to the 5 Bears site quite awhile ago when I got into the electronic ignitions. I bookmarked it for reference. When I was having trouble with burning up or shorting out Hall sensors I thought that maybe it was the sensors themselves as the ones being supplied by Alan Howell now are different from the ones his Dad was providing. I did a search for the HAL 506-UA and found one place in California that sold them. Other places like DigiKey have replacement types but being as 5 Bears picked that one I ordered 6 from out west. I wired up a couple as replacements and have tested them for a long duration and have had no trouble. 

 I guess to answer your question, I would think that Roy's ignition or the TIM-6 would work fine for your engine. 

 I am planning on being at Zanesville in October so we can swap notes there.
George


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## fltenwheeler (Aug 28, 2010)

Here's a link to a data sheet for HAL5** Hall Effect Sensor Family.

http://www.dsymcu.com/templates/200612199453300.pdf

Current information: http://www.micronas.com/en/automoti...xy/product_information/index.html?doc=1355238

Tim


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## tonyengines (Aug 28, 2010)

FANTASTIC ............. See this ;D

http://www.cncengines.com/orderpage.html


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## Lakc (Aug 28, 2010)

stevehuckss396  said:
			
		

> 4 X 8000rpm = 32,000



I try to make it a habit not to do math before 8am, shame on me. 

Ignition primary systems are mostly about current flow, as that is the factor that creates the magnetic field. Any installation that cannot provide large inrush current to the coil primary will limit spark energy to the point it could diminish at higher rpms. Same could be said for any coil with too high primary resistance. So, there are a lot of factors outside of the module itself to consider.


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## stevehuckss396 (Aug 28, 2010)

tonyengines  said:
			
		

> FANTASTIC ............. See this ;D
> 
> http://www.cncengines.com/orderpage.html



Hi Tony!

This site is Roy's site for the CDI module.


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## stevehuckss396 (Aug 28, 2010)

Lakc  said:
			
		

> I try to make it a habit not to do math before 8am, shame on me.
> 
> Ignition primary systems are mostly about current flow, as that is the factor that creates the magnetic field. Any installation that cannot provide large inrush current to the coil primary will limit spark energy to the point it could diminish at higher rpms. Same could be said for any coil with too high primary resistance. So, there are a lot of factors outside of the module itself to consider.




I have some time to figure it out but it would like to have all this stuff worked out in advance.


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## d-m (Aug 30, 2010)

Hi guys 
I may be missing something here but Ill throw this out. I have read several post on this topic and still am confused as to why your buying these modules to run your IC engines. It cant be size because your running a full size auto coil and oil filled at that! Has any one gone and bought a 35.00 delco 4 pin module and tried one, it wont do much over 5000 rpm but for most apps it will be fine. it is my first choice when refitting a burnt up module on any vehicle from Toyota to Ford some of the modules are vary spendy, take the Toyota igniter years ago they were well over 250$ the customer was vary happy when the bill was less than half.I have a friend that I put delco module on his Toyota and it has been on there for years trouble free. Here is how i see it it is just an electrical switch give it a signal and it will fire the coil.The 4 pin module is even marked as to how it is wired and has a tac connection. Be sure to put it on a heat sink and use dielectric on the surfaces.And if you need more rpm google used motorcycle parts and buy a moudle from a bigger rice rocket some of them are up 12+ rpm! and find yourself an E coil you wont regret it.
Dave


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## Rustkolector (Aug 30, 2010)

Steve,
I was talking to Roy Sholl today on a CDI module for one of my engines. I mentioned this thread to him, and his comment to me was that he can provide CDI systems up to 30,000/min. He doesn't have much calll for them, but he can provide them. You might want to give him a call. 
Jeff


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## fltenwheeler (Aug 31, 2010)

d-m  said:
			
		

> Hi guys
> I may be missing something here but Ill throw this out. I have read several post on this topic and still am confused as to why your buying these modules to run your IC engines. It cant be size because your running a full size auto coil and oil filled at that! Has any one gone and bought a 35.00 delco 4 pin module and tried one, it wont do much over 5000 rpm but for most apps it will be fine. it is my first choice when refitting a burnt up module on any vehicle from Toyota to Ford some of the modules are vary spendy, take the Toyota igniter years ago they were well over 250$ the customer was vary happy when the bill was less than half.I have a friend that I put delco module on his Toyota and it has been on there for years trouble free. Here is how i see it it is just an electrical switch give it a signal and it will fire the coil.The 4 pin module is even marked as to how it is wired and has a tac connection. Be sure to put it on a heat sink and use dielectric on the surfaces.And if you need more rpm google used motorcycle parts and buy a moudle from a bigger rice rocket some of them are up 12+ rpm! and find yourself an E coil you wont regret it.
> Dave



Hi Dave

Do you have a model/year or part number?

Thanks

Tim


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## gbritnell (Aug 31, 2010)

Hi Dave,
 The thing is were not running full sized automotive coils on these engines. The CDI unit the Roy Scholl sells is self contained with a coil. The whole unit is no larger than 3x2x1 inches. If one chooses to use the TIM-6 style ignition, it's about the same size as the S&S unit except that you need a separate coil. 
 The problem with using automotive electronics for small engine work is the compatibility of triggering devices. I'm sure in this wonderful world of electronics there are components out there that could be made to work but in all my years of playing with these things no one has stepped up to give a list of parts (automotive) that can be put together to work any better than the two systems being discussed. 
 I and many others started out with a 12 volt system with an automotive coil, ballast resistor, points and condenser to run our engines. The problem was that you needed to design miniature points and then you had high currents running through them that would make them erode in a very short time. If you look at some of the earlier multi-cylinder engines the distributors were made way out of scale to the engine. The reason being mainly to get a large set of points inside them. 
 With the Hall trigger ignitions a remote timer can be set up, it doesn't even need to be inside the distributor. The spark can then be sent from the CDI back to a scale distributor and then out to the appropriate cylinder. 
 The problems I had with my 302 over the years were 90% ignition because I was trying to use miniature points inside of a scale distributor. 
 As miniature engine builders we are all open to any better way to 'fire' these things but most of us have no background in electronics. We are just machinists.
gbritnell


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## Lakc (Aug 31, 2010)

I have a hunch that most of Roy's customers are from the model airplane fraternity, size and weight matter a whole lot to them.

The early solid state ignition systems were simple enough, and can be pressed into service easily if so desired. The 5 pin family, as I call them, consists of the 1971-90's? Chrysler 5 pin ECU, the 1973-90's? GM HEI system, and the Motocraft 1971-??? in the Fords. These are all basic ignition control systems, ground side switching like points. All need 5 wires to work, power, ground, coil negative, and both sides of the pulse generator. They use a reluctor setup similar to a lawnmower magneto where a rising voltage from the pickup in the distributor triggers the coil firing. They are simple, but they are made to trigger from an AC generator signal, *require* a ballast resistor or some form of current limitation, and may be difficult to trigger with a hall effect or optical pickup. They are all current hogs, and will suck batteries dry rather quickly. Except for the HEI, the domestic choices are not very small, but the HEI will soon fail without a full contact heat sink. 

Around the 1980's the ignition modules began to acquire a few extra pins, and abilities like timing adjustment. Some modules disappeared into large multi wire engine control units, others lived in the distributor still. The imports into the US would sometimes use optical pickups, but would still need the same 5 things to operate. Towards the end of the 80's distributors were disappearing, coil packs were appearing, but some of the truck lines still used the older systems.

Coils, as you probably have noticed, have changed quite a bit along the way as well. The old round oil-filled coils gradually got phased out by a more efficient, PCB oil free, E-core. Those coils require an entirely different driving strategy, as they lack their own cooling. 

Fitting automotive modules, especially if you get them and the associated harness pigtail connectors from a junkyard, is entirely feasible. Building them into a reliable ignition _system_ takes a little bit more work. 

Edit: Old age must be setting in, the HEI *does not* require any current limitation.


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## stevehuckss396 (Aug 31, 2010)

d-m  said:
			
		

> I have read several post on this topic and still am confused as to why your buying these modules to run your IC engines.



Roy's module is $58 complete. That includes the module, coil, and sensor. 

You could buy the delco module and a coil and then order a hall sensor and see if you can get the ignition to work. You also then need to get some wire and make a heat sink. The only way I wouldn't use his board is if it didn't do what i need as in the case of the V8.

Why do all that when Roy's is the same price and there is no guess work. It will also be 1/4 the size.


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## d-m (Aug 31, 2010)

Hi guys
 This is why I and so many like me read and ask questions on this board the knowledge base here is vast. Answers are to the point and relevant thanks for the info.
Dave


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## stevehuckss396 (Sep 1, 2010)

d-m  said:
			
		

> Hi guys
> This is why I and so many like me read and ask questions on this board the knowledge base here is vast. Answers are to the point and relevant thanks for the info.
> Dave



All part of the service!


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## kcmillin (Sep 1, 2010)

Steve, I cannot find the $58 kit on Roys website.

Cheapest I can find for a kit is $80.

Can you post a link to the page?

Kel


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## stevehuckss396 (Sep 1, 2010)

kcmillin  said:
			
		

> Steve, I cannot find the $58 kit on Roys website.
> Cheapest I can find for a kit is $80.
> Can you post a link to the page?
> Kel



http://www.cncengines.com/ic.html

About half way down there is the "Basic single spark CDI" for 50 bucks and a bit farther down is the hall sensor for 8 bucks. 

The sensor is seperate because the module can be triggered with points also.


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## fltenwheeler (Sep 1, 2010)

kcmillin  said:
			
		

> Steve, I cannot find the $58 kit on Roys website.
> 
> Cheapest I can find for a kit is $80.
> 
> ...



*Single spark CDI module*
Spark coil is soldered to power board includes 1 foot spark and ground wire.
Add hall sensor or 2 wire connector and spark plug end for a complete CDI
Does not include a hall sensor, magnet, or 2 wire connector for use with engine points. Please order these items separately.
$50.00


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## kcmillin (Sep 1, 2010)

Thanks guys, How did I miss that. it makes perfect sense now. 

Kel


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## jpeter (Sep 1, 2010)

Here's one that works. It'll spin my v8 to 7000 rpm. Been solid for months.
I found the tim-6 troublesome. I designed this one around the IGBT ignition switch. If anybody builds one don't leave out the 20k 1watt resistor in the HT wire. If the hall effect switch is to be in the distributor, I use it inside a 1 inch dia. distributor, use one able to take high ambient temperatures. I use 125 degrees C one, 150 would be better. All the parts come from digikey. I put the sensor and zeners in the distributor and everything else on a circuit board taped to the side of the coil. I cut the circuit board traces with a dremel tool cutoff wheel. Simple as it is I put a lot of time into the development. Had a lot of trouble with EMI and heat. Works now though. 

View attachment transistor ignition.pdf


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## gbritnell (Sep 2, 2010)

Hi Jim,
I gave a look at your schematic. For someone that is familiar with electronics it probably makes a lot of sense but for the uninitiated could you elaborate a little more like what kind of coil did you buy or use. The auto parts store isn't very helpful if you don't have a number or model. Next is the component between the signal side of the Hall sensor and the leg of the transistor. Then you have what looks like another voltage source VCC applied to the signal side of the Hall. Would it also be possible to give a list of the component numbers you use. I have a DigiKey catalog and when you start looking for an individual component without a number the options are mind numbing.
 I would sure like to give it a try but I'm afraid I can't build one from your information.
Thanks for your help,
gbritnell


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## gbritnell (Sep 2, 2010)

Gentlemen,
Here is a link to another ignition system. I don't know if anyone has tried it but the author, Paul Elsmore, seems to know what he's talking about. 
http://hnm.110mb.com/i.html
gbritnell


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## jpeter (Sep 2, 2010)

All good questions. All the voltages are 12 volts. Vcc is connected directly to the 12v battery +. In the distributor is the hall sensor, 2 zener diodes for EMI protection, and the 2 resistors that go with them. I use an aileron extension (3-wire cable) from the distributor to the electronic unit. One wire carries 12 volts, another carries the sensor output and the third is a ground. I devise a small circuit board which I generally mount under the distributor such that the sensor sticks up through the base of the distributor housing into the distributor. I use a shutter to switch the sensor. I've tried using multiple magnets but on small cams the magnetic fields interfear with each other making switching, at least for me, difficult. On large cams I have trouble with dwell timing. The JH website suggests multiple magnets. The igbt is a robust chip. I've never ruined one. They do get hot so I generally fasten them to the circuit board and apply a dab of heat sink grease. Not so for the hall sensor. They can get zapped by EMI and ambient heat so when you buy them, buy a supply. Regarding the coil; for a coil I use a standard old style automotive coil with a built in resistor. I've attached a sketch of a distributor design I use. It works well and the top of the shutter works well too for supergluing the rotor to, which I make from g10 to which I glue a strip of brass.
[ame]http://www.youtube.com/watch?v=B9zt3SF_Flc[/ame] 

View attachment distributor.pdf


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## Admiral_dk (Sep 2, 2010)

Hi Jpeter

Looking at you ignition I'm sure that you're having the diode in the IGBT gate connected the wrong way - it's supposed to help with turning the IGBT off as fast as possible ...!

I'm also surprised that you haven't got a strong buffer between the hall-effect sensor and the IGBT - I'm sure that the big heat you're experience in the IGBT is caused by the slow turn on and off times. If you place the diode correctly I'm sure you'll get a stronger spark, because you turn the IGBT faster off - it can be done with two transistors.


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## jpeter (Sep 2, 2010)

You may be right regarding the direction of the igbt gate diode but but then again you may not be. It sparks like hell and I'm not changing it. That portion of the circuit came directly from the IRC data sheet. I added the hall effect sensor and the zeners for EMI protection. Otherwise it's exactly as the manufacture suggested. Google for the data sheet and you'll find they recommend a diode acrossed the coil too. I couldn't get it to spark with that diode in place so I left it off. You know, I never actually understood the purpose of that diode in the gate circuit. I thought maybe it protected the switch or something. It was in the datasheet so I left it there. Come to think of it I did add the 20k pull up resistor and I'm sure the sensor pulls the gate down fast enough to spark the coil with or without the diode. Maybe its not necessary at all. Anyway, the circuit works really well, its about as simple a circuit as there is to build and the parts are really cheap. And, unlike the transistors in the tmi-6 circuit the igbt is really robust.


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## Admiral_dk (Sep 2, 2010)

Well I do understand the concept - don't fix it, if it ain't broke ... ;D

But I'm also interested in improving things, so I went looking for an application note on the IRF homepage - none, googled it - again none .... So I looked at the datasheet and I'm almost certain that you're referring to figure 15 - fine, BUT it's NOT how to use it, but how to measure the device .... 

I do not have a Hall effect sensor in my electronic simulation tool right now, so I can only show you how the modified circuit will look like .... that is if I succeed in attach the pdf .... ???

Your 20K resistor is replaced with R2 1K on my schematic, then follows the two transistors and another resistor and the IRFGH14C40L as you use, and the rest is just another way of drawing the same as your circuit. But it should be a much improved circuit .... but then again - it might not perform any better in your application - 


View attachment Ignition.pdf


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## Lakc (Sep 2, 2010)

As I look at my tenative order, I see I spec'd an IRG41BC5UD, but mostly for the reason that digikey has them in stock, and eagle has it in my library. I can be notoriously lazy at times, and have not done much hard research into yet, but this part has an integral supression diode already. This is mostly going to be an experiment for me with IGBT's, as I have not used them before. For any ignition system, you cant have enough zener diodes and buffer capacitors, so sprinkle them liberally. This is not a circuit you want to Muntz, or you will make hall effect and microcontroller suppliers rich. 

Years of fixing broken ignition systems has given me the itch to try my own hand at designing them. I could just be suffering from an overinflated designers ego, but if I try and fail, I *will* learn something, so its never a total loss. 

Somewhere along the line I need to figgure out how to make ltspice do what I want it to do. Testing anything but the simplest circuits is beyond me. So much to do and so little time....

There are several decent looking, open source, capacitive discharge systems out there. Thats not the direction I want to take, but it is an eloquent solution to a scaling problem if you dont want to use a full size coil. If you only get 1 tenth of the inductance to play with, you just hit the primary side with 40x the voltage.


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## jpeter (Sep 2, 2010)

Hey, I know just enough about electronics to be dangerous. I also know that igbt gates have a lot of capacitence, thus need current or time to charge. I haven't done the math or maybe I don't know how but I was surprised I could charge the gate to 7 or 8 volts quickly enough through that 20k pull up resistor. When I found could clamp the igbt with it I stuck with it cuz I didn't want to drain to much current through the sensor during the pull down period. Possibly the igbt would run cooler with a smaller pull up resistor, clamp it tighter that is. 
I haven't yet looked at your circuit but I'm gonna. That electronics stuff fasinates me. 
What I'd really like to find is a source for a small 12v coil. Hiding that big clunker in the base is tough on small engines. I have a couple of engines on which I use motorcycle coils. They work too and are a lot smaller, retro ones of course from old kettering ign systems.
Thanks for the circuit. I'll check it out. Say, I've had those igbt's around for a long time. Maybe they aren't still available.


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## Admiral_dk (Sep 3, 2010)

> Hey, I know just enough about electronics to be dangerous.


  ;D Been there and done it too, especially when younger  - Errare humanum est ;D

How did you measure the rise time on the gate ? I mean this can (normally) only be done with a oscilloscope, so a rise time of 1 uS or less with a 20K will impress me rather much.

IRF are certainly making them right now and I wouldn't be surprised to find them in a very high percentage of current automobiles and motorcycles - since I haven't found ANY similar product from a competitor, except those how make them under licence (those names vary a bit, but all contain 14C40L in the product number). They are made to be inside those spark plugcaps that integrate the ignition coil inside too. Find one of those and you found tiny ingnitioncoils - I will not promise that they come cheap, but then again - one for each cylinder on a modern engine ought to bring the price down.

I'm sure that you could improve your circuit quite a bit by just changing your 1K to 10-50R, the 20K down to 1K and change the direction of the diode. A capacitor with a value between 47nF and 470nF 630V either across the primary or across the IGBT (from ignition coil to ground), but NOT both - is very likely to raise the secondary voltage quite a bit too.


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## jpeter (Sep 3, 2010)

Hey Admiral, I'll assume your circuit works well but what's better about a circuit that adds 2 bipolar transistors along with two more resistors and stuff to get to the same place. I've got no burning desire to complicate the thing. Disregarding the switching circuit, I've got the igbt, 2 resistors and a diode. Had I chose to use a hall effect switch with a built in pull up resistor I could have cut back the parts list even more. I can't think of a more simple circuit to get the job done. 
The igbt from Digikey cost 3.39 in single unit quantities (just looked it up); the sensor cost 1.25. I'm doing TIM for under 5.00. Tough to beat that. I'm still gonna pull out that gate diode and see what happens. Anyone want to make a prediction?


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## gbritnell (Sep 3, 2010)

Gentlemen, as I had mentioned in my previous posting, some of you are more skilled at electronics than the rest of us and my question at that time was, could you please compile a parts list with the part numbers for us so we could also try your system. I would be thrilled to have a $5.00 ignition for my engines as I'm now up to about $275.00 for the 4 that I have. 
Thanks,
gbritnell


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## jpeter (Sep 3, 2010)

Which ever circuit you use it's going to cost you around $5.00. Bipolar transistors are less than a quarter a piece so Admiral's circuit is cheap to build too. Admiral, I've been having a lot of fun bantering with you but I'm convenced you've got a depth of knowledge about the subject; you know what you're talking about. Be reminded guys you're going to have to buy a resistor type ignition coil from the autoparts store for about $20 and spend a couple of bucks on incidentals. With shipping and running around and after a certain amount of frustration you'll have a working TIM for $35 or so. If you can buy one all ready to go for $50 than going that way might be a good choice too. I like to make my own stuff. I don't want to put words in Admirals mouth but I think he does too, like to make his own stuff.

Regarding the question about the rise time: I didn't worry about it cuz I figured the time to charge the coil wasn't too important to the function so long as it got charged in time. Right? Also, I was concerned about the health of my o-scope getting it around that much voltage. Rise time would be interesting though to know. I outta check that out.


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## Lakc (Sep 3, 2010)

jpeter  said:
			
		

> Regarding the question about the rise time: I didn't worry about it cuz I figured the time to charge the coil wasn't too important to the function so long as it got charged in time. Right? Also, I was concerned about the health of my o-scope getting it around that much voltage. Rise time would be interesting though to know. I outta check that out.


The magnetic flux built up in the coil primary is dependant on the *rate* of charge, so its rather important. 

Yes, its not a good thing to get your scope too close to the hv side, use an inductive pickup or make friends with a mechanic and use an automotive scope (with an inductive pickup).

George, dont worry, your on my short list of beta testers


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## jpeter (Sep 3, 2010)

Hey, I thought the strength of the flux field was determined by the strength of current flow in the inductor. I didn't think time played a role. I agree if the igbt doesn't clamp up in time then full primary current won't be reached. As long as full current flow was reached before the coil fires I thought that would be fast enough. Am I wrong?


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## Lakc (Sep 3, 2010)

jpeter  said:
			
		

> Hey, I thought the strength of the flux field was determined by the strength of current flow in the inductor.



I think that may only be partially correct for our application. If you check out here http://en.wikipedia.org/wiki/Magnetic_field

Under the Faraday's law section, it mentions


> In terms of magnetic field lines, the electrical voltage that is generated in an electrically conducting coil is proportional to the time rate of change of the number of magnetic field lines that pass completely through the loop. I didn't think time played a role.


And since its voltage that were looking for here... But I wholly admit there is a bunch of stuff on those pages I do not understand, and I wouldnt touch most of the math without Marv K at my shoulder. 


> I agree if the igbt doesn't clamp up in time then full primary current won't be reached. As long as full current flow was reached before the coil fires I thought that would be fast enough. Am I wrong?


I am not sure, but as velocity is usually the squared component in many energy type reactions, my gut feeling says speed counts. That could well be completely irrelevent too. 

We need another button aside from the "report to moderator" one, one which says "paging Marv we need math help in this thread" Rof}


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## Kermit (Sep 3, 2010)

The number of 'turns' of the coil is a primary factor in the inductance of the coil. 

Increased inductance will reduce the 'speed' at which maximum flux density can be reached.(slows down response of the circuit) 
Reducing the inductance will reduce the power of the spark, but increases the speed at which one can get to the next spark in the cycle

increasing the drive voltage will help, but then, you have the problem of more easily damaging other circuit components(transistor devices)

It is a balancing act, with higher speed motors needing, understandably, more expensive and intricate circuit designs.



Keeping it simple


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## Noitoen (Sep 4, 2010)

Here's the datasheet for the IGBT 

View attachment irgs14c40l.pdf


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## Noitoen (Sep 4, 2010)

Here is the hall package I got from Farnellinone ref 139853. It has a integrated magnet and switching frequency over 200khz 

View attachment hall.pdf


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## fltenwheeler (Sep 4, 2010)

stevehuckss396  said:
			
		

> I have been considering what to use for an ignition system for the small V8. Roy's module will only yield 12,000 sparks per minute.
> 
> (12,000 X 2) / 8 = 3000RPM
> 
> ...



Hi All

Would a MJ10012, ECG98, or BU931R HV Darlington Power Amp Fast Switch transistor work for the NPN power transistor? Can these power transistor be driving by an 2N2907?

Has anyone used a MC3334 HIGH ENERGY IGNITION CIRCUIT?

http://www.jaycar.com.au/images_uploaded/MC3334R0.PDF

Or this one?

Hall effect pickup ignition controller 

http://www.st.com/stonline/books/pdf/docs/1360.pdf

Thanks for any help.

Tim


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## Lakc (Sep 4, 2010)

Interesting find there Tim. 



> The MC3334 high energy ignition circuit was designed to
> serve aftermarket Delco fiveterminal ignition applications.



Essentially, this is the "thinking" part of an aftermarket GM 5 pin ignition unit, as mentioned a few pages back. Note that it uses a reluctor input, so expect to have to fiddle with the circuit a bit for a hall sensor input. It also expects to be controlling a GM HEI coil, so your out of the optimization curve if you deceide to use something different. I am not sure if all this optimization provides us any benefit in the first place.

As this chip appears out of production, you limited to whats left out there, and who has it. Motorola spun off its semiconductor business into ONSEMI and FREESCALE. Freescale recognised the part number and said they transferred the part to ON back in 1997, ON didnt recognise the number at all. 

As to your other question, the MJ10012 looks like it was made for this application, literally. The MC3334 datasheet calls out that as the driving transistor specifically. In real life, the answer, as usual, will be "it depends". Driver circuits depend mostly on what is being driven, so it may be overkill for smaller coils or not enough if your trying to drive a Tesla coil.  The 8mh coil it drives in that circuit is a *lot* of inductance. If you ever get hit by one of those, it ruins your day.


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## fltenwheeler (Sep 6, 2010)

Admiral_dk  said:
			
		

> Well I do understand the concept - don't fix it, if it ain't broke ... ;D
> 
> But I'm also interested in improving things, so I went looking for an application note on the IRF homepage - none, googled it - again none .... So I looked at the datasheet and I'm almost certain that you're referring to figure 15 - fine, BUT it's NOT how to use it, but how to measure the device ....
> 
> ...



Hi Admiral_dk

How does it work?

Points open, Hall effect without magnet.
R2 is holding the Base of Q1 and Q2 high. 
In this state current is flowing through Q1, but not Q2.

Is this correct?

Why do you use an Emitter Follower Switch.

Can this be used to drive and BU941 NPN transistor?

Thanks

Tim


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## stevehuckss396 (Sep 6, 2010)

I recieved a mail from Roy over at S/S. He confirmed that he has had some good result with CDI modules at 30,000. I hope to talk to him more if he goes to Zanesville Next month.


"Yes, I've been working on several possible mods to the CDI to get the higher RPM's and not create problems in the distributor.

I have bench tested in the 30,000 area and with 4.8 up to 6 volts there are some real good looking results. I would be very happy to work with you to get you what you need. Feed back is very important along with real world testing."

Roy Sholl


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## Admiral_dk (Sep 9, 2010)

My circuit is thought as an improvement of the circuit made by jpeter. Since he's using a IGBT you can't compare it with a circuit using a bipolar transistor - the Gate (input pin) on a IGBT isn't drawing any current at any point in time as such .... ??? 

Seen from the circuit in front of it, an IGBT is an (unwanted) capacitor. If you wish to change the voltage over a capacitor you need current to charge or discharge it - the faster you wish to change it the more current. This means that as long as you keep the Gate at a steady voltage it isn't drawing any current - the bipolar transistor needs a current running between it's Basis and Emitter pins in order to conduct any current between it's Collector and Emitter pins - the difference between those two currents are the Hfe (gain) of that device and most bipolar transistors suitable for use as the primary switch in a ignition system are low gain devices and therefore draws much more current that a typical Hall-Effect sensor can cope with .... For that reason you'll need at least one more bipolar transistor between those two devices.

The IRGS14C40LPbF IGBT is a device totally optimized for using as a primary ignition switch, including several internal protection circuits - one for protecting against the secondary not being connected (this rises the switched voltage well above the safe voltage for most transistors) and protection against to high voltages on it's input.

Ok back to my circuit. Since we want the switch (IGBT) to change as fast as possible, we need the Gate voltage to change fast and as explained this requires much current to charge and discharge the parasitic input capacitor. Apply power to the circuit and assuming that the magnet isnt near the Hall-Effect sensor (likely on a one cylinder engine, less and less likely the more cylinders), R2 will pull the Basis pin on both Q1 and Q2 high. Q2 will conduct a big amount of current, slightly limited by R1, for a very short time, in order to charge the parasitic Gate capacitor. This turns Z1 on and current starts to flow in the primary of the ignition coil. Turn the engine and the magnet enters the sensitive area of the Hall-Effect sensor. This makes the output of the sensor go low and this turns Q1 off and Q2 on. Q2 will very quickly discharge the Gate on Z1 and this makes Z1 stop conducting the primary current very fast => a very fast rise of secondary voltage until the voltage where the spark gap starts the spark.


> Why do you use an Emitter Follower Switch.


This is done in order to increase the current during switching and still keep (almost) the same voltage at the output.


> Can this be used to drive and BU941 NPN transistor?


Yes . BUT the resistors should be off different values . And it still wont be a great match for a bipolar transistor as the switch  so I wouldnt use it that way  Its a perfect match for a MOSFET or a IGBT as the switches.


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## fltenwheeler (Sep 9, 2010)

Thank you for explaining it. I was thinking that was the way it worked.

Tim


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## jpeter (Sep 10, 2010)

Hey Admiral_dk, I like your explanation but think about this: Keeping in mind the coil fires when the field calapses, what I tried to do was get the field to calapse as quickly as reasonable. Now, to get an igbt to conduct, build up the flux field in the coil, I wanted to excite the gate with at least 8volts positive which I got from the pull up resistor. This drove the coulombs out of the gate junction. At this point what I had was an igbt with a gate devoid of electrons, a large current in the CE junction and coil charged with flux; a large flux field, right? Here comes the magnet quickly switching the hall effect sensor into conduction mode, essentially grounding the igbt gate. Charges flood from B-, ground, through the hall effect switch, then through the diode (notice the direction of the arrow, the direction electrons flow) into the gate, thus clamping off the CE junction. This drop in current collapses the flux field and sparks the coil. The coil charging takes place between firings. Charging time is not too important as long as the flux field gets fully built before the next firing. If the engine rpm is too high to allow time enough between firings to charge the coil then more current is needed in the gate circuit, ie., smaller pull up resistor, to attempt to charge the coil more quickly. Right?


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## Admiral_dk (Sep 11, 2010)

Hi jpeter

Your diode is connected so it "shorts" when you charge the Gate on the IGBT and it's off when the Hall-Effect conducts and discharges the Gate on the IGBT - that's the reason I suggested that you turned it 180 degrees.

You're right that the most important issue is how quickly the field collapses and this has everything to do with how quickly you discharges the Gate on the IGBT. The turn on of the IGBT is kind of unimportant to the spark, as long as the field is on full strength when you turn it off again .... The reason the turn on time matters, has to do with the heating of the IGBT. 

P = U x I (Power = Voltage x Current)

So when the IGBT is off, you have 12v x 0 = 0, and when it's on you (ideally) have 0v x 3A (current is depending on coil) = 0 - fine so far .... But when the IGBT isn't turned all the way on (during turn on or off) you could have (values depending on coil data and time) 6v x 1.5A = 9 watt and this is more than enough to heat it up on a slow turn on.

You're right about the smaller resistor value at higher rpm.


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## jpeter (Sep 11, 2010)

Hey Admiral_dk, thanks for your patience. I did have the diode backwards. I guess I had a brain fart. I was thinking the line was on the anode end. Dah. Before I did these tests I reversed it.
Anyway, here's some stats you might find interesting. I put the scope on the igbt gate to ground and here's what I found:
Total time per cycle = 3ms. That works out to about 2500 rpm on the v8.
Gate charges for a total of 2ms.
Gate rise time = .25ms.
The gate voltage levels off at 7 volts positive after .25ms and dwells there at least twice as long as as at 0 volts. The gate voltage drop time is almost too short to measure, no doubt because of the diode and dwells at zero for about 1ms. 
I found these results very interesting. Obviously the long on time accounts for the warm igbt. Looks like I should reengineer the shutter in the distributor to shorten the on time. I was surprised the igbt gate charged so quickly through the 22k resistor. I added a small resistor in the switch lead to the sensor so I could measure the current through the hall effect sensor. Surprisingly, the switching current maxed out at about a mill, well within the hall effect switch specs. 

Its been fun. I'm glad I did these tests. I learned a lot.


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## gbritnell (Sep 11, 2010)

I have been following this thread from the beginning and when the electronic guys got to the point where their discussions were over the head of most of the people here I had to take a break. 
The bottom line fellows is this, do we have a viable answer (ignition) for Steve's engine and can we get a finalized schematic for it?
gbritnell


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## stevehuckss396 (Sep 11, 2010)

gbritnell  said:
			
		

> I have been following this thread from the beginning and when the electronic guys got to the point where their discussions were over the head of most of the people here I had to take a break.
> The bottom line fellows is this, do we have a viable answer (ignition) for Steve's engine and can we get a finalized schematic for it?
> gbritnell



I have been right there with you G! Sounds to me we are stuck at the 2500 RPM level. 

What is the limiting factor? Is it the coil wont charge fast enough or IGBT cant switch fast enough? Sounds like you two are getting somewhere.


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## Peter. (Sep 12, 2010)

Pardon me for butting-into an electronics discussion with a mechanical suggestion, but it seems to me that if the electronic limit is insurmountable (which I don't believe it is, ultimately) then a way of effectively doubling the rpm would be to use two ignition drivers and take the pickups from the camshaft rather than the crank.

Can anyone see a reason why this would not work?


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## stevehuckss396 (Sep 12, 2010)

Peter.  said:
			
		

> Pardon me for butting-into an electronics discussion with a mechanical suggestion,
> then a way of effectively doubling the rpm would be to use two ignition drivers and take the pickups from the camshaft rather than the crank.
> 
> Can anyone see a reason why this would not work?



For the record, butting in is allowed. That's how we learn.

I'm sure it would work but for simplicity a single ignition would be best. There are commercial units that can achive 7200 rpm. I will speak to the guy who sells them at the Zanesville show next month.


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## Lakc (Sep 12, 2010)

Peter.  said:
			
		

> Pardon me for butting-into an electronics discussion with a mechanical suggestion, but it seems to me that if the electronic limit is insurmountable (which I don't believe it is, ultimately) then a way of effectively doubling the rpm would be to use two ignition drivers and take the pickups from the camshaft rather than the crank.
> 
> Can anyone see a reason why this would not work?


Thats almost exactly what the auto manufacturers have done. There are plenty of electrical solutions to the switching speed problem, so they moved to multiple coils and waste spark.

The real problem, is that to store more energy in a coil, to have more spark energy, you need to increase its inductance. The more inductace a coil has, the slower the current inrush, and it takes longer to build up the magnetic field. There in lies the reason for multi coil systems.


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## stevehuckss396 (Sep 12, 2010)

Lakc  said:
			
		

> Thats almost exactly what the auto manufacturers have done. There are plenty of electrical solutions to the switching speed problem, so they moved to multiple coils and waste spark.



There has to be a way to do this with one coil. MSD has single ignition systems that deliver 60,000SPM (15,000RPM). I would never need to do that but I would think half of that would be attainable. If the IGBT cant switch fast enough, could something faster be substituted?


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## Lakc (Sep 12, 2010)

Part of the trick is you cant Muntz the circuit. 
http://en.wikipedia.org/wiki/Muntzing

Dont make your hall sensor trigger your drivers at all. Your hall sensor signal should be cleaned up with a schmidt trigger, and input to a microprocessor, or at least to a cascade/darlington type circuit. That then requires a lot of protection circuitry built into the system to shunt away the primary coil back emf after the field collapses. 

Frankly, this may sound like heresy, but I dont think were best served by hall effect sensors to begin with. They work great in full size applications, but thats because they have room around them, and they dont move the magnet, they move the flux with mechanical windows. For our purposes, the ultimate trigger is probably the optical encoder found in any old ball mouse.


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## stevehuckss396 (Sep 12, 2010)

Lakc  said:
			
		

> Part of the trick is you cant Muntz the circuit.
> http://en.wikipedia.org/wiki/Muntzing
> 
> Dont make your hall sensor trigger your drivers at all.
> ...



The problem with that is they are way to big. In the case of a V4 the trigger has to be in the distributor to fire correctly. 

What is the smallest photo/sensor pair you know of?


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## jpeter (Sep 12, 2010)

Hey, don't misunderstand me. I never said mine was limited to 2500 rpm. What I said was I ran the time tests at 2500 rpm. With my system I can spark my v8 to 7000 rpm for sure. I don't do it much and for lots of reasons the engine won't free rev much faster. My test show that at 2500rpm the coil completely charges in .25ms and then dwells at full charge for close to 2 more ms. Taking these facts into consideration I have no trouble believeing I could increase the rpm by a factor of 7 and still be spark'n the plugs. That's 17000 rpm. I think most would be happy with that.
I have the entire hall effect unit; magnet, sensor, shutter for switching and zeners for protection, rotor and cap built into a 1 inch outside diameter distributor. The electronics board is in the base, under the engine. Regarding the schmidt trigger, the rise time of the hall switch is pretty fast and clean. My scope shows the addition of a schmidt trigger would be of little value. I switch the hall effect sensor with a steel shutter. I'm not sure how switching with multiple magnets would work cuz with the small size of the distributor the 8 magnet style cam didn't work; the magnet interfered with each other too much. To see how it works check the link.[ame]http://www.youtube.com/watch?v=B9zt3SF_Flc[/ame]


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## stevehuckss396 (Sep 12, 2010)

gbritnell  said:
			
		

> The bottom line fellows is this, do we have a viable answer (ignition) for Steve's engine and can we get a finalized schematic for it?



Then we are back to G's original question.


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## Lakc (Sep 12, 2010)

stevehuckss396  said:
			
		

> The problem with that is they are way to big. In the case of a V4 the trigger has to be in the distributor to fire correctly.
> 
> What is the smallest photo/sensor pair you know of?


They are available in surface mount discrete components, I am looking at a detector approx 5x6x1 mm. You dont have to buy a pair already mounted, you can buy them seperately.


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## gbritnell (Sep 12, 2010)

Hey Jim,
Is there any way we could see how you have your components arranged inside that small distributor?
gbritnell


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## Lakc (Sep 12, 2010)

jpeter  said:
			
		

> My test show that at 2500rpm the coil completely charges in .25ms and then dwells at full charge for close to 2 more ms. Taking these facts into consideration I have no trouble believeing I could increase the rpm by a factor of 7 and still be spark'n the plugs. That's 17000 rpm. I think most would be happy with that.


From my poor memory I believe some operational problems begin to show up with the square of the speed, but my memory is not always to be trusted.  I look forward to doing some testing when I get my scope back. 


> I have the entire hall effect unit; magnet, sensor, shutter for switching and zeners for protection, rotor and cap built into a 1 inch outside diameter distributor. The electronics board is in the base, under the engine. Regarding the schmidt trigger, the rise time of the hall switch is pretty fast and clean. My scope shows the addition of a schmidt trigger would be of little value.



Thats great if you dont need it, but be sure of your testing. Every wire is an inductor, and under normal operating conditions I see some pretty crappy signals. Some hall effect sensors may already include the schmidt trigger on die.



> I switch the hall effect sensor with a steel shutter.



Thats great, that is how the auto companies do it.


> I'm not sure how switching with multiple magnets would work cuz with the small size of the distributor the 8 magnet style cam didn't work; the magnet interfered with each other too much.


I have heard others complaining about the same thing, as well as induced voltage from flying magnets.


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## Noitoen (Sep 15, 2010)

With such small distributors, I would think that optical sensors work better. They could be of the reflector type that's no bigger then a 4x4x4mm cube. The sensor can be a disk painted black and white or a little "star" of metal with reflective coating.


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## Lakc (Sep 15, 2010)

For a four cylinder, you only need to drill two holes at 90 degrees through the distributor shaft. For an 8 cylinder, you can use two pickups with that same simple setup. Which kind of brings me to another pet peeve of mine. At our scales, and with no real structural load, we should probably make our distributors, and especially the shaft, entirely out of plastic


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## gbritnell (Sep 15, 2010)

Hi Jeff,
You lost me on your last post. Make the distributors and especially the shaft out of plastic? With such small diameter shafts the plastic would twist off in no time not to mention the heat issues. You could make the body out of plastic but then if you had to tap any holes in it the holding power of the threads would be very marginal. 
By following this thread it looks like there are a few different trains of thought on ignitions for miniature engines, some viable and some not. As far as I can tell from a packaging standpoint (overall size) there's only 2 options out there, one is the Jerry Howell ignition (I see they have new coils available but very pricey) and the other is the S&S ignition. At this point for the money and performance I don't think you can beat the S&S. I have 2 of them, one with the voltage reducer for operating from either a 6 or 12 volt battery, and one working from 4 AA Nimh batteries. I have had very good performance from them and Roy Scholl is great to work with. 
When someone else comes up with something better, size, cost, simplicity and operation I would be more than willing to listen.
gbritnell


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## Lakc (Sep 15, 2010)

Hi George,

I guess we may have different visions of what the distributor shaft would turn. A spring and carbon button from the center of a cap to a thin brass strip for a rotor would not necessarily provide much of a load, even for nylon. There are a bunch of strong machinable plastics around now. I don't have any particular design in mind, but when we scale a distributor but cannot scale the electricity, non-conductive materials should be a great benefit. 

These days, even intake manifolds are plastic, if distributors were still used, I am sure they would have gone plastic long ago. Weight, cost, and heat dissipation all improve with plastic for the automakers.


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## Admiral_dk (Sep 15, 2010)

jpeter - thanks for your measurements. I'm a bit intrigued that your circuit actually works better than the theory suggest and glad on your behalf 

As to your to your thoughts about changing the dwell time - I wouldn't .... but then again - I would like to rev that wonderful engine of your out quite a bit more than you do in the video ;D Certainly NOT to the point of destruction, but open 'er up all the way for some 5-10 seconds at a time 

In a modern ignition you have a processor and a knowledge about where the crank is in degrees - or at least fractions of the rotation. My Suzuki DL 650 has a 24 tooth gear with two neighboring teeth removed "read" by a coil. That gives a 360/24 resolution of the crank rotation and direct indication of the sync info (the missing teeth) in one durable sensor. Since the system knows where the crank is in regard to ignition point and how long time there is to firing, it also knows when to turn on the ignition coil current so the coil only just reach max current before it's cut off again => minimum current consumption and maximum reliability in as little heating of the components as possible.

I'm sorry but I'm really busy in RL right now, so I haven't found time to draw a complete circuit.

On a simple system you have a resistor in series with the coil and use a coil for a lower voltage than you have available. This give you a system that will be up to max current in a short amount of time => Higher revs and still do not burn the coil.


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## Joachim Steinke (Sep 15, 2010)

Hi

I believe in contrast to thermo plastics like POM (Polyacetal) or Nylon (Polyamid) etc. a Duro Plast material like laminated fabric should be more convenient for the parts of a small distributor. 

This stuff is made of linen fabric soaked with phenol resin, nice to machine, a very good isolator and thermally resistant enough for our demands. And you can tap even miniature threads very well. I believe I will build my next ignition housing from this material 















And this material has very good wear characteristics too. I made the cam follower of my ignition lever from this duroplast, after several hours of running you can hardly see any structural change on the contact surface.














Achim


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## cidrontmg (Sep 15, 2010)

The brits would know this material as Tufnol.


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## ghart3 (Sep 15, 2010)

Made a distributor (fake magneto) using a plastic like nylon for a rotor with shaft and put inside a plastic housing.  This worked good for less then an hour.  Then failure from too much friction between the materials even though greased with a silicone grease. 










Replaced the plastic housing with phenolic laminate (Micarta) and now the Nylon rotor shaft gets along good with the Micarta housing.





For "points" use 2 magnets 180 degrees apart in flywheel with hall sensor. This works good for a 4 cylinder 4 cycle engine.  Don't see why 4 magnets 90 degrees apart wouldn't work for a 8 cylinder 4 cycle engine.

Gary


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## nj111 (Sep 16, 2010)

stevehuckss396  said:
			
		

> I have been considering what to use for an ignition system for the small V8. Roy's module will only yield 12,000 sparks per minute.
> Is there another module out there that will supply spark at that rate, or am I going to have to build my own.
> 
> There is one in Strictly IC I think it's issue No55 Page 5. Claimed to produce around 54000 sparks per minute.
> ...


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## stevehuckss396 (Sep 16, 2010)

nj111  said:
			
		

> over 50000 sparks per minute on the bench using an Automotive coil and the hall sensor activated by a 32 tooth spur gear



Hello Nick. 

How does a hall sensor fire off of a gear tooth? Is the gear magnetized? If that is the case why don't we machine up an 8 toothed thingy just like in the MSD distributor.


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## Lakc (Sep 16, 2010)

stevehuckss396  said:
			
		

> Hello Nick.
> 
> How does a hall sensor fire off of a gear tooth? Is the gear magnetized? If that is the case why don't we machine up an 8 toothed thingy just like in the MSD distributor.



You mount the magnet behind or just aside the sensor, and when the tooth cuts into the magnetic field, the sensor trips on the bending of the field across its face. Takes some rather precise positioning, and you cant have other magnetic materials nearby, but thats how many automotive sensors work. 



			
				Joachim Steinke  said:
			
		

> I believe in contrast to thermo plastics like POM (Polyacetal) or Nylon (Polyamid) etc. a Duro Plast material like laminated fabric should be more convenient for the parts of a small distributor.



Thats one of the materials I had in mind. Its (probably) a slightly more modern version of bakelite and goes by the trade name Garolite at McMaster Carr, here in the US. I use that a lot in transmitting antennas as its a very good high voltage insulator.


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## nj111 (Sep 17, 2010)

stevehuckss396  said:
			
		

> Hello Nick.
> 
> How does a hall sensor fire off of a gear tooth? Is the gear magnetized? If that is the case why don't we machine up an 8 toothed thingy just like in the MSD distributor.



Hall effect devices are sensitive to a change in magnetic flux, so to avoid attaching a magnet to a rotating shaft it is simpler to epoxy a magnet to the back of the hall device and let the presence of ferrous metal at the face act as a flux concentrator. This can be a slotted disc. I'll try to PM you some more info. Nick


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## jpeter (Sep 17, 2010)

You can buy a hall effect sensor with a built in magnet. It's called a gear tooth sensor.


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## Noitoen (Sep 17, 2010)

jpeter  said:
			
		

> You can buy a hall effect sensor with a built in magnet. It's called a gear tooth sensor.



That's not a hall sensor, it's a pickup coil. They are used in diesel engines to check the speed for the governor.


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## stevehuckss396 (Sep 17, 2010)

Noitoen  said:
			
		

> That's not a hall sensor, it's a pickup coil. They are used in diesel engines to check the speed for the governor.



If these devices switch as fast and require no external magnet, Why are we not using these instead of hall sensors. Seems to me it would be easy to mill up a disk into something with 8 points. Could steel be used or is iron (cast) better.

This could change the way we fire our engines. Things just got smaller.


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## Lakc (Sep 17, 2010)

stevehuckss396  said:
			
		

> If these devices switch as fast and require no external magnet, Why are we not using these instead of hall sensors. Seems to me it would be easy to mill up a disk into something with 8 points. Could steel be used or is iron (cast) better.
> 
> This could change the way we fire our engines. Things just got smaller.





			
				Lakc  said:
			
		

> Takes some rather precise positioning, and you cant have other magnetic materials nearby, but thats how many automotive sensors work.



Those are the basic problems involved. In full size practice they measure the tip of helical gears, but approx 4mod size. In window type openings they seem to design 10mm clearance for the gaps. Suitabily large enough windows and your loosing the scale factor but it can be made more compact if your willing to fiddle with it. Even in full size, we occasionally have problems with proper gap and clearance changes due to temperature.
Personally, I would still lean towards optical if I had to re-engineer it.


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## lee9966 (Sep 17, 2010)

Interesting to learn about the different sensor types.

What method does the sensor for automotive anti-lock brakes use? It too reads a toothed gear.

Thanks, Lee


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## Noitoen (Sep 18, 2010)

Here's a 1/4" pickup I use in a industrial project
http://pt.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0304172


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## Lakc (Sep 18, 2010)

LeeScrounger  said:
			
		

> Interesting to learn about the different sensor types.
> 
> What method does the sensor for automotive anti-lock brakes use? It too reads a toothed gear.
> 
> Thanks, Lee



Origionally, they used a voltage generating pickup, like old electronic ignitions. Then they moved to hall sensors triggered from the gap. Lately, yet another option, as a cost saving measure, they use thin magnet rings with alternating N/S poles like brushless electrical motors use. At least those are the ones I am currently familiar with.


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## jpeter (Sep 18, 2010)

> That's not a hall sensor, it's a pickup coil. They are used in diesel engines to check the speed for the governor



Check out this link for hall effect gear sensors.
http://www.allegromicro.com/en/Products/Categories/Sensors/ats.asp

I think coil, reluctor, pickups were used in early electronic distributors. The reluctor pickup is kinda large for use in a really small distributor. Remember it's a coil and as such requires some wraps of wire and a core. No doubt though they'd work. Autos used them for a long time.


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## jpeter (Sep 19, 2010)

Hey, wanna see my 1 inch distributor sparkn'? Here's a youtube link.
 [ame]http://www.youtube.com/watch?v=SBem_o_GqTA[/ame]


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