Model Engine Maker

Supporting => Engine Ancillaries => Topic started by: stevehuckss396 on December 26, 2012, 02:57:22 AM

Title: Ignition Circuit help
Post by: stevehuckss396 on December 26, 2012, 02:57:22 AM

I was hoping one of you electronics Guru's might be able to analize this circuit and tell me if it can be triggered by a hall sensor. The circuit was designed to upgrade using existing points. The ignition comes in kit form for 22 bucks + postage. I was hoping I could use it with a hall effect on my next engine because the modern CDI units wont do what I want/need them to do.

If it cant be used with a hall sensor, can it be modified to work with it? I have a round PCB about 3 inches in diameter to build the circuit.

Thanks in advance!!

Title: Re: Ignition Circuit help
Post by: Don1966 on December 26, 2012, 03:33:19 AM
The trouble with this circuit Steve is that the input transistor draws to much current to turn itself on in the order of 80 ma max. The Hall sensor is not design for a whole lot of current 20 ma on most and you have to find one that is in the 5 to 24 VDC range. Treminal no. 1 has to have voltage to it for this circuit to work. I will see with I can come up with to modify it to work but this circuit is designed for an auto ignition coil and a set of points where current is not that much an issue.

Don
Title: Re: Ignition Circuit help
Post by: Don1966 on December 26, 2012, 04:29:18 AM
Sorry Steve, but looking over the circuit and calculating currents you are best to find another circuit. One thing I see is that the TIP162 transistor will stay on and the 2N2219A transistor has to conduct to turn it off. What the points do is turn it on fully, where it is conducting some already. This could cause the ignition coil to burn by staying on when engine stops unless switch is turned off.

Don
Title: Re: Ignition Circuit help
Post by: stevehuckss396 on December 27, 2012, 01:34:25 AM
Thanks Don for taking the time to look at it. I am trying to fire a duel coil (V-twin) for a project i am going to do. I will have to look for another way, or another circuit.
Title: Re: Ignition Circuit help
Post by: Don1966 on December 27, 2012, 01:49:27 AM
Steve I would try these people this is there  contact information. They do sell Hall Device igition systems.
MJN Fabrication 3330 Neal Acres Rd., Dover, FL 33527 telephone (813) 719-3220 web site http://www.mjnfabrication.com Ignition systems for model IC engines. Otto Gas ...

check it out you might find what you are looking for.

Don
Title: Re: Ignition Circuit help
Post by: stevehuckss396 on December 27, 2012, 03:00:43 AM
Steve I would try these people this is there  contact information. They do sell Hall Device igition systems.
MJN Fabrication 3330 Neal Acres Rd., Dover, FL 33527 telephone (813) 719-3220 web site http://www.mjnfabrication.com Ignition systems for model IC engines. Otto Gas ...

check it out you might find what you are looking for.

Don


MJN has not been selling ignitions for a few years now. There are a few who do but there systems wont fit full size plugs or fire full size coils. I have been mailing back and fourth with Roy (S/S) and his stuff wont help me.

I have another circuit I found on my D drive that my pal louis designed for me years ago. I forgot it was there and I did test it and it works just fine. He designed it for the straight 8 project that I will work on for the rest of my life and never finish.

Title: Re: Ignition Circuit help
Post by: Don1966 on December 27, 2012, 03:38:04 AM
Real nice Steve, I like it but I know it's out of my league. I am just really getting into machining. You circuit should work fine with the proper transistors. You have a 18 Ma draw on both inputs bases of the transistors. If you don't produce a hot enough spark you can down size the T03 transistor input resistor, but you have to make sure you don't over current the  T092 transistor. Insure you have proper heat sinks.

Don
Title: Re: Ignition Circuit help
Post by: gbritnell on December 27, 2012, 11:38:14 AM
Hi Steve,
You could look into the earlier Harley ignitions. They had twin fire coils operated by points. That might work for what you're doing.
gbritnell
Title: Re: Ignition Circuit help
Post by: stevehuckss396 on December 27, 2012, 09:58:43 PM
Hi Steve,
You could look into the earlier Harley ignitions. They had twin fire coils operated by points. That might work for what you're doing.
gbritnell


I have already purchased the duel coil for the V twin engine. I am trying to trigger the coil with a hall sensor. I really don't want to go with points. I think the entire system is worked out.
Title: Re: Ignition Circuit help
Post by: stevehuckss396 on December 27, 2012, 10:00:28 PM
Insure you have proper heat sinks.

Don

The entire cover of the circuit enclosure will heat sink the TO-3. It is 3 inches round.
Title: Re: Ignition Circuit help
Post by: Mosey on February 13, 2013, 05:03:45 PM
I hope it is OK for me to piggyback my question on Steve's here.
I want to build an ignition system for the SilverBbullet I'm building (forever).
I have a Modelectric Coil in hand.
I'm prepared to build a breaker plate and conventional points as shown by Bob Shores.
I would like to use a modern Lipo battery as per my model airplanes.
I want to have small, compact components, all mounted on the engine brackets, external.
I thought it might be cool to put a Hall Sensor and magnet inside the rear where the breaker plate is supposed to go. Easy to get the sensor and magnet facing each other in there.
I would mount a small Lipo on the outside rack.
I could  put a small PCB somewhere outside as well.
I've spoken to Roy at S/S and he will help with what I need.
What do you gentlemen suggest?
Title: Re: Ignition Circuit help
Post by: Admiral_dk on February 13, 2013, 10:35:54 PM
Hi Steve

Problem nowadays .... How do you feel about soldering SMD components (D2PAC) ...?

I'm asking, because all serious switches (solid state silicon) are all IGBT's and they are very simple to match to a Hall-effect sensor and completely protected against almost all errors that might happen when running (but not against all problems at standstill with ignition power on - this requires some extras).

And ALL production on these has stopped as wired components (not of IGBT's for other applications than ignition).

You can make a simple ignition circuit from a Hall-sensor, a IGBT + two resistors and maybee a zener diode. This will most likely run your engine very well (admittedly without any auto advance).
Title: Re: Ignition Circuit help
Post by: stevehuckss396 on February 14, 2013, 03:34:21 AM
Hello Admiral!

It's too late for me but if you have a better design than what you seen in my compressor engine thread, post it up with some pics. Mosey needs an ignition and i'm sure there are more than a few interested people who would love to see what you have.

I have good soldering skills so I am lot afraid to try anything once.
Title: Re: Ignition Circuit help
Post by: Admiral_dk on February 15, 2013, 10:04:51 AM
OK - I'm going to put my money where my mouth is, so I ordered some Ignition IGBT's and Hall Sensors from Mouser.com yesterday evening in order to test a complete circuit before I post it here. I got the idea from HMEM (where the pictures of the schematic has been removed in the meantime).

I'll be back when I got something that's tested and working.

Steve - If you insist on using an old style bipolar transistor as the switch - have a look at the Bosh BIB373. It's admittedly not easy to come by, I only found two outlets on the net. Unlike all the other old style high tension transistors, it has the necessarily gain to ensure that it can easily be controlled by an MCU or a Hall sensor. It also contains all the necessary protection circuits - but it's not cheap ($7-8). Oh, I forgot to tell, no one designs anything with a TO-3 or has done so for more than 20 years - they are too expensive, takes up too much space, etc.
Title: Re: Ignition Circuit help
Post by: stevehuckss396 on February 15, 2013, 01:24:08 PM

Steve - If you insist on using an old style bipolar transistor as the switch - have a look at the Bosh BIB373. It's admittedly not easy to come by, I only found two outlets on the net. Unlike all the other old style high tension transistors, it has the necessarily gain to ensure that it can easily be controlled by an MCU or a Hall sensor. It also contains all the necessary protection circuits - but it's not cheap ($7-8). Oh, I forgot to tell, no one designs anything with a TO-3 or has done so for more than 20 years - they are too expensive, takes up too much space, etc.


I don't insist on anything. I considered many things from the hobby CDI boards to more modern circuits and even electronic ignition kits. I posted and emailed for a few days and was advised to go with what I have here. This circuit is at least 10 years old. Gotta admit it looks coll.

I will attach a pdf of the device that i used.

(http://i770.photobucket.com/albums/xx349/stevehuckss396/Compressor%20Engine/DSCN0660s.jpg)

Title: Re: Ignition Circuit help
Post by: Admiral_dk on February 15, 2013, 05:11:16 PM
OK - it should do the trick with the right resistor values vs. voltage.

Don't touch the transistor house when the engine is running  :zap:
Title: Re: Ignition Circuit help
Post by: Admiral_dk on February 15, 2013, 07:22:59 PM
Steve

I attached a .pdf with a design for your BU941Z device - hope it helps.

I realized that the value of R1 is too small - or more correctly - it's a good match for a 4.8 volt RC power. I would increase it to 1K5 with 6 volt supply and 4K7 with 12 volt power.
Title: Re: Ignition Circuit help
Post by: stevehuckss396 on February 15, 2013, 11:02:38 PM
Thanks Admiral!  Do you have another circuit design for the Isolated gate device? The more modern device you talked about earlier.
Title: Re: Ignition Circuit help
Post by: metalmad on February 15, 2013, 11:25:27 PM
Hi Guys
Would something like this serve for my V8 project?
On a good Day I can just about work out a simple single cyl points ignition system, but its a streach :noidea:
I hope to use a Hall system for the first time on this.
Thanks guys.
Pete
Title: Re: Ignition Circuit help
Post by: stevehuckss396 on February 15, 2013, 11:44:53 PM
Hi Guys
Would something like this serve for my V8 project?
On a good Day I can just about work out a simple single cyl points ignition system, but its a streach :noidea:
I hope to use a Hall system for the first time on this.
Thanks guys.
Pete

Yes it would! You could do many things. You could put a disk in the distributor with 8 magnets on it to trigger the sensor (Steve Huck). You could also put a sensor and magnet in the distributor and have a metal disk between them. The metal disk would have "windows" in it so when a window passed by the magnet and sensor "see" each other and operate (George Britnell). You could also put 4 magnets in the flywheel and mount the sensor in the bellhousing and trigger the sensor that way.

The reason I put the sensor in the distributor is it's real easy to adjust the timing. In the bellhousing you will need to figure out a way to move the sensor for timing adjustment.

If you want to just purchase something, S/S has the CDI boards and mini coils with the sensor. I have them in two of my engines and they just plain work.

When you get to that point drop me a PM and post in your thread and we can set you up with about 5 good ways to do it.
Title: Re: Ignition Circuit help
Post by: metalmad on February 15, 2013, 11:56:14 PM
Thanks for the help Steve!
I have a feeling im gunna need it :cheers:
Pete
Title: Re: Ignition Circuit help
Post by: Admiral_dk on February 16, 2013, 10:11:44 AM
As said in an earlier post - I just ordered the parts for a IGBT ignition, so I can do a test "muck up"  ;)

And I will most certainly post the results  8)

I would do it as in a lot of modern cars and as told by Steve above - a fixed magnet and a fixed Hall sensor with a rotating disk or drum with windows in. Remember that the ratio of window size vs land gives the dwell period. In my circuit above - it fires when a window opens and the sensor sees the magnet and the coil is "charged" when they can't see each other.

Best wishes

Per
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