ignition coil for single cylinder engines

[pchbreeze]

I'm thinking of shooting flames out the exhaust. PLEASE DONT TURN THIS THREAD ABOUT THAT...I just have a TECHNICAL question about something I've found.

Single cylinder engines have a simple ignition coil wire connected to a glow coil...with two leads to the coil. If I apply 12v to the coil, will I have constant spark at the spark plug?

Example:
eBay Motors: 4 Stroke Mini Pocket Bike Ignition Coil Part ATV Dirt (item 290220452429 end time Apr-12-08 14:28:00 PDT)

I'm trying to avoid mounting a big automotive coil that most 'kits' require. I don't really want/need a 'kit' for this anyways.

[DanG]

No, you won't get a continuous spark. Igniton coils fire a spark on a change (interruption) of current. If you keep the current constant nothing will happen (apart from the coil getting warm).

Anyway, for what you're trying to do, if it works, you probably don't need a continuous spark (pilot light, lol). Once the fuel is lit by a random spark, it will continue burning until all of it is gone.

Make sure you put up some pics when you get it going!!

[madmanmaigret]

is there enough unburnt fuel in the exhaust to do this? If so have you thought about an ignitor from a propane grill? just a push button and an electrode, makes a spark and can be bought from home depot for very little cash.

edit: also more concealable than a spark plug

[reiobard]

are you looking for a continuous flame? or just a pop here and there?


Might help to hollow out or eliminate your cat to help get more unburnt fuel as well. A spark p[lug will spark 20 times per second at idle (1200 rpm) and roughly 83.3 times per second at cruising speed (5000 rpm) faster on the highway...ect.


If the fuel is not staying ignited IE blowing itself out due to the airflow then getting this to somehow work off the bikes spark system would provide enough frequent sparks to seem as if it were constantly lit.


Also post some pics when you figure it out.

[wolfc70]

I doubt that will work. As stated above, the field interruption causes the spark. You will still need some device to break the field. The breaker points on older machines did this, now capacitors do the same thing. I would try and find some sort of spark ignitor for a older furnace, as these run off of 12 or 24v. The ignition system for what you are trying to do is actually the simpler part. Setting up solenoids and injectors to inject the combustable (propane, gasoline, white gas et cetera) is the tricky part. These bike have no choke, and with emissions requirements very little unburnt fuel leaves the combustion chambers.

Good Luck!!

[Grape]

Originally Posted by wolfc70

The breaker points on older machines did this, now capacitors do the same thing.

It is not my intention to be rude, but it is semiconductors, for example transistors or thyristors that breaks the current in modern ignition systems.

[pchbreeze]

There's plenty of fuel, and I will hollow out catalytic converters to be sure.

I'd like a continuous flame but a sparker from a BBQ grill would make it much easier and simpler.

I looked into glow coils from diesels (might not get hot enough) and hot surface ignitors from furnaces (24v).

I'll try to do some more research in the meantime. I'm looking for continuous flames. It's been a LONG time since I've done anything with those old fashioned type ignition systems.

[Fred]

Originally Posted by pchbreeze

There's plenty of fuel, and I will hollow out catalytic converters to be sure.

If your bike is puking enough fuel out the exhaust that it can ignite, you have a serious problem on the bike.

Every fire system out there has a way of adding extra fuel into the exhaust.

What comes out the tailpipe of a modern EFI vehicle isn't going to burn on its own. The engines run way too clean for that.

Fred

[madmanmaigret]

Originally Posted by pchbreeze

I'd like a continuous flame but a sparker from a BBQ grill would make it much easier and simpler.

my new grill sparker will spark multiple times if you hold down the button, so I assume that would make for a continuous flame.