For safety, cost, size, convenience get a piezo igniter like used in gas grills. No power required. Push the button and it creates a spark.

I would be happy, if I could keep it that simple.

Unfortunately, this ignition circuit is a small component of a larger sequence of Burner Management System where the commands for opening Pilot SOVs, Pilot flame sensing etc. are all weaved in a sequence.... Also the spark plug has to go deep inside a 3 - 4 feet burner where pilot flame would be lighted, sensed and subsequent events would occur.

All I am trying to do is to test this alternative ignition hardware which can replace an existing ignition hardware (which also involves a vehicle spark plug). in case of an emergency when we have run out of spares of the original OEM design... (In recent times the supply of spares are taking a significant amount of time, especially when they are to be imported)..

So just wanna keep an alternative design handy in case there is an urgent need to work around the existing one...

Thanks and regards,
Rahul

 

Surely there are other commercially available igniters that would work for you. Every gas furnace and oven as one.

 

You may want the igniter to generate a few pulses per second to insure ignition.
This could be done with a 555 timer configured as an astable oscillator, driving a MOSFET to interrupt the primary coil current.

 

Don't underestimate the Vds requirement of the MOSFET. IGBTs are available for ignition systems and they are generally rated at 400V.

 

Don't underestimate the Vds requirement of the MOSFET. IGBTs are available for ignition systems and they are generally rated at 400V.

The voltage to fire a spark plug at atmospheric pressure is perhaps only about 3kV (much less than in an engine under high compression pressure), generating a primary flyback pulse of ≈30V for a 100:1 coil, but you would want a high-voltage Zener across the device to protect against the high primary flyback voltage resulting from operating the device with no load on the secondary (accidentally, as the secondary should always have a load).

 

You may want the igniter to generate a few pulses per second to insure ignition.
This could be done with a 555 timer configured as an astable oscillator, driving a MOSFET to interrupt the primary coil current.

Thanks...

We were planning to interrupt using a relay driven by a GE FANUC PLC, which we already have for process. But got stuck with the basic circuit only.

But I get the overall drift now from the posts above. First, would like to use a capacitor across the primary interruptor contacts, before proceeding to the next step...!!

Actually, we are currently using all standard automotive components hitherto, which also includes the cables. If the spark sustains in strength, then next step would be to try out cables that we use here (High temp ignition cable) instead of the short length Automotive Spark Cables, that we are currently experimenting with.

We are looking forward to keeping the existing housing etc same. Not wanting to change much architecture. The existing ignition assy also has roughly a similar sized ignition coil, has a standard automotive spark plug etc. So we thot to use a similar replacement components, so that we dont have to get into the mechanical fitment issues etc...

Thanks and regards,
Rahul

 

So this is a retrofit to a thing in production? Maybe tell us or link to the item?

That said, to make use of a automotive coil easier you could use a common(or common before cars with a computer) HEI module. They come already equipped with all the things needed to fire a coil in a pretty small package. And are still readily available in the after market. Using a 555 circuit to trigger it like Crutschow suggested.

Here is a site telling how to use them for many different ways of triggering. I'm guessing you would use Fig.1, with the 555 circuit in place of the points.
http://gpzweb.s3-website-us-east-1.amazonaws.com/Ignition/GPZheiModForPoints.html

 

would like to use a capacitor across the primary interruptor contacts

You'll get a fatter spark that way and the contacts will last longer.

 

Came back here to convey my thanks to all the experts....

The Pilot Ignition Assembly worked...

Wouldnt have without the help and handholding here...!! Thanks a ton...!!

Could generate a reliable and repeatable blue pilot flame in just one shot (single interruption)...

So am extremely happy and glad...!! Thank you all... The capacitor was indeed crucial component which we missed from start...!!

I would like to use an electronic interrupter now using Arduino / some similar switching mechanism... Any thots on which FET/MOSFET would fit the bill...

Thank and regards once again
Rahul