Fun with spark plugs

The chamber is half inch thick aluminum. 




Site window is half inch thick Lexan.



I will need to make a little screen room for it to get some video.  Otherwise I am afraid it will damage the camera. 

Just using air.   It's very interesting to watch the spark as the pressure increases.   With the vent open, things are normal like what you see if you had your plug next to the motor.  As the pressure increases, the light starts to almost glow.  The plugs have a glowing ring around them.   As the pressure continues to rise things go bad and the plugs no longer have a controlled spark.    By this time the PC's USB bus has failed and the speakers play music that only the Gods understand. 

After playing with this, I wonder with any multi-spark ignition, it the flame did go out the pressure would be through the roof and could the flame really be restarted with the next spark.   

Edited by geek - 05 October 2009 at 2:09am

Purdy smart too!

That's a great depiction of how increasing boost pressure (which of course ramps up cylinder pressure) can affect spark capability.  I don't think enough folks understand this in sufficient detail.  Should you ever video this, please allow me to host it on my site as a lesson in spark performance under boost!

Actually, this type of fixture has been used for ignition research, examination and testing for decades in both automotive and motorcycle systems. Very fun to watch and see how cylinder pressure effects ignition output. Even the sound is distinct. One work of caution: Even with Lexan, wear eye protection!

Originally posted by lnelson Actually, this type of fixture has been used for ignition research, examination and testing for decades in both automotive and motorcycle systems. Very fun to watch and see how cylinder pressure effects ignition output. Even the sound is distinct. One work of caution: Even with Lexan, wear eye protection!

Stuffed all the high voltage parts into a screened box and attempted to get a video.    The camera was outside the screen and maybe 4" away from the window.  RF still gave the camera fits.   That's not the plugs or pumps you hear getting louder, it's the camera freaking out.  

Video is pretty boring to watch and you may doze off.   If you drink some coffee and then stare at the screen you will see some pretty big flashes from time to time. 

The chamber is vented at the start and then pressure  was increased during the entire video.  So larger flashes and more camera problems towards the end.   

http://www.youtube.com/watch?v=RC4fNnzNzNY

This is the first video I made showing the signal generator in action....
http://www.youtube.com/watch?v=CPkK509pRMo

If you have a slow connection, or don't want to stay up and watch the video, this is one
of the flashes caught on tape.  There are 2 plugs. The bottom one is pretty normal but notice the ring.    When the chamber is vented, things are pretty much black. 




Edited by geek - 05 October 2009 at 10:22pm

How much presure are you running up to?

Originally posted by PM720 How much presure are you running up to?   Scott

For the video I was running about 200 PSIG from the pumps with 0.035 gaps. 

I plan to run higher pressures with a more normal gap but need to make a few changes first.  The pressure gauge I had was only good for 200.   I will drop by the salvage yard this week and see what I can find.     The split lens clamps are not made for this and I doubt they would handle much higher pressures.   The first aluminum clamp I used split.    Was not even exciting when it let loose.  Just a pop.

I have not attempted to determine the pressure yet for my motor.  Then there is the whole problem that I am using air for my gas. 

I figure with all that blacklist posting, it's time to get people thinking about something besides screwing or worry about how they will be screwed. 



So I was looking around the internet for some information about mechanical stuff.  Not being a mechanical type, I have a simple question about running air pumps in series.  I saw lots of posts on the topic that all matched so I assumed people knew what they were posting and not just repeating what they had read on the internet.  Besides it sounded right. 

You could think of this question as a turbo driving a motor but for starts say two piston type pumps. 

For a matched set of pumps, does the pressure add when they are in series and flow doubles when they are in parallel?   Cause this is what I see all over the net.   But, it's not what I see on the bench.  

Both pumps have the same part number.   The pump 1 has a dead head pressure of 34 PSI.  Pump 2 , 42 PSI.    When I drive pump 2 with pump 1, I don't get 76 PSI.  Not even close.   What I read is 140 PSI.    

If I think of it in electrical terms,  each pump is an amplifier with gain.    It would seem that we really changed the atmospheric pressure that pump 2 sees.    So if one ATM is 14.7 and pump 1 is putting out 34 PSI.   That's 34/14.7 or 2.3139 higher atmospheres.   Now if we take 2.3129 X 42PSI we would have 97.14 PSI gain, plus the dead head of 42PSI, or 139 PSI.     This seems right to me and matches what I see.  I ran a few different pressures and it seems to work but does fly in the face of all the posts I saw on the internet.

Yea, I am sure its a lot more complex, being a compressible gas but I wonder if this is right for a ball park?

Originally posted by geek I figure with all that blacklist posting, it's time to get people thinking about something besides screwing or worry about how they will be screwed.