Author Topic: Ignition coil dwell & firing time  (Read 6682 times)

Skim

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Ignition coil dwell & firing time
« on: July 24, 2024, 07:03:03 PM »
Not really GS-911 related, but trust I can post. Need sanity check on calculations. Away from home today. Wanted to check an ignition coil. R1200, random misfire at times. Normally check with Picoscope. Today only had Hantek 1008 and small coil that I could use to see a bit of the induced ignition waveform. Got a crude waveform but dwell and fire time visible. Then only noted that the Hantek software suggests that the duration of the above is a few microseconds. See photo.  Somehow I was under impression that it should be a few millseconds, not microseconds?
My sanity check calculations below. Please help and TIA.

                                                                                                       Val   Unit
RPM @ idle                                                                                    1200   RPMin
Seconds per minute                                                                               60   Seconds
Thus : Revs per second                                                                       20   RPSec
Thus : Seconds per Revolution                                                    0,05   Seconds
One crank rotation (Degrees)                                                             360   Degrees
Assume dwell and Ignition duration degrees rotation                       55   Degrees
Calculated duration                                                              0,007638889   Seconds
Thus ; Approx Total Dwell & Burn Milliseconds duration       7,638888889   milli seconds


https://imgur.com/a/KhLVlUP
« Last Edit: July 24, 2024, 09:12:17 PM by Skim »