Understanding Dwell Time in Electronic Ignition Systems

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Discussion Overview

The discussion focuses on the concept of dwell time in electronic ignition systems, specifically in the context of non-contact breaker points systems. Participants seek to clarify the definition and implications of dwell time related to ignition coils and spark plugs.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant defines dwell time as the duration the ignition coil delivers power to the spark plug, suggesting a balance between charge time and dwell.
  • Another participant refines this definition, stating that dwell time specifically refers to the time the ignition coil's primary circuit has current flowing through it, particularly in points ignition systems.
  • This participant also notes that current is only sent to the spark plug when the points open, indicating that insufficient dwell time can lead to inadequate energy storage in the ignition coil.
  • A later reply acknowledges the correction and expresses understanding of the clarified definition.

Areas of Agreement / Disagreement

Participants exhibit some agreement on the general concept of dwell time, but there is a disagreement regarding the specifics of its definition and implications, particularly between the initial and refined explanations.

Contextual Notes

The discussion highlights potential confusion regarding the definitions and roles of dwell time in different ignition systems, as well as the implications of varying dwell times on ignition performance.

Andy
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Hey people, been getting very annoyed for the past few hours over this one been looking through all my textbooks and all over the net but can't find a decent explanation of dwell time. Here's my question, Explain dwell time in the context of electronic ignition systems (non-contact breaker points system)

Need help asap before i smash this keyboard through the monitor.

Aploagies for posting it twice but i really need help quickly.
 
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The basic definition I know of is that dwell is the time that the ignition coil is delivering the power to the spark plug. It's always a balance between charge time for the coil and the dwell. I know this is pretty general, so if you were looking for anything more specific, let us know.
 
Nope that's good, that's pretty much exactly what i just managed to find after many hours of looking. Thank you.

Don't you just hate the internet for providing very vague answers to whatever it is that you looking for?
 
FredGarvin said:
The basic definition I know of is that dwell is the time that the ignition coil is delivering the power to the spark plug.
That's not correct. The dwell time is the amount of time the ignition coil primary has current running through it. So in a points ignition system, it is the amount of time the points are closed. There is only current sent to the spark plug when the points open. So if the dwell time is too short, the current in the primary coils of the ignition coil has not been able to build up far enough so there is not enough magnetic energy stored in the coil to give a good spark.
 
I stand corrected.
 

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