explanations related to combustion and spark plug function- Pt1

 


The image provides illustrations and explanations related to combustion and spark plug function:

Key Points:

  1. Normal Combustion vs. Detonation:

    • Normal Combustion:
      • Cylinder pressure peaks slightly after TDC (Top Dead Center), aligning with the power stroke.
      • The pressure curve is smooth and controlled.
    • Detonation ("Knock-Ping"):
      • Pressure spikes abruptly before TDC due to uncontrolled explosion of the fuel-air mixture.
      • Results in hammer-like impacts that can damage engine components.
      • Audible as knocking or pinging; immediate action is required to prevent engine damage.

  2. Action on Detonation:

    • Stop using the engine if detonation occurs.
    • Identify and fix the issue to prevent damage (e.g., adjust timing, check fuel quality, or inspect the spark plug).

  3. Spark Plug Fouling:

    • Normal Spark Plug:
      • Current jumps across the gap, creating a spark that ignites the mixture.
    • Fouled Spark Plug:
      • Fouling on the insulator allows the current to short-circuit to the metal shell, preventing a spark.
      • This results in misfiring or no combustion in the affected cylinder.


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