ION SENSOR [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5]
id0140g5004400
Purpose/Function
• Detects ion generation in the combustion chamber for detecting pre-ignition.
• Detects ions, which occur due to fuel combustion as current, by applying bias voltage to the spark plug, which is amplified in the ignition coil internal circuit and sent to the PCM.
Construction
• Built into the ignition coil.
Operation
• Accumulates the secondary current of the ignition coil in the ion detection circuit (1), and detects ion current (2) by applying the voltage to the spark plug.
• Because the detected ion current is a very small current, it is amplified in the ion detection circuit (1) and sent to the PCM (3).
• After the spark plug discharges, voltage is applied to the center electrode and ion current generated inside the cylinder from the beginning to the completion of a combustion is detected.
• Generation of ion current varies depending on the combustion process. Because it varies similar to the combustion/pressure inside the cylinder, an abnormal condition is determined if ion current is generated except during a normal combustion.
Ion generation mechanism
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• Ions are generated based on: fuel combustion = chemical reaction / disassociation. The generated negative ions move to the center electrode of the spark plug to which bias voltage is applied, and positive ions move to the grounded engine wall surface, then current flows from the spark plug to the ignition coil.
Fail-safe
• Function not equipped.
