Knock sensor (178), Simtec
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Knock sensor (178), Simtec
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Knock sensor (178)
Screwed to engine cylinder block between cyl. 2 and 3 on rear of engine.
Informs ECM on engine knocking.
Piezoelectric, acoustic sensor.
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Pin No.
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Signal type
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Description
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1
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Signal
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High-ohm signal
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2
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Signal
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High-ohm signal
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3
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Ground
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Sensor's ground
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The sensor listens to the working sound of the engine and converters it to electrical signals. ECM processes these signals via band pass filtering to differentiate the characteristic sounds made when the engine knocks. ECM listens in so-called "windows", i.e. for a certain number of crankshaft angles to differentiate knocks from normal (mechanical) background noises made while the engine is running. Knock control is individual to each cylinder and consists of retardation and fuel enrichment.
