Knock Sensor: Description and Operation

GF07.04-P-6030MLK Knock Sensor, Component Description
- refinement package
- as of model year 09

Component Identification:

Location
The knock sensors are located at the top of the cylinder crankcase, in the V-angle of the engine.

Task
The knock sensors detect the vibrations on the cylinder crankcase (combustion knocking) for knock control.

Knocking can also be an indication of engine damage (e.g. increased engine noise by a widened piston groove).

Function
The vibrations on the cylinder crankcase are converted by the inner piezo crystals on the knock sensors into electrical DC signals.
The DC voltage signals are sent directly to the ME-SFI control unit (N3/10) over 2-pin shielded lines.

Component Identification:

Piezo-electric effect: An electrical voltage is generated by the mechanical force on a piezo crystal.