960 L6-3.0L VIN 95 B6304F (1993)
Crankshaft Position/Engine Speed Sensor: Description and Operation
Crankshaft Position And Speed Sensor
PURPOSE
The crankshaft position sensor generates an input signal for the ECU regarding crankshaft position and engine speed.
LOCATION
The sensor is mounted close to the flywheel (2) which is provided with a series of drilled holes or "windows" around the circumference.
CONSTRUCTION (A)
The sensor (1) consists of a permanent magnet (4), a pole tip (5) which concentrates a magnetic field at the end of the device and a coil (6). The
magnet creates a magnetic field which varies in strength depending on whether a hole or "window" is passing the tip.
OPERATION
Voltage is induced in the sensor as each "window" on the flywheel passes the tip. This voltage signal supplies the ECU with a unique electrical
picture from which the ECU can determine both the crankshaft position and speed.
SIGNAL (B)
The frequency (7) of the signal is used to determine the engine speed.
To provide a reference signal for the crankshaft position, one "window" on the flywheel circumference is made longer than the others. The ignition
ECU detects the crankshaft position by sensing the interruption in the signal (8) which occurs as the long "window" passes the sensor (90° BTDC).
This referance is used to determine the top dead center (TDC) position.
