Hall Effect Sensor: Description and Operation

Profile Ignition Pickup:

PURPOSE
The Hall effect sensor creates Profile Ignition Pickup (PIP) signal and indicates crankshaft position and engine rpm. The PIP signal is fed to both the Thick Film Integrated (TFI) module and the Electronic Control Assembly (ECA).

LOCATION
Internal components of the distributor.

CONSTRUCTION
The Hall sensor includes:

^ The stationary Hall effect device is made up of:

- a voltage regulator

- a Hall voltage generator (signal generator)

- Darlington amplifier (signal inverter)

- Schmitt trigger (digital signal shaper)

- and an open collector output stage integrated in a single monolithic silicon chip.

^ a stationary magnet

^ a signature PIP rotary vane cup; one of the tabs is narrower than the others.


OPERATION

PIP Signal Operation:

The Hall effect is a process in which current is passed in one direction through a slice of semiconductor material. By passing a magnetic field through this same semiconductor, a small change in voltage is produced in the output device.

The magnetic field stays strong and the voltage is high when one of the vane openings is in the gap between the Hall device and the permanent magnet. In this case the switch is OFF and the Hall Effect does not send a signal. When the TAB enters the gap, the armature cuts off the magnetic path to the Hall device and its voltage drops. In this case the switch is ON and the Hall Effect device sends a signal.

Signature PIP:

When the ECA reconizes the narrow tab of the signature PIP rotary vane cup it identifies number 1 cylinder at 10° BTDC. The width of the PIP signal generated by this tooth is smaller than that of the other teeth.

The signal can also be used by the TFI-IV module if the Spark Output (SPOUT) signal from the ECA is lost.