Expo LRV AWD L4-1834cc 1.8L SOHC 16 Valve (1992)
Camshaft Position Sensor: Description and Operation
Distributor Exploded View
SENSOR OPERATION
The Crank Angle Sensor and the Top Dead Center Sensor are located within the distributor housing. These sensors are incorporated into one unit,
being a disc and a pick-up unit. The disc is affixed to the distributor shaft and the light-transmitting unit is mounted stationary to the distributor
housing.
Crank Angle And #1 TDC Sensor
The disc contains 4 large slits around its circumference to indicate the crankshaft angle. An additional light-transmission slit located inward from
the edge is used to indicate number one cylinder's top dead center position.
The pick-up unit assembly uses two luminous diodes and two photo diodes, in order to detect the two different slits. There is a very slight
clearance between the luminous diodes and the photo diodes, and the disc rotates within this space.
As the distributor shaft rotates the slits at the discs edge pass between the light and the optical reading part of the unit. The light emitted from the
luminous diodes pass through the slits to the photo sensing diodes. When the photo diodes receive the light, they become conductive and generate
a signal, which is sent to the Control Unit.
