Solar Sensor: Description and Operation

CONTROL SYSTEM INPUT COMPONENTS




Sunload Sensor
The sunload sensor is located on the left defroster grille. It detects sunload entering through the windshield by means of a photo diode and converts it into a current value which is then input to the EATC unit.

Sunload Input Process
The EATC unit includes a processing circuit to "average" variations in detected sunload over a period of time. This prevents drastic swings in the EATC system operation due to small or quick variations in detected sunload.

For example, consider driving along a road bordered by an occasional group of large trees. The sunload detected by the sunload sensor will vary whenever the trees obstruct the sunlight. The processing circuit averages the detected sunload over a period of time. The (insignificant) effect of the trees momentarily obstructing the sunlight does not cause any change in the EATC system operation. On the other hand, shortly after entering a long tunnel, the system will recognize the change in sunload, and the system will react accordingly.