Absolute pressure sensor

ABSOLUTE PRESSURE SENSOR

WEBER PRT 03

The sensitive element is enclosed within a plastic container (1) and consists of a Wheatstone sridge screen printed to a very fine circular ceramic plate (diaphragm) fitted to the underside of a ring mount. The diaphragm separates two chambers: a vacuum is set up in the bottom sealed chamber while the top chamber communicates with the intake manifold indirectly through a rubber pipe (3). When the engine is off, the diaphragm bends according to atmospheric pressure level. Exact information on altitude is therefore provided when the key is inserted. When running, the engine sets up a vacuum that gives rise to a mechanical effect on the sensor diaphragm, which bends to alter the resistance level. Because the electrical supply is maintained constant (5 V) by the control unit, when the resistance is altered, the output voltage changes in proportion to the vacuum in the intake manifold.

Recovery

The pressure is calculated according to throttle angle and rpm level. If the butterfly valve position sensor is faulty, a fixed calibration value is assigned. Mixture self-adaption is inhibited. Lambda probe test is inhibited.

Wiring connector

The numbers in boxes indicate the corresponding control unit pins