ZEST BOLT Service Manual

ENGINE 1.3 QUADRAJET (75PS) 9 2 Fig. 179 OPERATION A current-carrying semiconductor layer immersed in a normal magnetic field (force lines at right angles to current direction) generates a potential dif ference known as a Hall voltage at its terminals. If current intensity remains constant, the generated voltage depends on magnetic field intensity alone. Periodic changes in magnetic field intensity are sufficient to generate a modulated electrical signal with frequency proportional to the speed of magnetic field change. To produce this change, a tooth on the inner part of the pulley periodically moves close to the sensor. Fig. 180 PIN_OUT Pin Description Signal type 1 Earth Earth 2 Timing signal Frequency output 3 Power supply 12 V input In the specific case of the timing sensor it receives a 5 Volt power supply from the engine management control unit. All the times the rotor passes in front of the sensor a variation in the actual sensor output volt age is produced through the Hall efect; this variation takes place for the entire duration that the rotor passes in front of the sensor after which the signal returns to the original value (5V). D. PRESSURE RELIEF SENSOR - FOR THE 75 CV VERSION SPECIFICATIONS The supercharging pressure sensor is fitted on the intake manifold and allows int ake pressures up to 1.5 bar to be measured (corresponding to 2.5 bar absolute). The sensitive element comprises a piezoresistive element whose signal is amplified by an electronic circuit built into the sensor . The sensor receives a direct 5 V supply from the electronic control unit and provides an output voltage directly proportional to the supercharging pressure. Fig. 181 10 ms 5 V 3 2 1 1 2 3 (v) 5 4.95 0.04 0 20 250 (kPs)