Sensors

Sensors

ENGINE COOLANT TEMPERATURE SENSOR

This sensor is fitted on the thermostat and detects the temperature of the engine coolant by means of an NTC thermistor with a negative resistance coefficient.

The sensor is produced using semiconductor technology, therefore if the temperature of the sensor element increases as the temperature of the coolant increases, the resistance value decreases as a result.

As the variation in the resistance is not linear, the same increase in temperature is greater at lower temperatures than at higher temperatures.

1. NTC resistance
2. Sensor body
3. Electrical connector

FUEL TEMPERATURE SENSOR

This sensor is fitted on the return manifold and detects the temperature of the fuel through an NTC thermistor which has a negative resistance coefficient.

For the operation of the sensor, refer to the previous description dealing with the coolant temperature sensor.

FUEL PRESSURE SENSOR

This sensor is fitted in the centre of the fuel supply manifold (rail) and has the task of supplying the injection control unit with a return ("feed-back") signal for:

• regulating the injection pressure;
• regulating the duration of the injection.