1. TEMPERATURE SENSOR

2. Temperature Sensor
Measures air and liquid temperatures between –40 °C and +130 °C.
For proper amount of fuel injection Commonly used Automotive Temperature Sensors are:
1. Coolant Temperature (ECT) Sensor Intake Air Temperature (IAT) Sensor Exhaust Recirculation Gas Temperature Sensor

4. Engine Coolant Temperature (ECT) Sensor
Usually located just before the thermostat. ● Responds to change in Engine Coolant Temperature. ● Critical to many ECM functions such as fuel injection, ignition timing, variable valve timing, transmission shifting, etc.

5. Intake Air Temperature (IAT) Sensor
●Detects the temperature of the incoming air stream.
●On a cold starts, heats up the incoming air.
●On vehicles equipped with a MAP sensor, the IAT is located in an intake air passage.
● On Mass Air Flow sensor equipped vehicles, the IAT is part it.

6. Exhaust Gas Recirculation (EGR) Temperature Sensor
The EGR Temperature Sensor is located in the EGR passage and measures the temperature of the exhaust gases. ●As the temperature increases, the ECM opens the EGR valve to allow the exhaust gases to flow into the intake manifold.

7. Thermistors
If Thermistors are exposed to external heat, their resistance drops drastically and, provided the supply voltage remains constant, their input current climbs rapidly. This property is utilized for temperature measurement.
●It is possible to measure a wide range of liquid temperatures. ● Thermistors comprised of metal oxides and oxidized mixed crystals. ●This mixture is produced by sintering and pressing with the addition of binding agents.

8. ECT, IAT, & EGR Temperature Sensor Operation:
As the temperature increases, the voltage signal decreases. ●The decrease in the voltage signal is caused by the decrease in resistance. The change in resistance causes the voltage signal to drop. ●When the sensor is cold, the resistance of the sensor is high, and the voltage signal is high. ●As the sensor warms up, the resistance drops and voltage signal decreases. ●From the voltage signal, the ECM can determine the temperature of the coolant, intake air, or exhaust gas temperature

9. PRESSURE SENSOR

10. PRESSURE SENSOR Pressure sensor • Application : Engine management
• Function : Barometric pressure measurement
• Installation : Printed circuit board (PCB)
• Sensing principle : Silicon micromechanics with integrated evaluation circuit
Low-pressure sensors for gaseous media
Application :Engine management
Function Registration of intake-manifold pressure or atmospheric pressure Installation Air-intake tract
Sensing principle: Micromechanics with piezoresistive sensor element (MEMS based)

11. HUMIDITY SENSOR
Sometimes, after rains, the air feels moist. The water seems to have suspended in the air. However, in certain AC’s you click some buttons and the atmosphere brightens up. How and why does it all happen? Moisture forms up in the air, resulting in humidity. However, the humidity sensor in your AC picks it up and cleans it up for you. Isn’t that wonderful? Let’s take a look how it does that.

12. A humidity sensor (or hygrometer) senses, measures and reports both moisture and air temperature. The ratio of moisture in the air to the highest amount of moisture at a particular air temperature is called relative humidity. Relative humidity becomes an important factor, when looking for comfort

13. Humidity sensors work by detecting changes that alter electrical currents or temperature in the air. There are three basic types of humidity sensors: capacitive, resistive and thermal. All three types of sensors monitor minute changes in the atmosphere in order to calculate the humidity in the air.
Capacitive: A capacitive humidity sensor measures relative humidity by placing a thin strip of metal oxide between two electrodes. The metal oxide’s electrical capacity changes with the atmosphere’s relative humidity. Weather, commercial and industries are the major application areas