Modern Engine Sensors

Today, Vehicle engine is Electronically controlled using Engine Control Module (ECM). The ECM receives the input from the engine by using the sensors. There are 8 sensors located inside an Engine:-

1. Oxygen or Exhaust sensor:- Senses the amount of oxygen in the exhaust gases so that the ECM decides the air-fuel ratio.
2. Engine temperature sensor:-Senses the coolant temperature and ECM sends rich mixture if engine is cold (Cold start).
3. Air flow sensor:- Senses mass of air entering for adjusting the quantity of fuel.
4. Air inlet temperature sensor:-Senses the temperature of air entering the intake manifold to estimate the density of air. ECM adjust the amount of fuel, more fuel for cold air (denser) and less fuel for hot air. 
5. Throttle position sensor:-Senses the position of throttle and adjusts the type of air-fuel mixture.
6. Manifold pressure sensor:-Senses the vacuum in the inlet manifold and adjusts the mixture strength
7. Camshaft positions sensor:-Senses the position of cam shaft to adjust the speed and timing of injection.
8. Knock sensor:-Microphone sensor detects pre-ignition noise in order to sense the knocking in the engine. If knocking is sensed, ECM retards the ignition timing.