 In this video, we will see about all the sensors used in modern cars. Most modern car engines are fitted with an array of different sensors, which gather data to calculate a perfect air-fuel mixture for the best fuel economy and best performance in all situations. Sensors are classified into three categories. Sensors for engine control, sensors for body control, and sensors for other components such as brakes, suspension and transmission. The engine control unit, or ECU receives information from various sensors on the engine, compares that information to predetermined programming decided on by the manufacturer, and then sends out ports to the spark plugs, fuel injectors and other components to allow the engine to run as effectively as possible. The first important sensor is crank position sensor. The crank position sensor is usually located in the crank case over the toothed wheel on the crankshaft. It monitors piston's TDC position in the engine, and also measures the rotation speed of the crankshaft. It counts the number of teeth on the crankshaft, sending this value to the ECU, where it finds the position of crankshaft and pistons. The rate of positional change is used to calculate the engine's rotational speed. Number two. Now let us see about cam position sensor. The cam position sensor is typically located in the cylinder head of the engine. The task of the cam sensor is to find the exact position of the cam shaft and valves. It works together with crank sensor for perfect ignition timing. If these sensors fails, starting of engine is not possible. Number three. The mass airflow sensor. The mass airflow sensor is located between the air filter and the engine's intake manifold. It is used to calculate the amount of air that enters the engine during the intake stroke. The measuring of air helps the ECU to determine how much fuel must be added for perfect air and fuel mixture to get better results. Number four. The manifold absolute pressure sensor or the map sensor is a device situated in the intake manifold and is used to calculate the pressure of air going to the engine. It is very similar to mass airflow sensor, which measures mass flow of air and map sensor measures the pressure of air. The higher the pressure, the higher will be the mass of air and hence more fuel can be used. This sensor helps the ECU in determining the amount of air and fuel that has to be sent to the engine. Number five. The knock sensor. Commonly the knock sensor is located outside the engine block. The term knocking means the ignition occurred even before the actual time. This creates the high vibration and high sound in engine. The knock sensor identifies the high frequency engine vibration of knocking and transmits a signal to the ECU. When the ECU receives an electric signal, the ECU retards the ignition timing and stops the occurrence of knocking inside the engine. This improves economy and power of an engine. Number six. Coolant temperature sensor. A car engine produces a lot of heat when it is running and must be cooled continuously to avoid engine damage. Generally this is done by circulating coolant liquid through passages to the radiator. Radiator contains thin metal fins, which gives more contact area to the radiator to open air in the atmosphere. And also radiator holds an electric fan which transfers the heat from radiator to atmosphere. The coolant in radiator cools down and sent back to engine and this process repeats. The coolant temperature sensor is located in between the engine and radiator passages. This coolant temperature sensor monitors the temperature of liquid coolant and sends the signal to ECU. The ECU uses this reading to calculate the coolant temperature and from there it adjusts the fuel injection and ignition timing and controls when the electric cooling fan is switched on and off. This information is also used to send an accurate reading of the engine temperature to a gauge on the dashboard. Number seven. Fuel temperature sensor. This measures the fuel's temperature and transmits the signal to the ECU. When the fuel is warm it's less dense and burns more readily so the ECU injects more fuel. When the fuel is cold it's more dense so the ECU injects less fuel. This optimizes engine's performance. Some brands place this sensor on send a unit which is located inside the fuel tank or in some other brands it is located on high pressure pump attached to the engine. Number eight. Crash sensor for airbag. The airbag system is one of the most important components in your vehicle's safety system. Crash sensors are small pieces of electronics, a design to tell when the vehicle has been damaged in an accident. The sensor signals to the airbag control unit within milliseconds after collision. When the control unit determines there is an accident it sends a signal to the inflator system. The inflator immediately fill up the airbag. This all happens in an instant usually within 25 to 50 milliseconds. This airbag provides a cushioning system for the people in the car and save lives. Crash sensor is located in front side of the car behind the bumper and also inside the side pillars or doors of vehicle's body. Number nine. We speed sensor for anti-lock braking system. In this system the brakes are applied and released numerous times in one second and hence the system ensures that the wheels do not lock up under hard braking. The vehicle slows down while maintaining its grip and the available traction allows the driver to give steering inputs. This helps the driver steer the vehicle to avoid an accident. The advanced anti-locking braking system offers significant benefits over normal brakes. In a vehicle, wheel speed sensors are located on all the wheels that monitor the speed of each wheel. The ECU reads the signal from each sensor. After the speed sensors detect the speed of any of the wheel is reducing drastically compared to others, the ECU sends the signal to the valves of the respective wheel to reduce the brake pressure and the valves get closed. After this, the wheels start to accelerate again and the signal is sent to the ECU one more time, which in turn sends the signal to open the valve and increase the brake pressure and hence, brakes are applied. The cycle repeats itself until the application of brakes becomes normal. Number 10. Parking sensors. Parking sensors are proximity sensors for vehicles designed to alert the driver of obstacles while parking. It is located in back bumper and also in front bumper of some vehicles. These sensors work either on ultrasonic or electromagnetic principle. When the driver engages reverse gear, rear parking sensors get activated automatically and send ultrasonic waves. When these waves hit the nearby object, they get reflected and are captured again by the sensors. This process measures the distance between the sensor and object. This indicates the driver about the distance between vehicle and object with visual indication and sound in dashboard for safe parking. Number 11. Rain wiping sensor. The rain sensor is located on the upper end of the windshield glass, senses the amount of rainfall and controls the wiping cycle for the proper interval. It sends out a beam of infrared light. When water droplets are on the windshield, the light is reflected back at different angles. This tells the system to activate the wipers as well as adjust wiper speed and frequency based on the intensity of the precipitation combined with the vehicle's speed. The more it rains, the faster the wiper operates automatically. Now, we completed discussing about commonly used sensors of the car. Thank you for watching.