Different types of sensors in a car and its functions

Team AckodriveJun 6, 2022

Modern cars have become a complex piece of machinery when compared to vehicles a couple of decades ago. A modern-day car comprises several electrical components as mechanical parts are getting replaced or aided by electronic devices. One such crucial electrical component of an automobile is the sensor. In this article, we throw light on different types of sensors in a car and their functions.

Different types of sensors in a car and its functions

What is a car sensor?

A car sensor is an electronic device that monitors various aspects of the vehicle and sends information to the driver or ECU (Electronic Control Unit). In certain situations, the ECU automatically makes adjustments to the particular component based on the information received from the sensor. The below points cover more details about car sensors.

  • Sensors can monitor various aspects of a car, such as its temperature, coolant system, engine, oil pressure, emission levels, vehicle speed, etc.

  • The human sense organs (eyes, nose, mouth, tongue and hands) are the best examples to understand the working principle of sensors. They send signals to the brain, which then makes a decision.

  • Similarly, car sensors send signals to the ECU to make appropriate adjustments or warn the driver.

  • The sensors are constantly monitoring the various aspects of the car from the moment the engine is fired up.

  • In a modern car, the sensors are everywhere, from the engine to the least essential electrical component of the vehicle.

Functions of automotive car sensor

The working principle of a sensor gives you a broad idea of the functions of car sensors. Since there are so many sensors in a car monitoring various systems and working of components, the functions of car sensors are broader than you imagine.

However, the primary function of a sensor remains the same regardless of the aspect it’s monitoring. It sends information about the system it is tracking to the ECU. The data is relayed via predefined algorithms, and based on that, the ECU makes adjustments. If the ECU is unable to make necessary changes, it sends a warning to the driver.

Types of car sensors

The below table denotes different types of sensors in a car and their functions.

Sensor Function
Air-flow sensor It measures the density and volume of the air entering the combustion chamber.
Engine knock sensor It monitors engine knocking and ensures the air-fuel mixture is ignited correctly.
Engine speed sensor It monitors the spinning speed and position of the crankshaft.
Camshaft position sensor It monitors the position and proper timing of the camshaft.
Manifold Absolute Pressure (MAP) sensor Monitors engine load by measuring the difference between the manifold and outside pressure.
Throttle position sensor Monitor the position of the throttle valve.
Voltage sensor It manages the idling speed of the vehicle.
Oxygen sensor It helps to measure the oxygen level present in the exhaust gases.
NOx sensor It measures the Oxides of Nitrogen (NOx) present in the exhaust gases.
Temperature sensor It monitors the engine temperature.
Fuel temperature sensor It monitors the temperature of the fuel entering the engine.
Speed sensor It measures the speed of the wheels.
Parking sensor It recognises any obstacle present in the front or rear of the vehicle.
Rain sensor It detects rain and sends a signal to ECU to activate the wipers.

 Below are more details of the car sensors that are mentioned in the above table.

1. Air-flow sensor

  • It is a type of sensor that measures the volume and density of air entering the engine.

  • It is placed inside the combustion chamber. 

  • It ensures the right amount of air-fuel mixture enters the combustion chamber for optimum performance.

  • Failure of the air-flow sensor can result in engine stalling or more fuel consumption.

2. Engine knock sensor

  • Knocking is a phenomenon where the air-fuel mixture ignites before the spark plugs produce the spark.

  • It reduces engine efficiency, and in the longer run, it can cause damage to the engine components.

  • The engine knock sensor detects knocking by monitoring the air-fuel mixture ignition process.

  • The sensor can warn the driver if there is any fault in the ignition of the air-fuel mixture.

3. Engine speed sensor

  • It is a sensor that monitors the speed and position of the crankshaft.

  • The sensor is fitted to the crankshaft.

  • It detects the crankshaft position and relays the information to the ECU.

  • The ECU then calculates the exact time for fuel injection and activate the spark plugs.

  • If the timing is not correct, the engine loses its efficiency.

  • It is one of the most important sensors in a car.

4. Camshaft position sensor

  • A camshaft controls the inlet and exhaust valves of an engine.

  • The camshaft position sensor monitors the timing of the camshaft so that the air enters the cylinder and burnt gases are sent out of the cylinder at the right time.

  • If the timing is off, it hampers the power output, and in the worst case, it may damage the cylinder.

5. Manifold Absolute Pressure (MAP) Sensor

  • It is a sensor that monitors the engine load.

  • It calculates the difference between the manifold and outside pressure.

  • The MAP sensor ensures that the engine relieves fuel based on the change in pressure.

  • The failure of the MAP sensor may result in high fuel consumption.

6. Throttle position sensor

  • It measures the position of the throttle valve when you press the accelerator pedal.

  • The sensor sends the information to the ECU, which then decides how much air-fuel mixture needs to be sent to the cylinder.

  • A faulty throttle position sensor hampers the power delivery.

7. Voltage sensor

  • The voltage sensor is responsible for managing the vehicle’s idling speed.

  • The sensor also ensures that idling speed is decreased or increased when required.

8. Oxygen sensor

  • As the name suggests, the oxygen or O2 sensor measures the amount of oxygen present in the exhaust gases.

  • Generally, the O2 sensor is located near the exhaust manifold and after the catalytic convertor.

  • The sensor helps determine whether the engine is burning a rich or lean air-fuel mixture.

  • A faulty oxygen sensor can cause high fuel consumption, jerkiness or a problem with idling speed.

9. NOx sensor

  • The NOx sensor monitors the Oxides of Nitrogen (NOx) present in the exhaust gases.

  • There are strict laws in respect to the permissible levels of NOx emission from a vehicle.

  • Hence, the NOx sensor is essential to monitor the emission of harmful gases.

  • The sensor will relay the information to the ECU, which then makes adjustments to the air-fuel mixture to achieve the required NOx levels.

10. Temperature sensor

  • It is a sensor that can monitor the temperature of the engine.

  • Thermal management is crucial for the smooth running of a vehicle. Hence, it is one of the critical sensors in a car.

  • The sensor is also responsible for the efficient functioning of the cooling system.

  • The sensor can also help to warn the diver if the engine is running low on coolant or if the radiator is not working correctly.

Also, read: ACKO Drive Online Car Buying Process

11. Fuel temperature sensor

  • It is a sensor that constantly monitors the fuel temperature to ensure that the fuel consumption is optimum.

  • If the fuel is cold, it takes more time to burn due to its high density. Similarly, if the fuel is warm, it ends up burning too quickly.

  • The fuel temperature sensor ensures that the fuel is supplied to the cylinder at the optimum temperature for the smooth running of the engine.

12. Speed sensor

  • As the name suggests, it monitors the speed of the car’s wheels.

  • A car’s wheels can travel at different speeds when going around a corner or while off-roading.

  • Hence, the speed sensor helps to track the speed of each wheel.

  • The data is sent to the ECU, and it can be utilised by safety features such as traction control, ABS (Anti-Lock Braking System).

  • The speed sensor is crucial, especially for 4x4 vehicles.

13. Parking sensor

  • It is a sensor that recognises any obstacles on the front or rear of the vehicle.

  • The sensor alerts the driver through a beeping sound. As the distance gets closer, the beeping intensifies.

  • It helps the driver to park the vehicle safely.

  • In high-end luxury vehicles, the data from the sensor is used for the autonomous emergency braking system. If the car gets too close to an obstacle, it automatically applies the brakes.

14. Rain sensor

  • It is a sensor that detects rain. It is generally located on the windscreen.

  • The sensor relays the signal to the ECU when it detects droplets of rain on the windscreen.

  • The ECU then activates the windscreen wipers, given the vehicle has an automatic wiper function.

  • The rain sensor acts as a safety device as it automatically activates the windscreen wipers.

Also, read: How to Charge a Car Battery from Another Car?

Advantages and disadvantages of car sensors

Below are the advantages of car sensors.

  • Car sensors make driving an easy task.

  • The sensors can easily detect faulty components in a vehicle.

  • Sensors ensure that the engine is maintained correctly.

  • Sensors also enable automatic control of specific functions such as windscreen wipers, headlights, etc.

  • The ECU can make precise adjustments with the information received from sensors.

  • Sensors can also relay warning information to the driver if there is any fault/malfunction with the car’s components.

Here are some of the disadvantages of car sensors.

  • One major disadvantage of having so many sensors on board is that they can fail over time.

  • A faulty sensor can lead to damage to vital components of the vehicle. Getting them repaired or replaced can be an expensive affair.

Frequently asked questions

Here are some of the most common queries and their answers related to car sensors.

How many sensors does a car have?

The car engine alone has around 15 to 30 sensors that track all functions of the engine. In total, a car can have over 70 sensors that monitor various aspects of the vehicle.

Do all types of cars have sensors?

Yes, all types of cars have sensors. From a small hatchback to a large SUV (Sports Utility Vehicle), all vehicles come equipped with sensors for the efficient functioning of the engine and other components.

What happens if the oxygen sensor is not working correctly?

If the oxygen sensor is at fault, the ECU will not get the information regarding the air-fuel mixture ratio that is supplied to the engine. It can also cause idling problems, jerkiness or issues with power delivery.

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