All vehicles manufactured today come with a variety types of vehicles sensors installed.
Automotive sensors keep track of almost everything happening in and outside a vehicle, allowing the onboard computers to make decisions. The decisions help to:
- Improve engine performance
- Reduce emissions
- Bring about convenience
- Enhance driving comfort
- Improve safety, and a lot more benefits.
The technologies in car sensor applications keep changing.
With the development of nano electromechanical systems, NEMS, for advanced driver assistance systems (ADAS), adaptive cruise control (ACC), and other systems, vehicles are becoming safer and more convenient to drive.
We compiled a list of 15 most common and essential automotive sensor types used in modern automobiles.
1. Automotive Radar Sensors
The ability to improve drivability and safety in today’s cars is amazing.
Automotive radar applications include warning or mitigating collisions, as parking aids, and lane change assist, among other uses.
Compared to visual sensors, radar technology offers a lot more information, which means higher resolutions.
Radar sensors are also not affected by weather, making them more reliable than other options.
Automotive radar sensors are part of Advanced Driver Assistance Systems, ADAs or Adaptive Cruise Control Systems, ACCs, of today’s automobiles. In autonomous vehicles, these sensors detect objects to avoid collisions.
2. Automotive Lidar Sensors
LiDAR is an acronym for Light Detection and Ranging.
It’s a sensing technology that’s increasingly being used in automobiles, especially autonomous cars.
Automotive Lidar sensors use a rotating beam of laser light. Using the light that’s reflected by objects and barriers, a vehicle is able to detect things within the area around it.
Lidar sensors are used by conventional vehicles to enhance safety through systems such as Anti-lock Brake System (ABS).
Most Automated MEMS sensors used in Adaptive Cruise Control (ACC), and Emergency Brake Assist, and lane change use this technology.
information obtained from Lidar sensors can be combined with the radar sensor signals to produce a better representation of the vehicle’s surroundings.
3. Automotive Oxygen Sensors
Among the different types of sensors used in cars is the oxygen sensor.
These measure the levels of oxygen gas in a vehicle’s exhaust system.
Using the proportion values transmitted by the sensor, the car computer calculates the amount of fuel and air needed to achieve the “perfect ratio” for efficient combustion.
Apart from ensuring proper engine performance, the oxygen sensor also ensures the catalytic converter is working optimally, thereby controlling emissions.
The oxygen sensor outputs a voltage that depends on the difference in the amount if oxygen in the exhaust gases and the atmosphere.
A low voltage of about 200 millivolts indicates a lean mixture, while a voltage spike to about 800 millivolts shows the fuel is burning rich.
A voltage midway between the high and low values means optimal fuel-air ratios.
4. Automotive Pressure Sensors
These sensors measure pressure and convert it into a voltage signal.
The electrical voltage then changes according to pressure variations.
Using the electric signals, the computer works actuators and other systems.
Car pressure sensor applications range from braking, window and door closing systems, exhaust to engine and steering systems.
Other applications of the pressure sensors used in cars include detecting pedal pressure to amplify braking force, at the exhaust to ensure clean exhaust filter and optimally performing catalytic converter, and in electric doors to detect obstruction such as a hand caught in a closing door.
The sensors are also used to detect impacts in airbag deployment systems.
Pressure sensors check the pressures of critical liquids and gases. These include engine oil, transmission and hydraulic oil, coolant, and fuel line pressures.
But one of the most important applications of these sensors is in optimising the fuel mixture to be in line with the air pressure.
The sensor for this purpose is called the manifold absolute pressure, MAP, sensor. It helps determine that right amount of air for optimal and smooth running of the engine.
5. Automotive Ultrasonic Sensors
These are mostly used as parking assists, helping to park a vehicle safely and conveniently.
Ultrasonic sensors work by emitting high-frequency sound pulses.
These are reflected by the objects near the car. The computer uses the time it takes for the pulses to bounce back to compute the distance between the car and the object.
This helps to determine the safest parking distance.
The frequency levels of the sound produced by ultrasonic automotive sensors is way above the hearing range of the human ear.
That means the sound remains inaudible, and can only be picked by the sensor and its computer. The history of these sensors is a long one.
Initially used to help the driver park safely, the ultrasonic sensor in the modern vehicle has advanced to help cars park automatically.
6. Automotive Temperature Sensors
Motor vehicles come with different types of temperature sensors.
These can be contact or non-contact depending on the application.
Although temperature sensors in automobiles are many and varied, two types stand out from the rest for being essential to engine performance. They are the fuel and air temperature sensors.
A car fuel temperature sensor monitors how hot or cold the fuel going to the engine is.
Warm fuel burns faster, which means a more efficient engine.
Cold fuel is denser and doesn’t combust as efficiently.
The intake air temperature sensor, IAT, measures the temperature of the air entering the engine.
The engine ECU uses the information to determine the density of the air and computes the right air-fuel mixture required.
7. Automotive Proximity Sensors
Vehicle proximity sensors are among the sensors used in cars for safety.
They warn the driver when the car is about to hit a wall, curb, or an object.
Unlike the sonic sensors described here that send sound waves, the proximity sensors we are referring to here emit electromagnetic waves.
The sensors relay the signals produced by the waves to the computer, which then maps out the area close to the vehicle.
You will find proximity sensors on the front bumper of a car as well as the rear.
They help to avoid collisions with barriers and objects when the car is in forward motion. When reversing, the sensors help the driver to avoid hitting things that cannot be seen from the side mirrors.
8. Automotive Rain Sensors
As the name suggests, rain sensors are just that- devices that detect rain.
These sensors send signals to the ECU when raindrops fall on the windscreen.
The computer then activates the windscreen wipers automatically.
Because everything happens without the driver’s input, rain sensors are safety devices that ensure the driver can see ahead even when the weather changes abruptly.
Most automotive rain sensors use total internal reflection to work.
A beam of infrared light continually hits the windscreen at 45°.
The sensor monitors the intensity of the reflected light. When the windscreen gets wet, the amount of reflected light diminishes. This sends a signal to the computer.
9. Automotive Current Sensors
Vehicles use electric power systems for almost every operation, from starting the engine, running various accessories, to working different actuators.
To optimize the systems, electric sensors are used.
These measure the current flowing through the electric pathways and devices, sending the signals to the computer which then prevents power wastage or failure.
Automotive current sensors use different technologies to work.
They can be direct or indirect sensors, with each having its advantages and disadvantages when used for different applications.
They’re the devices that monitor the output and condition of the battery, and known as car battery sensors.
Hall effect sensors are one of the most common current sensing devices used in automobiles.
10. Automotive Image Sensors
These sensors are used in vehicles with advanced systems such as advanced driver assistance system (ADAS), lane departure assist, adaptive cruise control ((ACC), blind spot and lane departure capabilities among other smart systems.
Image sensors take real images of scenes around the vehicle which enables a driver to monitor surroundings with greater accuracy.
These sensors are increasingly finding use in mainstream motor vehicles. But autonomous cars are also set to be the biggest beneficiaries in the coming years.
11. Automotive Speed Sensors
Car speed sensors help relevant ECUs to compute various functions to ensure proper performance of the car.
These include determining transmission shifts, the right air-fuel mixture ratios, and to time different operations in the engine.
Speed sensors in automobiles can be found in drive shafts, where they detect the speed of rotation as well as position.
In vehicles with anti-lock brake assistance capabilities, speed sensors are placed at every wheel to measure the rotational speed.
The computer uses these signals to operate the braking system that prevents skidding and other safety issues. Examples of sensors in this category include crankshaft and wheel speed sensing devices.
12. Automotive Parking Sensors
The modern car uses different parking technologies to make the task easy and safe.
Parking sensors can be acoustic signals, electromagnetic waves, or even real images.
Acoustic parking sensors are ultrasonic devices that use the sound reflected by things to sense barriers.
Electromagnetic parking sensors are radar devices that use pulses that bounce off objects to detect what’s within a vehicle’s vicinity.
Images sensors are cameras that help to relay pictures of the area near a vehicle. They can be used in both mainstream and autonomous cars.
13. Automotive Humidity Sensors
Automotive humidity sensors usually combine two different sensors in one device- one to measure moisture levels and another temperature.
Values for the two measurements are sent to the climate control computer which then activates the auto HVAC to regulate the interior of a vehicle.
Humidity sensors help to keep the inside of a car comfortable by adjusting humidity levels.
They also prevent misting of the windows by continually monitoring the amount of moisture in the car as well as window temperature.
14. Automotive Backup Sensors
Backup sensors are essentially a type of proximity sensors but which only scan the rear of a vehicle.
Usually mounted on the bumper, these types of sensors help to detect obstacles when parking.
Most backup sensors are sonic devices. That means they use the sound that bounces off things to create a picture of the rear area.
The installation kits of backup sensors usually consist of the sensor itself, control box, and often a display to show the scanned area.
Using the display, and a driver is able to reverse safely without much reliance on the side mirrors, especially when parking a vehicle.
15. Automotive Reverse Sensors
These are usually installed on the rear of a vehicle.
Reverse sensors help to alert the driver of objects behind the car, increasing safety when reversing.
A majority of these sensors emit sonic waves, while some are image sensors.
Reverse sensors that use sonic beams send signals of reflected waves as well as changes in the wave spectrum to the computer. The computer analyzes the information and determines the distance and size of the objects behind the vehicle.
Today’s motor vehicles use many different sensing devices, with each sensor serving a useful purpose.
Their number keeps increasing, too. And with the invention of the micro electromechanical systems, MEMS, automotive sensor technology has gotten even better and more sophisticated.
The automobile of the coming years will likely have several hundred sensors transmitting information to powerful ECUs and making the cars more efficient and safer to drive.