Modern vehicles are complex pieces of technology that are equipped with a lot of systems in order for us to drive in a safe, comfortable and powerful way. Among the numerous system, we can find sensor systems that are used to monitor different sensing features in order to evaluate our interaction with the environments and decide the best way to act.
These sensors are mainly small devices with one or more sensing interfaces that are mounted on different parts of the vehicle and work non-stop in order to give a real-time status to different electronic control unit (ECUs) located in different places of the vehicle. These ECUs process the information given by the sensors and control the systems in order to run them in the best way.
This article will briefly explain the importance of many types of sensors that are widely employed in recent vehicle systems, and will give a brief comment on them.
1. Understanding Vehicle Sensors: The Basics
What Are Sensors?
Sensors are devices that detect and measure physical properties, such as temperature, pressure, speed and position. For instance, a vehicle is outfitted with sensors that convert measurements into electrical signals, which can then be read and processed by the vehicle’s ECUs. Without these sensors constantly taking measurements, the vehicle would not be able to adjust to changing conditions, operate at optimal levels, or notify the driver when safety is at risk.
Types of Sensors
Our modern car have a huge number of different-purpose sensors: some are responsible for engine operating, and some are related to the exterior of the car, such as the steering wheel. In general we have:
Engine Sensors: Monitor parameters like air-fuel ratio, engine temperature, and exhaust emissions.
Safety Sensors: Pick up potential danger and trigger airbags, anti-lock brakes (ABS) and stability control.
Comfort and Convenience Sensors: ‘Manage vehicular systems, such as climate control, auto wipers, and park assistance.
ADAS Sensors: Allows for features such as lane-keeping assist, adaptive cruise control and collision avoidance.
2. Engine Sensors: Optimizing Performance and Efficiency
Oxygen Sensors (O2 Sensors)
These oxygen sensors are another important factor in obtaining the optimal mixing of air with fuel in the engine. Oxygen sensors are situated in the exhaust system, and they measure the concentration or the amount of oxygen in the exhaust gases; the ECU uses this information to boost or reduce fuel injection and ignition timing accordingly.
If the oxygen sensor stops working, you will use more fuel, produce unburnt hydrocarbons and waste oxygen. Regularly checking and replacing faulty O2 sensors is essential to be certain that the engine is working efficiently and therefore you can drive with an eco-friendly car.
Mass Airflow Sensors (MAF Sensors)
The mass airflow sensor serves to measure the amount of air being sucked into the engine. This is just one of the numerous parameters the ECU needs in order to calculate the correct quantity of fuel to inject for the air-fuel mixture with the optimal ratio for combustion.
If the MAF sensor is dirty or faulty, the engine will run on too much air or too much fuel, which affects how the ECM adjsuts the air and fuel. This can result in poor acceleration, rough idling, even reduced fuel economy, so cleaning or replacing the MAF sensor will keep things running smoothly.
Knock Sensors
Knock sensors is what’s responsible for detecting the engine knock. Engine knock is known for causing the air-fuel mixture in the cylinder to explosively ignite prematurely, which ultimately leads to unnecessary wear that could eventually burn out the engine if not corrected. Once the knock sensor notifies the ECU (engine’s computer) that there’s a knock occurring, it goes ahead to adjust the vehicle’s ignition timing so as to avoid knocking.
Knock sensor accuracy creates a feedback effect that keeps the engine running strong, makes it run as efficiently as possible, and protects the whole monstrous system from any potential damage.
Coolant Temperature Sensors
Another sensor that measures the temperature of something else is the coolant temperature sensor. This sensor measures the engine’s coolant (Antifreeze) temperature and sends the data to the ECU. The ECU uses this data to ensure the cooling system temperature is right. The cooling system prevents the engine overheating and keeps it at a temperature that helps it function at its best over the long term.
If a faulty coolant temperature sensor reports too high a reading, a car might overheat, therefore decreasing performance and causing considerable damage; likewise, if it reports too low a reading, the engine might run too cold, which will also lower performance and fuel efficiency.
3. Safety Sensors: Protecting the Driver and Passengers
Airbag Sensors
Examples of sensors that are common in many applications include airbag sensors for detecting a collision so that it can deploy airbags in a crash within milliseconds, protecting the occupants of a vehicle. In this application, sensors monitor the rate of deceleration (the sudden stopping of the vehicle) or the impact forces (these are forces that act upon and stop the vehicle), and subsequently actuate the deployment of airbags.
Modern vehicles are often fitted with multiple airbag sensors, namely front, side and rear impact sensors, in order to enable the vehicle to react simultaneously to multiple types of collisions.
Anti-lock Braking System (ABS) Sensors
ABS (antilock brake system) sensors monitor the wheel speed and prevent the wheel from locking up at maximum braking. Consequently, by modulating brake pressure, the ABS extends the time of controllable steering and reduces skidding of wheels (and hence, the braking distance) especially on surfaces that are wet or slippery.
These ABS monster SKUs are used for the electronic stability and braking system and the safety of this feature is highly dependent upon the accuracy of these sensors. Any variance in the readings of the ABS sensor can lead to compromising the braking ability of the system. So, these sensors need regular checkups, especially when a normal force generated on an ABS circuit drops below the Manufacturer specifications.
Tire Pressure Monitoring System (TPMS) Sensors
TPMS sensors relay the air pressure inside each tyre to the control computer, and a warning lamp in the instrument cluster alerts the driver of any underinflated tires. Maintaining proper tire inflation is very important for safe vehicle operation, good fuel economy and long tire life. Underinflation leads to poor vehicle handling, premature tire wear and a higher potential for tire failures.
TPMS sensors monitor pressure and provide real-time information to drivers so they can be sure that each tyre is adequately inflated and running as safely as possible.
4. Comfort and Convenience Sensors: Enhancing the Driving Experience
Rain Sensors
A typical rain sensor is mounted on the out of the car in front of the windshield. When this sensor detects moisture on the windshield glass, it will automatically turn on windshield wiper and adjust the speed of windshield wiper according to the intensity of rain. It is the additional feature that make it convenient for driver to see everything on road under precipitation.
Climate Control Sensors
Climate control sensors measure the temperature inside and outside the vehicle, as well as the level of humidity. With this data, the automatic climate control actuators can adapt the setting of the heating, ventilation and air conditioning (HVAC) system to keep the cabin environment at a comfortable level.
These sensors monitor the cabin’s environmental parameters so that interacting with the automobile is like being in a hibernation cocoon: no matter the prevailing ambient conditions – sweltering outside, biting wintry weather – the occupants within the cabin experience impeccably controlled ambient parameters.
Parking Sensors
Similar to the parking sensors found in the front and rear bumpers of most modern cars, these collision warning systems alert the driver of an impending collision as it occurs at low speeds near other vehicles while parking. This allows the driver to avoid collision with a nearby object providing audio or visual warnings at slower speeds while the vehicle approaches.
These sensors can also be part of an advanced parking system that helps a driver park along a curb or can even autonomously park the vehicle, further improving driver comfort.
5. ADAS Sensors: Paving the Way for Autonomous Driving
Radar and Lidar Sensors
The remote sensing components of this Advanced Driver Assistance Systems (ADAS) are radar and lidar sensors, which can both calculate the position and speed of other traffic objects. The radar sensor provides distance measurement based on the direction and speed of radio wave transmission, while the lidar sensor generates 3D mapping of the environment around the car with high-precision resolution.
These sensors are required for features such as adaptive cruise control, collision avoidance and autonomous driving, because they allow the vehicle to sense other vehicles, pedestrians and obstacles in its way in real-time.
Camera Sensors
Camera sensors play a crucial role in various ADAS applications including lane-keeping assist, traffic sign recognition and 360-degree surround-view systems, where visual data is captured by the sensors and then processed by the ECU to detect road markings, traffic signs and other vehicles.
With camera sensors operating at the rate of four frames per second per stream, the vehicle’s situational awareness can be better promoted and many accidental crashes can be avoided. As we’re entering a new era of self-driving vehicles, the camera sensor will be ever more important in their operation.
Ultrasonic Sensors
Park assist systems and blind-spot monitors use ultrasonic sensors that project sound waves at frequencies that are inaudible to the human ear (usually around 40 kHz) to detect objects within a short distance. The sensor uses the change in interval that occurs when reflected waves return to the source.
Ultrasonic sensors are most useful in slow-motion scenarios, for example to detect obstacles while parking; they are commonly used in automated parking systems.
6. The Future of Vehicle Sensors
Sensor Fusion and Autonomous Vehicles
In the next generation of vehicles, sensors will not only be indispensable for semi-autonomous features but also fully autonomous cars that need a mix of radar, lidar, cameras and ultrasonic sensors to drive in complex surroundings.
Sensor fusion – the process that combines information about the vehicle’s surroundings gathered from different sensors – is a key ingredient for enabling autonomous vehicles to operate safely. This means the vehicle can optimise decisions, such as when to change course or accelerate or slow down, depending on driving conditions.
Smart Sensors and Connectivity
There will also be the development of next-generation increasingly intelligent sensors capable of communicating with each other and with external systems, thus enabling a new generation of Vehicle-to-Everything (V2X) communication (in which the vehicles communicate with each other as well as with everything, from traffic lights to pavement markings to remote systems, including the psychological state of the driver, etc).
It will also help to improve traffic flows, reduce congestion and enhance road safety, since vehicles will be able to share insights on the state of the road, speed and traffic flows, counter-steering by vehicles in front, or potential dangers that drivers see but other cars do not.
Conclusion
Modern vehicles are full of countless horses, and barely visible to the naked eye. But these unicorns aren’t mythical animals: they’re sensors. These sensors are the unsung heroes of your vehicle. They provide the information that allows your powerplant to operate at optimal performance and fuel efficiency, and also enable your car to avoid accident and protect occupants. Tiny pieces of external equipment – sensors – can ultimately mean the difference between life and death. Without sensors, your car would be a black-box machine. It wouldn’t be able to optimise its performance and be efficient in terms of fuel economy and power delivery. It wouldn’t be able to work for and with you, but it would still kill you and anyone else in a fiery collision. Sensors aren’t new. Safety measures such as airbags rely on the simple presence of a sensor to deploy them. But with the increasing sophistication of sensor technology, more and more devices are being created specifically to process and utilise information that arises due to the presence of sensors in automobiles. All the advanced functions offered in tomorrow’s vehicles rely on the wealth of data offered by sensors.