The eyes and ears of a car are all about the sensors!

Over the past twenty years, sensors in the car have become increasingly important. As a result, cars have become much safer, more comfortable and cleaner. Read this overview of the most important sensors in a car.

Sensor function

Sensors continuously measure a specific actual value . They transmit recorded value to the electrical or radio signal control unit . Here the obtained actual value is compared with the programmed nominal value.

Depending on the nature of the deviation, this causes different reactions. , ranging from a simple signal to indicate the error code and ending with the inclusion of the emergency drive of the car.

• In a technical sense The sensors are surprisingly simple designs. Many sensors in a car are simple magnetic or bimetal sensors . Their simple design ensures a low price and guarantees maximum reliability.
• Other sensors much more difficult.
• Examples of high-tech sensors are lambda probes for measuring the oxygen content in exhaust gases or radar proximity sensors.

Types of sensors

Sensors can be roughly divided into the following categories:

1. Position sensors 2. Speed ​​sensors 3. Acceleration sensors 4. Pressure sensors 5. Temperature sensors 6. Force sensors 7. Flow sensors

1. Position sensors

Position sensors measure the position of a component within a given path , which can be linear or curvilinear.

• Linear position sensors can be found at the filling level of the fuel tank, engine oil or DEF tank.
• Position sensors for curved paths also called angle sensors . They register crankshaft position or steering wheel angle . Ultrasonic or radar sensors, mounted in the bumper are also considered position sensors.

2. Speed ​​sensors

RPM sensors measure component rotation speed . This applies especially to the engine: the speed of the crankshaft and camshaft is essential for engine control and is therefore constantly measured .

No less important ABS sensors . They constantly measure whether the wheel is spinning and at what speed. . The ABS sensor is a typical example of a simple but effective sensor. It is essentially a small electromagnet next to a rotating perforated disc.As long as the control unit receives a constant frequency of magnetic fields, it knows that the wheel is spinning. About 20 years ago simple ABS has been upgraded to an even more efficient ESP.

Sensors have evolved together.

3. Acceleration sensors

Acceleration sensors are especially important for passive safety . When the cars pick up speed seat belt pretensioners и airbags go into an "alarm" state. All podcast adapts to changing driving conditions.

4. Pressure sensors

Pressure sensors measure the characteristics of gases and liquids . They transmit actual pressure values ​​to the control unit in the following systems:

- fuel line - brake line - inlet channel - air conditioner – hydraulic pressure of the power steering - tire pressure

Constant control of the pressure in these systems is very important. A pressure drop in the brake line or power steering line causes loss of vehicle control. Lack of fuel pressure prevents the vehicle from starting. Too low tire pressure can cause the vehicle to skid. Therefore, the installation of a tire pressure monitoring system is mandatory for all vehicles from 2014 onwards. .

5. Temperature sensors

Temperature sensors register the heat of a specific component . This information is important not only for the driver. As a rule, temperature sensors serve as measuring sensors for the control unit. Only when the car's central brain is properly informed about the temperature conditions can it adapt the engine management accordingly. Temperature sensors are installed in the car at the following points:

- cooling system - inlet pipe - oil pan - fuel tank - salon - body - air conditioning - and possibly tires

6. Force sensors

Force sensors measure the resulting forces . They are necessary for driving dynamics and passenger safety . Force sensors can be found on the pedals, in the braking and steering system, and for motion measurement . Modern cars also have sensors in seats . They provide a seat belt warning and support the belt tensioner.

7. Other sensors

• The air flow sensor is used to measure the incoming air flow .

• Lambda probe located in the exhaust just before the catalytic converter. This sensor measures the oxygen content in the exhaust.

• Knock sensors monitor the combustion process in the cylinders .

• The throttle sensor measures the opening angle of the throttle.

Little effort, big effect

Sensors are wear parts, just like any other vehicle part. If they fail, failures will soon follow. .

In the past finding the cause of the malfunction required patience. Now control units check the received data from the sensors for plausibility and therefore the faulty component is easier to find.

Replacing the sensor usually provides a quick solution to the problem. Its availability varies considerably.

Some sensors can be easily replaced without tools. Replacing other sensors requires a major overhaul .

• Each sensor is essentially an electronic component. which can be connected to the wiring harness.
• Their forks are often an overlooked source of bugs . The contact points between the sensor and the cable harness are usually made of copper, which corrodes over time and interrupts the power supply. Therefore, it is worth looking for these plugs, thoroughly cleaning them and sealing them with contact spray.
• Engine problems that seem dramatic at first glance are often effectively dealt with this way.

But even if the sensor is really out of order, it only in exceptional cases means a complete economic loss of the car. Even replacing hard-to-reach components like the crankshaft sensor is worth it.

Therefore, owners of older vehicles are advised to learn about sensor replacement intervals. .

• Sensors make sense preemptively replace . In this way, more serious engine problems can be effectively avoided. This applies, for example , to the radiator temperature sensor .
• If his replace together with heat exchanger or radiator fan the fan will work reliably.
• Lambda probe should also be replaced regularly. This spares the catalytic converter and helps save fuel.