Modern vehicles are equipped with a wide range of electronic sensors. Numerous electronic sensors can be found in the engine area in particular. This applies to cars with combustion engines as well as electric cars. Find out all about engine sensors here.

The role of sensors in modern engines

The sensors in modern cars record physical variables and make them usable for engine control. These include values such as temperature, pressure and angle, as well as the composition of intake air and exhaust gas. In electric cars, various sensors increasingly measure currents, voltages and temperatures. The data collected enables optimized control and efficient operation of the car’s engines.

Types of sensors in combustion engines

Sensors are used for a wide variety of tasks in modern combustion engines. The main tasks of the various sensors are increasingly concerned with controlling the combustion processes and influencing the exhaust gases. Exhaust gas aftertreatment using catalytic converters and filters is becoming increasingly important. The engines of modern vehicles, which are trimmed for efficiency and performance, allow little leeway with regard to the composition of the ignitable mixture. Optimum cylinder filling and ignition at the best possible time enable ideal use of the fuel. To achieve this, the engine control unit requires data from numerous sensors on the engine.

Frequently installed sensors in combustion engines

• Temperature sensors: Numerous temperature sensors are installed in modern vehicles. These measure the coolant temperature or the oil temperature, for example. Sensors such as the intake air temperature sensor provide further important measured variables for engine control.
• Throttle valve sensors: The throttle valve sensor is located in the area of the throttle valve. Here, the sensor measures the opening angle of the component. The engine control unit can use the measured values to determine other variables such as the fuel quantity.
• Lambda sensors: Modern vehicles with a catalytic converter have one or two lambda sensors. These sensors are installed in the area of the exhaust tract. Here, the sensors measure the residual oxygen content in the exhaust gas so that the engine control unit can react.
• NOx sensors: An NOx sensor measures the proportion of nitrogen oxides in the exhaust gases of diesel engines. The measured values can be used to adjust the exhaust gas aftertreatment according to requirements. The increasingly stringent emission values are thus complied with.
• Boost pressure sensors: There are other sensors in modern turbo engines, such as the boost pressure sensor. The values determined by these enable the engine control unit to optimally adjust the combustion. It is also possible to control adjustable turbochargers.

The various sensors in electric car engines

Electric cars also require sensors to enable the systems to operate properly. The type of sensors used differs in part from those found in cars with combustion engines. In addition to recording electrical variables, the monitoring of temperatures plays a major role in electric cars. In electric cars, sensors are mainly used to monitor the electric motor or electric motors and motor control. Measuring sensors are also used to continuously monitor the battery system and its temperature control. This ensures a long battery life. Last but not least, sensors monitor all processes when charging the drive batteries.

Important sensors for electric motors

• Voltage sensors: The various currents and voltages are of particular interest in electric cars. This is why there are numerous voltage sensors and current sensors in electric cars. The corresponding values can be monitored using these sensors.
• Battery sensors: The battery is one of the main components of the electric drive, but the component is also considered to be very sensitive. Sensors monitor the condition of the battery, such as its temperature. Battery management can intervene if necessary.
• Rotor position sensors: In addition to sensors such as a temperature sensor, modern electric motors in electric cars also have a rotor position sensor. This sensor determines the exact position of the rotor shaft. Thanks to the values, the drive motors can be used more efficiently.

Troubleshooting and maintenance for motor sensors

Troubleshooting motor sensors is not always easy. Often, the symptoms present do not allow any clear conclusions to be drawn about the defect of a particular sensor. To begin troubleshooting, the car’s fault memory should be read out using a suitable diagnostic device. The subsequent check of individual sensors can vary depending on the type of sensor. Temperature sensors, for example, change their resistance. The function of the sensor can then be easily checked with a measuring device.

Maintaining the car’s sensors

With regard to the maintenance of sensors in the car, it is sometimes helpful to clean the measuring probes or measuring heads. Exhaust gas sensors in particular, which are located in the direct exhaust gas flow, often become very dirty. The same applies to sensors in the exhaust gas recirculation area. The function of other engine sensors can also be impaired by dirt, combustion residue or engine oil build-up. Sensors in the area of the engine or exhaust system should always be cleaned in accordance with the manufacturer’s instructions.

Defective sensors in electric cars

In electric cars, sensor defects are usually manifested by the failure of a function or by an error message. However, the fault cannot always be clearly localized by the layman. Sometimes it is necessary to take the vehicle to an approved workshop for electric vehicles for repair. The specialists not only have the necessary technology for diagnosis, but also experience. They are also appropriately trained in dealing with electric cars.

Effects of sensors on vehicle safety and emissions

The sensors in the engine and exhaust system help to avoid unnecessary pollutant emissions. The use of measuring sensors also reduces the car’s fuel consumption. The data supplied by the measuring points to the engine management system makes it possible, for example, to set an optimum mixture. Thanks to sensor technology, ignition also takes place at the best possible time. This in turn enables clean and particularly effective combustion of the fuels in the combustion engine. In addition to regulating combustion, exhaust gas aftertreatment can also be carried out in the best possible way thanks to sensors. Components such as catalytic converters or diesel particulate filters only function optimally if the installed sensors provide reliable measured values. Depending on the data from the lambda probe or NOx sensor, the engine management system can control combustion and exhaust gas aftertreatment. In electric cars, sensors ensure safety during the charging process and prevent battery damage during operation, for example.

Sensors on used engines and units

When buying used engines, the installed sensors play a special role. It is important to check whether the sensors are present and working properly. As a rule, the sensors and measuring heads are robustly constructed and correspondingly durable. Nevertheless, it is a good idea to take a look at the condition of the sensors on used drive units. Buyers of used engines should find out about the sensors on the engine in question in advance. This makes it possible to check the presence of the various sensors. The sensors can often be checked visually for damage. A test provides more certainty. To do this, it is necessary to measure each individual sensor with a measuring device.

Buying used motors: What you should look out for

When buying used engines online, you should pay attention to various points. These include the mileage of the engine as well as its visual condition. The sensors can often be seen in the photos of used drive units. In addition, the compatibility of external sensors and their connections can be compared with the engine’s connections. The scope of delivery must be taken into account for used engines. Additional units and the associated sensors are not always present. Furthermore, the sensors installed on used engines cannot always be checked on site and in detail. This makes it all the more important to purchase used motors from reliable sources. Trustworthy dealers often provide a guarantee.