Preh's automotive temperature sensor is equipped with a CAN interface and can be installed anywhere in the vehicle

(Photo source: Preh)

According to foreign media reports, whether hot or cold, everyone has their own healthy temperature, and this temperature affects personal behavior. A test conducted by American psychologists in South Carolina found that if the test subjects drove in freezing weather or too hot, their driving behavior would change. When the car was hot, if the vehicle in front did not start fast enough at the green light, their driving behavior would be more aggressive and honk the horn more frequently.

Therefore, the right temperature is not only a matter of comfort, but also a matter of safety. The air conditioner installed in the car can adjust the optimal temperature at any time, but one of the challenges is how to continuously and accurately monitor the temperature in the car. In the past, cooling fans and temperature sensors (NTC) were used to achieve monitoring. The air in the car would be sucked in by the cooling fan and flow through the temperature sensor. However, due to the following disadvantages of this method, such as being relatively expensive, requiring a relatively large installation space, the cooling fan is noisy, and the service life is limited, so far, the latest cooling fan-free temperature sensor has gone through 10 years of development time.

Most of the fanless temperature sensors currently used are analog stand-alone solutions, which means that one sensor measures the temperature at three locations, then provides the temperature information to the control unit, and then calculates the temperature inside the car as a parameter for climate control. However, in the future, users will have higher demands, and analog components can no longer meet the needs. The German company Preh has equipped its temperature sensors with a CAN (Controller Area Network) interface, so that the temperature sensors can be installed in different locations in the car and can implement climate control algorithms. Claudia Guck of Preh explained: "The digitalization of automobiles is developing faster and faster, and at the same time, LIN (Local Interconnect Network) sensors are being used. Thanks to this vehicle protocol language, we can implement software calculations directly in the sensor, thereby alleviating the working pressure of the ECU (Electronic Control Unit)."

However, this is not enough for future generations of cars. Sensors that communicate via the LIN protocol still have limitations in terms of data volume and transmission speed. Therefore, the next sensor generations from Preh will also offer a CAN interface. CAN-connectable sensors will contain not only the temperature measurement software, but also the climate control algorithms. Due to the higher data throughput of CAN temperature sensors, more functions can also be combined.

In addition, it also brings new possibilities for installation. As an independent sensor, the temperature sensor can be installed in a specific position in the car, or installed in an invisible design element outside the car. Its installation position is no longer determined by the installation position of the ECU. In addition to integration in the user interface, in series development, Preh also installed and tested temperature sensors in various positions (including B-pillars and C-pillars installed under the steering column of the car, and car roofs).

Preh is working with a car manufacturer to develop a sensor that can determine not only the temperature but also the humidity of the windshield. This sensor can be installed at the base of the rearview mirror. "The best place to install a temperature and humidity sensor is the windshield. For example, when it rains, the humidity of the windshield can be detected quickly and measures can be taken to prevent fogging. Due to the various possibilities of CAN-enabled sensors, their functionality can be expanded to enable them to control windshield wipers, and automatic lighting functions and solar radiation can be integrated into the same sensor," said Claudia Guck.