The carbon dioxide (CO2) sensor is an important component in automotive air conditioning control systems, primarily used to measure the CO2 concentration in the air inside the vehicle. Carbon dioxide is a waste gas produced during human respiration and continuously accumulates in the enclosed space of a car. Excessive CO2 concentration can affect human health and safety.

CO2 sensors mainly play the following roles in cars:

● Ensuring Driving Safety: Excessive CO2 concentration can lead to decreased driver and passenger attention and slower reaction times, increasing the risk of traffic accidents. CO2 sensors can monitor the CO2 concentration in real-time and automatically switch air circulation modes to avoid safety hazards caused by high levels.

● Improving Passenger Comfort: High CO2 concentration can cause symptoms such as dizziness, fatigue, and drowsiness, affecting comfort. The sensor can improve in-car air quality by reducing CO2 levels and enhancing comfort.

● Saving Energy: Excessive CO2 concentration causes the AC system to increase cooling power, which increases energy consumption. The CO2 sensor can automatically adjust the cooling power based on the CO2 concentration to save energy.

CO2 sensors are becoming increasingly widespread and are now standard in automotive AC control systems. As requirements for in-car air quality and safety continue to rise, their application in vehicles will expand further.

CO2 sensors are mainly applied in cars in the following ways:

● Internal Circulation Mode Switching: When the CO2 concentration reaches a certain threshold, the sensor sends a signal to the AC control system, which automatically switches to external circulation mode to introduce fresh air.

● Cooling Power Adjustment: The sensor can automatically adjust the cooling power based on CO2 concentration. When levels are high, the system increases power to quickly reduce temperature and humidity, improving air quality.

● In-car Air Quality Monitoring: CO2 sensors can work with other air quality sensors (such as PM2.5 or formaldehyde sensors) to achieve comprehensive monitoring of the cabin environment.

With technological progress, CO2 sensor performance—including sensitivity, accuracy, and stability—has significantly improved, while costs have decreased, making them more popular.

In the future, applications will expand even further. With the development of autonomous driving, CO2 sensors could be used to monitor driver fatigue and issue warnings to ensure driving safety.