What is the purpose of the O2 sensor in an automotive engine?

The purpose of the O2 sensor in an automotive engine is to measure the amount of oxygen in the exhaust gases. This sensor plays a critical role in the vehicle's emissions control system by providing real-time feedback to the engine control unit (ECU) regarding the air-fuel mixture being burned in the engine. By measuring the amount of unburned oxygen in the exhaust, the O2 sensor helps the ECU adjust the fuel injection and ignition timing to ensure optimal combustion. This not only improves fuel efficiency but also minimizes harmful emissions, keeping the vehicle compliant with environmental regulations.

The other options do not accurately reflect the function of the O2 sensor. For example, controlling engine temperature is primarily the responsibility of the thermostat and cooling system. Monitoring fuel quality is typically managed by other sensors and systems, while regulating tire pressure involves tire pressure monitoring systems (TPMS) separate from the engine's exhaust management. Thus, understanding the specific role of the O2 sensor emphasizes its importance in achieving efficient engine performance and reducing environmental impact.