What is the role of the oxygen sensor in emissions control?

The oxygen sensor plays a crucial role in emissions control by monitoring the level of oxygen present in the exhaust gases. This information is used by the engine control unit (ECU) to determine the appropriate fuel mixture for combustion. By adjusting the fuel mixture to optimal levels, the ECU ensures that the engine runs efficiently, reducing harmful emissions produced during combustion.

When the oxygen sensor detects excess oxygen, it indicates a lean fuel mixture, prompting the ECU to enrich the fuel flow. Conversely, if too little oxygen is detected, the sensor signals the ECU to reduce the fuel, leading to a leaner mixture. This process helps maintain a balanced air-fuel ratio, which is vital for efficient combustion and reducing emissions such as carbon monoxide and unburned hydrocarbons.

This key function underscores the importance of the oxygen sensor in meeting environmental regulations and standards for vehicle emissions.