What is the function of an oxygen sensor?
2 Answers
The function of an oxygen sensor: It measures the information about whether there is an excess of oxygen in the exhaust gas after engine combustion, i.e., the oxygen content, and converts the oxygen content into a voltage signal transmitted to the engine computer, enabling the engine to achieve closed-loop control targeting the excess air factor. It ensures that the three-way catalytic converter has the maximum conversion efficiency for the three pollutants in the exhaust gas: hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOX), maximizing the conversion and purification of emission pollutants. The oxygen sensor can also compensate for the air-fuel ratio errors caused by wear and tear of mechanical and fuel injection system components. In engines using a three-way catalytic converter to reduce exhaust pollution, the oxygen sensor is an indispensable component. Methods to check the oxygen sensor: Refer to the circuit diagram. Based on the circuit diagram, identify the corresponding wire harness color of the oxygen sensor for easy measurement; Measure the power supply line of the oxygen sensor heater. Unplug the sensor connector and check if there is power in the wire harness; Measure the control line of the oxygen sensor heater; Measure the heater resistance; Measure the signal line of the oxygen sensor; Measure the ground line of the oxygen sensor.
Speaking from real experience, last time my car's fuel consumption suddenly spiked and it was emitting black smoke. The mechanic checked it and immediately said the oxygen sensor was broken. This little thing is installed on the exhaust pipe, acting like the engine's nose, specifically sniffing the oxygen concentration in the exhaust. If there's too much oxygen, it means less fuel is being burned, and the computer immediately increases fuel injection. If there's too little oxygen, it means more fuel is being burned, and the computer reduces the fuel injection. It regulates in real-time like this, not only saving fuel but also making the exhaust cleaner. If it fails, the car's power becomes sluggish, fuel consumption skyrockets, and it can damage the catalytic converter—illuminating the engine's yellow warning light is the least of your worries. It's recommended to check this part every 80,000 kilometers, as replacing an original one can cost around a thousand bucks.
