What does an o2 sensor do in a car?
The Automotive o2 sensor, commonly known as the O2 (“ōtwo”) sensor, enables modern electronic fuel injection and emissions control. They help determine in real time whether the air-fuel ratio of the internal combustion engine is rich or lean. Since the oxygen sensors are located in the exhaust stream, they do not directly measure the air or fuel entering the engine, but when the information from the oxygen sensors is combined with information from other sources, the air-fuel ratio can be determined indirectly. Closed-loop feedback-controlled fuel injection varies fuel injector output based on real-time sensor data, rather than operating with a predetermined (open-loop) fuel map. In addition to enabling electronic fuel injection to operate efficiently, this emission control technology also reduces the amount of unburned fuel and nitrogen oxides entering the atmosphere. Pollution in the form of airborne hydrocarbons from unburned fuel, while nitrogen oxides (NOx gases) are a result of combustion chamber temperatures exceeding 1300 Kelvin, due to the excess air in the fuel mixture, thus contributing to smog and acid rain . Volvo was the first automaker to adopt this technology in the late 1970s, along with the use of a three-way catalyst in the catalytic converter.
The sensor doesn’t actually measure the oxygen concentration, but the difference between the amount of oxygen in the exhaust gas and the amount of oxygen in the air. A rich mixture creates an oxygen demand. This demand results in a voltage increase due to the transport of oxygen ions through the sensor layer. A lean mixture results in low pressure because there is too much oxygen.
Model Number | Model | Detection Range | Communication Method | Product Size | Product Features |
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FS01500 | Default: 0~25%Vol |
UART (3.3V_TTL Voltage level)
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32.3×32.3×16.5 mm |
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FS01501 | 0~25%Vol |
UART (3.3V_TTL Voltage level)
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32.3×32.3×16.5 mm |
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Modern spark-ignition internal combustion engines use oxygen sensors and catalytic converters to reduce exhaust emissions. Information about the oxygen concentration is sent to the engine management computer or engine control unit (ECU), which adjusts the amount of fuel injected into the engine to compensate for excess air or excess fuel. The ECU tries to maintain a certain air-fuel ratio on average by interpreting the information it gets from the oxygen sensor. The main goal is a compromise between power, fuel economy and emissions, and in most cases this is achieved with a near-stoichiometric air-fuel ratio. Used in spark-ignition engines (such as those burning gasoline or LPG) (as opposed to diesel), the three types of emissions that modern systems are concerned with are: Hydrocarbons (released when the fuel is not completely released when the air-fuel ratio), carbon monoxide (result of running) slightly richer and NOx (dominated in a lean mixture). Failure of these sensors, for example due to normal ageing, use of leaded fuel, or fuel contaminated with silicones or silicates, can lead to damage and costly repairs to a car’s catalytic converter.
Tampering or modifying the signal that the oxygen sensor sends to the engine computer could be detrimental to emissions control and could even damage the vehicle. When the engine is under low load conditions, such as accelerating very slowly or maintaining a constant speed, it will run in “closed loop mode”. This refers to the feedback loop between the ECU and the oxygen sensor, where the ECU adjusts the fuel amount and expects to see the resulting change in the oxygen sensor’s response. This cycle forces the engine to run both slightly lean and slightly lean in successive cycles as it tries to maintain most of the stoichiometry on average. If the modification causes the engine to run moderately lean, there will be a slight increase in fuel efficiency, emissions, higher exhaust temperatures, sometimes a small increase in power can quickly lead to misfire and a sharp loss of power, and in ultra-lean air can damage the engine and catalysis Converter (due to misfire) – fuel ratio. If the modification causes the engine to become richer, the power will increase slightly up to a point (after which the engine will start flooding with too much unburned fuel), but at the cost of less fuel efficiency and more unburned hydrocarbons In the exhaust it can cause the catalytic converter to overheat. Running rich for extended periods of time can lead to catastrophic failure of the catalytic converter. The ECU also controls the timing of the spark engine. As the fuel injector pulse width increases, whenever the fuel ignites too early or too late in the combustion cycle, modifications to the operation of the engine to make it lean or too rich can cause Inefficient fuel consumption.