Exhaust Sensor – O2 Sensor

In this topic, we will explain the exhaust or oxygen sensor, which is one of the most important sensors in the car that affect the performance of the car

Exhaust  Sensor O2 Sensor
The oxygen sensor is located in the exhaust pipe before the catalytic converter, and the oxygen sensor (exhaust sensor) measures the amount of oxygen in the exhaust gas.
There are two different types:
1- Zirconium
type oxygen sensor 2- Titanium type oxygen sensor.
Although the configuration and signals are different, the purpose of both sensors is the same. The oxygen sensor senses whether the ratio of air and fuel is plentiful or poor. Depending on the oxygen sensor signals, the ECU corrects the fuel injection amount to a lambda 1 ratio. This is necessary for the triple catalytic converter to operate at peak efficiency. Thus, it is a closed circuit between the oxygen sensor, the electronic control unit and the amount of fuel injected. Therefore, the oxygen sensor has an effect on the amount of fuel injected, and any error issued by this sensor results in problems with the amount of fuel injected, and it may cause an increase in fuel consumption.
The oxygen sensor has a heating element where the tooth is heated at the optimum operating temperature of 600 degrees Celsius, as the sensor is ineffective at temperatures below 600 degrees Celsius.
Newer systems use front and rear oxygen sensors to check the function of the catalytic converter. If the catalytic converter is in good condition, the signal from the rear sensor is very different from the front sensor in terms of signal height and especially in terms of frequency change. If the signals between the front and rear sensors are close to each other, this is an indication that the catalytic converter is intermittent (defective).

1- Zirconium type oxygen sensor.
Platinum is exposed to atmospheric air on one side, while the other side is exposed to exhaust gas. Because of the difference in the amount of oxygen between the atmospheric air and the exhaust gas, a potential difference is generated. When the air/fuel mixture is poor, the voltage generated is low. Conversely, when the mixture is plentiful, the voltage is high. A voltage higher than 450 mV indicates that the ratio of air to fuel is more elemental and the injection time is reduced. A voltage of less than 450 mV indicates that the fuel ratio is poorer than the elemental union, and the injection period is increased. Since the corrections take place alternately, the output signal shows a permanent shift if the operation is correct.
There are four parties in this sensitive, parties to the heater ( of Heater ) and the parties to sensitive. Since the heater voltage is 12 volts, and the two ends of the sensor are ground and the other is a signal.

2- Titanium type oxygen sensor.
Titanium changes its resistance depending on the concentration of oxygen. The oxygen sensor is supplied with a voltage of 5 volts. As the resistance of the sensor changes, the signal voltage in the ECU also changes. If the voltage drop is small, the mixture will be rich in fuel, and if it is high, the mixture will be poor in fuel. The output voltage is explored with a comparator. If it is above the 2.5 volt tipping point, the comparator output is high (fuel rich mixture). If it is less than 2.5V, the output is low (poor mixture).
There are four parties in this sensitive, parties to the heater ( of Heater ) and the parties to sensitive. Since the heater voltage is 12 volts, and the two ends of the sensor are ground and the other is a signal.

Whether the mixture is rich in fuel or poor in fuel is due to one of the following reasons:
1- Leakage, blockage or obstruction in the intake system.
2- A blockage or obstruction in the fuel system.
3- Fuel pressure.
4- Double ignition.
5- The heater inside the oxygen sensor.