Function And Features

A wide area oxygen sensor mounted on the exhaust manifold detects the oxygen concentration in the exhaust gas and corrects the amount of fuel. The PCM controls the pumping current to match the lambda (λ) value detected by the linear oxygen sensor to 1.0.

Mixer lean (lambda value over 1.0): PCM supplies pumping current to the oxygen sensor (+pumping current) to activate the oxygen sensor to show the characteristics of lambda 1.0. At this time, the PCM detects the oxygen concentration contained in the exhaust gas with the amount of pumping current flowing through the oxygen sensor.

Mixer rich (lambda value less than 1.0): PCM takes out the pumping current from the oxygen sensor (-pumping current) to reduce the activation of the oxygen sensor to show the characteristics of lambda 1.0. With the amount of pumping current taken from the oxygen sensor, the PCM detects the oxygen concentration contained in the exhaust gas.

Oxygen sensor operates most quickly and smoothly at normal operating temperature (450 ~ 600°C), and has a built-in heater (heating wire) to quickly raise and maintain the oxygen sensor to normal operating temperature.

The heater heating wire is controlled by PWM by PCM, and when the heater heating wire gets cold, the resistance value decreases and the current value increases. When the temperature of the heating wire increases, the resistance value increases and the current decreases to determine the operating amount of the oxygen sensor heater.