Malaguti DRAKON125 2022 Workshop Manual page 150

Oxygen Sensor
1. Outline drawing and pin definition
2. Working principle
SMa oxygen sensor is based on multilayer ceramic elements with flat plate structure, in
which zirconia layer is the core element. The working principle of zirconia element is
equivalent to a simple solid primary cell. According to the electrochemical principle, there
will be potential difference between the two electrodes due to the difference of oxygen ion
concentration. When the air-fuel ratio of the engine is lean, the oxygen ion concentration
in the exhaust gas is relatively high, the oxygen ion concentration difference between the
inner and outer electrodes is small, that is, the potential difference is small, and the
output voltage signal of the oxygen sensor is close to 0V; On the contrary, when the air-
fuel ratio is rich, the oxygen ion concentration in the exhaust gas is relatively low, the
oxygen ion concentration difference between the inner and outer electrodes is large, that
is, the potential difference is large, and the output voltage of the sensor is close to 1V.
3. Basic parameters
Exhaust temperature 450 ℃, characteristic parameters of oxygen sensor:
Concentrated gas mixture（λ＜1) The output voltage of the oxygen sensor is greater
than or equal to 750mV;
Lean mixture（ λ＞1) The output voltage of the oxygen sensor is less than or equal to
Oxygen sensor pin definition
NO. Corresponding cable
color
1 Red
2 White
3 Gray
4 Black
use
Heating positive
Heating negative
Signal ground
Oxygen sensor
signal