Oxygen Sensor: Operation
- The oxygen sensor functions to detect the concentration of oxygen in the exhaust gas. It converts those data to voltage, and inputs the resulting signals to the engine control unit. See Fig 1
.
- If the air/fuel mixture ratio is richer than the theoretical air/fuel mixture ratio (i.e., if the concentration of oxygen in the exhaust gas is sparse), a voltage of approximately one volt is output. If the air/fuel mixture ratio is leaner than the theoretical air/fuel mixture ratio (i.e., if the concentration of oxygen in the exhaust gas is dense), a voltage of approximately zero volts is output.
- The engine control unit, based upon those signals, regulates the amount of fuel injection so that the air/fuel mixture ratio becomes the theoretical air/fuel mixture ratio.
- Battery power supply is applied, by way of the control relay, to the oxygen sensor heater. As a result, the sensor element is heated by the heater, so that the oxygen sensor shows excellent response even if the temperature of the exhaust gas is low.
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.