Zirconium Sensors

The external surface of the zirconium element is in contact with the exhaust gas; the internal surface in contact with the reference air. Both surfaces are covered with a fine coating of platinum, that act like electrodes to lead sensor signal (from the zirconium element) until conducting wires.

An important characteristic of the zirconium element is that it becomes conductor of oxygen ions a temperature above of 300°C, generating an electrical voltage. This electrical voltage is generated will have a difference in the oxygen concentration between the internal and the external of the element. An eletrical voltage near the zero is generated if the air-fuel mixture will be lean ( > 1) and an eletrical voltage near the 1V ( < 1) if it will be rich.

When the air-fuel mixture nears the ideal ratio ( = 1), there is a sharp change in the generated voltage, from 0 to 1V.

The ECU uses the voltage produced by the Lambda Sensor to instruct the mixture system to control the fuel mixture.

Since the element only produces voltage when the element is above 300°C, the exhaust gas take some time to heat the element to the necessary temperature, after the engine is running. To reduce the time before the sensor begins functioning, many sensors today have an internal ceramic heater. These sensors have three or four conductive wires. NTK ceramic heaters rely on our extensive experience and ensure high performance and reliability .

Heated Zirconium Exhaust Oxygen Sensor

A ceramic heater is inserted into the sensor and heat its interior, allowing that it can be use at a wide range of temperatures of exhaust gas. Because the ceramic heater, the beginning of functioning is more quickly than the EGO type (withou ceramic heater) and has a lesser variation of its characteristics.

Heated Zirconium and Insulated Element Exhaust Oxygen Sensor

This sensor has an additional wire to the compound signal in relation to the conventional sensor with ceramic heater(HEGO). The stability of this signal is guaranteed by the complete insulation between the sensor element and the external metal casing, beyond to a special projected ceramics. This guarantees greater useful life the sensor, therefore it eliminates possible imperfections proceeding from oxidation between the exhaust pipe and the sensor.