Thick Film ZrO2 NOx Sensor

This paper describes the design concept and evaluation test results of a multi-layered, thick film zirconia NOx sensor which can be used for lean-burn engine management.

The oxygen concentration in the measuring gas is lowered to a predetermined level with an oxygen pumping cell, in the first stage. In the second stage, another pumping cell further lowers the oxygen concentration which results in simultaneous NOx decomposition.

The second stage pumping current is proportional to the NOx concentration in the measuring gas.