The NOx sensor is one of the core components of the diesel engine exhaust aftertreatment system—SCR (Selective Catalytic Reduction). It provides fundamental NOx concentration data for the SCR control system. Based on the NOx concentration, the SCR controller calculates the appropriate urea mass to be injected at the SCR inlet, resulting in low NOx emissions at the SCR outlet, typically 20-30 ppm for Euro VI/China VI standards.
The three core components of NOx sensors: SCU (Sensor Control Unit), ceramic chip, and product packaging. The first two are more technically challenging, while product packaging requires engineering expertise and debugging.