Nitrogen oxide / NOx sensors from the specialist in emission control

With nitrogen oxide or NOx sensors, Motorservice is enlarging its product range in the field of exhaust gas sensor systems from Pierburg. The available item numbers cover a global vehicle fleet of more than 13 million vehicles, including utility vehicles from the “big seven” – DAF, IVECO, MAN, Mercedes-Benz, Renault, Scania and Volvo.

These sensors are a key component for reducing harmful nitrogen oxides, NOx for short.

Our sensors in OE quality have proven themselves millions of times over across the globe. They are indispensable components, and several of them can often be found installed in one vehicle. That is why we keep on expanding our product range. High operating temperatures and aggressive exhaust gas place high demands on NOx sensors. You should therefore choose products from the specialist for emission control.

“Nitrogen oxide” is the collective term for gaseous pollutants such as nitrogen monoxide (NO), nitrogen dioxide (NO₂) andnitrous oxide (N₂O). These substances increasingly arise athigh combustion temperatures and when there is an excess of oxygen (λ>1).

The NOx sensor works according to a similar principle as the wideband lambda sensor and, similar to it, requires sensor heating which brings the sensor up to operating temperature (approx. 700°C).

The NOx sensor consists of two chambers arranged one after the other: 
The amount of residual oxygen in the exhaust gas is determined in the first chamber. This can be achieved by applying a voltagewhich “pumps” the oxygen out of the cell. Depending on the vehicle type and position of the sensor, the NOx sensor may therefore take on the function of a lambda sensor and replace it.

NOx is broken down into its constituent parts, nitrogen and oxygen, in the second chamber. The amount of oxygen that results as part of this process is measured by an additional pump electrode. 
The “pump current” expended for this is proportional to the NOx concentration in the exhaust gas. It is evaluated by the control unit at the NOx sensor and reported to the engine control unit via CAN bus.

• Make sure the NOx sensor and the NOx catalytic converter are working and positioned correctly.
• Prevent overheating of or damage to the NOx sensor or the NOx catalytic converter.
• If a NOx sensor ages, it may send incorrect signals to the control unit. This may result in the engine entering a limp home function with increased fuel consumption.
• The NOx sensor may be stored as faulty in the fault code memory, even though the cause is a defective NOx catalytic converter.
• Due to the aggressive exhaust gas, NOx sensors only havea limited durability. If two NOx sensors are installed, wetherefore recommend that both sensors are exchangedduring replacement.
• Note the tightening torques for the sensor head on exhaust tract: 50 Nm ±10 Nm.
• Read the instruction leaflet for more information.