NOx Modules

Measure NOx, Lambda, AFR, and O2

ECM offers three NOx Module Kits.  The NOxCANt and NOxCANf Kits are recommended for spark ignition and diesel engine applications.  The NOxCANg Kit has a more stable zero point and is therefore recommended for diesel and lean-burn combustion processes where the NOx level is less than 10 ppm.

The NOxCANt and the NOxCANg Kits have a cross-sensitivity to NH3.  For the NOxCANt, the cross-sensitivity is 1:1 (1 ppm NH3 looks like 1 ppm NOx to the sensor).  For the NOxCANg, the cross-sensitivity is approximately 1:0.67 (1 ppm NH3 looks like 0.67 ppm NOx).

The NOxCANf has a built-in and replaceable NH3 absorption filter.  The NOxCANf has zero cross-sensitivity to NH3, however the exhaust gas temperature cannot exceed 210℃ and the filter will require replacement at intervals as short as 20 minutes.

An understanding of NH3 cross-sensitivity is important for tailpipe installations (as opposed to engine-out installations), since three-way catalytic converters produce NH3 when running stoichiometric and richer and diesel engines will inject urea into the exhaust which turns into NH3.