What is normal NOx sensor readings?
As far as I know all testing is done via scan tool. With no DEF doser operation both inlet and outlet should read close to each other. When the injector is activated outlet nox should drop at least 70%. Normally under steady cruise the nox sensor on a duramax or ISB cummins is around 200-300 ppm.
What is SCR temperature?
The optimum temperature range depends on the type of catalyst used and the flue gas composition. Optimum temperatures vary from 480°F to 800°F (250°C to 427°C) (ICAC, 1997). Typical SCR systems tolerate temperature fluctuations of ± 200°F (± 90°C) (EPA, 2002). as low as 20 parts per million (ppm).
What does a NOx sensor read?
The NOx sensor is part of the NOx reduction aftertreatment system used in diesel vehicles with urea based SCR systems. The sensor located upstream of the SCR catalyst directly measures the engine-out NOx gas concentration, which helps determine the optimum amount of urea injection.
What kind of sensors are used in SCR systems?
Commercial sensors, available from several suppliers, are used for the control of NOx adsorber and SCR aftertreatment. NH 3 sensors have been also developed for use in SCR systems. The development of exhaust gas NOx sensors started in the 1990s.
What should the Doc outlet temp be during Regen?
If temp#3 is reading right and it is too hot that means the regen burn is happening in DPF, not the DOC. During a proper regen, DOC inlet temp, or temp #1, should be about 550-600. DOC outlet temp, or temp #2, should be 1000-1200 degrees.
Is the SCR capable of conducting or blocking current?
The SCR is capable of conducting OR blocking current in the forward direction, depending upon the gate signal. The SCR, like the diode, will always block current flow in the negative or reverse direction. The act of controlling or turning on an SCR, (i.e. telling it to conduct current) is also known as gating or firing the SCR.
Where does Selective Catalytic Reduction ( SCR ) take place?
Selective Catalytic Reduction Components And The Chemical Process That Occurs Inside The SCR Device Chemistry is well understood and controllable 11 22 33 DEF Injection •Small quantity of DEF injected •Proportional to NOx rate •32.5% solution in water, freezing point = 11° F •Stored in heated tanks •(NH 2) 2CO Hydrolysis