The reductant pump supplies urea to the dosing module. One unique function of the pump is that when the ignition is turned off, the pump pulls all of the reductant out of the lines. This prevents damage to the lines if the reductant was to freeze.
The reductant dosing module is controlled by the PCM. The reductant dosing module injects reductant into the exhaust system to reduce NOx coming out of the tailpipe. The injector is made to resist the corrosive properties of the reductant.
The reductant tank stores the reductant or DEF. Under normal use it needs to be refilled at the same interval as the oil change.
Reductant, also known as Diesel Exhaust Fluid (DEF) is 32.5% urea/ water solution. When injected into the exhaust, there is a chemical reaction that converts NOx into N2 and H2O. The freezing point of reductant is -11°C (12°F). Reductant is very caustic; take care not to spill onto connectors, wiring harnesses or the vehicle’s paint.
The SCR system components include the: • reductant or Diesel Exhaust Fluid (DEF) • reductant tank • reductant dosing module • reductant pump and heater assembly • reductant pressure line heater assembly • reductant tank heater and sensor assembly • reductant purge valve • reductant pressure sensor • NOx sensor and module • exhaust mixing… Read More »
The following can be negatively affected by not using the recommended API rated engine oil are: • increased Particulate Matter (PM) in the aftertreatment system may cause more ash build up in the DPF • more frequent DPF regenerations • reduction of DPF service life. • engine oil system
The electrical resistance of the sensor increases as the temperature increases, and resistance decreases as the temperature decreases. The varying resistance changes the voltage drop across the sensor terminals and provides electrical signals to the PCM corresponding to temperature. The PCM uses the input from four EGT sensors to monitor the exhaust gas temperature.
The EGT sensors are Resistance Temperature Detector (RTD) type sensors. The EGT sensors are inputs to the PCM. They measure the temperature of the exhaust gas passing through the exhaust system at four different points.
The DPF pressure sensor is an input to the PCM and measures the pressure before the DPF. The sensor is a differential-type sensor that is referenced to atmospheric pressure. The DPF pressure sensor is used by the PCM to monitor the amount of exhaust pressure produced by the DPF. An active regeneration is performed when… Read More »
The DPF is a highly engineered silicon carbide wall-flow catalyst that traps particulates, reducing the amount of black smoke emitted from the tailpipe. The three modes of DPF regeneratio are active, passive and manual.