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Diesel aftertreatment systems contribute significantly to pushing the clean diesel emission. Before that system, diesel has long had an image problem. They were famous for being noisy, slow, and dirty. But now diesel doesn’t stink like it used to. Many are extremely powerful and remarkably clean compared to the old days. The breakthrough came with the development of diesel exhaust aftertreatment systems.

Exhaust aftertreatment systems reduce pollutants and post-combustion gases such as oxides of nitrogen (NOx) and some oxygenated compounds (SO2, NO2, and O2). A well-maintained aftertreatment system ensures that emissions remain below according to the government transportation law.

To increase the lifespan and reduce the risk of breakdown, truck owners need to understand how aftertreatment systems work and what key pointers are to maintain them better.

SRB Equipment, an emissions repair shop Edmonton is here with valuable information about exhaust and aftertreatment systems. This information will help you to vehicle emissions repair with improved uptime and reduce costly repairs.

The 4 Components of an Aftertreatment System

Diesel Oxidation Catalyst (DOC) System

The engine’s exhaust first goes through the DOC, where the exhaust gases are oxidized to control carbon monoxide (CO) and hydrocarbon emissions.

Diesel Particulate Filter (DPF) System

After DOC, the next one is DPF, DPF is a device used to remove diesel particulate matter or soot from the exhaust gas of a diesel truck engine. The DPF removes over 99% of particulate matter from the exhaust stream.

Diesel Exhaust Fluid (DEF) Injection

The following process is called DEF injection. DEF is a solution of urea and water injected into diesel engine exhaust after it exits the engine and enters a catalytic converter. It’s part of a Selective Catalytic Reduction (SCR).

Selective Catalytic Reduction (SCR) System

The SCR stage removes the remaining NOx (nitric oxide and nitrogen dioxide). The decomposed urea and exhaust gases react with the active chemicals in the SCR to form carbon dioxide and water vapor.

Additionally, some sensors are attached to the aftertreatment system’s components.

  • A pressure sensor calculates the number of particles caught by the DPF.
  • Exhaust gas temperature sensors monitor the temperature of the system.
  • NOx sensors measure the NOx conversion.
  • PM (particulate matter) sensors or soot sensors are used to monitor particles in exhaust, mainly ash and soot.
  • These sensors throw signals when the aftertreatment system needs maintenance and repair.

Aftertreatment System Maintenance

Over time, DPF filter can be clogged. To make DPF continues to work effectively, DPF should be serviced regularly by an emissions mechanic.

Drivers must pay attention to aftertreatment system warning indicators and symbols. These indications notify the driver to take action to ensure the health of the aftertreatment system. It can result in reduced performance and possibly permanent damage to emission control components if ignored. So the fleet manager or driver must gain knowledge about vehicle emissions repair, which ultimately reduces truck failure problems on the road.

When to replace DPF filter: Engine manufacturers specify DPF service intervals, so read the service manual to determine how often your truck’s DPF needs to be cleaned or replaced. Generally, for on-highway vehicles, the DPF should be pulled off for its first cleaning after 100,000 to 150,000 miles and then every 400,000 miles after that for preventive maintenance cleaning. Even with cleanings every 400,000 miles, fleets should watch for an increased frequency of regenerations. SRB Equipment offers truck emissions repair Edmonton. We can also exchange your soiled DPF for a cleaned one.

Regeneration of the Diesel Particulate Filter (DPF)

DPF regeneration remove stored soot, oil, and ash caught in the DPF, ensuring that the filter remains in good working order. During active DPF regeneration, the exhaust temperature rises to more than 500C or 932F. These high temperatures allow for the oxidation of soot, which in turn cleans the filter.

Unlike automatic regeneration, which is controlled by the control module, manual regeneration, or parked regeneration, is controlled by the operator. Manual regeneration is performed when automatic generation isn’t possible.

Whenever a manual regeneration occurs in the vehicle, it is essential to ensure it is in a safe location because radiating temperatures can be dangerous and last up to 60 to 80 mins.


A damaged DPF can cause expensive repairs that can be avoided with preventive maintenance. You may contact SRB Equipment, a truck emissions repair Edmonton, to decrease truck breakdowns by emission issues. SRB Equipment provides complete emission system repair services to keep the engines running without destroying our environment.