What an SCR is/does

A Diesel Selective Catalytic Reduction (SCR) filter is an advanced emissions control technology used in diesel engines to significantly reduce nitrogen oxide (NOx) emissions. It is a key component in modern diesel exhaust aftertreatment systems.

How It Works:

1. 1. Injection of Diesel Exhaust Fluid (DEF): A urea-based solution (commonly known as DEF or AdBlue) is injected into the exhaust stream.
   2. Chemical Reaction in the SCR Catalyst: The DEF reacts with NOx in the presence of a catalyst, breaking it down into harmless nitrogen (N₂) and water (H₂O).
   3. Emission Reduction Compliance: This process helps diesel engines meet stringent emission standards such as EPA Tier 4 Final and Euro 6 regulations.

Key Benefits:

• • Significantly reduces NOx emissions (by up to 90%)
  • Improves fuel efficiency by allowing the engine to operate at higher combustion temperatures
  • Reduces environmental impact, making diesel engines cleaner

1. Crystalized DEF

If the closing system fails or the engine exhaust is at too low of temperature. DEF can crystalize into a white coating or hard rock-like obstruction.

2. Soot

If the DPF failed, soot can contaminate the SCR.

3. Damage

How do we Test an SCR?

• Borescope
• Airflow Pressure