Emission Control Systems
Diesel particulate filter (DPF)
A diesel particulate filter (DPF) is a device that removes harmful particles from the exhaust of diesel vehicles. DPFs are designed to reduce emissions and improve air quality.
How it works?
DPFs trap solid particles like soot and ash in a honeycomb-shaped ceramic structure
They allow gaseous components to escape
The trapped soot must be periodically burned off to regenerate the filter
Benefits
DPFs reduce harmful emissions and prevent black smoke from diesel vehicles
They help meet European emission standards
They improve air quality and health standards
Regeneration
The regeneration process involves burning off the trapped soot
This process usually requires driving the vehicle at over 50 mph for a short time
The regeneration process produces small amounts of water and carbon dioxide
History
DPFs have been in use for over 20 years
Euro 5 exhaust emissions legislation made DPFs mandatory in 2009
All modern diesel cars are fitted with at least one DPF
Common Problems
Common problems with a diesel particulate filter (DPF) include
Failed regeneration
When a regeneration cycle fails, extra fuel is injected into the cylinders but doesn’t burn, which can damage the engine.
Exhaust gas recirculation (EGR) issues
Carbon dust in the exhaust gasses can clog the EGR system, which can lead to a clogged DPF.
Symptoms of a DPF problem
· The DPF warning light on the dashboard is on
· The engine has reduced power
· The engine has difficulty revving to high RPMs
· The engine has trouble starting
· The exhaust emits black smoke when accelerating
· The cabin smells strongly of diesel fuel
· The fuel economy is reduced
· The start-stop function isn’t working
Exhaust Gas Recirculation valve (EGR)
An EGR valve, or Exhaust Gas Recirculation valve, is a device that reduces harmful emissions in a vehicle’s engine. It’s a key component of a vehicle’s engine management system.
How it works?
The EGR valve recirculates a portion of exhaust gases back into the engine’s intake system.
The recirculated gases are then burned a second time, which reduces toxic gas emissions.
This process also improves fuel efficiency and engine performance.
Where it’s found
The EGR valve is usually located between the exhaust and intake manifolds.
It can also be found near the exhaust manifold or inside the intake system.
Why it’s important
The EGR valve helps to reduce nitrogen oxide (NOx) emissions, which are a by-product of the combustion process.
It’s an important part of efforts to reduce climate change and meet increasingly strict emissions regulations.
When it might fail
The EGR valve can become clogged with carbon deposits over time, which can prevent it from working properly.
A clogged EGR valve can pollute more and damage the intake system.
You can also watch this video to learn more about EGR valves:
AdBlue system is a diesel exhaust fluid (DEF)
The AdBlue system is a diesel exhaust fluid (DEF) system that reduces harmful emissions from diesel engines:

What IS it?
AdBlue is a non-toxic, colorless liquid made of urea and deionized water that’s stored in a separate tank from the vehicle’s fuel tank.
HOW IT WORKS ?
When the engine is running, AdBlue is injected into the exhaust system and breaks down nitrogen oxide (NOx) emissions into nitrogen and water. This process is called selective catalytic reduction (SCR).
Why it’s important
AdBlue is essential for helping diesel vehicles comply with Euro 6 emission standards.
How to use it
The driver is responsible for keeping the AdBlue tank topped up. The car’s dashboard will provide updates on the AdBlue level and range. When the tank is low, the driver will receive warnings, and the car’s speed may be limited. If the tank is empty, the car won’t start. AdBlue is available at most fuel stations and car parts shops.
AdBlue Problems and Failures
AdBlue systems can experience a number of problems, including:
- Crystallization: AdBlue can crystallize in cold temperatures, causing blockages in the system. This can be due to improper storage or extreme temperatures.
- Injector failures: Deposits can build up on the AdBlue injector, causing poor spray patterns and reduced efficiency.
- Pump failures: Faults can be caused by contamination, poor quality AdBlue, or crystallization.
- Sensor failures: The AdBlue level sensor or temperature sensor may fail, leading to inaccurate readings.
- Heating failure: The AdBlue heater may fail.
- Nozzle failure: The AdBlue nozzle may fail.
- AdBlue system control unit failure: The AdBlue system control unit may fail.
- Faulty wiring: Faulty wiring can cause issues with the AdBlue system.
- Defective sensors: Defective sensors can cause issues with the AdBlue system.
- Signs of an AdBlue system failure include: warning lights and messages on the dashboard, reduced engine power, and countdown to vehicle immobilization.
- To help prevent AdBlue system failures, you can: Use high-quality AdBlue solution, Perform regular maintenance, and Use additives to prevent crystallization.
If your AdBlue system fails, feel free to get in touch, we have deep expertise in solving AdBlue system and related issues.