Choosing the correct Diesel Particulate Filter (DPF) system is essential for optimal engine performance and emission control. In this article, we will explore the differences between SMF-AR and CRT systems, helping you make an informed decision. 

What is a CRT?   

A CRT (Continuous Regeneration Trap) filter operates without the need for additional components to clean the filter. Here’s how it works: 

- Soot Collection: As the engine runs, the filter continuously collects soot. 

- Regeneration: Once the exhaust gas temperature reaches an optimal level, regeneration starts. The high temperature causes the soot to ignite and burn off. 

- Ash Collection: The burnt soot turns into fine ash, which is collected inside the filter housing. 

What is an SMF-AR? 

An SMF-AR (Sintered Metal Filter-Active Regeneration) system includes components that actively assist in burning the soot collected by the filter, making it suitable for vehicles that don’t reach the necessary exhaust temperature. Key components include: 

- Additive System: A ferrous liquid additive is pumped into the engine’s fuel system. 

- Heating Element: Located inside the filter housing, it helps ignite the soot. 

- Sensors and Reservoirs: Includes an additive reservoir, pump, filter, and air mass flow sensor. 

How SMF-AR Works: 

- The additive combines with the soot during combustion. 

- When backpressure reaches a set value, the Electronic Control Unit (ECU) activates the heating element, burning the soot and leaving fine ash in the filter. 

Key Differences Between CRT and SMF-AR 

Regeneration Method: 

  - CRT: Relies on exhaust gas temperature for passive regeneration. 

  - SMF-AR: Uses active regeneration with the help of an additive and heating element. 

Installation Flexibility: 

  - CRT: Needs to be installed close to the exhaust manifold or turbo to maintain high temperatures. 

  - SMF-AR: Offers more flexibility in installation location. 

Maintenance: 

  - CRT: Minimal, primarily dependent on exhaust temperature. 

  - SMF-AR: Requires periodic topping up of the additive and replacement of the additive filter after each service. 

Which System is Best Suited? 

The choice between CRT and SMF-AR systems depends on various factors including engine specifications, exhaust opacity readings, and exhaust airflow temperature. If you’re unsure which system is best for your engine, contact John Ratcliffe for expert guidance and the perfect solution for your needs.