What is the difference between an SMF-AR and CRT system?
Knowing the difference between these two systems is crucial in scoping and selection of the correct DPF (Diesel Particulate Filter) system. In this article, you will learn the differences between the two systems.
What is a CRT?
A CRT filter (Continues Regeneration Trap) does not require additional components or support to burn the filter clean.
The unit will continuously collect soot as the engine runs. Once the exhaust gas temperature reaches the ideal temperature, this will cause regeneration to start.
The soot on the filter will reach the required ignition point, by means of the exhaust gas temperature and subsequently it will result in the soot being ignited by the exhaust airflow. Soot on the filter will then turn into very fine ash collected inside the filter housing.
What is an SMF-AR?
An SMF-AR (Sintered Metal Filter-Active Regeneration) is a Diesel Particulate Filter with components that assist the exhaust system in burning the soot collected by the filter. It is primarily used in vehicles that don’t reach the required exhaust temperature.
Additional components that the SMF-AR have is the following:
- Additive reservoir
- Additive pump
- Additive filter
- The heating element is situated inside the filter housing
- Air mass flow sensor
The SMF-AR system has a ferrous liquid, also known as an additive, that is being pumped into the engine’s fuel system. After the combustion takes place inside the engine, the additive will be collected with the soot on the filter. As the backpressure reaches a set value, the Electronic Control Unit (ECU) will activate the heating element in the filter, and thus it will ignite the soot on the filter and burn it clean, leaving only a fine ash in the filter housing.
What is the Difference?
The CRT system has a passive regeneration trap that mainly relies on the exhaust gas temperature. The system requires it to be installed as close to the exhaust manifold/turbo as possible.
The SMF-AR system has more flexibility in where it is located on the machine, and the system does not mainly rely on preserving the exhaust temperature. The additive will need to be topped up when needed or prompted and the additive filter needs to be replaced after every service.
Which system is the Best Suited / Conclusion
It all depends on your engine specifications, opacity readings of your exhaust, and the temperature of your exhaust airflow. If you are not sure about the system that will be the best suited for your engine, contact John Ratcliffe, and we will provide you with the right system for your engine.