Diesel Particulate Filters

Diesel Particulate Filters

What are Diesel Particulate Filters?

Diesel Particulate filters (DPF) are devices constructed to trap harmful particulates from diesel engine exhaust, preventing them from being released into the atmosphere. There are several different types of filters, however, they all need to go through the process of regeneration in order to eliminate the trapped particles and keep themselves clean.


Why are they needed?

The US Environmental Protection Agency has determined that diesel particulates are harmful carcinogens that contribute significantly to poor air quality and cause serious health issues. Through the Clean Air Act, they have regulated the requirement for most diesel engines to reduce their overall emission levels including diesel particulates. DPFs applied to new and older engines significantly reduce these harmful emissions and allow operators to run their diesel-powered equipment in full compliance with the regulations.

How are they cleaned?

Cleaning is performed through the regeneration process. There are three types of regenerations: Passive, Hybrid Passive, and Active.


Passive filters rely on elevated exhaust gas temperatures to clean or “regenerate” the filter after the soot collects.  Hybrid filters use either a load bank or a fuel burner to artificially elevate the exhaust gas temperature in order to start the regeneration process. Both have cold start operation and load limitations that require maintenance personnel to closely monitor their operation or they run the risk of clogging the filter and shutting down or damaging the engine.


Active filter technology does not rely on raising the exhaust temperature for regeneration. For example, the Rypos system uses a sintered metal fiber filter mesh to trap the soot particles as the exhaust flows through the filter. The system measures the back pressure across the filter and periodically energizes the sintered metal mesh to quickly burn the soot that has been trapped and collected. This continual regeneration maintains the filter systems in a clean state so that the engine is always available to provide peak load during all phases of operation. For operators, there is no need to alter or monitor their operation to ensure they have full power available when needed.

How to learn more:

Contact one of our experts.


By providing intelligent emissions’ reduction solutions, Rypos is innovating the future of clean air. Rypos focuses particulate filtration in single modular systems.

Do you need more information on Rypos Inc.? We can provide more information on diesel particulate filters, our services, and leading technology when you contact us.