Emissions compliance: DPF or not DPF?

DPF means Diesel Particle Filter. This filter traps and removes particle matter also called soot (the black smoke) from the exhaust gas. It is a rare technology in yachting sector whereas it is common in automotive and off-highway industries.

Why is DPF seldomly used in yachting?

The main regulated Diesel pollutants are Particulate Matter (PM) and Nitrogen Oxides (NOx). The IMO MARPOL Annex VI is focusing on NOx and Sulfur Oxides (SOx) emissions. The new engine technologies listed in our Engine Optimisation article are sufficient to reach legal PM thresholds in most cases. So, there is generally no legal requirements to add an after-treatment dedicated to particle matter in yachts.

Nevertheless, some yachts are equipped with DPF. ?What are the benefits of this device?

Marine genset with Diesel Particle filter on top – black lagging on the device

• The exhaust gases are cleaned from harmful particles. The yachts surroundings are much healthier for the owner, the guests and the crew.
• The exhaust gases are much more discreet: no black smock anymore.
• The water around the yachts stays clean for swimming. No more unburned layer in the water.?
• The hull and deck stay clean. The painting close to exhaust outlet last much longer.

?These advantages make especially sense at anchor. The gensets are running non-stop to provide power on board. In this case; smoky gensets can really impact the yachting experience. Even if new engine generation are cleaner; DPF is the ultimate yacht feature to enjoy clean & healthy anchoring.

Zenoro marine genset with Diesel Particle filter on top

How does it work?

Basically, it is a filter designed to force exhaust gases to pass through porous walls. There are inlet channels and outlet channels separate by these porous walls. The soot is collected in the inlet channels and aggregates. These aggregates are removed thanks to a chemical reaction activated by a coating on the filter and high temperature: the regeneration. We will not go deeper into the different technologies. There is a control of the filter clogging by measuring pressure at inlet and outlet. A dedicated controller or the engine calculator can leverage different solutions to force regeneration. At least if the filter is too clogged, a manual cleaning with a special oven can be done.

DPF filters at NPS Yachting workshop

Zoom on filter channels

?Can we upgrade an existing equipment?

Absolutely; some companies like our sister company Xeamos are engineering DPF solutions for all Diesel engines. An equipment upgrade is quite easy but requires space in the engine room. Therefore, tailored designed are required like extra flat section and inlet/outlet position.

Xeamos Diesel Particle Filter with its controller. Source Xeamos

To summarize, DPF is a proven technology that cleans the Diesel exhaust gases form the soot. It is not common in yachting but it gets more and more popular to improve the owner and guest experience on board. It can be added to existing equipment without major change in the engine room.

Author: Olivier Krafft - NPS Yachting