A brief Intro on Emissions Regulation

Since several years news and articles about Diesel engine and air quality are booming. There are two main reasons to improve engine emissions:

• Fight against climate change by reducing greenhouse gas (GHG).
• Reduce particles that can be harmful for health.

United Nations Sustainable Development Goal 13. Source: United Nations website https://sdgs.un.org/sdgs.un.org/en/goals

Climate action is one of the 17 Sustainable Development Goals (SDG) of the United Nations (UN). Those goals are call for action by all countries to improve human being life and protect our planet.

Facts about climate change. Source: United Nations Infographics #13

Those major reasons pushed several authorities to define emissions threshold according to:

• Application field: on-road, off-road, emergency, marine or inland waterway and a lot more.
• Geographical location
• Engine power

Those points usually define which standard to comply with. Nevertheless; several specificities can modify compliance rules. Being exhaustive on this point would be…exhausting.

Let’s do a (very) little bit of physics and chemistry: Diesel engines use air compression and its temperature elevation to inflate pressurized Diesel. During combustion gases expand, push the piston and deliver mechanical power. The combustion reaction creates compounds we have to reduce (in red):

• NOx are Nitrous Oxyde
• HC + C are unburned particulate
• SOx are Sulphur Oxyde
• CO is Carbon Monoxyde

The International Maritime Organization (IMO) through the “International Convention on the Prevention of Pollution from Ships” convention (MARPOL) is aiming to minimize these compounds. MARPOL Annex VI is focusing on NOx and SOx emissions from ship exhaust.

International Maritime Organization logo. Source IMO website https://www.imo.org/

Those emission compliances are known as “Tier”. Tier I appears is 1997 and entry into force in 2005. Tier II and Tier III followed and defined lower threshold for NOx.

Chart of NOx limit according to Tier level

The above chart is showing the limit of NOx emissions according to engine speed:

• Blue line is Tier I limit. The limit remains constant after 2200rpm for all Tier.
• Green line is Tier II limit. It is a 20% reduction compare to Tier I.
• Red line is Tier III limit. It is a 80% reduction compare to Tier I.

Tier II limit can be reached with Diesel engine optimisation of combustion (we will cover this in the next article of NPS Yachting). Tier III needs additional technologies such as Selective Catalytic Reduction (SCR). Nevertheless, Tier III applies in NOx Emission Control Area (ECA). ECA are designed control area for more stringent control of emissions.

ECA Area. Source: Wikipedia https://fr.wikipedia.org/wiki/Zone_de_contr?le_des_émissions_atmosphériques

What we can see on the map:

• One ECA in North America plus Caribbean area
• One ECA in North Sea & Baltic Sea
• Mediterranean area is under proposal for near future.
• Other areas are under proposal

To guarantee engine compliance, an Engine International Air Pollution Prevention (EIAPP) certificate has to be issued for each engine.

As mentioned earlier; there are additional European or United States emissions standards for vessels. Thus, discussions with engine expert like NPS Yachting is mandatory to ensure good engine selection.

Author: Olivier Krafft - Business Manager at NPS Yachting