Rolls-Royce is further developing its proven large marine engines of the mtu 1163 and 8000 series to comply with the IMO Tier III emissions directive, the company announced at the SMM marine trade fair. From 2025, the engines are to be available in all cylinder variants – 16 and 20V respectively – in the power range between 4,800 and 10,000 KW. They will allow entry into the so-called Emission Controlled Areas (ECA), for example, in the Baltic and North Seas and off the North American coast. Rolls-Royce is developing the necessary exhaust gas after-treatment with the SCR system itself in order to be able to adapt it precisely to mtu engines and customer requirements. The company is also aiming to become an IMO emissions certificate holder, which would significantly reduce the workload for shipyard customers. The engines are to be approved for operation with sustainable fuels (EN15940, e.g., HVO) in the course of 2025.

In developing the new engine variants, Rolls-Royce pays particular attention to maintaining a maximum of common parts to the current versions in order to simplify maintenance and logistics. The electronics of all new engines are brought up to date. The most important change compared to the previous engines for IMO II is the new exhaust gas after-treatment, the core component of which is an SCR system in which nitrogen oxide emissions are reduced by 75 percent compared to the IMO II limits. It is a closed system in which the emissions upstream and downstream of the SCR system are continuously measured. This ensures optimal and compliant operation of the exhaust gas after-treatment system.