MTU begins introducing tug Tier 4 engines

Rolls-Royce subsidiary MTU has begun manufacturing engines for tugboats and workboats that meet US Tier 4 and IMO Tier III emission requirements

MTU will start introducing a new series of low emission engine systems that meet IMO Tier III and the US government’s Environmental Protection Agency (EPA) Tier 4 requirements for tugs and workboats from Q3 this year.

This Rolls-Royce subsidiary intends to begin commercial production of its MTU Series 4000 engines with selective catalytic reduction (SCR) exhaust gas after-treatment units for tugs. This follows approval of these systems to the latest IMO emissions requirements from ABS, Bureau Veritas, DNV GL, Korean Register of Shipping, ClassNK, Lloyd’s Register and Russian Register of Shipping.

This means that these engines comply with the emission regulations in accordance with IMO Marpol Annex VI for IMO Tier III. Representatives of these class societies witnessed tests of the 20-cylinder version and awarded their approval on the basis that this was representative of the environmental performance of the remaining versions, which will include 12- and 16-cylinder models.

MTU has begun manufacturing its Series 4000 engines with SCRs for other marine sectors, with the first two 16-cylinder Series 4000 M73 engines to be fitted to an 80 m superyacht under construction at the Istanbul-based Bilgin Yachts shipyard, for delivery in the middle of 2019.

Series 4000 IMO Tier III and EPA Tier 4 engines will cover a power range from 1,119 kW to 3,220 kW. There will also be new engines for patrol boats and yachts in the same three cylinder versions, but with a power range of 2,160 kW to 3,900 kW.

Although at the time of writing in late April MTU had not received any orders for the Tier 4/Tier III version of Series 4000, it has secured orders for these engines without SCRs.

MTU spokeswoman Silke Rockenstein told Tug Technology & Business that MTU gained orders for Series 4000 engines for 20 tug newbuildings at various shipyards operated by Sanmar, Damen, Vittoria, Icdas and Remontowa for owners such as Svitzer, Russia-based Rosrao, the Polish Navy and Ukraine-headquartered Nibulon. MTU has also gained contracts this year to supply Series 4000 engines for tugs from Med Marine, but none of these will have SCRs either.

MTU highlighted a number of benefits and advantages from Series 4000 Tier 4 engines, saying that these workboat engines would provide a 45% increase in output compared with its predecessor versions. MTU also said that this will be the only high speed workboat engine that delivers an output of up to 3,220 kW.

MTU has improved the turbocharger’s operating efficiency to reduce fuel consumption by a further 5% compared with the previous model. It has also advanced the combustion process and fuel injection of these engines.

Rolls-Royce said the introduction of SCR to MTU’s Series 4000 engines had reduced nitrogen oxide emissions by 75% compared with the Tier II versions and lowered particulate emissions by 65% compared with EPA Tier 3 engines, which means there is no requirement for an additional diesel particulate filter.

Flexibility has been included in the design to enable users to switch between IMO II and IMO III modes during operations, depending on whether they need to use the SCR system. There are also sensors on the SCR to measure NOx emissions to ensure that the precise amount of reactant is introduced regardless of the conditions.

MTU Series 4000 SCR engines

12-, 16-, 20-cylinder models

75% reduced NOx emissions

65% less particulate emissions

IMO Tier III, EPA Tier 4 compliant

45% increase in output

Power range: 1,119 kW - 3,220 kW