MODULAR EXHAUST GAS AFTERTREATMENT SYSTEM FROM MAN ENSURES IMO TIER III AS WELL AS US EPA TIER 4 COMLIANCE FOR WORKBOATS
The modular exhaust after-treatment System (EAT) from MAN Engines meets the requirements of the US Tier 4 emissions standard for workboats. This system stands out due to its great flexibility and extremely compact design, which are a distinct advantage in the varied installation situations on workboats, in which space is at a premium. The engineers of MAN Engines achieved this pioneering result by making the components freely placeable, allowing for an enormous range of variants of the EAT. This gives boat designers access to flexible system integration options with a high component density in a myriad of different installation situations.
But the essentially maintenance-free exhaust after-treatment System is also a particular benefit to end users: it allows the engine to be designed with a very favorable characteristics curve, so that the same performance can be achieved with lower fuel consumption. Thanks to the SCR catalyst being coated with vanadium, it is resistant to sulfur as well, and can therefore also be used in countries where only low-quality diesel fuel is available.
The modular exhaust after-treatment System is made up of an SCR (Selective Catalytic Reduction) catalyst, an SCR mixer and a metering unit for the 32.5% aqueous urea solution. This is injected directly into the exhaust train, in order to ideally convert the accumulated nitrogen oxides (NOx) into water (H2O) and nitrogen (N2). By reducing the system to just a few components, MAN Engines is offering an easy, simple, but nevertheless robust exhaust gas aftertreatment system. Airless injection of the urea solution saves yet more space and technical expense, as well as further reducing the installation volume of a system with an already very flexible installation. “Our MAN engines need no more than an SCR catalyst combined with optimized combustion to comply with the US Tier 4 standards. We have no need of a heavy and space-hungry diesel particulate filter or oxidation catalyst, which would also involve extra costs,” says Jürgen Haberland, Director of Sales Engines at MAN Engines & Components Inc. in Pompano Beach, Florida.
In other words, the MAN Engines modular exhaust gas aftertreatment system is a modern SCR-only system, which does without exhaust gas recirculation as well as bulky and heavy components like diesel particulate filters and oxidation catalytic converters. This saves additional costs and makes the system less complex as a whole.
Together with the optimized combustion of MAN engines, the SCR catalytic converter meets the requirements of both emission levels IMO Tier III and the US EPA Tier 4. Using the SCR means that specific fuel consumption was additionally reduced by up to 8% per engine while still maintaining the same power. Needless to say that MAN Engines are already known for their impressive fuel efficiency in the industry. Thereby the engineers at MAN Engines achieved to develop an efficient, simple and lightweight exhaust gas aftertreatment system that remains robust and versatile.
The foundation of the system is a result of the expertise at MAN Truck & Bus AG, which has successfully been using SCR systems in the group's own trucks in high-volume production since 2006. Furthermore, MAN Engines also benefits from the experience of fitting and installing after exhaust treatment systems gained in the agricultural and industrial sectors. Here the technology has been used since 2015 for in-line and V-engines. Also the SCR system is currently proving its practicality in field trials for commercial work boat applications.
As a result, the engines from MAN Engines for work boats are equipped to meet the IMO Tier III (within NOx ECA North Sea ECA & Baltic Sea ECA) emission standard, which will be mandatory from 2021 on. This standard stipulates a reduction in nitrogen oxides (NOx), depending on the engine’s maximum operating speed, by around 70 percent compared to its predecessor, IMO Tier II. Instead of the 7.7 g/kWh permitted previously, only 2.0 g/kWh will be allowed in the future.
The US Tier 4 emissions standard applies from 1 October, 2017 for all workboats flying US flags with a power output of more than 600 kW (816 hp) per combustion engine. For diesel engines, the legislation includes a reduction in nitrogen oxides (NOx) of nearly 68 percent to 1.8 g/kWh, as well as a reduction in particulate emissions of nearly 64 percent to 0.04 g/kWh.
With its 12-cylinder engines, MAN Engines currently offers a consistent range of outputs from 551 to 1,066 kW for the US Tier 4 emissions standard and up to 1,213 kW for the IMO Tier III emissions standard. This portfolio will be continuously expanded to include other power outputs.