- Manufacturers have developed diesel and dual-fuel engines to exceed IMO Tier III and EU Stage V requirements.
- These engines produce 99.8% less carbon monoxide, 99.8% less NOx and 99.8% less particulate matter than EU Stage I engines.
- Methanol is looking promising as a future marine fuel, while HVO biofuels are available now for tugs and workboats.
Engine manufacturers have introduced new workboat ranges enabling greater flexibility for power, performance and emissions reductions. MAN Engines introduced a dual-fuel engine for fast workboats and small tugboats for diesel and hydrogen consumption.
Low-emissions tugboat engine
Its D2862 four-stroke engine has 12 cylinders in V arrangement, single cylinder heads, direct diesel injection and hydrogen injection into charge air and an exhaust aftertreatment system for IMO Tier III compliance.
Weighing 2,270 kg, this 1,940-mm engine can produce 750 kW of power at 2,100 rpm and has a stroke of 157 mm and a bore of 128 mm. It has a displacement of 24 litres and a rated torque of 3,406 Nm.
MAN says the engine can run 4,000 hours per year at an average load of up to 60%. There is a single turbocharger with charge air intercooler and wastegate, while the engine is seawater cooled by a rubber impeller pup or two-circuit cooling system.
Aftertreatment system of IMO tier III compliance
A representative of MAN UK distributor PME Power Systems told Riviera Maritime Media this range could be extended with V12 engines at lower power and running speeds for other workboat applications in the next few years.
AGCO Power has developed a new diesel engine with power range of 155-201 kW with an aftertreatment system for compliance with IMO Tier III and European Union Stage V emissions requirements.
UK-headquartered Mermaid Marine was the first to receive this new engine at the Seawork exhibition in Southampton, UK, in mid-June.
Beginning of engines
Mermaid sales executive Julian Osborne says production of these 74 LFEN-M engines will begin August 2023.
This four-stroke engine has displacement of 7.4 litres and six in-line cylinders, common rail injection, turbocharger, air-to-water cooling, diesel oxidation catalyst (DOC) and selective catalytic reduction (SCR).
“There will be a 4.9 litre in-line four-cylinder engine soon,” says Mr Osborne. “This will be going through prototype design and should be approved by the end of Q3 2023.” DNV has already certified the 74 LFEN-M engine for use on workboats, harbour and fishing vessels.
Strict emission standards
Marine and Hazardous (M&H) Engines has shipped the first marine engines that comply with California Air Resource Board (CARB) Tier 4+DPF strict emissions standards for workboats to the western US state for installation in Q3 2023.
These 9-litre, six-cylinder diesel engines can produce 317 kW at 2,200 rpm, with a torque of 1,376 Nm and peak torque speed of 1,600 rpm.
M&H managing director Barry McCooey says these engines produce 99.8% less carbon monoxide, 99.8% less NOx and 99.8% less particulate matter than EU Stage I engines.
“Our engines are approved to meet CARB standards and the first two are on their way to California,” he says.
“Our engines have twin turbochargers, exhaust gas recycling and optimised aftertreatment that includes DOC, SCR and diesel particulate filters.”
Ultra-low emission range
This range with ultra-low emissions includes diesel engines with displacement of 4.5 litres and 6.8 litres. Mr McCooey says engines with 14 to 18 litres displacement are under development.
M&H marine engines with 4.5-litres are rated at 130 kW at 2,200-2,400 rpm and 6.8-litres develops 170-224 kW at 2,400 rpm.
Cummins displayed its new generator set for vessels of more than 20 m using a 200-kW rated engine.
This genset includes an Onan QSB7 diesel engine to produce electricity on board at 50-60 Hz and will be managed via a ComAp controller.
Marine engine with SCR
Hendy Power introduced the new Cursor 16 600 marine engine from FPT Industrial, which is designed for the commercial marine market to comply with IMO Tier III emissions regulations with an SCR.
Hyundai Seasall has developed two new common-rail diesel engines with IMO Tier III options for light-duty commercial workboats.
The four-cylinder version achieves 149 kW and the V6 version develops 207 kW. There are stern-drive and shaft-drive gearbox options.
Japanese developments
IHI Power Systems has tested its first dual-fuel ammonia-diesel engines in Japan in collaboration with NYK Line, Nihon Shipyard Co, Japan Engine Corp and ClassNK.
They completed a land-based test for the stable combustion of ammonia fuel having an 80% co-firing ratio in April 2023. The goal is to install these engines in a converted tugboat in 2024.
IHI Power Systems carried out operational tests at its Ota plant in the Gunma Prefecture on a 280-mm bore, four-stroke, ammonia-fuelled marine engine.
Its latest trials include testing exhaust gas aftertreatment devices and fuel supply systems, confirming emissions of di-nitrogen monoxide (N2O), which has a greenhouse effect about 300 times greater than CO2, and unburnt ammonia are virtually zero.
Development, manufacture and shop trials of the Niigata four-stroke, ammonia-fuelled engines will follow and IHI anticipates they will be installed on A-Tug in June 2024.
Methanol and HVO are ahead of the rest for tugs
Methanol is looking promising as a future marine fuel, while HVO biofuels are available now for tugs and workboats.
Methanol would be a good all-round replacement for diesel or biodiesel when compared with hydrogen and ammonia fuels, due to its availability and physical characteristics.
Caterpillar Marine global marine technology steward Marinus Jansen says its energy density, required onboard storage, combustion efficiency and fuel availability make it a strong candidate for future projects.
“Methanol can be stored as a liquid in mild steel tanks; needing two-times the volume of marine gasoil, but this is manageable in a vessel,” said Mr Jansen during a Nor-Shipping seminar.
Methanol can be fed into a combustion engine or into a reformer to release hydrogen into a fuel cell with proton exchange membranes.
Caterpillar is ready for methanol with its Cat 3500 E series and for upgrades with dual-fuel technology for fuel flexibility. Its engines are ready and extensively using biodiesel on tugboats.
Dual-fuel engine and biodiesel
Mr. Jansen expects tugs of the future to have dual-fuel engines to use methanol when it is available and biodiesel as the back-up.
Engines using HVO biofuel have “no impurities and no soot, so they are cleaner than marine gasoil.”
Caterpillar is evaluating using HVO with aftertreatment systems for IMO Tier III emissions compliance and provides advice for using other biofuels, which can lead to algae growth and oil filter clogging.
“HVO is perfect as a drop-in fuel, but it will not get us all the way to net zero,” he says. This is where environmentally sustainable methanol can come in.
Tugs could also have batteries combined with these dual-fuel engines for zero emissions in harbours, or to provide a power boost when required.
Mr. Jansen says owners should consider fleet upgrades instead of investing in one fully green vessel.
“It is actually better to knock down emissions on 10 vessels by 10% rather than being perfect on just one vessel,” he says.
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Source: Riviera
