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MAN Energy Solutions

MAN 12V35/44DF

Name: MAN Energy Solutions MAN 12V35/44DF
Brand: MAN Energy Solutions

MAN Energy Solutions L35/44DF Dual-Fuel Four-Stroke Marine Engine — Viertakt-Marinediesel, Bohrung 350 x Hub 440 mm, 750 rpm (GenSet), 720 rpm (auxiliary) rpm, 3180–5300 kW (6L–10L @ 750 rpm). Brennstoff: Natural gas (LNG/CNG), HFO, MDO, MGO, diesel pilot; L35/44DF CD methanol-ready 2026. Status: Production (L35/44DF CR active since 2015; L35/44DF CD launched 2023, deliveries 2024+). Verifiziert, Datenblatt verlinkt.

6720.0 kW

Power

Engine Specifications

Cylinders

350 mm

Bore

440 mm

Stroke

Components & Design

Component data being added…

Technical Data

Displacement per cylinder 42.3 liters

Power per cylinder @ 750 rpm 530 kW (L35/44DF standard); 560 kW (L35/44DF CD)

MEP (Mean Effective Pressure) 20.0–20.1 bar

SFOC liquid fuel @ 85% MCR 175.5 g/kWh

SFC gas operation 7440 kJ/kWh

Dry mass – 6L/7L/8L/9L/10L 40.5 / 45.6 / 50.7 / 55.0 / 59.7 tonnes

Methane slip reduction (CD variant) 85% vs. industry standard

Emissions compliance IMO Tier II (diesel) / Tier III (gas)

configuration V

rpm 720

fuel type LNG/HFO/MGO

technology Dual-Fuel Common Rail (LNG/HFO/MGO)

displacement l per cyl 42.3

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Common failures & inspection points

Methane slip via scavenging leakage – unburned methane escapes to exhaust when gas injection occurs before exhaust valve closure; mitigated in CD variant via op

Monitor exhaust methane concentrations; inspect valve timing; verify adaptive combustion control (ACC) system calibration

Combustion instability at low load (<0% MCR) in gas mode – risk of pre-ignition, knocking, and transient power loss during load fluctuations or fuel-quality var

Review engine load profiles during dredger/auxiliary duty; check fuel-gas methane number (spec ≥70 MN); monitor combustion pressure transients

Crankcase explosion hazard during transient operation – accumulation of unburned gas and oil mist in crankcase when switching fuels or under rapid load changes;

Inspect crankcase ventilation filter; check scavenging air receiver for oil/liquid accumulation; monitor crankcase pressure during fuel transitions

Fuel injection nozzle/pilot-fuel system fouling – common-rail pilot-fuel system susceptible to coke deposit buildup and relief-valve drift under variable dual-f

Periodic fuel nozzle inspection; relief valve pressure setting verification; fuel system cleanliness monitoring

Turbocharger bearing accelerated wear under rapid load transients – MAN documentation acknowledges the 35/44DF 'handles high load-fluctuations' in dredger duty,

Monitor turbocharger oil outlet temperature; inspect bearing clearance during scheduled maintenance; verify steady oil-supply pressure under transient load

Type-general inspection and maintenance points for this equipment category — not model-specific.

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Equipment Model #66691 · ✓ still in production