Main Engine 2-Stroke · Main Engines (2-Stroke)
Crew, engineers, and operators on board ships depend on reliable marine engines to ensure safe and efficient operations. The S50ME-GI by MAN Energy Solutions is a dual-fuel engine designed for vessels requiring flexibility in fuel use. With its high-pressure gas injection capabilities, it operates on LNG, HFO, VLSFO, or MGO, offering IMO Tier III compliance in gas mode. This engine supports 5 to 8 cylinders, delivering power from 5,450 to 9,960 kW at a direct drive configuration. The ME-GI family, launched since 2015, is known for its robust design and flexibility but may experience common failures such as gas admission valve issues or fuel oil/gas changeover problems during rapid transitions. Maintenance includes regular checks on the gas supply system and standard intervals for the engine, with critical spare parts like GAVs taking approximately 4-6 weeks for delivery.
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What our service work and the manufacturer documentation say about keeping this model running.
GAV: 6,000-8,000 hrs. Gas supply system: per Wärtsilä/MAN FGSS schedule. Otherwise standard ME-C intervals.
S für Super-Long-Stroke, 50 für Bohrung 500 mm, ME für elektronische Steuerung, GI für Gas Injection — Hochdruck-Dual-Fuel mit LNG-Einspritzung bei 300 bar im Dieselprozess. Specs: 5-8 Zylinder, Hub 2214 mm, IMO Tier III im Gasmodus.
Der S50ME-GI ist der effizienteste LNG-Dual-Fuel-2-Takt-Motor in der 500-mm-Klasse. Die Hochdruck-Gaseinspritzung bei 300 bar im Diesel-Cycle eliminiert praktisch den Methanschlupf — ein entscheidender Vorteil gegenüber Niederdruck-Otto-Cycle-Motoren (GA). Standard auf LNG-Carrier-Neubauten und zunehmend auf Containerschiffen. Im Gasmodus Tier III ohne SCR/EGR erreichbar.
| Parameter | Expected | Deviation means |
|---|---|---|
| Abgastemperatur nach Zylinder | 350-420 °C (Diesel ≈ GI) bei 85% MCR | Spread >20 °C → Gasinjektionsventil oder Pilotdüse prüfen |
| HP-Gasdruck vor Injektor | 250-350 bar | Druckschwankungen → HP-Kompressor oder Regelventil |
| Pilot-Fuel-Anteil | 2-5% im GI-Modus | Anstieg → Gasinjektions-Problem, Zylinder fällt auf Diesel zurück |
| Zylinderöl-Feed-Rate | 0.5-0.8 g/kWh (GI-Modus, schwefelarmer Betrieb) | BN-Anpassung an Pilot-Schwefelgehalt |
| Methan-Emission (Abgas) | GI: nahezu Null Methanschlupf | Messbarer Methanschlupf → Gasinjektions-Timing oder -Menge fehlerhaft |
Symptoms: Gas-Trip, automatischer Diesel-Fallback, Kompressor-Alarm
Causes: Ventilplatten-Bruch, Lager-Verschleiß, Inter-Cooler-Problem
Preventive: Ventilplatten nach Hersteller-Intervall tauschen, Schwingungsmonitoring, Redundanz nutzen
Symptoms: Leistungsabfall einzelner Zylinder im GI-Modus, PMI-Asymmetrie
Causes: Verbrennungsrückstände bei Diesel-Gas-Wechsel, Düsenspitzen-Erosion, Unzureichende Kühlung
Preventive: Gasinjektoren in festen Intervallen tauschen, MGO statt HFO als Pilotbrennstoff bevorzugen
Symptoms: Timing-Drift, Abgastemperatur-Spreizung
Causes: Steueröl-Kontamination, Dichtungsverschleiß
Preventive: Steueröl <10 µm filtrieren
IMO Tier III im Gasmodus ohne SCR/EGR — der GI-Motor erreicht Tier III inhärent durch niedrigere Verbrennungstemperaturen. IGF-Code Compliance obligatorisch. EEDI/CII: GI reduziert CO2 um 20-25% gegenüber HFO, kein Methanschlupf-Malus.
Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.
MAN PrimeServ. GAV-Teile: 4-6 Wochen. FGSS-Teile: separat über FGSS-Hersteller.
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