6S90ME-LGIM9.6
The MAN 6S90ME-LGIM9.6 is a low‑speed, six‑cylinder, two‑stroke main engine delivering up to 77 MW at 76 rpm, featuring dual‑fuel operation with high‑pressure methanol injection and diesel pilot ignition.
Engine Specifications
Inspector Detail
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Designation decoded
6 = number of cylinders, S = Super Long Stroke, 90 = bore 900 mm, ME = MAN Electronically controlled, LGIM = Liquid Gas Injection Methanol, 9.6 = Mark 9.6 control generation.
Background
The S90ME-LGIM is the Super-Long-Stroke variant of the 90 platform. Shorter stroke (3260 vs. 3720 mm) than the G90, higher speed. For very large tankers (VLCCs) and bulkers. The S90 platform is proven and is now offered as an LGIM for the methanol transition.
Calculated metrics
Inspector checklist
- High-pressure pumps 600-700 bar: large delivery quantities, redundancy
- Injection valves: 900 mm combustion chamber, spray penetration
- Double-wall piping: leak detection
- Changeover: complete purge cycle
- Liners 900 mm: BN 25-40, wear rate, bore polishing
- Piston rings: thermal deformation at 900 mm diameter
- Crosshead: S/B=3.62, the lowest ratio in the series results in lower side forces
- Stuffing box: drainage monitoring
- HPS: high flow rates, multiple units
- FIVA: methanol calibration Mark 9.6
- Cylinder pressure monitoring: Pmax measurement
- Methanol detectors: large engine room
- ESD: automatic diesel fallback
- Fuel prep room: UV/IR
- OMD: all cylinders
Logbook reference values
| Parameter | Expected | Deviation means |
|---|---|---|
| Exhaust temperature (methanol) | 290-380 °C | >25 °C spread: injector |
| Methanol injection pressure | 600-700 bar | Pump/filter |
| Cylinder oil consumption | 0.5-0.8 g/kWh | Dosing |
| OMD | <2.5% LEL | Leakage — STOP |
| Pmax spread | ±5 bar | Injection/compression |
Common Failure Modes
Expert tips
- 💡 The S90 with S/B=3.62 has the lowest stroke-to-bore ratio in this batch — this means lower crosshead loading, but also lower thermodynamic efficiency at low speeds vs. the G90.
- 💡 At 900 mm bore, methanol atomization in the large combustion chamber remains the central challenge — regardless of G or S.
- 💡 S90 at methanol part load: higher speed than the G90, hence a shorter injection window — prioritize timing control via the ECS.
Related components
Classification & regulatory
IGF Code, LFPF notation. IMO Tier II in methanol mode. Tier III requires SCR/EGR.
Reference content for inspector orientation. Always verify against manufacturer's manual, latest service letters and class society requirements.
Other Cylinder Configurations 47
Components & Design
Component data being added…
Technical Data
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