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Wärtsilä

9W34DF

Wärtsilä 34DF / 34SG — Viertakt-Marinediesel, Bohrung 340 x Hub 400 mm, 720, 750 rpm, 2610 (6L @ 520 kW/cyl aux) to 9800 (20V @ ~490 kW/cyl). Brennstoff: Dual-fuel (34DF): LNG/HFO/LFO/Biofuel; Gas-only (34SG): Natural Gas/Biogas/Syngas/H2-blend. Status: In production (34DF since 2009, 34SG based on proven 32 platform since mid-1990s; 34SG variants actively marketed 2022-present). Verifiziert, Datenblatt verlinkt.

4500.0 kW
Power

Engine Specifications

9
Cylinders
340 mm
Bore
400 mm
Stroke

Components & Design

Component data being added…

Technical Data

Power per cylinder (main engine 34DF) 500 kW @ 750 rpm
Power per cylinder (auxiliary 34DF) 520 kW @ 720-750 rpm
Mean effective pressure (main) 20.0-19.8 bar
Piston speed 9.6-10.0 m/s
Compression ratio (16V/20V) 12.6:1
Engine type 4-stroke, turbocharged intercooled non-reversible
Swept volume per cylinder 36.3 dm³
34DF Max output (16V main) 8000 kW
34DF/34SG Max output (20V genset) 9800 kW
34SG design Spark-ignited, lean-burn, pre-chamber
20V34SG dimensions L:12.7m × W:3.3m × H:4.65m
20V34SG weight 131,500 kg
configuration L
rpm 720
fuel type Dual-Fuel LNG/HFO
technology Dual-Fuel CR
power kw 4500

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Common failures & inspection points

Turbocharger bearing failure - bearing location pins can break, causing the shaft to rotate freely inside housing and potentially damaging the compressor wheel.
Fuel injector tip carbon deposits and clogging - when operating in backup fuel (diesel) mode, liquid fuel deposits on injector tip can thermally decompose ('cra
Gas valve unit (GVU) functionality criticality - GVU valve tightness and proper ventilation during stop sequences essential for safe operation; leakage prevents
Cylinder liner scuffing from insufficient lubrication - mirror polished finish and loss of crosshatch pattern indicate oil starvation; piston rings run dry caus
Load-sharing failures and abnormal shutdown sequences - improper sensor signals or fuel supply irregularities can trigger emergency stops; root causes (fuel sys

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

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Equipment Model #142665 · ✓ still in production