Wärtsilä 46DF

Optimal prime mover solution for, amongst others: LNG Carriers, Cruise ships, RO-RO/PAX, Ferries, large Offshore units.

The Wärtsilä 46DF is a four-stroke dual-fuel engine that can be run on natural gas, heavy fuel oil (HFO) or marine diesel oil (MDO).

The engine can smoothly switch from gas fuel to HFO/MDO operation and vice versa without loss of power or speed. The Wärtsilä 46DF design is based on the well proven and reliable Wärtsilä 46F and Wärtsilä 50DF engine families, which have operated successfully on the market since the early 2000s. Both engines have an outstanding track record, with more than 800 engines in operation and over 11 million running hours experience using Wärtsilä’s leading DF technology.

The Wärtsilä 46DF has extended Wärtsilä’s dual-fuel engine family by covering the power range from 6.2 MW to 18.3 MW at 600 rpm.


    The Wärtsilä 46DF is available with a choice of two performance criteria, depending on the application and customer requirements. The prime mover machinery can be optimized for either:

    • Power - to produce the best available power per weight ratio in its class
    • Efficiency - to give outstanding fuel energy consumption performance across the entire operating range regardless of the fuel mode selected

    Wärtsilä 46DF

    • Cylinder bore 460 mm
    • Piston stroke 580 mm
    • Cylinder output 1045/1145 kW/cyl
    • Engine speed 600 rpm
    • Mean effective pressure 21.7, 23.8 bar

    Key benefits

    • IMO Tier III Compliant
    • Lowest gas fuel consumption in the industry
    • Lowest fuel oil consumption in the industry
    • Most powerful 4-stroke gas engine on the market
    • Fuel flexibility
    • Proven and reliable dual-fuel technology
    • Long overhaul intervals
    • Low exhaust gas emissions
    • Low gas feed pressure
    • Embedded automation system

    Fuel flexibility

    Wärtsilä’s proven dual-fuel technology enables owners and operators to choose both gas and liquid fuel, and switch between the two according to cost, availability, and local environmental regulations.

    The switch between fuel types is made without loss of power or speed. The engine automation adapts automatically to the relevant fuel selection, both in normal and emergency modes.

    In gas mode, the natural gas is fed to the engine at low pressure. This facilitates a simpler and space saving engine room configuration, while providing easier and faster maintenance activities.

    The engine’s gas piping is double-walled as standard, and the advanced integrated automation system enables enhanced safety and local monitoring. This leads to safer and more reliable operations, under all conditions.The complete built-in automation minimizes the need for external controls, thus saving engine control room space.

    Technical data
    Wärtsilä 46DF IMO Tier III
    Cylinder bore 460mm Fuel specification:
    Piston stroke 580 mm Fuel oil 700 cSt/50°C
    Cylinder 1145 kW/cyl 7200 sR1/100°F
    Speed 600 rpm ISO 8217, ISO-F-DMX, DMA & DMB
    Mean effective pressure 23.8 bar BSEC 7490 kJ/kWh at ISO cond.
    BSGC 7450 kJ/kWh at ISO cond.
    Piston speed 11.6 m/s  

    Dimensions (mm) and weights (tonnes)
    Engine type A* A B C D F Weight
    6L46DF 8 670 8 953  3 255 3 185 3 750 1 430 102
    7L46DF 9 635 9 773  3 255 3 185 3 750 1 430 118
    8L46DF 10 310 10 590 3 445 3 185 3 750 1 430 130
    9L46DF 11 130 11 413 3 445 3 185 3 750 1 430 146
    12V46DF 11 120 10 350 3 670 4 555 3 800 1 620 184
    14V46DF 12 170 11 400 3 670 4 555 3 800 1 620 223
    16V46DF 13 450 12 700 3 860 5 174 3 800 1 620 235


    Rated power
    Engine type 1145 kW/cyl
    6L46DF 6 870
    7L46DF 8 015
    8L46DF 9 160
    9L46DF 10 305
    12V46DF 13 740
    14V46DF 16 030
    16V46DF 18 320


    The Wärtsilä 46DF is designed for a broad range of marine applications. Thanks to its fuel flexibility and the modular, compact design, the engine can be optimized for constant speed diesel electric operation. It also meets the need for direct drive main engine propulsion, operating at either constant speed or along a combinator curve. The multi-fuel operation capability offers new machinery opportunities for various vessel applications.

    Methane Number

    Wärtsilä Methane Number Calculator

    We have developed this tool for ship owners and operators to calculate the Methane Number of the fuel gas.
    The calculation result indicates whether or not the given gas quality is suitable for use in Wärtsilä dual-fuel engines.

    Methane CH4
    Iso-butane (2-Methylpropane)i-C4H10
    Iso-pentane (2-Methylbutane)i-C5H12
    Neo-pentane (2,2-Dimethylpropane) neo-C5H12
    Mix-hexaneMix C6H14
    Mix-heptaneMix C7H16
    Carbondioxide C02
    Nitrogen N2
    Hydrogen sulfideH2S
    Total mol%
    Wärtsilä Methane number (WMN)
    Propane Knock Index (PKI)
    The calculation tool is owned by Wärtsilä and is made for customer use and is for guidance only. Changes in the tool is reserved at any time.

    Product hologram


    The Wärtsilä Gas Valve Unit Enclosed...

    Wärtsilä’s dual-fuel engine technology is...
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