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 700 engines in operation and over 9 million running hours experience using Wärtsilä’s leading DF technology.

The Wärtsilä 46DF extends 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, EPA T3
      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 7060 kJ/kWh at ISO cond.
      BSGC 7020 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.

      Related press releases


      29 October 2014
      • Twentyfour7. article

      LNG Propulsion achieves the next step in technological evolution

      With the introduction of the Wärtsilä 46DF dual-fuel engine, the traditional design principles for LNG-powered...
      17 May 2013
      • In Detail article

      The Wärtsilä Gas Valve Unit Enclosed Design (GVU-ED™) for marine applications

      Wärtsilä’s dual-fuel engine technology is...
      29 October 2014
      • Twentyfour7. article

      Taking dual-fuel marine engines to the next generation

      Wärtsilä’s new 46DF engine represents a significant addition to the company’s existing range of dual-fuel...

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