Wärtsilä 46 Variable Injection Timing

A small adjustment with a big impact

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Wärtsilä 46 Variable Injection Timing

Wärtsilä 46 Variable Injection Timing (VIT) for Wärtsilä 46 engines is a low-load optimisation solution that reduces fuel oil consumption, and therefore emissions, by optimising fuel injection timing for the most commonly used engine loads, typically in the 50–85% load range.

VIT is implemented by changing the physical shape of the fuel pump element plunger. The injection timing and injected fuel volume are also carefully aligned and spare injection pumps and elements replaced.

Although the solution can be delivered as a standalone upgrade, it is recommended to combine it with other performance upgrade solutions such as the Wärtsilä 46 Performance upgrade – TPL 73-A4X and short overlap Miller upgrade. This enables greater fuel savings and means that the engine’s EIAPP technical file only needs to be updated once.


    • Reduce fuel consumption by approximately 3 g/kWh at 75% load 
    • Ensure lower smoke levels during low-load operation 
    • Reduce CO2 emissions

    Technical info

    Wärtsilä 46 VIT ensures optimum fuel consumption during part-load operation by adjusting the start of injection (SOI) according to the actual engine load.

    There are two options for performing the upgrade:
    1. By changing the fuel element (barrel and plunger) in the existing fuel injection pump
    2. By replacing the existing fuel injection pumps with VIT fuel injection pumps

    The solution has been performance tested and is EIAPP certified.


    The solution is applicable for Wärtsilä 46 engines with the following specifications:

    • Engine speed 500rpm and 514rpm
    • 1050kW/cyl and 1070kW/cyl
    • Compression ratio 16:1
    • Equipped with the following pump
      - Version A
      - Pump No: PFO-G10000
      - Element No: PFO-U10000

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