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Yanmar News


Yanmar Completes Development of the Cleaner and Highly Reliable 6EY26DF Dual-Fuel Engine for Vessels

6EY26DF dual-fuel engine

Yanmar Co., Ltd. has completed development of a new, reliable dual-fuel engine for vessels that enables the user to switch to and from liquefied natural gas (LNG) and diesel fuel during operation. The new International Maritime Organization (IMO) Tier 3 regulations, introduced in January this year, require an 80% reduction of nitrogen oxides (NOx) emissions from the Tier 1 levels, and a 20% improvement of CO2 emissions by 2020; representing an annual tightening of emissions for vessels. With the flexibility to operate using both LNG which offers superior environmental benefits and easy to obtain diesel fuels, the dual-fuel engine has drawn considerable attention in recent years as a solution that easily passes the demanding Tier 3 emissions controls.

While advanced electronic control is typically required for utilization of two different fuel types, the EY26DF employs high-precision air flow technology that optimizes combustion conditions delivering stability and reliability when in operation. From here on, Yanmar will continue its efforts towards expanding its dual-fuel engine line-up for vessels, delivering optimal solutions for a wide range of customers.

1. 6EY26DF Engine Features

Fuel Flexibility 

  • Switch between LNG and diesel fuel mode even under full engine loads
  • No power limitations even for LNG—a fuel source which sometimes causes knocking in other engines due to it having a low methane concentration    
Advanced Engine Control 
  • Utilizing Yanmar’s innovative technology to control the air-fuel ratio*1 and its knock detection system, the 6EY26DF delivers stability in gas mode.
  • Ignition with the micro-pilot injection system, when in gas mode, is as effective as a diesel engine 
Cleaner Operation and Greater Thermal Efficiency in Gas Mode  
  • Compared to the same-class EY26 diesel engine, the 6EY26DF delivers 84% NOx, 25% CO2, and 99% Sox and PM reductions, meeting IMO Tier 3 standards  
  • Gas mode exceeds Yanmar’s current diesel engine thermal efficiency ratios at 46.8%

2. 6EY26DF Specifications

Model 6EY26DF
Rated power (kW) 1533
Rated speed (min-1) 750
No. of cylinders 6
Bore x stroke (mm) 260 x 385
Mean effective pressure (MPa) 2.0
Fuel Heavy fuel oil for vessels, LNG (36.0 to 40.6 MJ/Nm2)

*1: Optimal air flow (air-fuel ratios) for combustion can vary with load fluctuations and methane concentrations. Additionally, as diesel and LNG air and fuel requirements differ, it’s crucial that the engine is equipped with a device for optimizing air-fuel ratios  

*2: By injecting minute quantities of diesel fuel, the LNG ignites speeding up combustion

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