Environmental Initiatives
Energy conservation through the introduction of new technologies
Electronically controlled main engine
A main engine provides propulsion to the ship. In an electronically controlled main engine, the timing of fuel injection and cylinder lubrication can be flexibly controlled according to the required engine power and conditions to optimize the engine performance. As a result, nitrogen oxide (NOx) and smoke emissions can be reduced, which improves environmental performance and energy efficiency.
Our “Nagara” (600-TEU vessel) is equipped with the system. There are only a few small and medium-sized vessels that use an electronically controlled main engine.
Appearance
＜Manufacturer＞ Hanshin Diesel Works Ltd.
Axial power generation system
An axial power system generates electricity by using the shaft that turns the propeller.
During a voyage, the shaft generator alone can supply the ship's internal power, eliminating the need to run an engine-driven generator.
As a result, energy is saved and noise in the engine room can be reduced.
The power system can be more efficient than other shaft power generation systems by adopting PWM (Pulse Width Modulation) and the shaft generator can operate independently or in parallel with other generators.
Three 200-TEU containerships and one 100-TEU containership of ours have adopted the shaft generator system.
＜Manufacturer＞ Taiyo Electric Co. Ltd.
Hub Vortex Reduction Equipment
Hub Vortexes are vortices that occur behind and near the center of the propeller and thus lead to reduced propeller efficiency.
There are various methods to recover this energy loss as follows.
■Fin method
A special fin is added to the center of the propeller to reduce hub vortices. The shape and name of the fins vary from manufacturer to manufacturer, and the ones developed by MOL Techno-Trade are called "PBCF".
Hub vortex without fins
With fins
Installation example
Experiment in the cavitation tank at the Akishima Research Institute, Mitsui Engineering & Shipbuilding Co.
＜Manufacturer＞ MOL Techno Trade Co.
＜Patent＞ No. 5405872 No. 5524496
■Propeller method
Propeller blades have a special shape to suppress hub vortices.
This special propeller shown below is produced by Nakashima Propeller which is called "NHV propeller".
Conventional propellers
Special Propellers
Installation example
Experiment in the cavitation tank at the Akishima Research Institute, Mitsui Engineering & Shipbuilding Co.
＜Manufacturer＞ Nakashima Propeller Co.
