New Maintenance Method (CBM Method) for Main Bearings Receives Classification Approval

Japan Engine Corporation (hereinafter “J-ENG") has been conducting joint research with shipping line and classification societies.
As a result of these efforts, the new maintenance method (CBM method, Note 1) for main bearings has been certified by the Nippon Kaiji Kyokai (hereinafter "ClassNK").


Background

In the shipping industry, time-based maintenance (TBM, Note 2) is usually practiced, but TBM requires periodic inspections regardless of the condition of the equipment, thus incurring repair costs and impacting the operation schedule.
Since November 2019, J -ENG started a joint research with NYK, MTI, together with ClassNK, on using CBM to optimize maintenance.

Outline of Certified CBM

This is a method to monitor the condition of the main bearings of large marine diesel engines as temperature data, which is adopted in the "CBM Guideline Version 2" issued by ClassNK in 2021.
"Diesel Engine Main Bearing Condition Monitoring System" was jointly developed to visualize ship operation data and bearing temperature data, which can be obtained by installing sensors on the main bearings of the main engine, and this system also can share the data in real time with shipping companies and classification societies. This system has been installed on the coal carrier "NOSHIRO MARU" owned by NYK.
In this effort, J-ENG conducted a risk assessment to select a condition monitoring method, to design and to install the condition monitoring system, and to set the criteria used to determine abnormalities in the main bearings. During the operation of the "Diesel Engine Main Bearing Condition Monitoring System", J-ENG contributed to the acquisition of certification by analyzing the measured data and making judgements to the condition.



Future Outlook

J-ENG will continue to study the application of maintenance using CBM for equipment other than the main bearings.
For efficient and safe operation, the CBM method is effective by constantly monitoring the condition of the engine plant to realize the optimal maintenance, and J-ENG intend to develop this method.
In addition, by applying the condition-monitoring technology established in the next-generation CBM, J-ENG aims to contribute to the marine industries by realizing manned autonomous ships through the advanced automation of ship management using IoT and AI technologies.



(Note 1) Condition-based maintenance (CBM)
A maintenance strategy that monitors the actual condition of an asset to determine what and when maintenance needs to be performed, rather than awaiting machinery failure or conducting maintenance on a regular basis.

(Note 2) Time-based maintenance (TBM)
A maintenance strategy in which replacement cycles are predetermined for equipment and parts that fail periodically.

[Related Releases]
＜CBM Adopted in ClassNK Guidelines＞

＜NYK Press Release＞

＜MTI Press Release＞

＜ClassNK Press Release＞