VIB 360 Detecting a Faulty Workmanship soon after the Maintenance
Customer Profile
- Asset : Port Main Engine ; Yanmar 6N 21A EV [4 stroke ]; 956 Kw@ 850 rpm
- Vessel Type : Shore-based mini bulk carrier
- System Status: Existing VIB360 user, with continuous operation onboard for ~1 year
Context
During routine engine maintenance onboard, ship staff carried out planned servicing of the fuel injection system with the objective of restoring optimal performance. Shortly after maintenance, VIB360 began consistently indicating an injection performance anomaly. As the maintenance had just been completed, the crew initially expected improved engine performance and were not convinced by the VIB 360 results as OEM Parameters were showing normal operation. Upon the Vessel Superintendent’s instructions, the crew re-examined the work carried to verify whether any assembly or workmanship error had occurred.
Problem Statement
Following routine maintenance, VIB360 consistently indicated an injection performance anomaly. The challenge was to validate the VIB360 alert and take corrective action without relying on assumptions that the completed maintenance was satisfactory and no OEM Alarms triggered.
Vib360 Measurement Setup (Solution Architecture)
- Flywheel-mounted Magnetic Pickup Unit (MPU)
- Continuous torsional vibration and angular acceleration monitoring through Intelligent Controller
- Peak pressure sensor for fault reference following the Firing Order
Physics-Based Diagnostics
- Persistent trending of injection performance anomaly detected in the Port Engine after maintenance
- Trend consistency confirmed the condition was real, not transient noise
- Alerts on the dashboard with suggested troubleshooting recommended
The anomaly was linked to abnormal fuel injection pump behaviour at the cylinder level.
Action Taken
- Following the VIB 360 results; Tech Superintendent suggested to reverify the last maintenance activity carried out
- Further; the ship staff was asked to dismantle these pumps and verify if there exists any human error in assembly and to correct the same
- Ship Staff did find error in the Pump assembly and corrected same before restarting the engine
- VIB360 immediately indicated restoration of normal injection performance
- VIB360 Dashboard was closely monitored for the next 24 hours to confirm normal operation
Outcome and Value
- Detection of faulty workmanship following routine maintenance
- Prevention of prolonged operation with incorrect assembly
- Immediate confirmation of successful corrective action
Technical Significance
- Detection of post-maintenance assembly error through combustion analytics
- Continuous validation of maintenance effectiveness
- Cylinder-level fault detection under normal operating conditions
- Demonstrates monitoring as a maintenance verification tool, not only fault detection
- Real-world proof of decision-grade insight in routine operations