03-22-2012 10:11 PM
I have just been informed from my engineer on the vessel that the engine is shutting down/stops when steaming at an rpm over 1100.Max rpm is 1200 and there are no safety shutdowns on this engine apart from the stop lever.At rpms below 1100 no problems.All temps and pressures are normal,as are the filter differentials.there are no electrical solenoids on this engine,it is pre electronic.I suspect something is going on with the govenor which is the mechanical version.Sorry I cannot give more details at the moment as the vessel is at sea and I'm on land.If more info required plese ask and I will do my best.At least they are not stuck and can motor at 1100 all day.
03-24-2012 10:00 AM
You claimed that all pressures are normal, does this include fuel pressure?
Can you install a sight glass into the fuel return to check for air in the fuel?
Has anyone visually witnessed what happens to the governor linkage when the unit shuts down?
If the linkage goes to full fuel just before it shuts down and stays at full fuel until it stops than its not the governor.
What about the air intake system? Is the air drawn in to air cleaners directly from the engine room or piped to the intake. Could there be something getting pulled into a screen or up against an inlet that would starve the engine for air and fall out of place when the engine stops. A collapsing pipe would do this (I have seen it)
I realize you are the middle man in this and that creates many challenges
03-24-2012 04:06 PM
Any chance that you have overspeed protection on the engine. It would be the norm to have it fitted. If so it is possible that it could be shutting you down?
03-25-2012 07:40 PM
Thanks for the input guys.Fuel pressure is 70PSI.The crew can probably rig something up to check for air in the fuel return line.I will inform them to check what happens to the govenor lever when it shuts down and get back re that.Air is drawn in from the engineroom which has air supplied from two large intake fans.No problem there.With re to the overspeed protection.Am I correct in assuming this would limit the rpm,rather than shutting the engine down?If there is this device on the engine,where would it most probably be situated on the engine and how does it work.Could it be malfunctioning causing a shutdown rather than limiting the rpm.As this is the main engine on the vessel,a shutdown at any time when not instigated from the bridge can have very serious consequences.
03-25-2012 08:16 PM
An overspeed protection would definitely shut down the engine when operating properly, not limit speed, that is the function of the governor. The overspeed protection is the final level in the event the governor looses control.
It normally needs to be reset in order to restart the engine. But if it is malfunctioning its anyone's guess as to the symptoms.
When the technician onboard watches the unit shutdown they must be very observant to what is happening.
As stated watch the governor linkage, watch fuel pressure and oil pressure, listen to the engine, does it change its sound? Does it smoke? Does it suddenly stop as if it was shut off or ramp down still fighting as if it was severely overloaded?
The more observations the better
Taking a video can be valuable
Since the unit will run all day at 1100rpm it may be wise to wait until its in port and have a technician come aboard
Having a potential issue with an overspeed shutdown or governor can cause severe damage if it gets away from you.
04-09-2012 12:30 AM
Hi Paul and RM.Been on holiday in Vietnam and before I left instructed the crew to just keep the rpms down.The vessel is working 24hours until around the 20th April when it will be back in port.The fuel burn increases dramatically once you get up near the top and they have no need to be running above 1100.With re to the overspeed protection unit I have said nothing to the vessel as I don't want them 'Fiddling" with something that could potentially cause a runaway engine.I've previously spent 3 months on this vessel and never have I seen anything remotely looking like an overspeed protection unit.This engine has no electronics that I am aware of.Just where would this unit be situated and how does it operate.I'm picking that it must cut the fuel supply in the same way as we stop the engine with the pull lever.