Question

(a) Difficulty has been experienced in maintaining engine speed at the set value. State the possible causes and how each of these causes may be detected. (8)

(b) Describe the action to be taken in order to ensure safe operation of the main engine plant in the event of complete failure of the remote control and sensing equipment. (8)

Answer 1

Part (a)

Possible causes and detection of difficulty maintaining engine speed at the set value:

Governor-Related Trouble

Faulty governor operation or improper adjustment.
Disconnect the governor and observe if hunting stops. If it does, the problem lies with the governor.

Sticking Fuel Pump Racks or Linkages

Mechanical obstructions or wear in the linkages or racks.
Disconnect and test each section of the linkage manually. Attempt to move each part individually to identify the obstructed component.

Air Lock in Fuel System

Air trapped in the fuel lines causing fluctuating fuel pressure.
Monitor the booster pump pressure; fluctuating readings indicate air in the system.

Water or Contaminants in Fuel

Contaminated fuel may disrupt smooth operation.
Inspect fuel filters and separators for water or debris.

Fuel Pump Plunger Issues

Plungers sticking intermittently due to wear or contamination.
Check the consistency of fuel delivery and inspect pump components.

Part (b)

In the event of a complete failure of the remote control and sensing equipment, the following actions should be taken:

Carefully disconnect the governor actuator from the fuel pump control. Manually hold the control lever firm at a position maintaining the required RPM. This should be done cautiously, ideally in open waters, to avoid sudden alternator tripping due to low voltage.

To determine if the problem lies with the governor or the engine, make small adjustments to the electrical load. If manually adjusting the lever restores the RPM after increasing or decreasing the load, the problem is likely with the governor. If the operation remains erratic even with manual adjustments, the engine itself is likely at fault.

Troubleshooting Engine Issues: If the engine is the problem, potential causes include:

Fuel pump racks sticking.
Airlocks in the fuel system.
Water in the fuel.
Fuel pump plungers sticking.

Troubleshooting Governor Issues: If the governor is the problem, potential causes include:

Actuator linkage sticking.
Improperly adjusted Magnetic Pick-Up unit (MPU), resulting in varying air gaps.
A defective MPU.
Improperly adjusted governor (too high gain causing hunting; gain needs reduction).
Loose electrical connections.
Problems in the electronic circuitry or PCB.

Speed Reduction (if necessary): If the situation cannot be controlled through manual adjustments, reduce the engine speed. If this fails to stabilize the engine, lock the fuel rack in a specific position to override the governor and maintain a fixed fuel input. This will cause RPM fluctuation due to varying propeller load, but the engine operation will be steady with consistent fuel supply. Ensure that the auxiliary blower can continue operating without stopping, particularly if the main turbocharger is ineffective.

Additional Safety Considerations:

All actions should prioritise safe navigation and the prevention of hazards.
Maintain constant monitoring of engine parameters such as temperature and pressure to prevent further damage or incidents.
Consult engine manuals and manufacturer's recommendations for specific procedures and troubleshooting guidelines.
In the case of extended operation with malfunctions, always contact the engine manufacturer for guidance on the Emergency Running Procedure.

✓ Verified Model Answer (Text Solution)

Possible causes and detection of difficulty maintaining engine speed at the set value:

In the event of a complete failure of the remote control and sensing equipment, the following actions should be taken: