Maneuvering Diagram with explanation. (MAN B&W)

Before going to the Maneuvering diagram, just understand how the fuel pump and air distributor is reversed,

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MAN B&W (Starting of the engine in Ahead position.)

MAN B&W ENGINE STARTING SYSTEM (SIMPLIFIED)

The system shown shows the valves in position whist an ahead start is in progress. There are two control levers (not shown); a stop-start-run lever and an ahead/astern lever.

Valve 1, the stop signal solenoid valve is activated throughout the air start sequence. This operates valve 5, which in turn operates valve 8 which puts an air signal on the fuel pump puncture valves, preventing high pressure fuel being pumped to the injectors. It also sends an air signal to operate valve 13 which will allow 30 bar control air as far as valves 12 and 14 when valve 16 is operated.

The direction lever in the control room is set to AHEAD. This activates solenoid valve 2 which sends a signal to operate valve 14 which will allow 30 bar control air to the distributor when valve 16 is operated. It also operates valve 11 which allows air to the fuel pump cam follower servo motor.

When the lever is moved into the start position, it activates solenoid valve 4. This operates valve 6 which in turn operates valve 9. This allows air to operate the automatic valve. Should solenoid valve 15 be activated, then only the slow turning valve will open. Valve 16 is also activated allowing 30 bar air to the start air distributor.

When the lever is moved to the run position, solenoid valves 1 and 4 are deactivated and vented. This causes valve 8 to vent, shutting the fuel pump puncture valve. Valve 13 also vents, as does valve 16, venting the air start distributor. Valve 16 moves across allowing control air to shut the automatic and slow turning valves.

 Points to Note:

·     Valve 6 has a 1 second delay timer fitted. This allows the main starting valve to remain open, so as to supply air to those cylinders that are in the start position.

·     There is a manual shut off valve fitted between the air start manifold and valve 16 for maintenance purposes.

·     The fuel pump reversing servo motor is fitted with relief valves and restrictors to damp operation.

·     Valve 7 is vented by engaging the turning gear. This prevents a start sequence taking place.