BRIDGE CONTROL UTILISING AN ELECTRONIC GOVERNOR (NORCONTROL)

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Bridge control of the main engine is now standard on many vessels. This hand-out explains the Autochief 4 unit, which is supplied by NorControl for the MAN B&W MC series of engines. The control system comprises of four units:

1.         Remote control system, Autochief 4 unit, fitted on the bridge

2.         Engine control system

3.         Engine protection system

4.         Digital Governor system

1.          Remote control system

This comprises two units fitted at the bridge, namely the manoeuvring handle/engine telegraph, and the remote control system which indicates the various status and alarms present in the system. The following indications are visible from the remote control system:

a)      Starting air pressure

b)      Engine speed requested, and actual engine speed

c)      Engine shutdown or slowdown present

d)      Control functions active, such as load-up programme, critical speed limiter, starting air active, repeated start, crash manoeuvre active, etc

e)      Push button to select bridge or engine room control

The display and telegraph unit on the bridge are inputs to the main control panel situated in the engine room control room. The control room panel indicates the present status of the bridge command, and also a mimic diagram to illustrate the changes which occur during the manoeuvring state.

Bridge /ECR   Indicates the command position.

Stop           Indicates that the control lever is at the stop position.

Ahead/Astern        Indicates the requested direction, NOT camshaft position.

Start block    Starting is prevented due to one or more of the following:

2.         Start fail (x3)

3.         Start air/control air/safety air pressure low

·           Reversing fail

·           Start air on too long

·           Both shaft RPM detectors have failed

·           Engine tripped

·           Automatic start air valve blocked

·           Start air distributor blocked

·           Turning gear engaged

Above reversing level         Indicates that the engine speed is above the maximum

level at which braking air can be supplied.

AHD/AST cam        Indicates fuel pump reversing mechanism position.

Slow turning/Start    Indicates slow turning or start activated.

 Repeated start No.1/ No.2    Indicates a repeat start command from the engine control   system if engine RPM does not reach start level within preset time. After three attempts   (Heavy starts/limiters cancelled) the engine will trip and need resetting.

Fuel off      Indicates fuel injection is prevente3d by activation of fuel pump puncture valves.

AHD/AST rotation     Indicates actual direction of propeller rotation.