Operation
2728−1/A1
Winterthur Gas & Diesel Ltd.
1/ 2
Starting Valve
1. General
A starting valve is installed in each cylinder cover (6, Fig. 1). The starting valves start
the engine, or decrease the engine speed for reversing.
The engine control system (ECS) monitors and controls the starting valve operation
(see 4002−1, paragraph 3.1). The Cylinder Control Modules (CCM−20) open the
starting valves electronically at the correct crank angle to release starting air into the
combustion chamber.
The parameter settings of the starting valves are adjustable. The ECS gives access to
the parameter settings.
For more data, see the schematic diagrams, 4003−2.and 4003−9.
2. Function
2.1 Initial Conditions
Starting air (SA) pressurizes the air chamber (P2). The compression spring (4) keeps
the valve closed. The pipe (7) in the cover (1) has the starting air pressure.
2.2 Engine Start
The CCM−20 activates the 3/2-way solenoid valve (8). The air chamber (P
1
) is
pressurized, the valve opens and starting air flows into the combustion chamber. The
piston (2) moves down, starting air flows into the combustion chamber and the engine
starts to turn.
When combustion starts, the higher pressure (firing pressure) in the combustion
chamber keeps the starting air valve closed.
2.3 Engine Slow-down (to Reverse the Engine)
If the combustion and thus the propulsion stops (or a slower speed is selected from
the remote control), the movement of the ship continues. The flow of water has an
effect on the propeller.
To start the engine in the opposite direction, it is necessary to slow the engine speed
to below the set limit. This operation is related to the engine speed and propeller
configuration, and can be some minutes.
At the specified engine speed, the ECS opens the starting valve at approximately
100_ before TDC. The starting air flows into the combustion chamber. The piston in
the cylinder moves up, compresses the air and the engine speed decreases and then
stops.
The engine then turns in the opposite direction and starts. For more data about
reversing, see 0260−1, paragraph 3.4.
2014
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