Operations of an IC Engine as Main Propulsion Engine: Warming Up, Manoeuvring, Starting, Reversing, and Full Away
Introduction:
Operating an internal combustion (IC) engine as the main propulsion engine requires various steps to ensure its efficient and safe functioning. This article outlines the key operations involved, including warming up, manoeuvring, starting, reversing, and running at full power. We will explore the necessary procedures and precautions for each operation.
Warming Up (Preparation for Standby):
Before starting the main engine after a port stay, a warming-up process is essential. The duration of warming up depends on the engine’s size, but in modern engines, it is typically performed around half an hour before the estimated time of departure (ETD). During warming up, several tasks must be carried out:
1. Check supply tanks, filters, valves, and drains.
2. Start the jacket cooling water (JCW) system.
3. Gradually raise the JCW temperature to allow engine parts to expand uniformly.
4. Increase the temperature of lubricating oil, fuel oil, and steam tracing systems gradually towards their operating temperatures.
5. Verify the correct operation of all controls and alarms.
6. Open indicator cocks, engage the turning gear, and rotate the engine to remove any accumulated water from the cylinders.
7. Ensure manual cylinder lubrication is provided.
8. Start auxiliary scavenge blowers, if applicable.
9. Close the indicator cocks.
Manoeuvring – Starting:
To initiate maneuvering, the direction handle is positioned ahead or astern. This handle, often integrated with the telegraph reply lever, adjusts the camshaft’s position relative to the crankshaft to control fuel injection and valve operation. The maneuvering process involves the following steps:
1. Move the maneuvering handle to the “start” position, allowing compressed air to enter the cylinders in the correct sequence for engine rotation in the desired direction.
2. As the engine reaches its firing speed, shift the maneuvering handle to the “running” position to admit fuel and accelerate the combustion process, causing the engine to gain speed.
Manoeuvring – Reversing:
When manoeuvring at lower speeds, reversing the engine requires additional steps. These include:
1. Start the auxiliary scavenge blowers, if necessary.
2. Shut off the fuel supply to stop the engine.
3. Position the direction handle astern to reset the camshaft for astern running.
4. Admit compressed air to rotate the engine in the astern direction.
5. Readmit fuel to accelerate the engine and initiate combustion while stopping air admission.
Manoeuvring – Reversing (When running at full speed/full power):
Reversing the engine when running at full speed or full power involves the following steps:
1. Start the auxiliary scavenge blowers, if applicable.
2. Shut off the fuel supply to slow down the engine.
3. Set the direction handle to astern for resetting the camshaft.
4. Utilize compressed air bursts to decelerate the engine from its ahead running direction.
5. After stopping the engine, introduce compressed air to rotate it in the astern direction.
6. Readmit fuel to accelerate the engine, allowing the combustion process to occur.
7. Cease air admission.
Full Away (Full Power / Full Speed):
Operating the engine at full power or full speed is essential for optimal vessel performance. This operation involves maintaining the engine at its maximum capacity while adhering to the manufacturer’s guidelines and operating limits. It ensures the engine delivers the required power output for propulsion.
Conclusion:
Operating an IC engine as the main propulsion engine involves a series of critical steps, including warming up, maneuvering, starting, reversing, and running at full power. Following proper procedures during these operations is crucial for the engine’s efficiency, reliability, and overall vessel performance. Adhering to manufacturer guidelines and taking necessary precautions ensures safe and optimal engine functioning.