The main engine does not start. Troubleshooting

Greetings! Today we have a problem with starting the main engine; the engine cannot be started with air by the telegraph command “Forward” and setting a certain speed (the telegraph and the speed controller are not one common device here).

In the article we will find out what the problem is and what you should pay attention to during routine maintenance of the main engine control unit.

You can imagine the panic atmosphere in the ECR and on the bridge.

General diagram of the electronic governor of the main engine

By the way, this is another problem with the main engine MITSUI MAN B&W 6S50MC-C. In the next article, I will describe the failure of the main engine protection due to a failed power supply.

In such a situation, it is necessary to carefully examine the pneumatic system of the main engine, which is located in the emergency control unit of the main engine.

Emergency main engine control station

On this vessel, the search comes down to the Unit Box, which contains the main engine pneumatic system (control solenoids).

Unit Box

Pneumatics of the main engine inside the Unit Box

According to the electro-pneumatic diagram, we are interested in the VAH solenoid valve number 86, which stands for Valve Ahead, valve that receives power when the “Forward” telegraph button is set.

Solenoid VAH No. 86

A complete diagram of the main engine pneumatics is available at the link: MAIN ENGINE ELECTRIC-PNEUMATIC MANOEUVRING SYSTEM

Solenoid valve VAH No. 86 (instructions)

Electrical diagram Unit Box (3 - 4 VAH)

The complete electrical diagram of the main engine control unit is available at the link: ENGINE REMOTE CONTROL SYSTEM EXTERNAL CONNECTION DRAWING

As can be seen from the electrical diagram of the main engine pneumatics, via wirings 3 - 4, the VAH solenoid receives power upon the “Forward” command and setting the speed of the main engine.

As a result of a thorough inspection, a break was found in the third wire in the Unit Box distribution box of the main engine pneumatic system. This break was not immediately visible, I had to pull the wirings to pull the broken cable strands out of the special casing on the terminal.

Cable break in the Unit Box (3rd wire on the terminal)

It would seem that the problem is obvious and from the outside it may seem that it can be easily and quickly detected. However, first overcoming the panic, and then the search itself took about 2 hours. Few people are ready for such situations, but as the saying goes, “the eyes are afraid, but the hands do.”

The cause of the break in this situation was increased vibration in the area of ​​the main engine emergency post. So my recommendation, no matter what type of engine you have, periodically check the main pneumatic distribution boxes.

By the way, the photos in this article are taken from different ships, but with the same main engines. The last photo is original (from the original source).

The main engine on a merchant vessel is a crucial component, driving the ship and enabling it to transport goods across oceans. The main engine can vary in type and size depending on the vessel's requirements, but it is generally a large internal combustion engine, typically a two-stroke diesel engine for its efficiency and durability. Here are the key aspects and components of the main engine on a merchant vessel:

1. Types of Main Engines

• Two-Stroke Diesel Engines: Commonly used in large merchant vessels for their high efficiency, reliability, and lower fuel consumption.
• Four-Stroke Diesel Engines: Often used in smaller vessels or as auxiliary engines due to their higher power-to-weight ratio.
• Dual-Fuel Engines: Can run on both diesel and gas, providing flexibility and reduced emissions.
• Gas Turbine Engines: Used in some high-speed vessels, though less common due to higher fuel consumption.

2. Main Components of the Main Engine

• Cylinder Block: The main structure housing the cylinders where combustion occurs.
• Crankshaft: Converts the linear motion of pistons into rotational motion to drive the propeller.
• Connecting Rods: Connect the pistons to the crankshaft, transmitting the force of combustion.
• Pistons: Move up and down within the cylinders, compressing the air-fuel mixture and converting combustion energy into mechanical work.
• Cylinder Liners: Protective sleeves within the cylinder block that house the pistons.
• Fuel Injection System: Delivers precise amounts of fuel into the cylinders for combustion.
• Turbocharger: Increases the engine’s efficiency and power output by forcing more air into the cylinders.
• Exhaust System: Expels exhaust gases from the engine and may include components like scrubbers to reduce emissions.
• Cooling System: Regulates engine temperature using water or air to prevent overheating.
• Lubrication System: Provides necessary lubrication to reduce friction and wear of engine components.

3. Operation of the Main Engine

• Starting Procedure: Engines are typically started using compressed air or an electric starter motor.
• Combustion Process: Involves the intake of air, compression, fuel injection, combustion, and exhaust phases, particularly in two-stroke engines which complete this cycle in two movements of the piston.
• Fuel Management: Efficient fuel management ensures optimal combustion and performance, often monitored by automated systems.
• Control Systems: Modern engines are equipped with electronic control systems for precise management of engine operations, monitoring parameters like speed, fuel consumption, and emissions.

4. Maintenance and Inspection

• Regular Inspections: Periodic checks to identify and address wear and tear, ensuring continuous and safe operation.
• Overhauls: Comprehensive maintenance activities at scheduled intervals to replace or refurbish key components.
• Condition Monitoring: Use of sensors and diagnostic tools to continuously monitor engine condition and performance, predicting and preventing potential failures.

5. Environmental and Regulatory Compliance

• Emissions Control: Compliance with international regulations (e.g., MARPOL) to limit emissions of sulfur oxides (SOx), nitrogen oxides (NOx), and other pollutants.
• Ballast Water Management: Ensuring that ballast water is managed and treated to prevent the spread of invasive species.
• Energy Efficiency: Implementation of energy-efficient technologies and practices to reduce fuel consumption and emissions, including slow steaming and hull optimization.

6. Safety Features

• Emergency Shut Down: Systems to automatically shut down the engine in case of severe faults or emergencies.
• Fire Detection and Suppression: Equipment to detect and suppress fires in the engine room.
• Alarm Systems: Alerts for abnormalities such as low oil pressure, high temperature, and unusual vibrations.

7. Crew Training and Documentation

• Training Programs: Regular training for engine room personnel on operation, maintenance, and emergency procedures.
• Manuals and SOPs: Detailed documentation to guide the crew in operating and maintaining the main engine safely and efficiently.

The main engine on a merchant vessel is a complex and powerful machine, essential for the propulsion and operation of the ship. It requires careful management, regular maintenance, and adherence to safety and environmental regulations to ensure efficient and reliable performance. Properly trained crew and advanced monitoring systems play a vital role in maintaining the health and functionality of the main engine.

I also recommend reading the article: “Failure of the main engine control system. Actions of the ETO”, where another interesting case with the main engine is described.

Main engine: MITSUI MAN B&W 6S50MC-C.