What work should be done when preparing a diesel engine after a short-term shutdown?

The main purpose of preparing a diesel engine and its system before use is to ensure uniform heating of all components and supply of lubricating oil to the friction surfaces. Because the components of the main engine have different masses, insufficient preheating will increase the temperature difference after starting, leading to increased thermal stress and potential damage to the parts. Insufficient cylinder preheating will also exacerbate corrosive wear. If the lubricating oil supplied during startup is too viscous or insufficient in quantity, it will cause semi-dry friction, accelerating wear and scratches.

Generally speaking, after a short-term shutdown, a diesel engine should be prepared in advance before use, and the preparation time should be strictly adhered to. Although the preparation procedure may vary, it generally includes: verification and calibration; engine warm-up; and preparation of all systems.

1) Engine Warm-up: Engine warm-up refers to first heating the circulating fluid in the diesel engine's cooling and lubrication systems, and starting the cooling water circulation pump and lubricating oil circulation pump to increase the engine body temperature and supply lubricating oil to the moving friction surfaces. The purpose of engine warm-up, besides preheating the main engine components and reducing thermal stress, is to facilitate diesel engine starting and ignition, and to reduce low-temperature corrosion of the cylinder walls and piston tops by sulfur. This is especially important for engines using high-sulfur, heavy fuel oil.

2) Preparation of the Lubricating Oil System

(1) Check the oil levels in the main engine circulating oil tank, turbine oil tank, shaft system, and lubricator. If the oil level is insufficient, replenish to the specified level.

(2) Start the lubricating oil circulation pump as early as possible and adjust it to the specified oil pressure to deliver lubricating oil to all lubrication surfaces, thus preheating and cleaning them to reduce wear during startup.

(3) For independent lubrication systems of exhaust gas turbochargers with separate oil pumps, the turbine oil pump should be turned on to circulate oil in the bearings of the exhaust gas turbocharger.

(4) For oil-cooled pistons, the piston temperature will gradually increase after the lubricating oil circulation pump is started, achieving the warm-up effect. At this time, carefully observe the return flow and temperature of the cooling oil returning to each cylinder piston.

3. Preparation of the cooling system:

(1) Check the water level in the main engine expansion tank. If the water level is insufficient, replenish it to the specified level.

(2) Check that all valves in the system are in normal condition.

(3) For water-cooled pistons, turn on the piston cooling water pump. Also, observe the flow of cooling water in each cylinder piston.

(4) Check the fuel injector cooling tank level. If insufficient, replenish it. Start the fuel injector cooling pump; preheating may be necessary.

4. Preparation of the fuel system:

(1) Check the fuel levels in the light diesel and heavy diesel daily fuel tanks. If the fuel level is insufficient, transfer fuel to the specified level and drain any water.

(2) Turn on the low-pressure fuel delivery pump to start the fuel injector pumping operation. If the main engine also has a low-pressure delivery pump, turn it off after the diesel engine is running normally.

5. Preparation of the compressed air system:

(1) Turn on the air compressor to replenish the air to the specified pressure, and drain the oil and residual water from the air cylinder.

(2) Open the air cylinder outlet valve, the main air shut-off valve, or set the automatic main start valve to the "automatic" position.