Analysis of difficult starting faults of marine diesel engine

1. Failure phenomenon

When it is found that the starting failure is difficult, there are the following situations:

⑴ When starting, the crankshaft does not move at all or rotates slowly, that is, the starting speed is too low.

⑵ When starting, the starting speed is normal, but the marine diesel engine does not catch fire.

(3) Although the marine diesel engine was on fire at the time of starting, the marine diesel engine was not operating normally, the speed was unstable, and even the fire was extinguished.

2.Cause analysis

⑴Starting system: gas pipeline is leaking or the gas pipeline is too long, the pressure of the gas source is insufficient, and the air compressor is damaged.

⑵Fuel system: the fuel pressure is low, the parking control lever is not lowered, the fuel tank valve is not open, the fuel tank is empty, the fuel tank is too low, there is air in the fuel line, the diesel filter is too dirty, the overspeed parking device is not reset, and the gear The stick is not in the refueling position, the injector is not atomized, the fuel injection pump is not pumping or the fuel injector is not injecting fuel.

(3) Intake and exhaust system: air filter is blocked, intercooler is blocked, the explosion-proof valve is not open, the timing of gas distribution is incorrect, and the exhaust system is blocked.

⑷Combustion system: The compression pressure is insufficient, the clearance between the piston and the cylinder head is too large or too small, and the cylinder head protrudes from the plane of the cylinder head too much or too small.

⑸External conditions: start with load, oil temperature is too low, viscosity is too high; water temperature is too low, freezing in the pump; diesel temperature is too low, viscosity is too high.

⑹Internal conditions: the valve touches the piston or there is a foreign object in the cylinder; burning the tile, holding the shaft, pulling the cylinder.