Analysis on the Causes of Unstable Speed of Marine Diesel Engine Parts

1. Trouble phenomenon When the marine diesel engine is running normally, the speed of the marine diesel engine is stable depending on the automatic adjustment function of the governor. The fluctuation value is only a few revolutions, and the fluctuation rate is within 0.5%. When the speed is unstable, there are two phenomena:

⑴. The marine diesel engine fluctuates regularly. Commonly referred to as "traveling" and "gasp". This situation mostly occurs in low-speed operating conditions of marine diesel engines.

⑵. The speed of marine diesel engine fluctuates irregularly.

2. Analysis of the reasons The reasons for the unstable speed of marine diesel engines are as follows:

⑴. Reasons for the fuel supply system: there is air, water, air resistance or water resistance in the fuel system, resulting in unstable fuel supply; poor atomization of the fuel injector, unstable fuel injection, fuel injection every other time, or intermittent fuel injection Oil; fuel injection pump plunger delivery valve wear is too large, fuel supply is unstable; fuel injection pump rack stuck, injector needle valve stuck; fuel injector spring, fuel delivery valve spring, fuel injection pump spring broken; fuel injection pump The oil volume adjustment ring gear is loose; the oil supply of each cylinder is seriously uneven.

⑵. Reasons for the speed control system: too much oil in the governor; the governor spring is deformed, broken, or the stiffness is reduced; the governor fly iron sleeve is seriously worn; the governor moving parts are stuck or worn seriously.

⑶. External reasons: the clutch of the marine diesel engine with a gearbox is poorly engaged and slips; the load of the working machinery is seriously unstable.