Why Does Diesel Generator Automatically Shut Down

During the operation of diesel generator, due to improper use and maintenance, some parts will fail, and the speed will decrease and the engine will automatically shut down. According to the urgency of the speed reduction before the diesel generator flameout and the exhaust smoke color, the main parts and causes of the diesel generator fault can be judged.

1. During flameout, the rotating speed gradually decreases, and there is no abnormal change in the sound and smoke color of 64kW diesel generator. This fault often occurs in the fuel system. Based on the principle of (easy first, difficult later), check whether there is fuel in the fuel tank and whether the fuel tank vent is blocked. If there is no oil in the fuel tank, it cannot be supplied, the ventilation hole is blocked, and a negative pressure is formed in the fuel tank, resulting in poor fuel supply. If there are no above issues, gradually inspect the low-pressure oil circuit to the high-pressure oil circuit to see if there are any debris blocking the oil circuit and if air is entering. The failure of the high-pressure oil circuit is often caused by the inability of the fuel injection pump to supply high-pressure oil or the jamming of the needle valve coupling of the fuel injector for single cylinder engines; For multi cylinder engines, it mostly occurs in the power transmission part of the fuel injection pump, such as the transmission gear rolling key, the keyboard fixing screw falling off or breaking, and the wheel axle breaking.

2. When the engine is turned off, the speed is unstable and the exhaust pipe emits white smoke. The cause of this fault is mostly water in the diesel fuel. If the exhaust pipe still emits white smoke and stalls after removing the water in the oil, it may be due to the cylinder gasket being burned and connected to the water channel, causing water to enter the cylinder. If the cylinder gasket is intact, it may be a crack or fracture in the cylinder liner, or there may be a crack in the cylinder head that connects to the water channel, allowing coolant to enter the cylinder.

3. When the engine is turned off, the speed gradually decreases and the exhaust pipe emits thick smoke. The cause of this malfunction is severe overloading of the diesel engine, or delayed fuel supply, insufficient intake (blocked intake pipeline, excessive intake valve clearance, excessive wear of the valve mechanism, etc.), resulting in a rich mixture that cannot be completely burned. This fault is often caused by a combination of several reasons, so when troubleshooting, it should also be analyzed and checked item by item.

4. When the engine is turned off, the speed drops sharply and the exhaust pipe emits black smoke. There are two main reasons for this type of malfunction: a. insufficient oil pressure in the main oil duct (lack of oil, stuck oil return in the starting position, oil pump not supplying oil, or oil deterioration, etc.), resulting in poor lubrication on the surface of the crankshaft and bearing shells, causing burning and holding of the shaft, forcing the diesel engine to shut down; 

b. When replacing the piston and cylinder liner, the clearance between the two is too small. After the diesel engine is put into operation, the piston expands due to heat, which hinders its movement in the cylinder and causes the diesel engine to stall.

5. During flameout, the power of 1000kW diesel generator drops suddenly, the speed drops sharply, and there is an abnormal noise. The main causes of this fault include broken crankshaft or piston pins, broken connecting rod bolts or loose nuts, broken valve springs or broken valve stem ends, etc. Careful inspection should be conducted to identify the specific cause of the malfunction and eliminate it. Do not start the diesel generator again until the cause of the fault is found out and eliminated.