Home > Faq

What are the general precursors of diesel generator sets before major failures occur?

May 17, 2022
During the use of diesel generator sets, large and small faults will inevitably occur. When some major faults occur, there will generally be some precursors. Users should take corresponding measures to avoid the occurrence of faults as much as possible. The following JUNVOCH introduces you to some precursors that diesel generator sets generally appear before major failures occur.
 1. The precursor of diesel generator set valve drop cylinder
The valve falling into the cylinder is generally caused by the broken valve stem, the broken valve spring, the cracked valve spring seat, and the valve lock clip falling off. When the cylinder head makes a "dangdang" knocking sound (piston touching the valve), "chattering" friction sound (piston touching the valve) or other abnormal noises, when the engine is not working stably, it is often a precursor to the valve falling into the cylinder. At this time, stop the engine immediately, otherwise it will damage the piston, cylinder head and cylinder liner, and even top-bend the connecting rod, break the body, and break the crankshaft.
2. The precursor of diesel generator set sticking to the cylinder
Cylinder sticking usually occurs when the diesel generator set is seriously short of water. Before the cylinder sticks, the engine runs weakly, and the water temperature gauge indicates over 100°C. When a few drops of cold water are added to the machine, there is a "hissing" sound and white smoke. The water droplets evaporate quickly. At this time, the engine should be run at low speed or idle speed to reduce the temperature of the car. If the engine is turned off immediately, it will cause the piston and the cylinder liner to stick to the cylinder.
3. The precursor to burning watts of diesel generator sets
During the operation of the diesel generator set, the speed suddenly decreases, the load increases, the engine emits black smoke, the oil pressure drops, and the crankcase emits a "chirp" dry friction sound, which is a precursor to burning tiles. In this case, stop the machine immediately, otherwise it will further aggravate the wear of the bearing bush, the surface of the journal will expand rapidly, the bearing bush and the journal will soon stick and lock, and the engine will stall.
Fourth, the precursor of diesel generator set pounding the cylinder
 The ramming cylinder is a destructive mechanical fault. Except for the ramming of the cylinder caused by the falling of the valve, most of them are caused by the loosening of the connecting rod bolts. After the connecting rod bolt is loosened or stretched, the matching clearance of the connecting rod bearing increases. At this time, a "click" can be heard in the crankcase. Or broken, the connecting rod and bearing cap are thrown out, breaking the body and related parts.
Five, the precursor of diesel generator set "speeding"
Before "speeding", the diesel generator set will generally appear blue smoke, oil burning or unstable speed. At the beginning, the speed of the diesel generator set is not controlled by the accelerator, and it rises rapidly until it exceeds the rated speed, and the engine emits a lot of black smoke or blue smoke. At this time, if measures such as cutting off oil, gas, and decompression are not quickly taken to stop it, the engine speed will continue to rise and make a roar, the exhaust pipe will be filled with smoke, and the speed will be out of control, which will cause major accidents such as smashing the cylinder. occur.
6. The precursor to the fragmentation of the flywheel of the diesel generator set
When there is a hidden crack in the flywheel, hitting it with a hammer will make a hoarse sound. When the engine is working, the flywheel will make a knocking sound. When the speed changes, the sound will increase and the engine will shake. At this time, if the machine is not stopped for inspection, it is easy to cause serious accidents such as the sudden fragmentation of the flywheel, the flying of fragments and injury to people.
7. The precursor to the broken shaft of the diesel generator set
When a hidden crack occurs at the crankshaft journal shoulder of the diesel generator set due to fatigue, the symptom of the failure is not yet obvious. The engine emits black smoke, and soon, the knocking sound gradually increases, the engine vibrates, the crankshaft breaks, and then the olefin fires. Therefore, when there is an abnormal sound in the crankcase of the engine, it should be stopped immediately for inspection.