1、 The transmission gear is worn and the clearance is too large.
There is a strange sound coming from the front cover plate. When the Cummins diesel generator set suddenly slows down, a collision sound can be heard. At this time, the backlash should be adjusted and the gear should be replaced according to the wear situation;
2、 The gap between the intake and exhaust valves is too large.
Abnormal noise and damage analysis during the operation of diesel generators. A rhythmic and loud noise can be heard at the cylinder head, and the valve clearance should be recalibrated at this time;
3、 The valve touches the piston.
During operation, the cylinder head emits a heavy, even, and rhythmic tapping sound. Gently grip the nut of the cylinder head cover with your fingers and feel a collision. Remove the cylinder head cover, inspect the cause of the collision, adjust the valve clearance, and if necessary, inspect the diesel generator for abnormal noise and damage during operation. Analyze whether the piston model is adjusted incorrectly. If there is a collision, dig the valve depression deep or add a sheet with a thickness of 0.2mm or 0.040mm, A copper gasket with the same shape as the bottom surface of the cylinder;
4、 There is no oil between the rocker arm adjustment screw and the spherical seat of the push rod, causing abnormal noise during the operation of the diesel generator.
Fault analysis: A "squeaking" sound can be heard from dry friction at the cylinder head. At this time, the cylinder head cover should be removed and engine oil should be added;
5、 The radial clearance of the crankshaft rolling bearing is too small.
The diesel generator emits a particularly sharp sound during operation, which becomes clearer when the throttle is increased; The radial clearance of the crankshaft rolling main bearing is too large: there is a "Hoho" sound during operation. At this time, the rolling curve bearing with the sound should be detected and replaced if necessary;
6、 The valve spring of the diesel generator is broken, the tappet is bent, and the push rod sleeve is damaged.
A rhythmic slight tapping sound is emitted throughout the cylinder. At this time, the diesel generator parts should be inspected and damaged parts should be replaced, and the valve clearance should be adjusted. How to adjust the valve of the diesel generator set
7、 Excessive clearance between piston and cylinder liner.
When the diesel generator is running, a collision sound is heard on the outer wall of the cylinder. As the speed increases, this collision sound intensifies. At this time, the piston should be replaced or the cylinder liner should be replaced depending on the wear situation;
8、 The wear of the front and rear thrust bearings of the spindle and the excessive axial clearance cause the spindle to move forward and backward.
When the diesel generator is running and the collision sound of the crankshaft moving forward and backward is heard, the axial clearance and the wear degree of the thrust bearing should be checked, and replaced if necessary;
9、 The fit between the piston pin and the connecting rod small end bushing hole is too loose.
There is a light and sharp sound during the operation of the diesel generator, which is particularly clear during constant speed operation. Replace the connecting rod small end bushing to make it within the specified clearance range;
10、 Diesel generator fuel injection time too early or too late.
The cylinder emits rhythmic and crisp metal tapping sounds or low and unclear tapping sounds, and the fuel injection advance angle should be adjusted at this time.