1. Abnormal noise of diesel generator bearing

（1）主轴承异响。其主要原因是，轴颈与轴承协作空位过大，在作功的瞬间彼此撞击所发生的响声。判别时要细心倾听，当遽然改动发动机速度，宣告接连一阵沉重而有力的敲击声，即为主轴承响。其他，使发动机达到正常温度，带上负荷，中速工作，然后逐缸连续作业，当连续某缸作业时，响声略有减小，一起连续相邻两缸的作业，响声显着减小或消失，即为相邻两缸之间的主轴承有响声。

(1) Abnormal noise of main bearing. The main reason is that the coordinative vacancy of journal and bearing is too large, and the noise occurs when they collide with each other at the moment of work. When the engine speed is suddenly changed, a series of heavy and powerful knocking sounds are announced, that is, the main bearing rings. The other is to make the engine reach the normal temperature, load the engine, work at medium speed, and then operate continuously from cylinder to cylinder. When a certain cylinder is operated continuously, the noise decreases slightly. When two adjacent cylinders are operated together, the noise significantly decreases or disappears, which means that the main bearing between the two adjacent cylinders has a sound.

（2）连杆轴承异响。其主要原因是：连杆轴承与轴颈磨损，协作空位过大；连杆轴承合金焚毁或坠落；修补质量低，安装空位过大或轴承表面刮削不平。判别时，可在不同转速下细听，由怠速遽然转入中速时，有显着的接连敲击声。连续可疑气缸的作业，响声减小或消失。当灵敏康复该缸作业的瞬间，宣告“当”的一声敲击声，即为该缸连杆轴承响0如有两道连杆轴承响，当连续某缸作业后，响声只能减小不能消失，只要连续发生响声的两只气缸的作业，响声才能进一步减小或消失。

(2) Abnormal noise of connecting rod bearing. The main reasons are as follows: the connecting rod bearing and journal wear, the cooperative vacancy is too large; the connecting rod bearing alloy is burned or dropped; the repair quality is low, the installation vacancy is too large or the bearing surface is scratched unevenly. When judging, you can listen carefully at different speeds. When you suddenly change from idle speed to medium speed, there is a significant continuous knocking sound. The noise decreases or disappears when the suspicious cylinder is operated continuously. At the moment of sensitive rehabilitation of the cylinder operation, a knock sound of "Dang" is announced, that is, the cylinder connecting rod bearing rings 0. If there are two connecting rod bearings ringing, the noise can only be reduced and can not disappear after the continuous operation of a certain cylinder. As long as the two cylinders with continuous noise are operated, the noise can be further reduced or disappeared.

2.柴油发电机缸塞组异响

2. Abnormal noise of diesel generator cylinder plug group

（1）异响原因分析

(1) Cause analysis of abnormal noise

①活塞敲缸。柴油机冷态敲缸，一般由活塞与缸壁空位过大、机油压力短少或油道阻塞导致的缸壁光滑不良构成；热态敲缸，一般由连杆弯曲、扭曲构成活塞在气缸内运动“走形”，连杆衬套轴向偏斜，连杆轴颈与主轴颈不平行，活塞与缸壁空位过小，活塞变形，活塞环端空位过小构成；柴油机冷、热两种情况都存在敲击，一般由活塞销与连杆小头过盈量太大，连杆轴承安装过紧，活塞裙部圆度超差等原因引起。

① The piston knocks. Cold knocking of diesel engine is generally composed of excessive piston and cylinder wall vacancy, short oil pressure or poor cylinder wall smoothness caused by blockage of oil duct; hot knocking generally consists of bending and twisting of connecting rod, and piston moves "out of shape" in the cylinder; connecting rod bushing is axially skewed; connecting rod Journal and main journal are not parallel; piston and cylinder wall vacancy are too small; piston deformation; piston ring end vacancy It is generally caused by excessive interference between piston pin and small end of connecting rod, too tight installation of connecting rod bearing and out of tolerance of roundness of piston skirt.

②活塞销敲击。活塞销与连杆衬套由于光滑不良构成的磨损过甚，或加工不当发生了空位，活塞销折断，连杆小头衬套外圆在小头孔内松旷等；由于温度升高，构成的活塞销与孔协作空位进一步增大等。

② The piston pin strikes. The piston pin and connecting rod bushing are worn too much due to poor smoothness or improper processing, resulting in vacancy, broken piston pin, loose outer circle of connecting rod small end bushing in small end hole, etc.; due to the increase of temperature, the cooperative vacancy of piston pin and hole is further increased.

（2）活塞环漏气噪声。活塞环弹力短少，构成环与缸壁密封不良；活塞环折断、活塞环卡死在环槽内及活塞环对口等发生的漏气。

(2) Piston ring leakage noise. The elastic force of piston ring is short, which leads to poor sealing between ring and cylinder wall; air leakage occurs when the piston ring is broken, the piston ring is stuck in the ring groove and the piston ring is opposite.