在修后试车时,发现有些柴油机,特别是修理过又使用一段时间后,都不同程度地存在着功率下降的现象。检查表明,这些柴油机的喷油泵供油量、压缩系统配合间隙和零部件均符合技术要求,但气缸压力低且各缸压力不一致。进一步检查又发现,活塞到达上止点时,一般低于缸体平面0.08～0.24毫米,个别缸甚至达到0.5～0.8毫米。按要求,活塞到上止点时,应和缸体上平面平齐。低于缸体平面时,使燃烧室内容积增大,压缩比下降,进而导致柴油机功率下 In the test after repair, found that some diesel engines, especially after repairing and using for a period of time, there is varying degrees of power decline phenomenon. Inspection showed that these diesel engine fuel pump fuel supply, compression systems with clearances and components are in line with technical requirements, but the cylinder pressure is low and the pressure of each cylinder is inconsistent. Further examination also found that the piston reaches the top dead center, generally lower than the cylinder plane 0.08 ~ 0.24 mm, individual cylinder even reach 0.5 ~ 0.8 mm. On request, the piston to the top dead center, and the cylinder should be flush with the plane. Lower than the cylinder plane, the combustion chamber volume increases, the compression ratio decreased, which led to the power of diesel engine