1. Piston — Cylinder liner seal failure causes oil to leak upward into the combustion chamber, resulting in blue smoke from the exhaust;

II. For turbocharged diesel generators, low boost pressure due to light loads can degrade the sealing effectiveness of the turbocharger oil seal (non-contact type). This allows engine oil to leak into the turbocharger housing and enter the cylinders with the intake air;

III. Some of the oil entering the cylinder participates in combustion, while some oil cannot be fully burned. This forms carbon deposits on valves, intake passages, piston tops, piston rings, etc., and another portion is expelled with the exhaust. Consequently, oil gradually accumulates in the cylinder liner exhaust passages, also forming carbon deposits;

IV. When oil accumulates to a certain level in the turbocharger's boost chamber, it will leak out from the turbocharger's mating surfaces;

V. Prolonged operation of the generator under low load will further exacerbate wear on moving components of the generator set, deteriorate the engine's combustion environment, and lead to premature overhaul.

These impacts severely compromise the performance and service life of Cummins generator sets. It is essential to fully recognize this. For both naturally aspirated and turbocharged diesel generator sets, minimize low-load/no-load operation time, and ensure the minimum load does not fall below 25%–30% of the unit's rated power.