If a diesel generator set operates under low load for an extended period, the following faults may occur:

1. Poor sealing between the piston and cylinder liner may allow engine oil to enter the combustion chamber, resulting 

in blue exhaust smoke during combustion.

2. For turbocharged diesel engines, low or no-load operation leads to low turbocharging pressure. This can reduce the 

sealing effectiveness of the turbocharger oil seal (non-contact type), allowing oil to leak into the turbocharging chamber 

and enter the cylinder along with the intake air.

3. Some of the oil that enters the cylinder participates in combustion, while some may not burn completely, forming carbon 

deposits on valves, intake ports, piston crowns, piston rings, etc. The remaining oil is expelled with the exhaust. Over time, oil 

and carbon deposits can accumulate in the cylinder liner exhaust passages.

4. When oil accumulates in the turbocharger's boosting chamber to a certain extent, it may leak from the joint surfaces of the turbocharger.

5. Prolonged operation under low load can lead to accelerated wear of moving parts, deterioration of the engine's combustion 

environment, and other issues that may shorten the time until a major overhaul is required.

Therefore, foreign diesel engine manufacturers emphasize minimizing low-load or no-load operation for both naturally aspirated 

and turbocharged engines, specifying that the minimum load should not fall below 25%–30% of the unit’s rated power.

Foshan Generator -- Guangdong Longhong Electromechanical Equipment Co., Ltd.