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Why Does Diesel Generator Emit Blue Smoke When Exhaust

Jul. 22, 2021

When using diesel generators, blue smoke produced by diesel generators is one of the most common faults. The root cause of blue smoke in the exhaust of diesel generators is that the engine oil of diesel generators is related to combustion. That is, oil enters the combustion chamber abnormally. The main reasons why diesel engines burn engine oil are as follows.


1.The oil content is too high.

If the engine oil is refueled too much, the surface of the engine oil is too high, which will also cause the exhaust gas pressure in the crankcase to increase. The result is the same as the failure of a respirator, which will cause a large amount of oil to enter the combustion chamber and severely emit blue smoke. There used to be a diesel generator with an external fuel tank, which caused serious smoke and fuel consumption. At first, it was considered that the piston ring and cylinder liner were severely worn, but after removing the cylinder head, the piston ring and cylinder liner were normal. After gradual disassembly and analysis, it was finally found that the oil return pump inlet in the diesel generator tank was blocked, and a large amount of oil could not be returned to the external tank, and it was all inside the diesel generator, causing serious smoke from the diesel generator.


2.The cylinder liner and piston ring are seriously worn.

Due to some reasons (including poor running-in, poor air filter quality, long-term low-speed and low-temperature operation, unqualified oil quality, etc.), leading to early or abnormal wear of the piston ring and cylinder liner of the diesel generator, and worsening the sealing condition of the piston ring and cylinder liner. In this way, on the one hand, the oil directly enters the combustion chamber for combustion; on the other hand, because the cylinder liner and piston ring are not tightly sealed, the combustion gas enters the crankcase, increasing the exhaust pressure, and forcing the oil into the breather pipe through the respirator. If the diesel generator is equipped with a closed respirator, a large amount of oil will enter the intake pipe and burn through the inhaled cylinder. When the diesel generator is used, blue smoke will be severely emitted, if an open crankcase respirator is installed on the diesel generator, engine oil will come out of the exhaust port.


diesel generator set

3.The piston ring is aligned.

If the piston rings are aligned, even if the cylinder liner and piston rings are not worn, blue smoke will be emitted when the diesel engine burns. When we call piston ring alignment, it means that the piston rings of a certain cylinder or the entire cylinder open in the same direction. In this way, the oil will escape from the piston ring opening into the combustion chamber to burn, causing the diesel generator to burn the oil severely and emit blue smoke. When this kind of failure occurs, diesel generators consume a lot of oil.


4.The air compressor is malfunctioning.

Many diesel generators are equipped with air compressors. Generally speaking, diesel generator oil is used to lubricate and cool the internal parts of the air compressor. If the piston ring of the air compressor is worn or the cylinder is pulled, a large amount of compressed air will randomly flow back into the crankcase, resulting in lower exhaust. This will cause a large amount of engine oil to be produced during the intake process, and the negative pressure of the cylinder will be sucked into the combustion chamber to participate in the combustion, causing the exhaust to emit blue smoke.


5.The turbocharger is faulty.

In a supercharged diesel generator, when the floating bearing on the press side of the supercharger is damaged, a large amount of oil may enter the intake pipe of the diesel engine through the press, and then into the combustion chamber, causing blue smoke when the diesel generator is running.


Jiangsu Starlight Electricity Equipments Co.,Ltd. was founded in 1974, as a wholly-owned subsidiary of Jiangsu Starlight Power Group, it is one of the earliest manufacturers of generator sets in China. Starlight Power has 64 sales services, long-term technical advice for users, free debugging, free maintenance, free training services. For more details, please contact us with sales@dieselgeneratortech.com

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