Causes of excessive pressure on crankcase exhaust of diesel engine (2)

- Nov 13, 2018-


One of the common faults of diesel engine is that the lower exhaust (crankcase exhaust) is too large.There are many reasons for the high pressure of diesel crankcase exhaust gas.

1、Too much oil.

Too much oil will lead to the increase of crankcase exhaust pressure, which is due to the limited space inside the crankcase, too much oil will be added, high-speed moving parts such as crankshaft link will seriously hit the oil and make it splash, oil mist and cause the crankcase exhaust pressure to increase.

Concomitant phenomenon: crankcase exhaust pressure, high oil level.

2、Serious air channeling in air compressor

If the piston ring of the air compressor is seriously worn, the compressed gas oil of the air compressor will flow into the crankcase and increase the pressure of the crankcase exhaust gas.When there is no problem in checking piston ring, cylinder liner, respirator, etc., and the exhaust pressure of crankcase is still high, it is necessary to check the air compressor accordingly.

Concomitant phenomena: the crankcase gas pressure increases, the engine oil consumption increases, and the air system pressure of the equipment is slow and the engine oil is available.At this time, the quality of the air compressor should be checked, the air circuit system of equipment should be dredged, and the air compressor (piston ring, etc.) or gas safety valve should be replaced as appropriate.

3、The main differences between piston ring or cylinder sleeve factors and other factors leading to high crankcase exhaust pressure.

(1) Piston ring or cylinder sleeve wear, feeding into the crankcase is combustion gas, therefore, crankcase exhaust has a strong combustion gas flavor, while other factors do not have this flavor.

(2) To extend the piston ring or cylinder liner factor channeling gas easy to make the oil black in the short term, other factors of the oil black time normal.

(3) If the piston ring or cylinder liner factor channeling air will lead to the diesel engine power shortage, black smoke, abnormal noise inside the cylinder, and other factors channeling air does not have these phenomena.

4. Great harm of crankcase exhaust pressure

(1) Increases engine oil consumption;

(2) The diesel engine in niigata seriously emit blue smoke;

(3) It is easy to cause carbon deposition on the top of piston or piston ring groove, resulting in cylinder fault;

(4) Exposure to the closed cycle crankcase respiratory system (i.e., the exhaust pipe of the respirator is directly introduced into the intake pipe of the diesel engine) can easily cause ablation failure on the top of the piston.