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Four Ways to Remove Air in Oil Circuit of Diesel Generator

Jan. 04, 2020


If there is air in oil circuit of diesel generator set, what will happen?

Air has great compressibility and elasticity. When there is a leak in the oil pipe from the oil tank to the oil delivery pump section of diesel engine, the air will infiltrate, which reduces the vacuum degree in this pipeline. So that the suction of fuel in the tank is weakened, or even cut-off occurs, which causes the engine failure to start.

 

If there is fewer air in the oil circuit, the oil flow can still be maintained and sent to the injection pump by the oil transfer pump, but the engine will be difficult to start or it will shut down automatically soon after starting.

 

If there is more air in the oil circuit, it will cause fuel cut-off or significant reduction of fuel injection volume of the cylinder, and the diesel engine can not be started. At this time, it is necessary to remove the air in the oil circuit.

 

Once air enters oil circuit of diesel generator set, the diesel engine will be difficult to start up or run unstably, if serious, will shut down. Therefore, when use the unit, we should pay attention to check whether there is air in the oil circuit.


Shangchai generator set

 

How to remove air in oil circuit of diesel generator set?

1.If need to remove air during operating the unit, we can first loosen the bleed screw on the injection pump or any connector between the diesel filter and the injection pump. Then drive mechanical oil transfer pump by starting. This leakage point will spray unobstructed and bubble free fuel, then tighten the above leakage point you loosen.


2.Use a screwdriver or wrench to unscrew any exhaust screw at the upper end of both sides of the fuel injection pump for several turns, press the manual oil pump by hand until the discharged diesel oil is continuous, free of bubbles and makes a "squeak" sound. Then screw out the bleed screw and manually press the oil pump back to its original position.


3.For trailer diesel generator set, during the operation, if you do not have a suitable driver or wrench to turn on the bleed screw on the fuel injection pump, you can turn on the hand pump first, then loosen any coupling between the diesel filter and the injection pump, then press the manual oil pump repeatedly until the oil flow without bubbles is discharged from the joint. Then press the manual oil pump and fasten the joint, and finally press the manual oil pump back to its original position.

4.If you do not have the wrench to loosen the connector in the pipeline, you can press your manual oil pump repeatedly until the pressure of the low-pressure oil circuit from the oil transfer pump to the injection pump section is high enough, fuel flows from the relief valve into the fuel return line, air in oil circuit will be discharged from the overflow valve.


When there is air in the oil circuit of diesel generator set, different treatment methods can be adopted in different situations, so as to solve the air problem in the oil circuit quickly. Hope the above information can help you.

 

How to find the leakage point in the oil circuit of diesel generator set?

 

The soft rubber hose is mostly used in the low pressure oil circuit of fuel supply system of diesel generator. The hose is easy to rub with the parts, resulting in oil leakage and air intake. It's easier to find the oil leakage point, but it's not easy to find the air leakage point in the pipeline. Here are some methods to judge the air leakage point in the low pressure oil circuit:


1.After the engine is started, find out the leakage of diesel oil, which is the leakage point.

2.Loosen the bleed screw of the fuel injection pump and pump the oil with the manual fuel pump. If it is found that a large amount of air bubbles begin to flow from the vent screw, and after repeated manual pump, the air bubbles still do not disappear. It indicates that there is a leak in the negative pressure oil circuit from the tank to the oil pump. This section of pipeline should be removed, then pressurize gas and place in the water, and the place where the air bubble found is the leak point.


The fuel supply system of diesel generator set consists of low pressure oil circuit and high pressure oil circuit. The low-pressure oil circuit refers to the oil circuit from the oil tank to the low-pressure oil cavity of the injection pump. High pressure oil circuit refers to the oil circuit from the plunger cavity of the high-pressure pump to the injection nozzle. In the supply system of the plunger pump, there is no air leakage in the high-pressure oil circuit. But if there is leakage, will cause fuel leakage. We just need to find out the leakage point and block it.

 

In addition to the pipeline problems, various gaskets at the pipeline joints will also cause air leakage due to improper installation, deformation, aging damage, etc., which will become the leakage point. Before detailed inspection of the pipeline, these nodes should be inspected first.

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