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The Reason For The Increase Of Oil In The Generator Oil Return System

Jun. 15, 2022

The oil return system of the diesel generator set belongs to the main function of the fuel supply system. It is to ensure that when the piston moves upward to a certain degree before the compression dead point, high-pressure fuel is injected into the combustion chamber qualitatively, quantitatively and regularly, so as to make the diesel engine work.


When the generator set is working, the fuel pump will suck the fuel from the fuel tank, send it to the fuel filter, and then enter the fuel injection pump after filtering.


In order to ensure the normal fuel injection of the fuel injection pump, the low-pressure fuel supply volume is much larger than the maximum fuel injection volume of the fuel injection pump, and the excess oil needs to be discharged into the fuel tank (or returned to the low-pressure fuel supply circuit). The pressure of the low-pressure oil supply circuit is controlled by a one-way valve, and the excess oil can be returned to the oil tank or the low-pressure oil circuit through the one-way valve for recirculation. The oil return part is to ensure that there is sufficient fuel supply and to drain excess fuel in time.


The oil return from the oil return pipe of the diesel generator set is caused by the unfinished oil from the injector flowing back to the oil return pipe through the gap between the injector needle valve and the needle valve body. Under normal circumstances, the quantity should be very small. If a large amount of oil return is found, it means that the contact surface of the oil passage between the injector and the needle valve body of the injector is not in good contact, so that the diesel generator set flows from here to the top of the injector and leaks through the oil return pipeline.


diesel generator set

With the increase of working time, the gap between the needle valve in the injector and the needle valve body increases due to wear and tear, and the leakage of diesel oil from the gap also increases. It is required that the pressure regulating spring is not removed first, and then the fuel injector tightening nut is removed, resulting in a loose pressing between the upper end of the needle valve body and the lower section of the injector body. During assembly, the debris on the two planes is not removed, or the tightening nut of the fuel injector is not tightened tightly, so that the tightness of the two tight-fitting sections is damaged. In addition, the surface of the needle valve body is eroded by high-pressure diesel oil containing impurities, which may also increase the oil return.


Note: Do not connect the oil return pipe directly to the oil inlet pipe of the unit.


The above is the oil return pipe function analyzed by Jiangsu Starlight Electricity Equipments Co.,Ltd. for you and the reason for the increase in oil return.


Jiangsu Starlight Electricity Equipments Co.,Ltd. is one of the earliest manufacturers of generators and diesel generator sets in China. The company was established in 1974 and the company occupies an area. With an area of 86,000 square meters and a building area of 45,000 square meters, it has 64 sales and service departments across the country to provide users with one-stop service of design, supply, debugging and maintenance at any time. Welcome customers to come to consult and visit. Looking forward to your inquiry, please send email to us for details sales@dieselgeneratortech.com.

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