Introduction of Cummins Diesel Generator Oil System Knowledge

The oil circuit system of Cummins diesel generator set includes oil tank, filter, oil-water separator, high-pressure oil pipe, fuel transfer pump, fuel injection pump (including governor), fuel injector, low-pressure oil pipe and return oil pipe. The tank is filled with precipitated and filtered diesel, which is the diesel fuel pump and the person pumped out from the tank. The diesel Frega filters the impurities and enters the injection pump. The high pressure and diesel output from the self-injection pump are injected into the combustion chamber through the high pressure system oil pipe and injector. Since the fuel supply of the pump is far greater than that of the fuel injection pump, the excess diesel oil is returned to the pump through the return pipeline. The fuel pump from the fuel tank to the population of this oil is called low-pressure oil. The low-pressure control oil circuit is only used to supply filtered fuel to the fuel injection pump.

The oil pressure from the fuel injection pump to the fuel injector is established by the fuel injection pump, which is generally greater than 10MPa, so this section of oil circuit is called high-pressure oil circuit. Based on the fuel spray spray, the combustion chamber mixes with air through the injector to form a combustible mixture.

1. Oil tank

The fuel tank is a container for storing diesel oil. The fuel tank is generally welded and connected with steel plate stamping technology. In order to prevent the development of diesel oil inside the oil tank from forming a foam after being impacted by severe social changes, in addition to rust prevention treatment, some students also use diaphragms to separate more spaces on the internal control surface of the oil tank. The oil filler is located at the top of the oil tank, and the filter screen is generally installed under the oil filler. In order to avoid some vacuum in the internal management of the tank, the upper part of the tank cap is generally equipped with a breather. Enterprises at the bottom of the oil tank are generally equipped with oil drain.

2. Diesel filter

The diesel filter is usually installed before the pump to remove the diesel particulate impurities. There is a paper filter type, slit metal, chip, and similar grid. The fine filter of diesel engine is usually set after the pump is installed to remove a small amount of impurities in diesel, and the paper type of felt filter and metal mesh is used.

The paper filter element uses the structural design of the diesel filter. The diesel oil from the fuel transfer pump enters the filter from the oil inlet and the gap between the shell and the paper filter element technology. Then we filter the system through the air filter element, and then the central rod flows out through the oil outlet. A pressure limiting valve is set on the filter cover. When the oil pressure exceeds a certain standard, the pressure limiting valve opens normally, and the excess diesel oil is directly returned to the diesel tank through the pressure limiting valve adjustment at the oil inlet.

3. Fuel injection pump

Fuel injection pump, also known as high-pressure pump, has a complex structure and principle.

4. Fuel injector

The fuel injector is an assembly that introduces the low pressure fuel radiated from the combustion chamber to the Cummins diesel generator set oil system knowledge. According to the request of Cummins diesel generator set, atomized diesel oil from low-pressure oil pump will be injected into the specific position of combustion chamber with certain injection pressure, spray fineness, injection discipline, range and spray cone angle, and mixed with air for combustion. The injector nozzle and nozzle installed on the cylinder head are fixed by and embedded in the injector nozzle holder. The structural design of fuel injectors can be divided into two types: open type and closed type. The high pressure cavity of open type fuel injector can be directly connected with the combustion chamber through the injection holes, while the appearance of closed type fuel injector can be separated by adding a needle valve during the analysis. The foundation of diesel generator of modern diesel turbine unit adopts closed fuel injector, which is divided into hole type fuel injector and pin type fuel injector, which are used in different combustion chambers.

5. Oil-water separator

The function of oil-water separator is to separate the water mixed in the oil, which is made by using the light water weight principle of oil. When the buoy reaches or exceeds the red line, it is necessary to drain the oil drain plug and water. After the oil drain, the air in the fuel system should be discharged through the hand pump.

6. Fuel transfer pump

The oil transfer pump is an indispensable primary component in Cummins diesel generator set. Its function is to transfer the fuel tank to the injection pump. In order to ensure the circulation of diesel fuel in the low-pressure oil circuit in China, and to supply the fuel injection pump with sufficient capacity for enterprises and certain social pressure, the fuel delivery volume should be 3 to 4 times of the maximum fuel injection volume affected by the load, so as to ensure the normal operation of the national machinery. It can be divided into linear type and distributed type. The in-line oil pump consists of inlet check valve, piston, piston spring, plunger tappet, push rod, outlet check valve, hand oil pump and pump body. It is installed on the side fuel pump of the fuel pump. The eccentric cam of the camshaft is reciprocated by the plunger and tappet push rod in the injection pump, pressurizing the fuel until the fuel injection pump is driven. This kind of fuel transfer pump sometimes needs to discharge the air in the fuel at the low pressure side of the traditional fuel management system (from the fuel transfer pump to the fuel injection pump), so we have prepared a manual fuel transfer pump to deliver the fuel pressure to the fuel injection pump. The oil pump can be divided into horizontal type and up and down type according to the fuel path.

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