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Nine maintenance precautions for excavator diesel pumps

2022-03-29

The fuel injection pump is an important part of the diesel engine fuel supply system, and its working condition directly affects the power, economy and reliability of the diesel engine. Therefore, the correct maintenance of the fuel injection pump is an important part of ensuring the normal operation of the diesel engine.

1 to ensure the cleanliness of diesel
Generally speaking, due to the characteristics of the diesel engine fuel supply system and the formation of the combustible mixture, it is determined that the diesel engine's filtration requirements for diesel are far higher than the gasoline engine's requirements for gasoline. the precipitation. In addition, it is necessary to strengthen the maintenance of the diesel filter, clean or replace the filter element in time; clean the fuel tank in time, and completely remove the sludge and water at the bottom of the fuel tank, so as to prevent impurities in the diesel oil from affecting the plunger pair of the fuel injection pump and the oil outlet valve coupler. parts causing severe corrosion or wear.

2 Guarantee the quality of oil

Before starting the diesel engine, the quantity and quality of the oil in the fuel injection pump should be checked (except for the fuel injection pump that is forced to lubricate by the engine) to ensure that the quantity and quality of the oil are sufficient. If the engine oil is deteriorated due to mixing with water or diesel oil, the lighter ones will cause early wear of the plunger pair and the oil outlet valve pair, resulting in insufficient power of the diesel engine and difficulty in starting; Due to the internal leakage of the oil pump, the poor operation of the oil outlet valve, the wear of the tappet and the casing of the oil transfer pump, and the damage to the sealing ring, the diesel oil will leak into the oil pool and dilute the oil. Therefore, it should be replaced in time according to the quality of the oil. When replacing, the oil pool should be thoroughly cleaned, and the sludge and other impurities at the bottom of the oil pool should be removed. The amount of oil should be appropriate. Too much oil in the governor will easily lead to the "speeding" of the diesel engine. Too little oil will cause poor lubrication. The oil dipstick or the oil plane screw should prevail. In addition, when the diesel engine is not used for a long time, be sure to check whether there are impurities such as water, diesel oil, etc. in the oil in the oil pool of the oil pump, and replace it immediately if necessary.

3 Regularly check the oil supply advance angle and oil supply interval angle

During use, due to the loosening of the coupling bolts and the wear of the camshaft and roller body parts, the advance angle of oil supply and the oil supply interval angle of each cylinder often change, which makes the diesel combustion worse, and the power and economy of the diesel engine change. Poor, at the same time difficult to start, unstable operation, abnormal noise and overheating and other abnormalities. In actual use, most drivers tend to pay attention to the inspection and adjustment of the overall fuel supply advance angle, but ignore the inspection and adjustment of the fuel supply interval angle (involving the adjustment of the single-pump fuel supply advance angle). Timing, but the oil supply of the remaining cylinders is not necessarily timing due to the wear of the camshaft and roller transmission components, which will also lead to difficulty in starting the diesel engine, insufficient power, and unstable operation, especially for the fuel injection pump that has been used for a long time. It is said that more attention should be paid to the inspection and adjustment of the oil supply interval angle.

4 Regularly check the fuel supply of each cylinder

Due to the wear of the plunger coupler and the oil outlet valve coupler, the internal leakage of diesel oil will cause the fuel supply of each cylinder to be reduced or uneven, resulting in difficulty in starting the diesel engine, insufficient power, increased fuel consumption, and unstable operation. Therefore, it is necessary to regularly check and adjust the fuel supply of each cylinder of the fuel injection pump to ensure the performance of the diesel engine power. In actual use, the fuel supply amount of each cylinder can be determined by observing the exhaust gas of the diesel engine, listening to the sound of the engine, and detecting the exhaust gas temperature.

5. Regularly check the sealing condition of the oil outlet valve

After the fuel injection pump has been working for a period of time, the wear of the plunger and the working condition of the fuel pump can be roughly judged by checking the sealing condition of the fuel outlet valve, which is beneficial to determine the repair and maintenance method. When checking, unscrew the high-pressure oil pipe joints of each cylinder, and use the hand oil pump of the oil delivery pump to pump oil. If oil flows out of the oil pipe joints at the top of the fuel injection pump, it means that the oil outlet valve is not well sealed (this will also happen if the oil outlet valve spring is broken). ), if the sealing of the multi-cylinder is bad, the fuel injection pump should be thoroughly maintained and the coupling parts should be replaced.

6 Regularly check keyways and bolts

Mainly refers to the camshaft keyway, the coupling flange keyway (the oil pump that uses the coupling to transmit power), the semicircular key and the coupling fixing bolt. Due to long-term use, the keyway, flange keyway and semicircular key of the fuel injection pump camshaft will wear out, which will widen the keyway and change the oil supply advance angle; if the semicircular key falls off, the power transmission will fail. Repair or replace worn parts.

7. Replace the plunger pair and the oil outlet valve pair in time

When it is found that the diesel engine is difficult to start, the power decreases, and the fuel consumption increases, and the fuel injection pump and fuel injector are still not improved by adjusting the fuel injection pump, the plunger pair of the fuel injection pump and the fuel outlet valve pair should be dismantled and inspected. If the plunger pair and the oil outlet valve are worn to a certain extent, they should be replaced.

8 Use standard high-pressure fuel lines

During the fuel supply process of the fuel injection pump, due to the compressibility of diesel oil and the elasticity of the high-pressure oil pipe, the high-pressure diesel oil will form pressure fluctuations in the pipe. It takes a certain amount of time for the pressure wave to transmit in the pipe. In order to ensure that the oil supply interval angle of each cylinder is consistent, the oil supply amount is uniform, and the diesel engine works smoothly, the length and diameter of the high-pressure oil pipe are selected after calculation. Therefore, when the high-pressure oil pipe of a certain cylinder is damaged, the original standard oil pipe of the same length, diameter and material should be replaced. In actual use, due to the lack of standard oil pipes, other high-pressure oil pipes of diesel engines are used instead, regardless of whether the length and diameter of the oil pipes are the same. Although they can be used in an emergency, it will lead to changes in the oil supply advance angle and oil supply amount of the cylinder. , resulting in unstable operation of the whole machine.

9. Correctly maintain the accessories of the fuel injection pump

The side cover of the fuel injection pump, oil dipstick, filler plug (respirator), oil spill valve, oil pool screw plug, oil level screw, oil pump fixing bolt, etc., must be kept intact. These accessories also play an important role in the operation of the fuel injection pump. For example, the side cover can prevent the intrusion of impurities such as dust and moisture, the respirator (with filter) can effectively prevent the deterioration of the oil, and the oil overflow valve ensures that the fuel system has a certain pressure and does not enter the air. Therefore, it is necessary to strengthen the maintenance of these accessories, and repair or replace them in time if they are damaged or lost.

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