Preventive measures for oil circuit failure of the

2022-08-10
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As we all know, preventing various mechanical faults is more important than troubleshooting. As long as it is properly maintained, checked and adjusted in time, and hidden troubles are eliminated in advance, the failure rate will be significantly reduced. The faults of diesel engines often occur in the oil circuit system. The prevention of oil circuit faults is discussed below in combination with the actual situation in use

1. Air resistance and prevention of low-pressure oil circuit

under the suction effect of the oil transfer pump or fuel injection pump, the fuel is sent from the fuel tank through the low-pressure oil circuit to the high-pressure oil circuit. If the low-pressure oil circuit is not tightly sealed, or the oil level in the oil tank is too low, or the oil volume in the oil tank is small and the vehicle is parked and driven at an inclination, air will take the opportunity to enter the oil circuit; If the temperature is high and the fuel evaporates, air resistance will also be formed in the low-pressure oil circuit, resulting in unstable engine operation, automatic flameout or engine failure to start

1) regularly check the sealing conditions of oil pipes, oil pipe joints and sealing gaskets, oil transfer pumps and hand oil pumps in the low-pressure oil circuit. If there is oil leakage and air intake, it should be repaired or replaced in time. If there are cracks, sand holes in the low-pressure oil pipes or when the gaskets of oil pipe joints are damaged, uneven, grooved and burred, it should be replaced in time

2) the route of the oil pipe shall not be in contact with the angular parts and the machine body to avoid wear and leakage, and it is not allowed to change the route of the oil pipe at will to avoid hollowing and breaking. If possible, metal wires can be wrapped around the oil pipe for protection

3) after the fuel in the tank is used up, the air in the oil circuit should be drained in time when refueling

4) when assembling the fine filter cover, fuel transfer pump cover and fuel injection pump cover of the diesel engine, first check whether the sealing paper gasket is intact and whether there are scars, burrs and impurities at the joint, and then tighten the fastening screws between the cover and the housing evenly as required

5) in hot weather, cover a wet cloth on the oil transfer pump and drip water continuously to slow down the evaporation of fuel

2. Prevention of oil circuit blockage

the common parts of oil circuit blockage mainly include oil pipe, filter, diesel filter, oil tank cover vent, etc. However, in fact, the whole oil circuit may be blocked, so the blocking should be prevented as a whole, and the following three aspects should be done well

1) the key to prevent oil circuit failure is to ensure fuel cleaning and oil circuit sealing. Specifically, it should be: ① strictly control the selection and filtration of diesel oil, and the diesel oil should be precipitated for 48 hours before filling; ② The refueling tools should be clean. It is best to use sealed pipes for refueling, and pay attention not to insert the oil suction pipe into the bottom of the barrel. The filter at the filler of the oil tank must be intact, and the oil tank should be regularly discharged; ③ The oil tank should be full when refueling

2) the oil circuit should be maintained regularly, and the maintenance and cleaning must be complete. Do not mix impurities and do not make the oil pipe concave

3) strengthen the cleaning and maintenance of the diesel filter, clean or replace the filter element in time, clean the diesel tank in time according to the operating environmental conditions, and completely remove the oil sludge and water at the bottom of the tank

in addition, do not use bottles, cotton yarn and other items to take oil from the oil tank, so as to prevent sundries, cotton yarn and other easily blocked items from entering the oil tank

3. Prevention of diesel engine fuel injection pump

1) qualified and clean diesel should be used. If the cetane number of diesel does not meet the requirements, its commissioning system will become the requirements of stepless speed regulation, which will cause weak engine operation, large exhaust gas volume, increased faults, especially the high fault of fuel injector

2) the quantity and quality of oil in the fuel injection pump meet the requirements. The quantity and quality of oil in the fuel injection pump should be checked before starting the diesel engine every time (except for the fuel injection pump lubricated by the engine forcibly). If the engine oil deteriorates due to mixing with water or diesel oil, the light one will cause early wear of the plunger and oil outlet valve coupling, resulting in insufficient power of diesel oil and difficult starting, and in serious cases, it will cause corrosion or rust of the plunger and oil outlet valve coupling

3) regularly check and adjust the oil supply advance angle and the oil supply interval angle of each cylinder. During use, the oil supply angle and the interval of each cylinder will change, resulting in poor diesel combustion, poor power and economy of the diesel engine, difficult startup, unstable operation, abnormal and overheating, etc

4) regularly check the camshaft clearance. If the axial clearance is too large, add shims on both sides for adjustment: if the radial clearance is too large, generally replace it with a new one

5) regularly check and adjust the fuel supply volume of each cylinder. In practical application, the fuel supply volume of each cylinder can be determined by observing the exhaust smoke color of the diesel engine, listening to the engine sound, touching the exhaust manifold temperature, etc

6) regularly check the sealing condition of the oil outlet valve coupling due to the extensive involvement. If there is a poor sealing phenomenon in multiple cylinders, thoroughly debug and maintain the fuel injection pump and replace the coupling

7) regularly check the wear of relevant keyways and fixing bolts. Due to long-term use, the light one will wear, which will widen the keyway, the semicircular key will not be installed firmly, and the oil supply advance angle will change; The key will roll down if it is heavy, resulting in the failure of power transmission. 2. According to the service condition of the machine and the service life of the oil, it is necessary to check regularly and repair or replace the worn parts in time

8) the situation has not been improved after the good parts have replaced the suspicious parts of the dissolution activity rate tester. Replace the worn plunger and oil outlet valve coupling in time. When the diesel engine is difficult to start, the power decreases, and the fuel consumption increases, and the fuel injection pump and injector are still not improved by adjusting, the plunger and oil outlet generation coupling should be disassembled and inspected. If the wear is to a certain extent, it should be replaced in time

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