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What  should  be  paid  attention  to  in  daily  maintenance  of  diesel  engine?

What should be paid attention to in daily maintenance of diesel engine?

Diesel engines need regular maintenance in daily work, and maintenance mainly includes the following aspects, ITCPower needs to let you know.

  1. New diesel engine or diesel engine after overhaul should be run-in:
    After the new diesel engine was overhauled, parts such as cylinder liners, pistons, piston rings and bearing bushes were replaced. They did not undergo sufficient running-in and worked under load, which easily caused early wear and tear of the parts, and some even showed cylinder pulling and bush burning.
  2. Do not run the diesel engine at high speed immediately after cold start:
    After the diesel engine is cold-started, because it is in the “cold car” state, the oil viscosity is high, the flow resistance is large, the time for the oil entering is lagging, the various parts of the diesel engine are not fully lubricated, and the gears and bearings of the diesel engine are damaged due to poor lubrication and aggravated Wear of cylinder and bearing bush. Especially supercharged diesel may cause ablation of the shaft of the turbocharger. Therefore, the diesel engine should work independently for a period of time after starting, and the speed can be increased after the oil temperature rises, the fluidity improves, and the diesel engine is fully lubricated. This is more important in the cold winter.
  3. The diesel engine turns off suddenly:
    When the supercharged diesel engine suddenly turns off when it is running at high speed, the oil pump immediately stops rotating, and the oil in the supercharger also stops flowing. If the temperature of the exhaust manifold is very high at this time, its heat will be absorbed into the turbocharger housing, and the oil that stays there will be roasted into carbon deposits, blocking the oil inlet, causing the bushing to run out of oil and speeding up the shaft The wear and tear of the shaft sleeve can even produce other more serious consequences. Therefore, the load must be turned off before the supercharged diesel engine stops, and the diesel engine can work independently for a few minutes, and then turn off after the temperature of the diesel engine drops.
  4. Use low-quality diesel:
    When unqualified diesel is used, the cetane number does not meet the standard, resulting in poor combustion of the diesel engine, excessive carbon deposits, and sintering of the piston ring causing cylinder pull. At the same time, inferior diesel will accelerate the wear of fuel injection pumps, delivery valves and fuel injector nozzles.
  5. Wrong use of diesel engine oil:
    (1) The diesel engine misuses gasoline engine oil. Since the compression ratio of a diesel engine is more than twice that of a gasoline engine, the main parts are more impacted by high pressure and high temperature than a gasoline engine, so the materials of some parts of the two are different. For example, the main bearing and connecting rod bearing of a gasoline engine can be made of Babbitt alloy with a softer material and good corrosion resistance, while the bearing of a diesel engine must be made of high-performance materials such as copper-lead alloy or tin-aluminum alloy. Poor, even a small amount of acid in the engine can cause severe corrosion, causing spots, pits, and even a piece of metal to fall off the bearing bush. Therefore, in the refining process of diesel engine oil, it is necessary to add more anticorrosion agent, so that a protective film can be formed on the surface of the bearing during use to reduce the corrosion of the bearing and improve its wear resistance. In addition, the sulfur content of diesel is higher than that of gasoline. This harmful substance will form sulfuric acid or sulfurous acid during the combustion process, which will flow into the oil pan together with high-temperature and high-pressure exhaust gas to accelerate the oxidative deterioration of the oil. Therefore, it is used in diesel engine oil refining. Some antioxidants need to be added during the preparation process to make the oil alkaline. If acidic gas enters, it can neutralize the oil to a certain extent and prevent the oil from oxidizing and deteriorating too quickly.
    (2) Engine oil is only added and not replaced. Many users only pay attention to the amount of diesel engine oil and add it according to the standard, without paying attention to checking the quality of the engine oil, and neglecting the replacement of the deteriorated engine oil. Due to the deterioration of the oil, the lubrication function will be lost, resulting in diesel engine running parts always running in a poor lubrication environment, accelerating its wear, and eventually causing some failures. Therefore, when checking the oil quantity, the quality of the oil must be carefully checked. If the oil is deteriorated, the oil must be replaced in time.
    (3) Add more oil than less. Some users are afraid that the lack of engine oil will burn the tiles, and think that adding more engine oil is better than adding less, and often causes the amount of engine oil to exceed the standard. In fact, too much oil will increase the rotation resistance of the diesel engine crankshaft, which will not only increase the oil consumption, but also reduce the output power of the diesel engine; a large amount of oil will enter the combustion chamber and be burned, causing blue smoke from the exhaust gas and increased oil consumption; making the combustion chamber The increase in carbon deposits makes diesel engines prone to deflagration, which increases the wear of cylinders and pistons. Therefore, the diesel engine oil should not be too little or too much. Generally, the oil level should be kept slightly below the upper limit of the oil dipstick.
    (4) Not paying attention to checking the engine oil level and adding oil in time, causing the engine to run under the condition of low oil level and insufficient oil pressure, causing failure; the oil filter element cannot be replaced regularly, and the effect of the oil filter element is poor, thus Excessive wear and tear of mechanical parts may even cause malfunctions; during operation, the oil pressure is not observed carefully, or the oil pressure is found to be too low and the cause is not found in time, and the operation continues. Eventually, poor lubrication causes the bearing bush to burn out and the diesel engine damages.
  6. Long-term overload operation of the engine:
    Some users only pursue temporary economic benefits, so that the diesel engine is overloaded for a long time, resulting in the early wear of the diesel engine parts. The test shows that when the diesel engine speed is unchanged and the load power is increased by 2 times, the diesel engine wear is also close to 2 times. If the diesel engine is overloaded for a long time, it will cause the failure of burning bush and axle.
  7. Diesel engine idling for a long time:
    (1) If the diesel engine is idling for a long time, its combustion will deteriorate, and then some failures will occur, such as diesel engine overheating, exhaust pipes emitting black smoke, power drop, mechanical wear and tear, which will reduce its life, resulting in cylinder pulling or tile burning. , Crankshaft distortion, etc. When the diesel engine is idling for a long time, due to the low speed and the reduction of the fuel injection pressure, it will cause poor diesel atomization, incomplete combustion of the mixture and formation of carbon deposits. Carbon deposits can easily block the nozzle holes of the fuel injectors, causing the power of the diesel engine to drop and the exhaust pipes to black smoke. Excessive carbon deposits can sometimes block the exhaust pipe muffler, turbocharger and other parts, making the diesel engine unable to work normally.
    (2) When the diesel engine is idling for a long time, the oil pressure is low, the oil circulation speed is reduced, and the cleaning ability is reduced, the sealing effect is not good, the heat transfer ability is reduced, the splash lubricated parts receive less lubricating oil, and the acceleration movement zero surface The wear and the service life are reduced. Such as: the wear between the piston, piston ring and cylinder wall increases; the wear of the transmission parts of the air distribution mechanism increases: the life of the main bearing and connecting rod bearing is reduced.
    (3) When the diesel engine is idling for a long time, the atomization of the mixture is poor and the combustion is not complete. The fuel condensed in the combustion chamber or unburned fuel vapor will flow into the oil pan along the cylinder wall, thereby diluting the crankcase. Engine oil reduces the viscosity of the engine oil and even deteriorates the engine oil. This destroys the lubricating effect of the engine oil, resulting in worsening of poor lubrication and abrasion of the moving parts of the diesel engine, and the phenomenon of bush burning and cylinder pulling may occur.
  8. Failure to clean the air filter or replace the filter element regularly:
    The air filter is an important part of the diesel engine supply system, which can purify the air entering the air pipe. If the air filter is not maintained in time, it will cause early wear of the cylinder liner, piston ring, intake and exhaust valve and other parts, reduce the engine power, and even shorten the service life of the diesel engine. Tests have shown that if the diesel engine is not equipped with an air filter, the cylinder wear increases by 8 times, the piston ring wear increases by 9 times, and the wear of other mechanical parts also increases. If the air filter is not maintained in time or is of poor quality, its filter effect will be significantly reduced. In order to save fuel, some users do not install the air filter, or do not replace the filter in time when the filter is damaged, or the connecting hose is not replaced in time after aging or damage, which will cause a large number of impurities in the air to enter the cylinder and aggravate the damage of the machine. Wear.
  9. Do not strengthen the precipitation and filtration of diesel, and the filter element of the diesel filter is not cleaned or replaced in time:
    Because impurities such as dust and moisture are mixed into the fuel during storage, transportation and use, the fuel will oxidize and gel, which will aggravate cylinder wear and cause early engine damage. In fact, the wear of the precision parts of the diesel engine oil supply system is mainly caused by the hard abrasive particles in the diesel oil. Therefore, strengthening the precipitation and filtration of diesel oil can greatly extend the service life of precision parts. If the diesel filter element is not cleaned and replaced regularly, and the diesel tank is not cleaned regularly, the fuel supply system will be blocked, resulting in insufficient fuel supply. At the same time, the fuel injection pump and the precision coupling parts of the fuel injector will be caused by the unclean diesel. Wear.
  10. Careless and omission to install small parts during engine maintenance and assembly:
    When servicing the engine, some small parts may be missed due to negligence. Some people even think that it does not matter whether it is installed or not. This is very dangerous and harmful. The valve lock plates should be installed in pairs. If they are not installed or installed incorrectly, the valve will lose control and damage the piston and other parts; the cotter pins, iron wires (lock plates) or spring washers on the connecting rod bolts and flywheel bolts are anti-loosening devices. Once missing, it may cause serious failure during use; the piston pin lock ring is used to prevent the piston pin from moving, if it is missing, it will produce abnormal noise or damage the cylinder liner; it is used for lubrication in the engine timing gear chamber If the oil nozzle of the gear is missing, it will cause serious oil leakage in this place, causing the diesel engine oil pressure to be too low; the loss of the water tank cap, fuel filler cap, and fuel tank cap will invade the cooling, lubrication, and fuel system due to sand, dust, etc. Will aggravate the wear and tear of various parts.