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Common Failure Maintenance Of Diesel Engines
Nov 06, 2018

Common failure maintenance of diesel engines
1, diesel engine start-up difficulties
(1) Check low pressure oil routes
1 Check whether the diesel switch in the lower part of the diesel tank is open and use the exhaust valve to release the water and oil in the diesel tank; Check and remove water and oil from diesel filters and filters.
Unscrew the discharge screw on the pump body of the high-pressure oil pump and pump the oil manually to observe whether the low-pressure oil supply is smooth and sufficient. If the air in diesel is to be continued to remove the non-clean air, it should be checked that there is no leakage in the front pipe of the manual pump, such as whether the pipe joint gasket is damaged, whether the pipe joint is tightened, whether the pipe is damaged, there are cracks, etc.. When pumping oil with a hand pump, if the oil is difficult and the oil is not absorbed, indicating that there is a blockage in the low-pressure oil road, check whether the diesel filter filter, diesel filter filter or pipeline is blocked. When the temperature is low, it should be checked whether the diesel brand is correct or whether it is blocked by diesel wax or water ice. Eliminate blockage until oil absorption is smooth and no bubbles are discharged.
3 When pumping oil with a manual pump, if it is not for the above reasons and can not pump diesel fuel, it means that the manual pump piston is overworn, or the valve is covered with dirt, damaged, or the manual pump seal is damaged. The manual pump should be replaced.
(2) Check high-pressure oil routes
If the low-pressure oil road is not malfunctioning and still can not be started, the work of the high-pressure oil road should be checked.
Check whether the oil volume of the high-pressure oil pump is flexible to adjust the gear bar movement, whether it is stuck in the oil stop position, or because of other forms of damage caused by the non-supply of oil.
Check whether the time of oil supply by high pressure pump is correct. If the fuel supply time is not correct, it should be adjusted to the standard timing.
3 Exclude the air in the high-pressure tubing. If there is air in the diesel high-pressure tubing, it is sometimes difficult to rule out the diesel engine by driving the engine. The diesel engine is also difficult to start. For this purpose, the bolts of each injector connecting the high-pressure tubing should be loosened, and the start button(or rotating the start key to "start") is used to drive the diesel engine to rotate until each high-pressure tubing emits fuel, and then the high-pressure tubing connection bolt is tightened.
4 If the diesel engine still can not start up at this point, it should check whether the injector and the high-pressure pump itself are malfunctioning. Oil injectors mainly include failure such as burning, poor atomization, and incorrect adjustment of oil pressure. The high pressure pump mainly has the plunger side wear limit, resulting in insufficient oil supply pressure, speed adjustment spring break and other failures. It should be noted that the adjustment of the high-pressure oil pump must be carried out on the high-pressure oil pump test table; The same is true of the injector, which must have a pressure tester.
2, diesel engine smoke when working
(1) Check the water temperature
The low water temperature of the diesel engine will cause the temperature in the diesel engine combustion chamber to be too low. After the diesel fuel is sprayed, it is not easy to atomize and burn. Some diesel oil is still droplet with exhaust gas, and the smoke color is white. When the diesel engine is working, when the water temperature is below 67 °C, it is called cold; The diesel engine is working in an overcooled state, which is very unfavorable to its life. Measures should be taken actively to prevent the diesel engine from working in an overcooled state. After the diesel engine is started, it should be idled and turned 3-5 min, and then work with the throttle and medium and small loads to carry out the local car heater. After the diesel engine water temperature reaches the green range of the water temperature table, it will work with a large throttle.
(2) Check and speed injection advance angle
The early angle of the oil injection is too small. After the diesel injection, it is too late to atomize and burn. The oil mist is brought out with the exhaust gas. The smoke color is white or gray.
(3) Check diesel quality
Diesel is of poor quality, or diesel contains too much water. When burned, excessive water vapor is generated and white or grayish smoke is discharged.
3, diesel engine smoke when working
(1) Check the air supply system
If the air intake of the firewood machine is insufficient, the amount of air entering the firewood room is relatively small, diesel fuel is not fully burned, and some diesel fuel becomes carbon black particles under high pressure to form black smoke. At this time, it should be checked: whether the air filter core and inlet are blocked; Supercharger working conditions, intake
Whether the manifold is leaking; The change of the phase of gas distribution, whether the valve is correct, whether the intake and exhaust door seat leaks; Is the piston, piston ring and cylinder sleeve excessively worn and poorly sealed.
(2) Check diesel supply system
The poor oil supply of diesel engines will lead to poor mixing. Even if the air intake is sufficient, it can not be completely burned, thus forming black smoke. At this time, it should be checked: whether the high-pressure oil pump is improperly adjusted, resulting in a large amount of oil supply; Whether the discharge valve is not working well, causing the Injector to spray or drop oil twice; Whether the injection pressure of the injector is reduced, resulting in poor atomization, oil drop of the injector, or the injector sealing pad is more or less loaded so that the injection oil is not in place; Whether the poor quality of diesel fuel causes poor combustion.