There are many reasons for the failure of agricultural diesel engines, and when you find that your engine is difficult to turn off, it is likely because the engine has been damaged. So what are the specific reasons? A total of 6 points are summarized, which will be divided into two articles for detailed analysis. This paper mainly focuses on three judgment methods: poor operation of the exhaust brake device, improper assembly of the fuel injection pump, and "flying speed" of the diesel engine.
1.The exhaust brake device is not working well.
The shutdown of the diesel engine is accomplished using the exhaust brake device. When you turn off the engine, you need to put your foot on the exhaust brake button valve. After waiting for ventilation, the power cylinder of the exhaust brake butterfly valve will work, and the spool of the butterfly valve will rotate to block the exhaust pipe. At the same time, you will step on the exhaust brake button valve, stop the oil cylinder action, and turn off the oil volume to the minimum position to achieve the purpose of engine stalling.
There are several reasons for this phenomenon. First, because of the failure of the exhaust brake button valve. Air leakage or pipeline rupture and ventilation, resulting in the butterfly valve power cylinder not working, and the engine exhaust pipe is blocked after the valve spool does not work. There is also the stop cylinder is not ventilated or leaking, and the amount of oil is still in a certain position, resulting in the engine can not be extinguished.
The second is because the exhaust brake butterfly valve power cylinder is faulty. If the exhaust brake butterfly valve power cylinder leaks or does not work, you will find that although you step on the exhaust brake button valve, due to the power cylinder leakage, the piston stroke is not large, and the exhaust pipe cannot be blocked, it cannot be extinguished.
Third, the linkage mechanism of the exhaust brake butterfly valve and the power cylinder is loose. At this time, although the power cylinder has action, it can not block the exhaust pipe, resulting in engine stalling difficulties.
The fourth is that the plunger of the injection pump is bitten and the plunger spring is broken. At this time, although the oil cylinder is stopped, it cannot pull the throttle adjustment rod, resulting in the engine still rotating at a certain speed and cannot be extinguished.
If you are driving when one of the above four situations occurs, you need to be repaired or replaced, if your linkage is loose, should be tightened in time, if the phenomenon of leakage, you need to replace the pipeline.
2.Improper assembly of the fuel injection pump
When assembling a diesel engine injection pump, if the sleeve positioning screw is not screwed into the positioning groove, it will cause the sleeve to rotate when the diesel engine is running, thus changing the relative position of the spiral groove on the injection pump plunger and the oil return port on the sleeve.
When the throttle control handle is pulled to the flame-off position, the straight groove on the plunger can not be aligned with the oil return port on the sleeve, which will cause the injection pump not stop pumping oil, and the diesel engine can not be extinguished.
At this time, the fuel injection pump should be disassembled and reassembled as required. When assembling the fuel injection pump, if the marks of the three parts of the rack, gear, and plunger are not aligned or are not assembled according to the regulations, it will also make the throttle control handle pull to the flame off position, the straight groove on the plunger can not be aligned with the oil return port on the sleeve, and the fuel injection pump can not stop pumping oil, resulting in the diesel engine can not be extinguished. At this time, the fuel injection pump should be disassembled and reassembled as required.
If there are marks on the three parts of the rack, gear, and plunger, the marks should be aligned. If there is no mark, the rack should be placed in the middle position and the plunger notch slot on the gear should be adjusted to a horizontal position so that the rack and gear mesh in this position. At this time, the return oil on the plunger straight grooving upward. Assembly according to this requirement, when the rack is in the oil stop position, the oil return straight groove on the plunger should be aligned with the oil return hole on the sleeve, to ensure that the fuel injection pump stops oil.
3.The diesel engine has a "flying car" situation
Diesel engine "flying car" refers to the diesel engine speed out of control, sharply increased, more than the rated speed, and accompanied by violent vibration and abnormal sound.
When the diesel engine "flying car", if it can not be stopped in time with effective methods, it will cause significant property losses and even casualties. The main reasons for the diesel engine "racing" are as follows: First, a large amount of oil enters the cylinder and burns; The second is an oversupply of fuel. Although the performance of the engine is overspeed, there are also differences. A lot of oil goes into the cylinder burning, exhaust pipe blue smoke; When the fuel oversupply causes the "flying car", the exhaust pipe emits thick black smoke.
If your diesel engine has a "flying car" situation, you must be calm and calm to deal with, first judge the exhaust pipe color. If blue smoke is emitted from the exhaust pipe, measures can be taken to block the intake pipe or open the decompression, because the method of cutting off the fuel line is ineffective at this time; If the exhaust pipe emits thick black smoke, the method of cutting off the fuel oil circuit can be used, that is, quickly loosen the coupling nut of the high-pressure oil pipe. At the same time, block the intake pipe or open it to decompress.
Conclusion
The above is the third of the reasons for the failure of the agricultural diesel engine, the reasons for the failure are also the deformation and damage of the fuel injection pump rack, the shutdown solenoid valve is not strictly closed and the throttle control mechanism is improperly adjusted, which will be interpreted in detail in the next article.
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