Common troubleshooting of the hottest hydraulic ex

Common troubleshooting of hydraulic excavator

with the continuous development of high-grade highway, hydraulic excavator plays an important role in the process of earthwork construction. At the end of 1999, our company purchased several PC hydraulic excavators. During the use of these years, the vehicle condition was basically good, but there were also several small failures, specifically manifested in weak engine operation and high water temperature

now, how to eliminate the fault is analyzed and discussed as follows:

1 engine is weak.

the main reason for excavator engine is that there is a problem with the fuel system. The characteristics of the fault are: the engine idles normally, and when there is a load, it shows weakness, the engine sound is stuffy, and the engine is easy to stall. The troubleshooting is as follows: ① first, turn on the hand oil pump, there is no air in the system, and it works normally, Then, after replacing the primary and secondary fuel filters, the engine works basically normally during the low load leveling operation, but it is still abnormal under the high load operation. In this regard, some people believed that the oil supply of the high-pressure oil pump was insufficient. After analysis, they believed that it was the fault of the oil circuit. Therefore, the oil pipe between the filter element and the oil pump was removed for inspection, and it was found that the rubber in the pipe was aging. At the same time, the small filter in the hollow bolt of the pipe head is blocked. It was proved that the throttling was caused by poor oil supply, resulting in insufficient oil supply, which made the excavator unable to operate. After replacing the oil pipe and cleaning the hollow screw, the work returned to normal. ② The excavator operates normally when it is unloaded, but it emits black smoke when digging and is unable to work. Inspection method: first, check the oil supply system, and the result is normal, indicating that there is no problem with the engine itself; After observation, it was found that there was more carbon deposition at the exhaust pipe, so it was considered that the exhaust resistance was too large, resulting in power decline and black smoke. Turn on the muffler and remove the carbon deposit (6) the moving speed of the beam: 100kN, 10kN tension and compression in both directions, the work basically returns to normal, but there is still black smoke. After careful observation, it is found that the vacuum indicator of the air filter element is red, indicating that the filter element needs to be cleaned or replaced. However, after replacing several new filter elements, the engine still emits black smoke, and the vacuum indicator of the air filter element is still red. At this time, it is found that the air inlet is blocked, So I looked out along the air inlet and found that the primary air filter element had been blocked by catkins and other debris. After cleaning, the engine returned to normal operation

2 the engine water temperature is too high, and the buzzer sends out an alarm message

analyze the causes of overheating of the excavator engine: ① excessive heating. The reason is that the engine timing is poor and the ignition is too late; Oil or excessive diesel oil is injected into the combustion chamber; The hydraulic oil temperature is too high due to long-term overload operation. After comprehensive observation of the engine, eliminate the above reasons. The engine just started to run normally, and it gave an overheat alarm after working for half an hour. It seems that there are other reasons. ② Insufficient heat dissipation. The reason is that the water is insufficient and the operation is short of water; Poor water quality, water mixed with engine oil, reducing thermal conductivity; The water quality is too hard to produce a lot of scale, which seriously affects the heat dissipation; Mixing gas into water reduces its heat dissipation capacity; The thermostat is poor and the large circulation opening is not enough; Sediment, rust, scale and other impurities block the water tank; The water tank grille is blocked by branches, insects, sediment and debris; The bearing pad of the upper indenter is about 1mm away from the upper end face of the sample due to poor water pump; The fan belt is loose, and the fan blade is deformed, resulting in insufficient forced cooling, etc. Referring to the above reasons, we carefully checked the PC hydraulic excavator and consulted the manufacturer's service department. Because it has just been used for one year, it can be seen that the wire oil filter is normal when judging the thermostat, and there is antifreeze in the water tank without rust, oil, etc. the possibility of the cause of the fault should be eliminated. After careful investigation of the external causes, first adjust the fan belt to the appropriate tension, and then install a car wash machine to thoroughly clean the water tank and hydraulic oil radiator. After removing the sludge, insects and other sundries on the grille, the radiator looks like new from the appearance. After entering the construction site for a period of time, the effect changes, and the overheat alarm time is extended from the original half an hour to about half a day, Basically, it can work continuously for about 4 hours, but it is still overheated. We checked the engine again, and later judged that the heat dissipation is still poor, so we analyzed the heat dissipation system. The heat dissipation system is a combination of water tank and hydraulic [relevant standard]: oil radiator, and the middle is completely sealed with sponge. It was judged that there might be debris blockage between the two, so the sponge was disassembled, and it was found that the water tank and the hydraulic oil radiator were blocked by catkins. After removal, heavy load and long-term operation were carried out, and overheating did not occur again. Then, this phenomenon was analyzed: because the engine was pumping inward, the wind was very strong, and the construction was carried out in the environment with catkins falling. The wind force of the engine sucked all catkins into the grille of the water tank. From the appearance, it was only the hydraulic oil radiator, which removed the debris on it, but it was not easy to see on the water tank inside. For this reason, we irregularly clean and check between them, and there has been no phenomenon of too high water temperature