Reduced and improved the damage of the hydraulic booster for rotary excavators.
减少和改进了旋转式挖掘机液压增压器的损坏：
1.密封圈升起。回转式挖掘机的密封圈和下密封圈损坏后，油被削弱以降低压力。旋转挖掘机密封圈损坏，油进入燃烧室。避免了密封圈的损坏，高温降低了壳体，使发动机机油碳化，并从排气尾管排放白烟。
2.浮动轴承磨损。转动轴、轴承及轴承孔不得降低或增加，并应避免漏油。
3.避免下降。通过降低下环，防止中间的油压增加，并削弱油。
4.曲轴箱气压下降，分离器堵塞。燃烧室爆炸引起的部分减速通过活塞环泄漏到曲轴箱，废气减少，空气压力无序进入增压器，导致减速。
5.进气负压大。空气增加和减少，回转挖掘机的后部减少。广东旋挖钻机培训中，旋挖机液压增压器存在多种故障。
6.发动机改进了。发动机的增加使得减速器也更高，导致减速器增加，导致密封圈失效。
油太脏了。油结焦，润滑性能降低。
8.油泵损坏。机油泵的工作不下降，导致机油压力低，无法正常下降，导致增压器的增减。
只要我们避免通过降低操作程序来降低液压增压器，旋转挖掘机就可以在不缩短缩短的情况下提高降低，从而更大程度地降低液压增压器的降低，延长其使用寿命。
驱动液压增压器的动力来自发动机的废气。发动机低速运转时，排气压力和温度低，液压转速也低（约1000r/min）。因此，压缩机泵轮不能产生进气增压压力。在这种状态下，发动机的进气效果与自然吸气发动机没有明显区别；随着发动机转速和负荷的增加，排气压力和温度显著升高，液压转速也随之升高。当液压达到一定转速时，增压启动（现代发动机Z可以在约1500r/min的低速时进入增压状态）。发动机满负荷运行时，液压转速可达（10~15）×104r/min.2。废气旁通阀控制废气旁通阀控制的主要目的是有效控制和调整增压压力，以防止因增压压力过高而损坏发动机。同时，它还可以在较宽的发动机转速范围（如1500~4500r/min）内保持液压增压的有效性。如下图所示，液压增压器使用废气旁通阀控制电磁阀、废气旁通阀执行器和废气旁通阀来控制增压压力。
某些发动机的液压增压器采用常开废气旁通阀，即发动机停机时废气旁通阀打开。因此，必须调整废气旁通阀执行器的内部结构和ECM对废气旁通阀控制电磁阀的控制，以满足液压增压控制的要求。
1. Sealing ring failure. When the sealing ring and lower sealing ring of a rotary excavator are damaged, oil leakage occurs, reducing pressure. If the sealing ring of a rotary excavator is damaged, oil enters the combustion chamber. This prevents damage to the sealing ring, but the high temperature causes the housing to overheat, leading to engine oil carbonization and the emission of white smoke from the exhaust pipe.
2. Wear of the floating bearing. The rotating shaft, bearings, and bearing bores must not be worn down or enlarged, and oil leaks must be prevented.
3. Prevent pressure drop. By lowering the lower ring, prevent an increase in oil pressure in the middle and reduce oil pressure.
4. Crankcase air pressure drops, and the separator is clogged. Part of the combustion chamber explosion escapes into the crankcase through the piston rings, reducing exhaust gas volume. Uncontrolled air pressure enters the supercharger, causing a drop in speed.
5. High intake vacuum. Fluctuations in air intake and reduced airflow at the rear of the rotary excavator. During Guangdong rotary drilling rig training, various faults in the hydraulic supercharger of rotary drilling rigs have been identified.
6. Engine modifications. Engine modifications increase the load on the supercharger, leading to higher operating temperatures and seal failure.
7. Contaminated oil. Oil sludge reduces lubrication performance.
8. Faulty oil pump. If the oil pump fails to operate properly, it results in low oil pressure, preventing normal operation and causing fluctuations in the booster’s performance.
By avoiding improper operating procedures that degrade the hydraulic booster, rotary excavators can maintain optimal performance without compromising efficiency, thereby minimizing wear on the hydraulic booster and extending its service life.
The power driving the hydraulic supercharger comes from the engine’s exhaust gases. When the engine is running at low speed, exhaust pressure and temperature are low, and the supercharger speed is also low (approximately 1000 rpm). Therefore, the supercharger impeller cannot generate intake boost pressure. In this state, the engine’s intake performance is not significantly different from that of a naturally aspirated engine; as engine speed and load increase, exhaust pressure and temperature rise significantly, and the supercharger speed increases accordingly. When the hydraulic system reaches a certain speed, turbocharging begins (modern engines can enter turbocharged mode as low as approximately 1,500 rpm). When the engine is operating at full load, the hydraulic speed can reach (10–15) × 10⁴ rpm. The primary purpose of the exhaust bypass valve is to effectively control and adjust the boost pressure to prevent engine damage caused by excessively high boost pressure. At the same time, it maintains the effectiveness of hydraulic turbocharging across a wide engine speed range (e.g., 1,500–4,500 rpm). As shown in the figure below, the hydraulic turbocharger uses an EGR bypass valve control solenoid, an EGR bypass valve actuator, and the EGR bypass valve itself to regulate boost pressure.
In some engines, the hydraulic supercharger employs a normally open EGR bypass valve, meaning the valve remains open when the engine is shut off. Therefore, the internal structure of the EGR bypass valve actuator and the ECM’s control of the EGR bypass valve solenoid must be adjusted to meet the requirements of hydraulic supercharger control.