The engine speed drop of excavator refers to the phenomenon that the engine speed drops during the operation of excavator. The performance of excavator engine speed drop is that the excavator engine speed drops slightly within 200rpm. The engine speed of the excavator drops more than 300rpm seriously, which may lead to the blocking fault of the excavator. The following four explanations are given for the speed drop of excavator engine:
1. Some cars use solenoid valve to control the oil circuit to cut off oil, so as to achieve the purpose of flameout. Similar problems have been encountered. The clearance of the solenoid valve is too large, just like the half effect of flameout wire drawing. The load leads to insufficient oil supply, so the speed drop leads to insufficient oil supply of the diesel pump. This is a vicious circle, which eventually leads to flameout.
2. The influence of temperature is relatively small. After all, there is a cooling device, and the impact of the environment is mainly the air pressure. For high altitude areas, the air is thin, the oxygen content is low, and the engine combustion is insufficient, which affects the engine performance, but the air booster also reduces the impact of high altitude. The main reason affecting the engine speed loss is the change of load. When the hydraulic system fails, the displacement cannot be changed, which is easy to lead to speed loss or vehicle suffocation.
3. There are two main reasons for speed loss. The engine performance is degraded and there is a problem with the main pump. Check the engine and the main pump. You can take out all the hydraulic filter elements by yourself. If you see a lot of copper powder on the filter element, there is a problem with the main pump, and the main pump needs to be overhauled. You can also enter the monitoring panel to check the engine speed. The minimum throttle idle speed is more than 1000rpm, the maximum throttle idle speed is more than 1300rpm, and the maximum throttle during operation is more than 1900rpm. If there is no copper powder and the engine speed is normal, the two solenoid valves on the main pump can be removed for cleaning, which can basically eliminate the problem.
4. If the engine output power is much lower than the rated power, if it is judged at the construction site, the simplest method should be used. First, check whether the fuel filter element is blocked, whether there is air leakage in the fuel circuit, whether the plunger, fuel injection head and oil outlet valve in the fuel pump are seriously worn, whether the air inlet of the air filter element is unobstructed, whether the engine with turbocharger is damaged, whether the engine is fast and high temperature, and the oil viscosity decreases, resulting in loose cylinder wall sealing and reduced compression ratio, Whether the wear of cylinder liner components causes serious gas crosstalk in the cylinder and lax engine valve sealing are the factors that seriously affect the engine power. If we exclude the insufficient output power of the engine itself, we should consider the matching between the flow of the hydraulic pump and the output power of the engine.
