I.High temperature of water and oil is a common phenomenon in excavator construction.
Water temperature is high, why can water temperature be high?
The water tank is used to dissipate heat, which is cooled by wind, which is the fan driven by the excavator engine.
Therefore, the reasons for the high water temperature are as follows:
1. The thermostat is stuck and cannot be opened. At this time, the water can only go through a small cycle, not through the radiator.
2. The water in the water tank is dirty and the water is not flowing smoothly, which can be used to detect the temperature above and below the water tank with the temperature measuring gun.
3. Insufficient fan speed and clutch failure.
4. The rubber strip around the radiator is damaged or not damaged. At this time, the vortex is generated in the back, and the hot air is circulated, so the cooling effect cannot be achieved.
5. For the fifth point, it is easy to ignore, that is, whether there will be false alarm and the sensor is broken, which is also possible.
II. High oil temperature
The temperature of the oil is similar to that of the water temperature, and there's also a size cycle, but instead of going through the thermostat, it has a return oil one-way valve, and if this valve gets stuck, the temperature of the oil will be high, and everything else will be the same as the water temperature.
Of course, the excavator is driven by fan pump fan motor speed adjustment, there is also a overflow device, generally high oil temperature, check these places can be solved.
1. High oil temperature is harmful to the engine
Excavator engine temperature is too high, refers to the excavator engine oil temperature, water temperature over 90 ℃.
When both of these temperatures are too high, it will affect the normal operation of the engine and bring certain harm to the engine: the clearance shrinks, resulting in severe wear or "pull cylinder".
Oil temperature mainly shows how much heat is produced compared with heat dissipation.
Crankshaft and bearing heating due to friction, oil is the most of its heat dissipation, and the balance between heat production and heat dissipation (performance for the oil temperature stability) is relative. When heat yield more than heat dissipating capacity, bearing shell temperature rises, the local temperature reaches the melting point of lead, lead in bearing shell will melt, precipitation. After lead a large amount of precipitation, bearing more and more small and uneven, load surface wear, serious when local temperature can exceed copper melting point (1083 ℃), copper also began to melt, eventually lead to serious ablation or produce crankshaft and bearing the consequences of "tile" holding shaft.
According to the test, when the oil temperature reaches 110 ℃, the temperature inside the oil film bearing clearance of up to 150 ℃. When the oil film temperature above 150 ℃, that is easy to rupture and half dry friction. Due to the crankshaft bearing is copper lead, if reduce improper measures, will make the bearing temperature is too high and the lead melting exhalation, consequence is unimaginable.
Therefore, when the temperature of oil and water is too high, the oil temperature should be lowered first.
2. Lowering oil temperature can slow down the increase of water temperature
At this time, although the coolant has a long heat exchange time at the high temperature parts, the water flow speed slows down and the heat dissipation time is prolonged. At the same time, due to the reduction of load and the reduction of speed, the heat generated by friction of various moving parts is also reduced accordingly.
Therefore, lowering the oil temperature can not only reduce the heat generated by the excavator engine, but also indirectly reduce the heat absorbed by the cooling fluid, thus slowing the rise of water temperature.