Why the oil temperature is too high in cooler hydraulic system?

- Jul 17, 2018-

What are the reasons for the excessive oil temperature in the cooler hydraulic system? Hydraulic system oil temperature is too high for both design reasons and reasons for use.


The design of the hydraulic system is unreasonable, resulting in congenital deficiency:

1. The fuel tank capacity design is too small, the cooling and heat dissipation area is not enough, and there is no oil cooler installed, or the oil cooler does not match the hydraulic system, and the heat dissipation is insufficient.

2. The size of the selected valve components is too small, causing the flow rate of the valve to be too high and causing the pressure loss to increase.

3. The fixed pump oil supply system that selects the pump capacity according to the fast-forward speed, most of the excess flow will overflow from the overflow valve and generate heat under the high pressure (work pressure) during the work.

4. The unloading circuit is not designed in the system. When the pump stops working, the pump does not unload. The entire flow of the pump overflows under high pressure, causing overflow and heat loss, resulting in temperature rise, unloading circuit, but failure to unload.

5. The hydraulic system has a high back pressure.

6. The system piping is too thin and too long; too much bending, partial pressure loss and pressure loss along the path are too large, and the system efficiency is low.


The heating temperature rise caused by the use:

1. The brand, quality and viscosity grade of the oil selection oil are not in compliance with the requirements, or the hydraulic oil of different grades is mixed, resulting in the hydraulic oil viscosity index being too low or too high.

2, the pollution is serious, the construction site environment is bad, with the increase of the working time of the machine, the oil is easy to mix impurities and dirt, the contaminated hydraulic oil enters the matching gap between the pump, the motor and the valve, which will scratch and destroy the mating surface. The precision and roughness increase the friction and wear, while the leakage increases, causing the oil temperature to rise.

3. The oil level in the hydraulic oil tank is too low. If the oil quantity in the hydraulic oil tank is too small, the hydraulic system will not have enough flow to take away the heat generated by it, resulting in an increase in oil temperature.

4. The air is mixed into the hydraulic system. The air mixed into the hydraulic oil will escape from the oil and form bubbles in the low pressure zone. When it moves to the high pressure zone, these bubbles will be crushed by the high pressure oil and subjected to rapid compression. A large amount of heat is released, causing the oil temperature to rise.

5. The oil filter is clogged. When the abrasive particles, impurities and dust pass through the oil filter, it will be adsorbed on the filter element of the oil filter, causing the oil absorption resistance and energy consumption to increase, causing the oil temperature to rise.

6. The hydraulic oil cooling circulation system works poorly. Typically, a water-cooled oil cooler or an air-cooled oil cooler is used to forcefully cool the oil system's oil temperature. Blockage and uncleanness of the cooler passages will result in a decrease in heat dissipation efficiency and an increase in oil temperature.

7. The parts are seriously worn, the gears of the gear pump and the pump body and side plates, the cylinder block of the piston pump and the motor and the distribution plate, the cylinder hole and the plunger, the valve stem of the reversing valve and the valve body are all relying on If the gap is sealed, the wear of these components will cause an increase in internal leakage and an increase in oil temperature.

8, the ambient temperature is too high, the ambient temperature is too high, and the long time of high load use will make the oil temperature too high