What are the aspects that affect the heat dissipation effect of excavators
1. Prevent the backflow of hot air during use
The filling around the radiator is commonly known as "sponge". But it cannot be replaced by any 'sponge'. The requirements for hydraulic excavators are good corrosion resistance, temperature resistance, and poor ventilation, as their main function is to prevent hot air reflux. To prevent the cold air drawn in from the front of the radiator from rising in temperature and entering the rear of the radiator (engine compartment), it cannot flow back to the front of the radiator. If some high-temperature gas flows back to the radiator, it will inevitably reduce the system's heat dissipation effect, causing an increase in oil and water temperature, which will prevent the engine from working properly and result in early damage. Therefore, during the use of hydraulic excavators, it is essential not to neglect the inspection and repair of the "sponge" around the radiator, and the damaged parts should be replaced in a timely manner.
2. Ensure smooth discharge of hot air
① The partitions in the engine compartment behind the radiator cannot be dismantled or discarded at will, otherwise it will cause vortices to form during the circulation of hot air, affecting the exhaust of hot air The exhaust holes in the engine compartment must be kept unobstructed, especially the exhaust holes of the lower protective plate of the engine and oil pump, which must not be blocked or placed with objects, otherwise it will hinder the exhaust of hot air. The decrease in intake air volume leads to an increase in cabin temperature, which in turn causes an increase in intake air temperature. Electrical components are damaged due to early aging caused by high temperatures.
3. Ensure the air circulation area of the heat dissipation part
The ventilation area of the radiator core is prone to blockage during the use of hydraulic excavators due to air flow and various reasons. If there is a protective net, the blockage should be cleaned up in a timely manner. If there is no protective net, the external pollution of the radiator should be cleaned and washed in a timely manner according to the changes in the environment and construction conditions. Otherwise, the blockage of the air flow channel will reduce the ventilation area and inevitably lower the heat dissipation efficiency. It is more important to prevent contamination inside the radiator. During use, it is necessary to strictly follow the random technical documents, regularly replace the antifreeze and clean it, and do not add contaminated water to replace the antifreeze. If it causes blockage of the internal liquid flow channel, it is difficult to inspect and clean, and the only solution is to replace the radiator.
4. Ensure the intake air volume of the heat dissipation part
The most important factors affecting the air intake, besides preventing hot air reflux and ventilation area, are the air guide hood and fan. At present, there are mainly three types of air deflectors: Wenduli type, ring type, and box type. There are strict requirements for the installation position of the fan and air guide cover, as well as the distance between the fan and the engine. Because air deflectors are usually used to improve fan efficiency, distribute air more evenly on the radiator core, and prevent hot air from flowing back into the engine compartment. According to the recommended installation requirements for Cummins engines: ① The distance between the fan and the radiator core is 50.8-101.6mm. ② The maximum linear velocity of the fan blade tip is limited to the range of 4000-5200 meters per minute The gap between the fan blade tip and the air guide hole is 1.5% of the fan diameter. The smaller the gap, the higher the efficiency. When the gap is greater than 2.5%, the fan's air supply will sharply decrease. Therefore, during the use, maintenance, and repair process, the size and geometric shape of the air guide cover and fan cannot be changed, nor can the installation position of the radiator and fan be changed, otherwise the original heat dissipation effect and reliability cannot be guaranteed. Especially for fans, most of them are made of non-metallic materials and will deform when exposed to high temperatures. If there is deformation, it will reduce the air supply of the fan.
5. To ensure that the intake resistance and intake temperature are within the standard range (Cummins 6BT5.9 engine intake resistance standard is ≤ 15inH0o, engine power decreases by 1% and heat dissipation increases by 1.5% for every 6 ℃ increase in intake temperature above 38 ℃)
