Cavitation: it occurs around the engine combustion chamber. Although the feedback from the vehicle water temperature gauge is about 90 °, the engine combustion work, especially most wet cylinder liners, the temperature of local surface exceeds the boiling point of water, which is much higher. When water is near the boiling point, a large number of bubbles will be generated, which repeatedly impact the cylinder liner surface, and the pressure of the shock wave under the micro level reaches 15-20000 psi. In our daily life, when the teapot is boiling, the bubbles generated at the bottom of the pot are similar.

發動機使用的冷卻液，通常沸點溫度超過130度。如果破壞冷卻液的成分比例，乙二醇成分減少。氣缸套暴露在較低的沸點下，醇類物質無法附著在表面。穴蝕發生將無法避免，例如200小時后，兌水后的冷卻液實驗，發動機已經產生缸套激烈氣蝕情況，產生更嚴重的穴蝕。

The coolant used in the engine usually has a boiling point temperature of more than 130 degrees. If the composition ratio of the coolant is destroyed, the ethylene glycol composition will be reduced. The cylinder liner is exposed to a low boiling point and alcohols cannot adhere to the surface. Cavitation cannot be avoided. For example, in the coolant test after mixing water 200 hours later, the engine has produced severe cavitation in the cylinder liner, resulting in more serious cavitation.

為什么有些全自動混凝土攪拌機的發動機加水表面看起來很正常?

Why does the water adding surface of some automatic concrete mixer engines look normal?

中等排量發動機：冷卻系統要求不高腐蝕狀況較突出

Medium displacement engine: the cooling system does not require high corrosion

國內中等排量的發動機，從上世紀70年代技術上演變而來，僅相當于國外50年代的水平，本質上并沒有改變。因此發動機設計之初，冷卻系統要求不高，燃燒室并沒有強化，氣蝕現象同樣存在，但并非明顯感受，相比腐蝕狀況就比較突出，例如爛水堵。

Domestic medium displacement engines have evolved technically from the 1970s, only equivalent to the level of foreign engines in the 1950s, and have not changed in essence. Therefore, at the beginning of the engine design, the requirements for the cooling system are not high, the combustion chamber is not strengthened, and the cavitation phenomenon also exists, but it is not obvious. Compared with the corrosion condition, it is more prominent, such as rotten water blocking.

現今國產大排量卡車發動機，采用了增壓，高壓縮比，活塞行程縮短，轉速更低，這樣的強化設計，燃燒室的局部溫度，強制散熱要求，多通過活塞機油噴嘴，更高的冷卻液循環量，和使用更高沸點溫度的冷卻液來實現。因此冷卻液少量補充水，短期內可以應急，長時間使用弊大于利，一個局部頻繁“開鍋”的發動機，壽命大大縮短。

Nowadays, domestic large displacement truck engines adopt supercharging, high compression ratio, shortened piston stroke and lower speed. Such enhanced design, local temperature of combustion chamber and forced heat dissipation requirements are mostly realized through piston oil nozzle, higher coolant circulation and coolant with higher boiling point temperature. Therefore, a small amount of coolant make-up water can be used for emergency in a short time. The disadvantages of long-term use outweigh the advantages. The service life of an engine with local frequent "boiling" is greatly shortened.

今天這篇文章為大家講解了全自動混凝土攪拌機的氣缸套致命氣蝕穴蝕的知識，大家以后再遇見這種情況應該可以很好的了吧！

Today's article explains the knowledge of fatal cavitation of cylinder liner of full-automatic concrete mixer. You should be able to solve this situation in the future!