大家知道什么是氣蝕嗎?首先我們先來看看自動攪拌一體機的氣蝕現象。
Do you know what cavitation is? First of all, let's take a look at the cavitation phenomenon of the automatic mixer.
氣蝕現象:發生在發動機燃燒室的周圍,雖然我們從車輛水溫表的反饋來看是在90°左右,但發動機燃燒做功,特別是大多數濕式氣缸套,局部表面的溫度超過水的沸點,要高出一大截。水在沸點附近,會產生大量氣泡,這部分氣泡反復沖擊氣缸套表面,微觀下的沖擊波的壓力達到15-20000PSI。我們日常生活中茶壺燒水,滾水沸騰時壺底產生的氣泡,道理相似。
Cavitation: it occurs around the combustion chamber of the engine. Although it is about 90 ° according to the feedback from the vehicle water temperature gauge, the work done by the engine combustion, especially for most wet cylinder liners, the local surface temperature is higher than the boiling point of water, which is much higher. A large number of bubbles will hit the surface of the cylinder at the pressure of 15-20 000. In our daily life, when the teapot is boiling, the bubble at the bottom of the pot is 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,康明斯Cummins NTC400發動機已經產生缸套激烈氣蝕情況,產生更嚴重的穴蝕。
![](http://www.cqkangxinda.com/uploadfile/2020/1202/20201202120322941.jpg)
The coolant used in the engine usually has a boiling point of more than 130 degrees. If the composition ratio of the coolant is destroyed, the glycol composition will be reduced. The cylinder liner is exposed to a lower boiling point and alcohols cannot adhere to the surface. Cavitation will not be avoided. For example, 200 hours later, the coolant test after mixing water shows that Cummins ntc400 engine has produced severe cavitation of cylinder liner, resulting in more serious cavitation.
為什么有些自動攪拌一體機的發動機加水表面看起來很正常?
Why do some of the automatic mixer engine water surface looks normal?
自動攪拌一體機
Automatic mixing machine
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: low requirement of cooling system and serious 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。
China's medium displacement engine, developed from the 1970s, is only equivalent to the level of foreign countries in the 1950s, essentially unchanged. Therefore, at the beginning of engine design, the cooling system requirements are not high, the combustion chamber is not strengthened, cavitation phenomenon also exists, but it is not obvious. Compared with the corrosion situation, 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, the domestic large displacement truck engine adopts supercharging, high compression ratio, shorter piston stroke and lower speed. Such enhanced design, local temperature of combustion chamber and forced heat dissipation requirements are mainly realized by piston oil nozzle, higher coolant circulation volume and higher boiling point temperature coolant. Therefore, a small amount of coolant water can be used as an emergency in a short time, and the disadvantages outweigh the advantages of long-term use. The service life of an engine with local frequent "boiling" is greatly shortened.