自動排氣閥在應用中有時會損壞，那么出現這種情況的原因是什么呢？讓我們一起來看看。
Automatic exhaust valves are sometimes damaged in use, so what is the reason for this? Let’s take a look.

1.燃料燃燒不良及其造成的積碳影響。

排氣溫度升高使排氣閥的工作環境變差，疊加其他條件后排氣閥的燒損加劇。燃燒室中的部分積碳會隨著廢氣排出，也會像前面提到的顆粒一樣粘在排氣閥和閥座的密封面上。特別是重油加熱溫度控制不好，噴入氣缸的燃油粘度過高，難以霧化，高壓油泵柱塞磨損造成反燃燃燒不良，會使良工閥門排氣閥和閥座密封面被積碳污染。此外，燃料中含有的雜質在燃燒室內經過各種復雜的熱過程后，在排氣閥盤和閥座的密封錐上沉積成一層與碳粒混合的玻璃狀硬脆物質，與硫酸鈉、硫酸鈣、氧化鐵等物質混合。當這種玻璃狀沉積物的沉積厚度過大時，在氣閥關閉時的沖擊力作用下會產生裂紋，反復撞擊后會發展為剝落，從而形成高溫氣體噴射通道燒壞氣閥。
1. Poor fuel combustion and its effect on carbon deposition. The increase of exhaust temperature makes the Working Environment of exhaust valve worse, and the burning loss of exhaust valve increases after adding other conditions. Some of the carbon in the combustion chamber is expelled with the exhaust gas and sticks to the sealing face of the exhaust valve and seat, as is the case with the aforementioned particles. Especially heavy oil heating temperature control is not good, injection into the cylinder fuel viscosity is too high, it is difficult to atomization, high-pressure oil pump plunger wear caused by poor back combustion, will make good valve exhaust valve and valve seat sealing surface carbon pollution. In addition, impurities contained in the fuel deposit a layer of glassy hard brittle material mixed with carbon particles on the sealing cones of the exhaust disc and seat after various complex thermal processes in the combustion chamber, mixed with sodium sulfate, calcium sulfate, iron oxide and other substances. When the thickness of the glassy deposit is too large, the crack will be produced under the impact force when the air valve is closed. After repeated impact, it will develop into spalling, thus forming a high temperature gas jet passage and burning out the air valve.

2.燃料含有不可燃的顆粒雜質。

當進入燃燒室的油中混入不可燃的雜質顆粒時，這些雜質顆粒會隨著廢氣排出氣缸，在排氣閥關閉時，它們有一定的幾率會卡在排氣閥和閥座的密封面上。結果，排氣閥不能完全關閉，這種卡住的顆粒雜質的直徑和排氣閥的開度一樣大。雖然可以通過噴油器的噴孔進入燃燒室的顆粒雜質很小，但當燃油混合氣爆炸燃燒時，燃燒室的爆炸壓力很高，微小的閥門開度也會導致高溫高壓的燃燒氣體逸出。此時逸出的燃燒氣體溫度很高，瞬時峰值接近2000℃，遠高于排氣沖程中流經排氣閥密封面的廢氣溫度。良工閥門排氣閥的密封面材料可以承受正常排氣時廢氣的侵蝕，但不能承受這種高壓高溫燃燒氣體的侵蝕，會導致排氣閥在短時間內燒壞。特別是閥門被混在重油中的氧化鋁、二氧化硅等極硬顆粒卡住。在排氣閥沒有關緊的情況下，普通排氣閥的密封錐在工作溫度下不會很硬。在關閉閥門的沖擊下，沉積的硬燃燒產物顆粒也會將顆粒嵌入密封面，在高溫氣體的沖刷燒蝕下出現凹坑，凹坑穿透密封面形成漏氣，從而燒壞閥門。
2. The fuel contains non-flammable particulate impurities. When oil entering the combustion chamber is mixed with non-flammable particulate matter that is expelled from the cylinder along with the exhaust gas, there is a reasonable chance that it will get stuck on the sealing face of the exhaust valve and seat when the exhaust valve is closed. As a result, the exhaust valve can not be completely closed, and the diameter of the stuck particulate impurities is as large as the opening of the exhaust valve. Although the particles that can enter the combustion chamber through the injector’s injection hole are very small, when the fuel mixture explodes, the explosion pressure of the combustion chamber is very high, and the tiny valve opening will cause the high temperature and high pressure combustion gas to escape. At this time, the temperature of the escaping combustion gas is very high, the instantaneous peak value is close to 2000 °C, which is much higher than the exhaust gas temperature flowing through the exhaust valve sealing surface in the exhaust stroke. The sealing surface material of valve exhaust valve can bear the erosion of exhaust gas, but can not bear the erosion of high pressure and high temperature combustion gas, which will lead to exhaust valve burning out in a short time. In particular, the valve was mixed with heavy oil in aluminum oxide, silicon dioxide and other extremely hard particles stuck. When the exhaust valve is not closed tightly, the sealing cone of the Common Exhaust Valve is not very hard at working temperature. Under the impact of closing the valve, the hard combustion product particles will also be embedded into the sealing surface, in the high-temperature gas erosion pits, pits through the sealing surface to form a leakage of gas, thus burning the valve.

3.燃料油中含有釩、鈉等易造成金屬高溫腐蝕的元素。

目前航運市場常用的劣質燃料中含有大量的釩、鈉、硫等元素。在燃燒過程中，硫、釩、鈉等元素形成氧化硫、五氧化二釩和氧化鈉(這些氧化物的化學成分取決于過量的氧氣和燃燒溫度)。氧化物會相互反應，還會與潤滑油中的鈣形成低熔點鹽，如硫酸鈉、硫酸鈣和不同成分的釩酸鈉。這些鹽混合物的熔點通常在535℃左右，并且它們具有很強的腐蝕性。當零件的溫度高于550℃時，足以使釩和鈉處理的工作臺處于熔融狀態并粘附在零件表面。排氣閥工作時，由于各種原因，當閥的溫度達到550°C以上時，它以液體形式沉積在閥瓣和閥座的過渡面以及閥桿和閥面上。這時，即使是高耐蝕性的硬質合金鋼也會被腐蝕。由于腐蝕，密封錐面上會形成凹坑，通過密封面連接后會造成漏氣，燒壞氣閥。特別是上述麻點出現在氣閥和閥座的密封面上后，容易沉積腐蝕液，加速麻點的形成。由于上述腐蝕發生在高溫下，故稱為“高溫腐蝕”。在上述高溫腐蝕的有害元素中，釩的危害。
3. The fuel oil contains vanadium, sodium and other elements which are easy to cause metal corrosion at high temperature. At present, there are a lot of elements such as vanadium, sodium and sulfur in inferior fuels commonly used in the shipping market. During combustion, elements such as sulfur, vanadium, and sodium form sulfur oxide, divanadium Pentaoxide, and sodium oxide (the chemical composition of these oxides depends on excess oxygen and combustion temperature) . The oxides react with each other and form low melting point salts with calcium in the lubricant, such as sodium sulfate, calcium sulfate, and sodium vanadate of various compositions. These salt mixtures usually have a melting point of about 535 °C and are highly corrosive. When the temperature of the part is higher than 550 °C, it is enough to cause the vanadium and sodium treated worktable to melt and adhere to the surface of the part. When the exhaust valve is in operation, for various reasons, when the temperature of the valve reaches above 550 °C, it is deposited in the form of liquid on the transitional surface of the disc and seat and on the stem and face of the valve. At this point, even the high corrosion resistance of hard alloy steel will be corroded. As a result of corrosion, the sealing cone will form a pit, through the sealing surface connection will cause gas leakage, burn out the gas valve. In particular, the pits appear on the sealing surface of the valve and the valve seat, easy to deposit corrosion fluid, accelerate the formation of pits. As the above corrosion occurs at high temperature, it is called “High temperature corrosion.”. Among the above harmful elements, vanadium

4.空氣閥的閥轉換器出現故障。

為了減少上述、二、三種原因對氣門壽命的影響，燃燒重油的四沖程柴油機設計了排氣門的旋轉機構。使排氣閥在每次開啟和關閉時自動旋轉一個角度，以清除粘在密封面上的顆粒和積碳，避免顆粒和積碳在排氣閥密封面上堆積。如果這個良工閥門排氣閥的換閥器出現故障，在工作過程中不能保持排氣閥不斷轉動，或者轉動與排氣閥的關閉行程不協調，很快就會燒壞排氣閥，大大縮短排氣閥的使用壽命。
4. The valve converter of the Air Valve is out of order. In order to reduce the influence of the first, second and third reasons on the valve life, a four-stroke diesel engine which burns heavy oil has designed the rotating mechanism of the exhaust valve. The exhaust valve is automatically rotated at an angle each time it is opened and closed to remove particles and carbon deposits stuck to the sealing surface to avoid accumulation of particles and carbon deposits on the sealing surface of the exhaust valve. If the Valve Changer of the valve fails, the valve can not be kept rotating continuously during operation, or the rotation is not in harmony with the closing stroke of the valve, the valve will soon burn out, greatly shorten the service life of the exhaust valve.

5.氣閥質量問題。
5. Quality Problem of air valve. 

6.排氣閥和閥座研磨不良或其他原因導致排氣閥和閥座密封面漏氣。
6. Exhaust Valve and seat seal face leaking due to poor abrasion or other causes. 

7.氣閥間隙調整不當，間隙過小導致工作時排氣閥未關閉。

Kill. Improper adjustment of valve clearance, clearance is too small to work when the exhaust valve is not closed.