自动排气阀在应用中有时会损坏，那么出现这种情况的原因是什么呢？让我们一起来看看。
Automatic exhaust valves are sometimes damaged in use, so what is the reason for this? Let’s take a look.

1.燃料燃烧不良及其造成的积碳影响。

排气温度升高使排气阀的工作环境变差，叠加其他条件后排气阀的烧损加剧。燃烧室中的部分积碳会随着废气排出，也会像前面提到的颗粒一样粘在排气阀和阀座的密封面上。特别是重油加热温度控制不好，喷入气缸的燃油粘度过高，难以雾化，高压油泵柱塞磨损造成反燃燃烧不良，会使良工阀门排气阀和阀座密封面被积碳污染。此外，燃料中含有的杂质在燃烧室内经过各种复杂的热过程后，在排气阀盘和阀座的密封锥上沉积成一层与碳粒混合的玻璃状硬脆物质，与硫酸钠、硫酸钙、氧化铁等物质混合。当这种玻璃状沉积物的沉积厚度过大时，在气阀关闭时的冲击力作用下会产生裂纹，反复撞击后会发展为剥落，从而形成高温气体喷射通道烧坏气阀。
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.燃料含有不可燃的颗粒杂质。

当进入燃烧室的油中混入不可燃的杂质颗粒时，这些杂质颗粒会随着废气排出气缸，在排气阀关闭时，它们有一定的几率会卡在排气阀和阀座的密封面上。结果，排气阀不能完全关闭，这种卡住的颗粒杂质的直径和排气阀的开度一样大。虽然可以通过喷油器的喷孔进入燃烧室的颗粒杂质很小，但当燃油混合气爆炸燃烧时，燃烧室的爆炸压力很高，微小的阀门开度也会导致高温高压的燃烧气体逸出。此时逸出的燃烧气体温度很高，瞬时峰值接近2000℃，远高于排气冲程中流经排气阀密封面的废气温度。良工阀门排气阀的密封面材料可以承受正常排气时废气的侵蚀，但不能承受这种高压高温燃烧气体的侵蚀，会导致排气阀在短时间内烧坏。特别是阀门被混在重油中的氧化铝、二氧化硅等极硬颗粒卡住。在排气阀没有关紧的情况下，普通排气阀的密封锥在工作温度下不会很硬。在关闭阀门的冲击下，沉积的硬燃烧产物颗粒也会将颗粒嵌入密封面，在高温气体的冲刷烧蚀下出现凹坑，凹坑穿透密封面形成漏气，从而烧坏阀门。
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.燃料油中含有钒、钠等易造成金属高温腐蚀的元素。

目前航运市场常用的劣质燃料中含有大量的钒、钠、硫等元素。在燃烧过程中，硫、钒、钠等元素形成氧化硫、五氧化二钒和氧化钠(这些氧化物的化学成分取决于过量的氧气和燃烧温度)。氧化物会相互反应，还会与润滑油中的钙形成低熔点盐，如硫酸钠、硫酸钙和不同成分的钒酸钠。这些盐混合物的熔点通常在535℃左右，并且它们具有很强的腐蚀性。当零件的温度高于550℃时，足以使钒和钠处理的工作台处于熔融状态并粘附在零件表面。排气阀工作时，由于各种原因，当阀的温度达到550°C以上时，它以液体形式沉积在阀瓣和阀座的过渡面以及阀杆和阀面上。这时，即使是高耐蚀性的硬质合金钢也会被腐蚀。由于腐蚀，密封锥面上会形成凹坑，通过密封面连接后会造成漏气，烧坏气阀。特别是上述麻点出现在气阀和阀座的密封面上后，容易沉积腐蚀液，加速麻点的形成。由于上述腐蚀发生在高温下，故称为“高温腐蚀”。在上述高温腐蚀的有害元素中，钒的危害。
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.空气阀的阀转换器出现故障。

为了减少上述、二、三种原因对气门寿命的影响，燃烧重油的四冲程柴油机设计了排气门的旋转机构。使排气阀在每次开启和关闭时自动旋转一个角度，以粘在密封面上的颗粒和积碳，避免颗粒和积碳在排气阀密封面上堆积。如果这个良工阀门排气阀的换阀器出现故障，在工作过程中不能保持排气阀不断转动，或者转动与排气阀的关闭行程不协调，很快就会烧坏排气阀，大大缩短排气阀的使用寿命。
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.气阀质量问题。
5. Quality Problem of air valve. 

6.排气阀和阀座研磨不良或其他原因导致排气阀和阀座密封面漏气。
6. Exhaust Valve and seat seal face leaking due to poor abrasion or other causes. 

7.气阀间隙调整不当，间隙过小导致工作时排气阀未关闭。

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