In the application of automatic exhaust valve, sometimes it will be damaged. What is the reason for this? Let's take a look with Lianggong valve manufacturers.

1、燃油燃烧不好以及因此造成的结碳的影响。

1. Poor fuel combustion and the resulting carbon deposition.

燃烧不好不但会引起排温升高，而且会在燃烧室形成结碳。排温升高使排气阀的工作环境更加恶劣，叠加其它情况后加剧了排气阀的烧损。燃烧室中的结碳会有一部分随着废气排出，它也会像前面说的颗粒一样卡在排气阀和阀座的密封面上。

The combustion is not good, but it will increase the exhaust temperature and form carbon deposition in the combustion chamber. The increase of exhaust temperature makes the working environment of exhaust valve worse, and aggravates the burning loss of exhaust valve after superposition of other conditions. Part of the carbon deposit in the combustion chamber will be discharged with the exhaust gas, and it will also be stuck on the sealing surface of the exhaust valve and valve seat like the particles mentioned above.

尤其是重油的加热温度控制不佳，粘度太大造成喷入气缸的燃油难以雾化，高压油泵柱塞磨损造成的燃烧后移等原因引起的燃烧不好，会使排气阀和阀座的密封面被积炭污染，加上燃油中含有的杂质在经过燃烧室内的各种复杂热过程后。

In particular, the heating temperature of heavy oil is not well controlled, the viscosity is too large, which makes it difficult to atomize the fuel injected into the cylinder, and the poor combustion caused by the backward combustion caused by the wear of the plunger of the high-pressure oil pump will pollute the sealing surface of the exhaust valve and valve seat by carbon deposition. In addition, the impurities contained in the fuel after various complex thermal processes in the combustion chamber.

在排气阀阀盘及阀座密封锥面沉积成一层混有碳粒的玻璃状较硬较脆物质，其内混有硫酸钠、硫酸钙、氧化铁等物质。当此层玻璃状沉积物沉积厚度过大时，在气阀关闭时的撞击力下会发生裂纹，反复撞击后进而发展成剥落，从而形成高温燃气喷出通道使气阀烧损。

A layer of glassy hard and brittle material mixed with carbon particles is deposited on the sealing cone of exhaust valve disc and valve seat, which is mixed with sodium sulfate, calcium sulfate, iron oxide and other substances. When the deposition thickness of this layer of glassy sediment is too large, cracks will occur under the impact force when the gas valve is closed, which will develop into spalling after repeated impact, so as to form a high-temperature gas injection channel and burn the gas valve.

燃油中含有不可燃烧的颗粒杂质。

The fuel contains incombustible particulate impurities.

当进入燃烧室的油品中混有不可燃烧的杂质颗粒物时，这些杂质颗粒会随着排气排出气缸，在排出的过程中会有一定的几率在排气阀关闭时被卡阻在排气阀和阀座的密封面上。造成排气阀不能完全关闭，这个卡住的颗粒杂质的直径有多大，气阀的开度就有多大。虽然能通过喷油器的喷孔进入燃烧室的颗粒杂质都较小，但在燃油混合气体爆炸燃烧时，燃烧室的爆炸压力很高，微小的气阀开度也能造成高温高压燃烧气体的窜出。

When incombustible impurity particles are mixed in the oil entering the combustion chamber, these impurity particles will be discharged from the cylinder with the exhaust. During the discharge process, there is a certain chance that they will be stuck on the sealing surface of the exhaust valve and valve seat when the exhaust valve is closed. As a result, the exhaust valve cannot be completely closed. The diameter of the stuck particle impurities depends on the opening of the air valve. Although the particle impurities that can enter the combustion chamber through the nozzle hole of the fuel injector are small, the explosion pressure of the combustion chamber is very high during the explosive combustion of the fuel mixture, and the small opening of the gas valve can also cause the channeling of high-temperature and high-pressure combustion gas.

这时候窜出的燃烧气体的温度很高，瞬间的峰值接近2000℃，远远高于排气冲程中流经排气阀密封面的废气温度。排气阀的密封面材料可以经得起正常排气时的废气的冲刷，但经不起如此高压和高温的燃烧气体的冲刷，很短的时间就会造成排气阀烧损。

At this time, the temperature of the emitted combustion gas is very high, and the instantaneous peak value is close to 2000 ℃, which is much higher than the temperature of the exhaust gas flowing through the sealing surface of the exhaust valve in the exhaust stroke. The sealing surface material of the exhaust valve can withstand the scouring of exhaust gas during normal exhaust, but it can not withstand the scouring of combustion gas with such high pressure and high temperature, which will cause the burning loss of the exhaust valve in a very short time.

尤其阀门卡住的是混在重油中的氧化铝和二氧化硅这些极硬颗粒，在造成排气阀关闭不密的同时，普通排气阀密封锥面在工作温度下硬度并不是很高，沉积的硬质燃烧产物颗粒在闭阀的撞击下，还可使颗粒嵌入密封面，并在高温燃气的冲刷和烧蚀下出现凹坑，凹坑贯穿密封面后形成漏气从而烧损气阀。

In particular, the valve is stuck with extremely hard particles such as alumina and silica mixed in heavy oil. While the exhaust valve is not closed tightly, the hardness of the sealing cone of the ordinary exhaust valve is not very high at the working temperature. The deposited hard combustion product particles can also make the particles embedded in the sealing surface under the impact of the valve closing, and pits appear under the scouring and ablation of high-temperature gas, After the pit penetrates the sealing surface, an air leakage is formed, which burns the air valve.