在維修汽車發動機這么多年，但對于發動機上的很多孔要是不知道是干什么的，下面帶你一起去看看這些孔的作用和原理！
I have been repairing the automobile engine for so many years, but if I don't know what many holes on the engine are for, let's take you to see the function and principle of these holes!
曲軸箱上的排氣孔
Exhaust hole on crankcase
發動機工作時，一部分可燃氣體和廢氣總會通過活塞環與氣缸壁之間的間隙進入曲軸箱。曲軸箱內冷凝的燃油蒸氣會稀釋機油，廢氣中的酸性物質和水蒸氣會腐蝕零件，使機油性能惡化（稀釋、老化和結焦）。
When the engine is working, some combustible gases and exhaust gases always enter the crankcase through the gap between the piston ring and the cylinder wall. The fuel vapor condensed in the crankcase will dilute the engine oil, and the acidic substances and water vapor in the exhaust gas will corrode the parts and deteriorate the performance of the engine oil (dilution, aging and coking).
此外，進入曲軸箱的氣體會使箱內溫度和壓力升高，導致油從油封、墊片等處滲出；由于活塞的往復運動，曲軸箱內的氣體壓力周期性變化，影響發動機的正常運轉，嚴重時會導致曲軸箱內的機油向上跑到燃燒室和氣缸蓋罩內。
In addition, the gas entering the crankcase will increase the temperature and pressure in the box, resulting in oil leakage from oil seals, gaskets, etc; Due to the reciprocating motion of the piston, the gas pressure in the crankcase changes periodically, affecting the normal operation of the engine. In serious cases, the oil in the crankcase will run up to the combustion chamber and cylinder head cover.
為了避免上述現象，發動機配備了通風裝置，以平衡曲軸箱內外的氣壓。如果在使用過程中出現燒機油、沿結合面漏油、機油過早變質、發動機怠速運轉不穩定等現象，檢查曲軸箱通風裝置是否有效；確保通風孔通暢，負壓閥板不得變形、粘連或安裝錯誤，呼吸管不得彎曲或堵塞，單向閥不得裝反，堵頭不得用木塞代替。
In order to avoid the above phenomenon, the engine is equipped with ventilation device to balance the air pressure inside and outside the crankcase. In case of oil burning, oil leakage along the joint surface, premature deterioration of oil, unstable idle running of engine and other phenomena during use, check whether the crankcase ventilation device is effective; Ensure that the ventilation hole is unobstructed, the negative pressure valve plate shall not be deformed, adhered or installed incorrectly, the breathing tube shall not be bent or blocked, the one-way valve shall not be installed reversely, and the plug shall not be replaced by a wooden plug.
油箱蓋上的排氣孔
Vent on tank cap
為防止油箱內的燃油因振動而飛濺、油蒸氣逸出和外部灰塵進入，應將油箱蓋好并密封。但當因油耗降低油位時，油箱內會形成一定程度的真空，使油泵失去吸油能力；另外，當溫度高時，燃油會蒸發，油蒸氣會導致油箱內壓力過大。
In order to prevent the splashing of fuel oil in the oil tank due to vibration, the escape of oil vapor and the entry of external dust, the oil tank shall be covered and sealed. However, when the oil level is reduced due to oil consumption, a certain degree of vacuum will be formed in the oil tank, resulting in the loss of oil absorption capacity of the oil pump; In addition, when the temperature is high, the fuel will evaporate, and the oil vapor will lead to excessive pressure in the fuel tank.
當罐的內部和外部之間發生壓力差時，這兩種情況都需要與大氣自動連通。為此，在油箱蓋上設有通氣孔，以平衡油箱內外的氣壓。使用過程中，確保油箱蓋上的通風孔暢通無阻。油箱蓋丟失后，如果通風口堵塞或用塑料片堵住油箱，發動機工作時油位下降，油箱內部會形成負壓，導致在發動機運行不穩定、功率下降、自動熄火和發動機故障時，在暖機狀態等情況下難以啟動。
When there is a pressure difference between the inside and outside of the tank, both cases need to be automatically connected to the atmosphere. Therefore, a vent hole is arranged on the oil tank cover to balance the air pressure inside and outside the oil tank. During use, ensure that the ventilation hole on the fuel tank cover is unobstructed. After the fuel tank cover is lost, if the vent is blocked or the fuel tank is blocked with plastic sheet, the oil level will drop when the engine is working, and a negative pressure will be formed inside the fuel tank, which will make it difficult to start under the condition of warm-up in case of unstable engine operation, power decline, automatic flameout and engine failure.
散熱器箱上的進排氣孔
Air inlet and exhaust holes on radiator box
濟南哪里有寶馬汽車維修的人員認為發動機工作時，封閉式冷卻系統中水溫的升高會導致冷卻水汽化并產生高壓，從而導致散熱器芯管因膨脹開裂而泄漏。當發動機負荷降低或停止運轉時，冷卻系統中的水蒸氣會凝結成水，其壓力會下降。壓力差可能導致芯管被壓扁，阻礙冷卻水的正常循環。
Jinan where BMW car maintenance personnel believe that when the engine is working, the rise of water temperature in the closed cooling system will lead to the vaporization of cooling water and high pressure, resulting in the leakage of radiator core pipe due to expansion and cracking. When the engine load decreases or stops running, the water vapor in the cooling system will condense into water and its pressure will drop. The pressure difference may cause the core tube to be flattened and hinder the normal circulation of cooling water.
為此，在散熱器蓋上設置了一個空氣蒸汽閥，并有一個與大氣相通的公共氣孔。當水溫升高時，散熱器內產生水蒸氣，打開蒸汽閥，水蒸氣從該孔排出；當水溫下降時，壓力下降，空氣閥打開，外界空氣將從這個孔進入散熱器，從而保證散熱器。內壓穩定。在使用過程中，一定要確保這個孔是暢通的，不能被堵塞，否則會影響散熱器和發動機的散熱性能。
Therefore, an air steam valve is set on the radiator cap, and there is a public air hole connected with the atmosphere. When the water temperature rises, water vapor is generated in the radiator. Open the steam valve and the water vapor is discharged from the hole; When the water temperature drops, the pressure drops, the air valve opens, and the outside air will enter the radiator from this hole, so as to ensure the radiator. The internal pressure is stable. During use, make sure that the hole is unblocked and cannot be blocked, otherwise it will affect the heat dissipation performance of radiator and engine.
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