柴油發(fā)電機組故障的原因通常是多方面因素造成的,不同故障表現(xiàn)出不同的現(xiàn)象,要排除故障,必須先查明故障的原因,在實踐中通過看、聽、摸、嗅等感覺,來發(fā)現(xiàn)柴油機異常的表現(xiàn),從而發(fā)現(xiàn)問題、解決問題,消除故障。
判斷柴油機故障的一般原則是:結(jié)合結(jié)構(gòu)、聯(lián)系原理、弄清現(xiàn)象、結(jié)合實際,從簡到繁、由表及里、按系分段、查找原因。在長期的生產(chǎn)實踐中,人們摸索總結(jié)出“一看、二聽、三摸、四嗅”的一套檢查方法,通過儀表監(jiān)測和人體器官的感受,去觀察和判斷柴油機的運行情況。
運轉(zhuǎn)異常
柴油機長期運轉(zhuǎn)后,發(fā)生了故障,通常會遇到下列幾種現(xiàn)象。
(1)運轉(zhuǎn)時聲音異常柴油機運轉(zhuǎn)時發(fā)出不正常的敲擊聲、放炮聲、吹噓聲、排氣聲、周期性的磨擦聲等。
(2)運轉(zhuǎn)異常柴油機不易啟動、工作時出現(xiàn)劇烈震動,拖不動負(fù)載,轉(zhuǎn)速不穩(wěn)定等。
(3)外觀異常柴油機排氣管冒白煙、黑煙、藍煙,各系統(tǒng)出現(xiàn)漏油、漏水、漏氣等。
(4)溫度異常機油溫度或冷卻水溫度過高,軸承過熱等。
(5)氣味異常柴油機運行時,發(fā)出臭味、焦味、煙味等氣味。
柴油發(fā)電機組運行進,發(fā)現(xiàn)上述異?,F(xiàn)象后,必須進行仔細(xì)的調(diào)查,根據(jù)故障現(xiàn)象,分析判斷找出故障的部位和原因。有時一種故障可能有好幾種異?,F(xiàn)象,例如高壓油泵磨損后,既可表現(xiàn)啟動困難,也可表現(xiàn)輸出功率不足,還可表現(xiàn)低速運轉(zhuǎn)不穩(wěn)定等現(xiàn)象。有時一種異?,F(xiàn)象,可能有幾種故障造成的。因此,柴油機運行時出現(xiàn)異?,F(xiàn)象,必須認(rèn)真查清產(chǎn)生異?,F(xiàn)象的原因,這就要求我們善于作分析推理判斷,透過現(xiàn)象抓實質(zhì),找出發(fā)生故障的原因和部位,將故障排除。
檢查方法
(1)根據(jù)異常的聲響來判別故障的部位用一把通心改錐或用一根半米長一端磨尖的細(xì)鐵條,進行“聽針判斷”,一端貼耳,另一端觸及各檢查部位表面,可較清晰地監(jiān)聽到異常聲響產(chǎn)生的部位,聲響的大小和性質(zhì)。不同部位發(fā)出聲響往往是不同的。例如主軸承間隙過大發(fā)生沖擊聲是沉悶的,氣門與活塞碰擊聲是清脆的,若飛輪鍵槽配合松動發(fā)出“唝!唝!”的撞擊聲等等,因此,根據(jù)不同聲響,來判斷故障的部位。
(2)用局部停止法來判斷經(jīng)故障分析后,若懷疑故障是由某一汽缸引起的,可停止該缸工作,觀察故障現(xiàn)象是否消失,從而確定故障原因和部位。例如柴油機冒黑煙,分析為某缸噴油嘴噴孔堵塞,可對該缸停止供油,若黑煙消失,說明判斷正確。
(3)用比較法來判斷根據(jù)故障分析,懷疑故障可能是由于某一零、部件所造成的,可將該零件(或部件)更換一只新件,然后開機運行比較柴油機前后工作情況是否有變化,從而找出故障原因。
(4)用試探法來判斷根據(jù)分析故障原因一時難以判斷,可用改變局部范圍內(nèi)的技術(shù)狀態(tài),觀察柴油機工作性能是否有影響,以此來判別故障的原因。例如柴油機發(fā)不出規(guī)定的功率,懷疑某缸壓縮沖程壓力不足,是汽缸與活塞間隙較大密封不嚴(yán)造成的,此時將缸蓋打開向汽缸注入少量機油,以改善密封狀況,然后重新裝好缸蓋,開機試驗若壓力增大,輸出功率增加,說明分析是正確的。
柴油發(fā)電機組經(jīng)長時間使用后,其故障現(xiàn)象很多,由于柴油機各種型號不同,國產(chǎn)的和進口的其結(jié)構(gòu)和使用環(huán)境不同,故障原因也有所不同,因此,在處理問題時,對具體問題應(yīng)根據(jù)不同情況作具體分伯。正確分析和判斷柴油機故障的原因,是一項細(xì)致的工作,不應(yīng)在未弄清故障原因之前就亂拆一通,這樣不但不能消除故障,而且可能在重裝拆開的零、部件時,達到不技術(shù)要求造成新的故障。
The causes of faults in diesel generator sets are usually caused by various factors, and different faults exhibit different phenomena. To eliminate faults, it is necessary to first identify the cause of the fault. In practice, by looking, listening, touching, smelling, and other senses, the abnormal performance of the diesel engine can be discovered, and problems can be found, solved, and eliminated.
The general principle for judging diesel engine faults is to combine structure, connection principles, clarify phenomena, and combine reality, from simple to complex, from the surface to the inside, segment by system, and find the cause. In long-term production practice, people have explored and summarized a set of inspection methods of "one look, two listen, three touch, and four smell", which observe and judge the operation of diesel engines through instrument monitoring and the feeling of human organs.
Abnormal operation
After long-term operation, diesel engines often encounter the following phenomena when they malfunction.
(1) Abnormal sound during operation: The diesel engine produces abnormal knocking, blasting, blowing, exhaust, periodic friction, etc.
(2) Abnormal operation: The diesel engine is difficult to start, experiences severe vibrations during operation, cannot drag the load, and has unstable speed.
(3) Abnormal appearance: The diesel engine exhaust pipe emits white smoke, black smoke, and blue smoke, and various systems are leaking oil, water, and gas.
(4) Abnormal temperature, high oil temperature or cooling water temperature, bearing overheating, etc.
(5) Abnormal odor: When the diesel engine is running, it emits odors such as foul smell, burnt smell, and smoke smell.
After the operation of the diesel generator set and the discovery of the above-mentioned abnormal phenomena, a careful investigation must be conducted to analyze and determine the location and cause of the fault based on the fault symptoms. Sometimes a fault may have several abnormal phenomena, such as difficulty in starting, insufficient output power, and unstable low-speed operation after the wear of the high-pressure oil pump. Sometimes an abnormal phenomenon may be caused by several faults. Therefore, when abnormal phenomena occur during the operation of diesel engines, it is necessary to carefully investigate the causes of the abnormal phenomena. This requires us to be good at analyzing, reasoning and judging, grasping the essence through the phenomena, identifying the causes and parts of the faults, and eliminating them.
Inspection method
(1) To determine the location of the fault based on abnormal sounds, use a through center screwdriver or a thin iron bar that is half a meter long and sharpened at one end for "listening needle judgment". Place one end on the ear and touch the surface of each inspection site at the other end to clearly monitor the location, size, and nature of the abnormal sound. The sound produced by different parts is often different. For example, if the clearance between the main bearing is too large, the impact sound will be dull, the collision sound between the valve and piston will be crisp, and if the flywheel keyway is loose, it will make a "唝! 唝!" impact sound, etc. Therefore, based on different sounds, the location of the fault can be determined.
(2) Using the local stop method to determine after fault analysis, if it is suspected that the fault is caused by a certain cylinder, the cylinder can be stopped to observe whether the fault phenomenon disappears, in order to determine the cause and location of the fault. For example, if a diesel engine emits black smoke, it can be analyzed as a blockage in the fuel injector hole of a certain cylinder, and the fuel supply to that cylinder can be stopped. If the black smoke disappears, it indicates that the judgment is correct.
(3) Using the comparative method to determine, based on fault analysis, if it is suspected that the fault may be caused by a certain component or part, the component (or part) can be replaced with a new one, and then the diesel engine can be started and operated to compare whether there are any changes in the working conditions before and after, in order to identify the cause of the fault.
(4) It is difficult to determine the cause of the fault based on the analysis using the probing method. By changing the technical state within a local area and observing whether the performance of the diesel engine is affected, the cause of the fault can be determined. For example, if a diesel engine cannot produce the specified power and it is suspected that the compression stroke pressure of a certain cylinder is insufficient, it is caused by a large gap between the cylinder and the piston and poor sealing. At this time, the cylinder head is opened and a small amount of oil is injected into the cylinder to improve the sealing condition. Then, the cylinder head is reinstalled. If the pressure increases and the output power increases during the start-up test, it indicates that the analysis is correct.
After long-term use, diesel generator sets have many fault phenomena. Due to the different models of diesel engines, as well as the different structures and operating environments of domestic and imported ones, the causes of faults are also different. Therefore, when dealing with problems, specific problems should be classified according to different situations. Accurately analyzing and determining the cause of diesel engine failures is a meticulous task, and should not be dismantled without understanding the cause of the failure. This not only fails to eliminate the fault, but may also result in new failures due to non-technical requirements when reinstalling disassembled parts and components.