柴油發電機組排氣煙色故障分析

柴油機工作溫度正常情況下，所排出的煙色應該是無色或淡灰色，所謂無色不是完全無色，不能像汽油機那樣無色，而是在無色中伴有淡淡的灰色，這是正常排氣煙色。柴油機在怠速時排氣煙色可能重一些，在高速、高負荷時也可能重一些，要留意觀察正常排氣煙色，才能對非正常的排氣煙色進行判定和分析。柴油機燃料完全燃燒後，正常顏色一般為淡灰色，負荷略重時為深灰色。柴油機在工作中，會經常出現冒煙現象，柴油機排煙有黑煙、藍煙、白煙和灰色四種，它們是判定柴油機故障的條件之一，具體分析如下：

一、排氣冒黑煙（碳煙）

黑煙又痴辜煙，柴油機排氣冒黑煙最主要原因是燃料混合氣過濃，可燃混合氣形成不良或燃燒不完善等原因造成的。柴油機在高溫、高壓燃燒條件下，局部缺氧、裂解並脫氫而形成的以碳為主要成分的固體微小顆粒，是燃燒室內燃料燃燒不完全的表現。由於柴油機是非均質燃燒，燃燒室內各區域的化學反應條件是不一致的，而且隨著時間而變化的，所以黑煙很可能是由很多不同途徑天生的。柴油是複雜的碳氫化合物，噴進燃燒室內未燃燒的柴油受高溫分解，形成炭黑，排氣時隨同廢氣一起排出形成玄色煙霧。黑煙是不完全燃燒產物，是烴燃燒在高溫缺氧情況下裂解過程釋出並聚合而成的。某些情況下燃油噴射在燃燒室壁面上，形成液態油膜，油膜是最後蒸發的一部分，它的燃燒取決於其蒸發速度和燃料蒸氣與氧的混合速度。假如四周氣體中氧的濃度太低，或混合的速度不夠時，從油膜蒸發的燃料氣體將被分解，併產生未燃烴、不完全氧化產物和黑煙。

柴油機燃燒過程中黑煙的產生可以概括為三個階段——成核階段、單粒階段、單粒的燃燒消失或附聚成更大絮團。影響其天生的主要原由於：

１、活塞環、氣缸套等磨損　氣門、活塞環、氣缸套磨損後，引起壓縮壓力不足以及機油上竄燃燒試冬負氣缸在壓縮行程結束時，混合氣混合的正常比例改變，使燃油在無氧條件下燃燒，燃燒過程輕易產生積炭，排出的廢氣形成大量玄色煙霧。

２、燃燒室外形改變燃燒室外形因製造質量及長期使用導致技術狀況下降，使壓縮余縫過大、過小以及活塞位置裝錯，都會使燃燒室外形和容積改變，從而影響燃油與空氣混合質量，使燃油燃燒條件變壞。

３、噴油器工作不良，柴油機排氣煙度與燃油霧化品質的關係密切，在柴油機噴油過程中，每次噴油臨結束時，噴油壓力下降，霧化質量差，使液滴直徑比主要噴射階段的油滴大4-—5倍（體積約增大100倍），這些油滴蒸發與燃燒的時間短，四周氧的濃度低，輕易產生碳煙。噴油器不霧化、霧化不良或滴油，使燃料不能充分地與氣缸內的空氣混合，也不能完全燃燒。由噴油器工作不良引起的排黑煙現象在柴油機低速運轉時較為明顯，由於低速運轉時氣缸內進氣渦流較弱，油滴或油束被氣流衝散的可能性減少並且停留的時間較長，更輕易形成碳黑排出。)

４、供油量過大供油量過大，使進進汽缸內的油量增多，造成油多氣少燃油燃燒不完全。另外，工作負荷過重、燃油質量低劣、工作溫度過低也會引起排氣冒黑煙，柴油機中燃料的高溫裂解反應是不可避免的，特別是在空間混合燃燒的柴油機中，由於高溫氣體包圍著液態的油滴，造成了有利於裂解反應的條件，因此在燃燒初期產生了大量的碳粒，這一點已為燃燒過程的高速攝影所證實。柴油機在正常燃燒時，在排氣門打開以前，燃燒初期所形成的大量碳粒可以基本燒完，排氣基本上是無煙的。只是在某些不利工況下，碳粒不能及時燃燒反而團圓吸附，在氣缸中和排氣過程中形成更大的碳煙粒子或絮團，使排氣冒黑煙。

５、供油提前角調整不當

（１）供油提前角過大，燃油過早噴進燃燒室內，由於此時氣缸內壓力溫度較低，燃料不能著火燃燒，當活塞上行，氣缸內達到一定壓力和溫度，可燃混合氣燃燒。在直噴式柴油機中，當其它參數不變時，加大噴油提前角可以降低排氣煙度。由於加大噴油提前角會使滯燃期加長，使著火前噴進氣缸的油量增加，預混合量增加，預混合氣增多，加快了燃燒速度，燃燒可較早結束，從而使主燃期的形成碳粒具有較高的溫度和高溫下停留較多的時間，有利於碳粒氧化消失。然而過早的噴油增加了預混燃料量，使柴油機工作粗暴，燃燒噪音增大，並引起較大的機械負荷，以及較多的黑煙（COX）排放。

（２）供油提前角過小，噴進汽缸內的燃油過遲，一部分燃料來不及形成可燃混合氣就被分離或排出，致使部分在排氣管中隨廢氣排出的燃油料受高溫分解、燃燒，形成黑煙隨廢氣一同排出。

二、排氣冒藍煙

排氣冒藍煙，一般情況下是柴油機使用日久，慢慢開始燒機油引起的，隨著藍色煙霧的加重，燒機油越來越多，就應考慮維修柴油機了。有時燃油中混有水分，或有水分漏進燃燒室中，引起燃燒的改變，柴油機會冒淺藍色煙。影響其天生的主要因素為：

１、空氣濾清器阻塞，進氣不暢或油盆內油麵過高（油浴式空氣濾清器），使進進汽缸內的氣量減少，燃油混合氣正常比例改變，造成油多氣少燃油燃燒不完全，也會引起排氣冒藍煙。

２、油底殼內潤滑油加進過多，柴油機運行中潤滑油易竄進燃燒室。

３、長期低負荷（標定功率的40%以下）運轉，活塞與缸套之間的間隙過大，使油底殼內潤滑油輕易竄進燃燒試冬與氣缸中的燃料混合氣混合，改變混合氣正常比例，燃燒不完全，引起排氣冒藍煙。

４、活塞環卡住或磨損過多，彈性不足，安裝時活塞環倒角方向裝反，使機油進進燃燒試冬潤滑油燃燒後產生藍色水氣煙霧排出。

５、在機體通向氣缸蓋油道四周的氣缸墊燒毀，活塞、氣缸套磨損以及活塞環對口等狀況將致使潤滑油上竄燃燒試冬並與燃油混合氣一同燃燒。

三、排氣冒白煙

白煙是指排氣煙色為白色，它與無色不同，白色是水蒸氣的白色，表示排煙中含有水分或含未燃燒的燃油成分。白煙呈液珠狀態，和藍煙相比較直徑稍大，一般大於1μm。在光的折射下呈白色，柴油機的白煙是未燃烴（含燃油和潤滑油）、水蒸氣以及不完全燃燒的中間產物（如含氧碳氫），除水蒸氣外，它們也都屬於微粒範疇。柴油機在剛起動時或冷機狀態時，排氣管冒白煙，是由於柴油機氣缸內溫度低油氣蒸發而形成，冬季尤為明顯。柴油機在嚴冷天氣運行時，柴油機溫度低，排氣管溫度也低，有水蒸氣排氣凝聚成水氣形成白色排煙，是正常現象。若當柴油機溫度正常，排氣管溫度也正常時，仍然排出白色煙霧，說明柴油機工作不正常，可判定為柴油機故障。影響其天生的主要因素為：

６、柴油機剛啟動時，個彆氣缸內不燃燒（特別是冬天），未燃燒的燃油混合氣隨其它工作缸的廢氣排出形成水氣煙霧。

7、活塞、氣缸套等磨損嚴重引起壓縮力不足，造成燃燒不完全。

8、燃油中有水份和空氣。水和空氣隨著燃油噴射進氣缸形成不均勻燃油混合氣，燃燒不完全，產生大量的未燃烴排出機外。

9、氣缸套有裂紋或氣缸墊損壞，隨著冷卻水溫度和壓力的升高，冷卻水進進氣缸。排氣時形成輕易形成水霧或水蒸氣

10、供油提前角過小。活塞上行至氣缸頂前噴進氣缸的燃油過少，形成較稀的可燃混合氣，過遲的噴油減少了預混燃料量，預混合量減少。預混合氣減少，降低了燃燒速度，燃燒結束較晚，燃燒形成大量的水氣煙霧。

四、排氣冒灰煙

排氣冒淡灰色煙，柴油機工作還算正常，但煙霧顏色加重呈灰色或接近於玄色就不正常了，除了上述排煙玄色的原因外，還可能有進氣不暢即空氣供給不好的原因。當取下進氣空氣濾清器後，排氣煙色由深變淺甚至變為無色時，就是空氣濾清器堵塞了，應檢查引起進氣不暢的原因。

噴油器霧化不良，噴油壓力過低，有滴油現象。在氣缸中燃油混合氣不均勻，燃燒不完全，產生大量的未燃烴，排氣時輕易形成水霧或水蒸氣。

Failure Analysis of diesel generator set exhaust smokecolorDiesel engine operating temperature under normalcircumstances, the color of the exhaust fumes should be colorless or pale gray,the so-called colorless is not completely colorless, not like the gasolineengine as colorless, but accompanied by a touch of gray in colorless, which isnormal exhaust smoke color. Diesel engine at idle, the exhaust smoke color maybe heavier, high-speed, high load may be heavier, to observe and normal exhaustsmoke color can conducted to determine and analyze non-normal exhaust smokecolor. Complete combustion of diesel fuel, the normal color is generally lightgray, the load is slightly heavier than dark gray. Diesel engine at work, oftensmoke in diesel engine exhaust smoke, blue smoke, white smoke and gray four,they are one of the conditions that determine the diesel engine failure,specific analysis is as follows:An exhaust black smoke (soot)Another crazy black smoke the Gu smoke, diesel exhaustblack smoke most important reason is the fuel mixture is too thick, combustiblemixture formation causes bad or burning imperfect. The diesel engine in thehigh-temperature, high pressure combustion conditions, local hypoxia, crackingand dehydrogenation and the formation of tiny carbon as the main ingredient ofsolid particles, the combustion chamber fuel incomplete combustion performance.Diesel non-homogeneous combustion, chemical reaction conditions of each regionof the combustion chamber is inconsistent, and change over time, so the blacksmoke is likely to by many different ways natural. Diesel is a complexhydrocarbons, sprayed into the combustion chamber unburned diesel fuel bypyrolysis, the formation of carbon black, along with the exhaust gas when theexhaust discharge to the formation of black smoke. Black smoke is a product ofincomplete combustion of hydrocarbon combustion under anoxic conditions in thehigh-temperature pyrolysis process of release and polymerization. Fuelinjection in the combustion chamber wall, under certain circumstances, theformation of a liquid film, the film is part of the final evaporation,combustion depends on the evaporation rate of fuel vapor and oxygen mixturevelocity. Four weeks the concentration of oxygen in the gas is too low, or amixture of speed is not enough, the film evaporation from thefuel gas will decompose and produce unburned hydrocarbons, incomplete oxidationproducts and smoke.Black smoke diesel engine combustion process inherentlycan be summarized into three stages - nucleation stage, single grain stage,single grain of burning disappears or agglomeration into larger floc. Affectits natural original due to:1, piston rings, cylinder linerwear of valve, piston rings, cylinder liner wear, caused by compressionpressure is insufficient, and the channeling of the oil burning test winternegative cylinder at the end of the compression stroke, the normal change inratio of the mixture is mixed, so that the fuel in the absence of oxygen underthe conditions of combustion, the combustion process is easily produce coke,the exhaust air from the formation of a large number of black smoke.2, the shape of the combustionchamber to change the combustion chamber shape because of manufacturing qualityand long-term use of the technical conditions of the compression I sew toolarge, too small, and the piston position is wrong, will cause the combustionchamber shape and volume changes, thus affecting the fuel and air mixture thequality of fuel combustion conditions deteriorate.Bad injector diesel engine exhaustsmoke and fuel atomization quality is closely related to diesel fuel injectionprocess, the end of each injector Pro, injection pressure decreased, the poorquality of atomization, so that the droplets diameter 4-5 times larger than themain injection phase of the oil droplets (volume about 100 times larger), thesedroplets evaporate burning time is short and the surrounding oxygenconcentration is low, and easily produce soot. Injector atomization,atomization, poor or drop of oil, fuel and air mixture within the cylinder cannot be fully nor complete combustion. Injector bad work caused by the emissionof black smoke phenomenon is more obvious when the diesel engine at low speed, low speed cylinder intakeswirl is weak, reducing the possibility of oil droplets or oil beam by air tobreak up and stay longer than long, the more easily the formation of carbonblack discharge. )4, oil overload oil overload, the increase in theamount of fuel into the cylinder, resulting in incomplete combustion of fueloil and more gas less. In addition, work overload, poor fuel quality, operatingtemperature is too low will cause the exhaust black smoke, diesel fuel in hightemperature pyrolysis reaction is inevitable, especially in the spacecombustion of diesel, due to the high temperature gas surrounded liquiddroplets, resulting in the cracking reaction conditions, so early in thecombustion generated a lot of carbon particles, this has been confirmed byhigh-speed photography of the combustion process. The diesel engine in thenormal combustion, before the exhaust valve opens, burning the early formationof carbon particles can basically burn the exhaust is basically a smoke-free.Only in certain adverse conditions, carbon can not be timely burning butreunion adsorption www.zfdjz.com larger soot particles or floc formed in thecylinder and exhaust process, so that the exhaust black smoke.5, the fuel supply advance angle adjustment improper(1) fuel supply advance angle is too large, fuel premature sprayed into the combustionchamber, low pressure and temperature within the cylinder, the fuel is notignited, reaches a certain pressure and temperature within the cylinder whenthe piston upward, combustible mixture combustion. In direct injection dieselengine, when the other parameters constant, increase the fuel injection advanceangle can reduce exhaust smoke. Increase the fuel injection advance angle willmake longer ignition delay period, the increase in fuel sprayed into thecylinder before ignition, premixed increased pre-mixed gas increased to speedup the combustion speed, combustion may end earlier, so that the main theformation of the combustion of carbon particles has to stay more time underhigh temperature and high temperature, carbon particle oxidation disappears.However, the increase in premature fuel injection amount of premixed fuel,diesel crude, combustion noise increased, and caused a large mechanical load,and more smoke emissions (COX).(2) The fuel supply advance angle is too small, fuel sprayed into the cylinderlate part of the fuel is too late to formation of the combustible mixture to beseparated or discharged, causing part of exhaust gas in the exhaust pipe withthe fuel material by pyrolysis, combustion, the formation of black smoke alongwith the exhaust discharge.Second, the exhaust take LanyanExhaust take Lanyan general diesel engine after prolonged use, and slowly beganto burn the oil caused, with the blue smoke worsens, more and more burning oil,you should consider the maintenance of diesel engines. Sometimes fuel mixedwith water, or water to leak into the combustion chamber, causing the change ofcombustion, the diesel engine will take the light blue smoke. Affect thenatural main factors:An air filter, intake poor or oil basin oil is too high (oil bath air filter),so that the gas into the cylinder to reduce the normal change in ratio of thefuel mixture, resulting in more oil gas less incomplete combustion of fuel,will cause the exhaust to take Lanyan.2, the lubricating oil sump added too much lubricant easy coming into thecombustion chamber diesel engine running.3, less than 40% of long-term, low-load (rated power) operation, the gapbetween the piston and cylinder is too large, so that the lubricating oil sumpeasily flee in the fuel mixture in the combustion test of winter and thecylinder gas mixture and change the Blend gas the normal proportion ofincomplete combustion, causing the exhaust to take Lanyan.4, the piston ring stuck or excessive wear and tear, lack of flexibility wheninstalling the direction of the piston ring chamfer hold against the oil feedinto the blue water gas smoke emissions after combustion in the trial of winteroil combustion.5, in the body leading to the cylinder head oil passages around the cylinderpad burned piston, cylinder liner wear and piston ring counterparts conditionsresulting in lubricants Upward combustion test in winter, and with burning andfuel mixture.Third, the exhaust white smokeWhite smoke is the exhaust smoke color white and colorless, white water vaporwhite, said exhaust contains water or containing unburned fuel components.White smoke was the state of the droplet, and blue smoke compared with thediameter slightly larger, typically greater than 1μm. Refraction of light iswhite, the white smoke of the diesel engine is unburned hydrocarbons (includingfuel and lubricant), water vapor and incomplete combustion intermediates (suchas oxygen-containing hydrocarbon), in addition to water vapor, they also belongto particle areas. The diesel engine is just starting or cooler state, theexhaust pipe white smoke is due to the low evaporative emission of dieselengine cylinder temperature formation, especially in winter. Diesel engines incold weather to run in strict diesel engine temperature is low, the exhausttemperature is low, water vapor exhaust is condensed into water vapor to form awhite smoke is normal. When the diesel engine to normal temperature, exhausttemperature is normal, still emit white smoke, indicating that the dieselengine is not working properly, can be judged to be the diesel engine fault.Affect the natural main factors:6 diesel engine has just started within the individual cylinder combustion(especially in winter), unburned fuel mixture with the other cylinder exhaustdischarge to form water vapor smoke.7, piston, cylinder liner wear serious cause compression force, resulting inincomplete combustion.8, fuel, water and air. Water and air with the fuel injection into the cylinderto the formation of uneven fuel mixture, combustion is incomplete, resulting ina lot of unburned hydrocarbons discharged outside the machine.9, the cylinder liner crack or cylinder head gasket is damaged, with thecooling water temperature, pressure, cooling water feed into the cylinder.Venting the formation of easily formation of mist or vapor10, the fuel supply advance angle is too small. The piston up to the fuel sprayinto the cylinder before the cylinder top is too small, the formation of themore dilute the combustible mixture, the late injection to reduce the premixedfuel consumption, pre-mixed reduced. Pre-mixture is reduced, reducing thecombustion speed, combustion end of the late burning the formation of a largenumber of water vapor of smoke.Fourth, the exhaust take MistyExhaust to take light gray smoke, diesel engines work is fairly normal, but thesmoke color heavier gray or close to the xuan is not normal, in addition to thesmoke xuan of reasons, may also have poor intake air supply does not goodreason. Remove the intake air filter, exhaust smoke color deep shallow or evenbecome colorless, that is, air filter blockage, should check the cause of thereasons for poor intake.Poor injector spray, the injection pressure is too low, drip phenomenon. Fuelmixture in the cylinder, uneven, incomplete combustion and produce largeamounts of unburned hydrocarbon exhaust easily the formation of mist or vapor.