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According to the engine color of smoke, how to determine the digging machine malfunction?

In construction machinery, when the engine failure may be “smoke”, and of course here that the “smoke” is not normal smoke. Usually people exception of the engine exhaust smoke color is divided into three types: blue smoke, black smoke and white smoke. Generally, the blue smoke caused by the burning oil; smoke is caused due to incomplete combustion; while white smoke is caused because the water. However, in practice, to describe a smoke color easier said than done, in addition to the continuity of the smoke color change, but also must take into account the observation of the external environment of smoke color, for the same cigarette smoke color is manifested:
1), day and night are not the same.
2) in the morning and afternoon is not the same.
3), there is no sunlight is not the same.
4), indoor and outdoor different.
5), sunny cloudy day is not the same.
6), high and low temperatures are not the same.
7), because of different water content in the air are not the same.
In addition, you have to consider to make you smoke colored people are not color weakness color blindness.
Taking these reasons, there is no way you almost smoked the engine for a precise description. Therefore, when you ask others to describe the smoke color, rather than ask the color of smoke just ask: thick, pale, cold smoke, hot car smoke, there is no load or load tobacco smoke, there is the environment in which the device.
So how do you determine the cause “smoke” because it?

Since the liquid smoke is made up of three burning occurs, then let’s have a look at what kind of site will cause them burning:
A water:
Since the white smoke because “boil” cause, that white smoke that is water vapor, water vapor in the exhaust gas usually from three sources:
1. Caused by the combustion of fuel vapor. Fuel used in construction machinery are usually hydrocarbons, hydrocarbon combustion produces carbon dioxide and water vapor in the exhaust gas which is the first source, which is always no way to avoid the normal steam discharge often because the engine exhaust velocity and high temperatures which can not be found, and low winter temperatures can be found. Such as winter we will find car exhaust would be a hint of white smoke, and the summer is not.
2. Fuel oil in the water caused by the “white smoke.” Construction machinery in the use of diesel engines, diesel engine fuel supply system has a water separator and fuel filter, use the device if the normal maintenance (time and sediment discharge tank, oil-water separator discharge time The precipitate was timely replacement of diesel filter), the water in the tank in order to pass along with the diesel fuel injection into the cylinder head combustion is almost impossible, not only is the true cause of the water because of maintenance problems with the diesel fuel into the cylinder , that failure is often associated with diesel fuel and oil pump plunger head is damaged, the engine power is not enough, even a sudden stop.
3. Cooling water directly into the cylinder combustion. Causing cooling water directly into the cylinder and the cylinder mattress often causes damage related to certain locations due cylinder mattress damage, causing the cooling water and the communication between the combustion chamber. In the engine intake stroke, the negative pressure of the gas in the cylinder and the pressurized cooling water, will be part of the cooling water into the combustion chamber, the work of this part of the cooling water is vaporized, the white smoke is discharged, when the cooling water abnormal consumption, while accompanied by abnormal smoke, there may be damage to the cylinder head gasket, then the performance of the cooling water will be “non-heat boil” or, worse, may also cause the engine will not start (does not rotate), even crank rod bent or damaged (see engine failure case a).

Engine failure Example:
Hitachi EX200-5
Symptom: cold smoke, cold boil, cylinder head gasket replaced twice, the fault remains.
Open the cylinder head and found: four-cylinder camshaft medial side of the cylinder subsidence losses from the nearest watercourse waterway leading to the cylinder bed with LOI small groove. Three, four, five-cylinder with strain.
Disintegration found: one, six-cylinder piston free access, two, three, four, five-cylinder can not. Remove and found three, five-cylinder piston front and rear (on the engine) is the direction of the piston pin retainer at a strain, two-cylinder piston skirt has strained, four-cylinder piston in the cylinder can not be killed out (the last with a hammer play), and the rod is bent, and has hit the cylinder, the cylinder played on a few millimeters deep notch (but change will not affect the working cylinder).
Crankshaft, cylinder inspection: cylinder without deformation, the crankshaft is not bent. Replace three cylinder, four pistons, a rod. Assembled test machine properly.
Rod bent Analysis:
Generally speaking, the reason should be bent rod cylinder fell into debris. When the air filter and turbocharger is no problem when the majority is left valve repair broken or foreign matter, then top of the piston are hitting marks, and this piston crown intact. Should be of a particular analysis of the reasons Ding Ding car engine start position in the cylinder or the intake end of the exhaust position (the valve is not closed), the combustion chamber to the atmosphere at this time, no internal pressure, and the tank is pressurized (pressure is 0.9?), cylinder bed damage caused by the cylinder and the combustion chamber of the tank communicates, the cooling water into the combustion chamber. Starting cylinder chamber due to the cooling water can not be compressed leaving the rod bent. This is most unfortunate that the middle Ding Ding car engine crankshaft position, if four-cylinder is Ding BDC position will not cause the curved rod, because there can not be started.

Second, the oil:
Make the oil into the cylinder only the following several parts: 1, turbocharger. 2, valve guides. 3, the piston rings.
1. Turbocharger exhaust gas is used as the engine power, to drive the pump through the turbine wheel for supercharging the engine intake. Under normal circumstances, the speed of tens of thousands turn to, sometimes up to hundreds of thousands rpm, spindle lubrication is attracted by the main oil from the pressure of oil pressure in general 1-6kg/cm ², far greater than the supercharger the ends of the pressure of the gas, when the turbocharger shaft and sleeve wear serious or poor turbocharger oil return occurs when the turbocharger oil leakage. Leak to the intake side of the engine oil into the combustion chamber to generate so-called “blue smoke”; into the exhaust pipe is formed on one side of the oil mist, oil or high temperature carbonization with exhaust gas discharge. When the turbocharger shaft and sleeve wear serious, often accompanied booster “sweep chamber” whistling while lack of engine power; when poor oil return, they tend to be a lot of exhaust pipe leak oil . (See engine failure cases two).

Engine failure cases two
Komatsu PC200-5
Symptom: cold smoke, power diminished, no lower exhaust turbocharger outlet muffler interface leaking.
Had made a deal: the new diesel pump and replace adjustable plunger, delivery valve, injector head, new replacement turbocharger.
Failure Analysis: Power unabated, no instructions under the exhaust pistons, piston rings, cylinder trouble; momentum unabated, no abnormal sounds description turbocharger is working properly, no cold boil description cylinder head gasket cylinder bed properly.
Check processing: The above analysis should be the turbocharger oil return is not smooth. Open the oil filler after all the fault disappears; engine oil filler cap, disconnect the exhaust tube from the upper fault disappears. So far has been to determine the cause of the fault: the exhaust pipe is not blocked (exhaust pipe guard and lower body are caused by clogged exhaust pipe extrusion is not smooth).
Final Conclusion: Since the exhaust pipe blocked, so that the crankcase pressure increased, resulting in high pressure turbocharger oil return, respectively, from a part of the oil leaking turbocharger ends, or into the combustion cylinder, or with an exhaust fan.
2. Cylinder, piston, piston rings: the piston reciprocates in the cylinder, piston rings and piston, with the cylinder into a closed combustion chamber of the engine can be made before the work, at a high temperature, high-speed movement of the piston and The friction between the piston ring by splashing or spraying of the oil lubricated the piston, between the piston and the cylinder when the clearance is greater than a certain range, there will be some oil into the combustion chamber to generate so-called “blue smoke”, and At the same time there will be a part of the exhaust gas from the crankcase into the gap and then discharged from the exhaust hole, that when the dependent piston, piston ring gap larger and burning oil, always associated with a larger lower exhaust.
3. Valves, valve guides, valve seal. Between the valve and valve guide oil spill caused by burning oil burning oil can be considered a third reason. With turbocharger similar to the catheter through the intake valve leaking oil into the combustion chamber to generate blue smoke; exhaust duct leakage through the formation of oil mist, oil or high temperature carbonization with exhaust gas discharge. By the experience, valves, valve guides, valve seal life is longer, thereby causing the burning oil can be said to be negligible, someone had done the test, even if the valve seal is not installed, the resulting combustion engine oil is also extremely not easy to find, it will not be discussed here.

III. Diesel:
As diesel engines can not be caused by incomplete combustion exhaust smoke is an exception in one of the most important reason, is usually caused by incomplete combustion of reasons: inadequate intake, excessive oil, the compression ratio is not enough, the ignition timing is wrong, spray nozzle atomization bad.
1, inadequate intake: engine, the piston is drawn into the cylinder on the air is compressed to produce high temperature and pressure, fuel injector to spray mist into the diesel fuel to burn for power. When the intake is not enough to meet the diesel fuel is injected into the complete combustion to carbon dioxide and water, it will become a part of the carbon with an exhaust fan, this is what we often say “smoke”, then often accompanied by underpowered. Caused by inadequate intake of the main reasons are: air filter clogging; supercharger failure; in individual cases is also possible that the valve failure.
2, excessive oil: with the “inadequate intake,” the same as when the oil is too large, the normal amount of air into the cylinder can not meet the excess diesel fuel is injected into the complete combustion of diesel fuel can also cause carbonization, with the exhaust smoke is discharged. Caused by excessive oil is often the reason people get involved: for example, adjust the oil pump.
3, the cylinder pressure is not enough; talking about here is the cylinder pressure during the compression stroke cylinder engine produces a maximum air pressure, when the piston ring leak, valve closed lax, inadequate intake cylinder pressure will be enough. At this time can not generate a sufficient pressure and temperature, so that the combustion chamber of the diesel combustion is not well acting acting not burn and become even coke discharge. For a long time the engine, such a situation is more and more, especially when the exhaust is more serious, often above phenomenon, this time is usually the engine needs an overhaul.
4. Ignition timing (injection timing) right: Each engine has a fixed injection timing, injection timing of this work is to ensure that the engine is a very important condition, in advance when the angle of oil supply corresponding cylinder pressure, temperature and other conditions are very conducive to diesel combustion, or because of poor combustion and exhaust. Such failures often occur after the dismantling diesel pumps; sometimes because diesel pump shaft and the relative position between the timing gear accidents arising from changes.
5. Poor atomization: When the piston to run to a compression top dead center position (supply advance angle) diesel fuel mist is sprayed into the combustion chamber to be successful, the atomization of a direct impact the quality of combustion. When the diesel fuel quality is not guaranteed injector head is very easy to cause damage or stuck not even leaving poor atomization spray. At this point is often associated with diesel pump plunger damage and lack of motivation.

Engine failure cases three
Thirty-one SY65
Telephone report to the failure phenomenon: a new car, black smoke, oil burning, outward from the muffler outlet spray oil, but oil is not reduced. When asked how the exhaust, the answer is not known. This failure can be said that at the mess, but there are two very clear: the smoke is very strong, outward from the muffler outlet injector.
Analysis and examination:
(1), used in this SY65 4BJ1 engine, no turbocharger,
(2) Check no next exhaust, you can exclude cylinder, piston, piston ring failure.
(3), the new car is usually the case the valve should not have much of a problem.
(4), outwardly from the discharge outlet of the muffler is not like oil.
(4), the cooling water without exception.
(5), diesel quality assurance.
To sum up: the point of failure should be in the fuel supply system, the constant sound of breaking 1,2,4 cylinder becomes smoke, smoking unchanged after breaking three-cylinder sound.
Conclusion: 3 cylinder oil without success.

In summary, for normal engine, the work should not smoke or extremely difficult to be found only hint of smoke. When the engine or the exhaust smoke suddenly becomes larger, it should first consider the part caused by smoke, causing exhaust system parts each have their own separate and the associated characteristics, when you have some of its understanding, causing smoke problems also like analysis and more. You can be ruled out one by one, eliminating the “No problem areas” after only “problem areas” of the.

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