Abstract from the perspective of environmental protection and use of diesel engine exhaust and the reasons for excluding unusual methods to improve equipment utilization, reduce maintenance costs have practical significance.

Key words: flue gas emission diesel engine combustion system

Diesel engines for its good economic performance and power, are widely used in mining machinery, engineering machinery and other industries. Diesel engines in the course of day-to-day use, in accordance with its color changes to smoke fault judgement, thus achieve timely maintenance, in order to reduce economic losses. On the following three kinds of engine exhaust common abnormalities and the causes for the failure exclusion methods are introduced.

A smoky, and the reasons for exclusion method

The phenomenon is due to incomplete combustion of fuel arising. Smoky, accompanied decreased engine power, exhaust temperature is too high, the water temperature too high, resulting in the mechanical engine wear and reduce engine life. The causes of the phenomenon (leading causes of incomplete combustion many), and exclude the following manner.

(1) or high exhaust back pressure exhaust pipes blocked. This will cause the feed rate, so impact on air and fuel mixture ratio, resulting in excessive fuel. This situation: First, the exhaust pipe bends (especially the 90 ° bend) too much, should be minimized; Second, the internal muffler was too much ash obstruction, should be removed.

(2) into the air intake inadequate or blocked pipes. In order to investigate the reasons for, the following examination should be carried out: First, whether the air filter blocked the second is whether the leakage into the trachea (if this phenomenon, due to engine load increases with the more strident gas howling); 3 Turbocharger is whether the damage. Should check the exhaust supercharger round and round the damaged blade rotation is smooth and flexible in the cold for four is whether or not blocked.

(3) valve gap adjustment is not correct, Valve Seal Line bad contact. Gap should check valve, valve springs and valve seal situation.

(4) high-pressure pump oil in the cylinder uneven or too large. Uneven supply will have speed instability and intermittent smoky, should be adjusted to balance or within the specified scope.

(5) injection too late, the injector should be adjusted advance angle.

(6) Fuel Injector working poor or damaged, should be removed cleaning inspection.

(7) Injection Type wrong choice. Imports of high-speed engine by the fuel injector matching the strict requirements (jet aperture, a few holes, spray angle), such as improper and will have smoky engines, even if the same type of engine, the use of different occasions (output power, such as the speed at the same time), the request to use the injector models is not the same. If matching errors, should be replaced with the correct type of fuel injection.

(8), or poor-quality diesel fuel grades is wrong. Porous injector equipped with the direct injection combustion chamber of imports high-speed diesel engines, fuel injector aperture small, high precision, quality and grades of diesel have more stringent requirements, it will cause the engine smoky, and even engine can not operate normally. Therefore, we should choose clean qualified light diesel oil, the proposed use of diesel Baihao, by the summer of 0, or +10 winter use, or -20, -10, -35 cold regions of the selection.

(9) cylinder, piston components wear more serious. This situation, Piston Ring Mibianbuyan, serious in-cylinder pressure drop, resulting in diesel combustion and smoky not fully, and the engine power dropped dramatically, seriously, with the load, the engine will automatically flameout. Should replace worn parts.

2 emissions Layan and the reasons for the exclusion method

Layin the result of emissions from the combustion chamber is excessive caused by burning oil. This fault for the following reasons:

(1) increase oil sump excessive. Too much oil, with high-speed operation of the crankshaft to Gangbi spatter, and Cuanru chamber. Exclude downtime is about 10 minutes, then check the oil benchmark, the row will be an excessive amount of oil swap.

(2) cylinder, piston components wear serious gap too large. If the gap too large, oil will be a substantial Cuanru combustion chamber, accompanied by the engine crankcase emissions increased approach is timely replacement of worn parts.

(3) piston rings lost role. Piston Ring flexibility such as inadequate, the death card in the Central coke bed, or in the mouth with the ring has been online, or circular hole to plug oil, the oil will lead to a large number Cuanru combustion chamber, there Layin emissions. Approach is removed piston rings, removing coke, the heavy cloth ring I (Upper and Lower Central mouth recommendations staggered 180 °) and, if necessary, replacement of piston rings.

(4) valve and catheter gap too large. As wear, resulting in a gap between a large, in the inlet, rocker oil by the amount of respirable indoor combustion chamber, the approach is the replacement of worn valve and catheter.

(5) to take Layin of other causes. If too thin oil, and high oil pressure, engine running-not good, it will cause oil combustion and run Layan.

3 grey smoke emissions and the reasons for the exclusion method

     Engine exhaust from the gray, some of the fuel for low-temperature, gas atomization bad, there was no time to burn fuel from the exhaust pipe in the discharge. The reasons for this phenomenon are:

(1) injection late and injector leakage when fuel injection, injection pressure is too low, fogging performing well, the low-temperature combustion, and there was not enough time to form white smoke to be discharged. Approach, the correction injection time to check the status of the injector.

(2) a low pressure within the cylinder. The cylinder, piston ring wear components, as well as bad valve seal caused the engine running when in the recently launched grey smoke, and then with the rise of temperature, smoke or into desalination smoke. Approach is the replacement of the cylinder liner wear, the piston ring or repaired valve, valve seat ring. 

(3) diesel fuel in the water. If the engine after launch out gray smoke, along with machine-rise, gray smoke still exist, and will very likely be a diesel mixed with too much water. Solution is to boot a day before the fuel tank drainage valve will be open, bottom sediments and water emissions swap.

To sum up, the engine exhaust anomaly is a comprehensive reflection of the internal fault. Therefore, the exhaust is not normal working conditions good or bad judgement engine one of the important symbols, if timely treatment can guarantee that the ideal use of diesel engines, to avoid unnecessary economic losses.