The reason and elimination method for black tail gas of diesel engine

Diesel engine as a power source, with its relatively high thermal efficiency, strong power, low fuel consumption, low harmful exhaust etc., are widely used in industrial and agricultural production, transportation and other fields. For the diesel engine with good technology, under normal conditions, the color of exhaust gas from the exhaust pipes should be “colorless transparent” or close to colorless transparent gas. Only diesel engine runs at high load operation at high speed or startup in a short time, is tail gas grey or dark grey. If under normally working conditions, the exhaust gas has a certain color, such phenomenon declares that diesel engine has a fault. This not only can increase fuel consumption and lead to insufficient power, but also can cause pollution of the atmosphere. Diesel engine, therefore, in the daily operation, according to the change of the exhaust smoke, we can judge the fault. So we can achieve timely maintenance in order to reduce economic loss.

The reason and elimination method for black tail gas

This phenomenon is mainly caused by too thick fuel, poor or incomplete combustion formed by combustible mixture etc. When black smoke erupted from exhaust pipe, often accompanied by decreasing power output of diesel engine, too high exhaust temperature, too high water temperature, resulting in engine component wear & reducing the service life of diesel engine. The reason and elimination method for such phenomenon is as follows.

(1) dirty air filter, inlet pipe blockage and exhaust pipe blockage, too dirty turbocharger compressor casing, insufficient air inflow caused by damage of the turbocharger, these affect mixture ratio of the air and diesel fuel, bring about too much fuel. The elimination method is to replace air filter element firstly; Secondly, unclog the smoke and dust within the inlet and exhaust pipe and silencer; Thirdly, check if the air inlet pipe is air leaking. If has such phenomenon, the diesel engine will accompany a howling cacophony of gas by the increased load; Fourthly, talking about the diesel engine with turbocharger, should check if both exhaust gas’ wheel of turbocharger and blade of turbocharger’s wheel are damaged or rotated smoothly and flexibly.

(2) The gap adjustment on valves is not correct; The valve seal is poor contacted. You should check gap adjustment on valves, valve spring and conditions of valve seal.

(3) The fuel delivery to engine cylinder from high pressure fuel pump is uneven or too big. Uneven fuel injection will lead to speed instability, intermittent black smoke. This should be adjusted and be balanced within the prescribed scope.

(4) The advance angle of fuel injection is too small, which leads to late injection and make some fuels combustion in the exhaust pipe. The later fuel injection is, the heavier black smoke is. You should adjust the advance angle of fuel injection in a right position.

(5) The fuel injector has a poor work, such as injection pressure is too low, fuel injector has dripping phenomenon, needle valve binding, no atomization of fuel, etc. or the fuel injector is damaged. You should dismantle injector, clean injector, inspect injector or replace injector.

(6) The quality of diesel fuel is poor or model of diesel fuel is wrong. The inferior fuel means poor performance of atomization and incomplete combustion, which leads to black smoke in the exhaust pipe. The imported high speed diesel engines with combustion chamber of direct injection, especially equipped with multiple orifice nozzles, due to small fuel injector aperture, high precision, so there will be much stricter requirements. Otherwise, it will make the engine coughs out black smoke and even the whole engine cannot run normally. Therefore, we should choose qualified light diesel fuel. When choosing the diesel fuel model, it is recommended that the summer adopts 0 or + 10, winter chooses a 10 or 20, No. 35 will be chose in the cold region.

(7) The airtightness of cylinder is poor. Incorrect valve timing causes that inlet valve and exhaust valve do not close fully. Heavily damaged cylinder and piston components, bad airtightness of piston rings, these not only decrease the cylinder temperature, cylinder pressure and swirl intensity after compression, but also the missing the air volume increase & lack of oxygen during burning result in incomplete combustion of diesel fuel and black exhaust gas. Simultaneously, accompanied with engine power goes down sharply, in more serious cases, when adding loads, the diesel engine will automatically shut down. The elimination method is to adjust or replace cylinders, pistons, piston rings, piston pins and the correspondingly quick-wear parts etc.