(1) lack of compressive force: after the wear of the valve, piston ring and cylinder liner, the compression pressure is not enough, the pressure and temperature of the end of compression can not meet the requirement, the combustion condition of the fuel oil is poor, and carbon smoke is easy to be generated;

(2) the shape of the combustion chamber and combustion chamber shape: volume change due to manufacturing quality and long-term use of the technical condition of drop, compression clearance will also alter the shape of the combustion chamber and the volume change, thus affecting the fuel mixed with air quality, the combustion conditions deteriorate. The position of the piston is reversed, so that the cooperation of the injector, the combustion chamber and the intake port is affected, and a good mixture can not be formed, and incomplete combustion occurs;

(3) injector work is bad: injector work is poor, mainly in three aspects: first, poor quality of spraying; two is insufficient fuel injection pressure; three is the injector leakage. These three conditions make the fuel not sufficiently mixed with the air in the cylinder, so that it does not completely burn. In addition, if the selected fuel injector does not match the original engine, it will also cause engine exhaust smoke;

(4) excessive oil supply: excessive oil supply, resulting in mixed gas partial combustion and incomplete;

(5) improper advance angle of fuel supply:

The advance angle of fuel supply is too large. In the direct injection diesel engine, when other parameters remain unchanged, it is possible to increase the injection advance angle to reduce the exhaust smoke. Because of increased fuel injection advance angle makes the ignition delay period is lengthened, the spray into the cylinder before ignition oil quantity increase, premixing volume increase, premixed gas increase, accelerate the combustion rate, combustion may end earlier, so that the rapid burning of carbon particles formed during the period of stay more time at high temperature, is conducive to the carbon particle oxidation disappear.

However, premature injection, due to lower cylinder pressure and temperature, is not conducive to evaporation and mixing of fuel, resulting in black smoke emissions. At the same time, due to greatly increasing the amount of premixed fuel, the diesel engine work rough, combustion noise increases, and cause larger mechanical load;

The fuel supply advance angle is too small: the fuel injected into the cylinder during the late part of the fuel will not form a combustible mixture can be separated or discharged, resulting in the fuel mixture in the exhaust pipe with the exhaust from the high temperature decomposition, combustion, the formation of black smoke with gas discharges.

(6) the exhaust resistance is too large, the exhaust resistance of engine intake exhaust ambassador, not net, thus affect the charging efficiency of the exhaust back pressure is too high or the exhaust duct obstruction; the Baotou North Benz accessories air filter or air intake duct obstruction.

(7): incorrect valve clearance adjustment of valve clearance valve assembly makes the maximum opening reduction and shorten the opening time, resulting in insufficient air intake valve clearance is too small; the valve is easy to leak, thereby affecting the cylinder compression force. In the two case, the proportion of air in the mixture is reduced, causing incomplete combustion;

(8) engine with gas phase change: Baotou North Benz engine accessories with gas phase due to parts quality and assembly quality changes lead to changes in valve opening and closing time, thus affecting the engine combustion process. Gas phase change serious will cause a serious accident against the valve and piston;

(9) the fuel injection pump is not working well:

The plunger injection pump or valve wear, injection pump plunger or individual or all out of the oil valve will cause serious wear of injection pump pressure drops, the injector (mouth) pressure is relatively backward, the injection delay after combustion is increased, so the black smoke for diesel engine;

The Baotou North Benz parts of fuel injection pump the pump cylinder fuel variation and fuel supply advance angle is consistent: the amount of oil is not uniform, some large cylinder oil cylinder oil, some small amount of oil supply of large cylinder incomplete combustion, exhaust smoke; a small amount of oil cylinder to. When the fuel delivery advance angle is inconsistent, some cylinder oil supply early, and some cylinder oil supply late. Because usually in the daily adjustment of oil supply advance angle is often based on a cylinder, so the consistency of the advance angle of oil supply is generally not taken seriously;

(10) the quality of diesel fuel is poor, its performance index can not meet the requirements, poor combustion.