The black smoke emitted from the exhaust of a diesel engine is a phenomenon in which diesel fuel is not fully burned and is decomposed at a high temperature to discharge carbon with the exhaust gas. Exhaust smoke black smoke, not only reduces the engine power, increased diesel consumption, and easy to form carbon deposition, shorten the engine life. The reasons are as follows: 1. Insufficient fresh air in the cylinder. Causes: (1) Excessive dust accumulation in the air filter element; (2) Corrosion, carbon deposition or oil contamination of the muffler. (3) The clearance between the inlet and exhaust valves is too large, which causes the valve opening to decrease. (4) The parts of the actuator mechanism are loosened, worn, and deformed. The relative positions of the camshaft gear and the crankshaft timing gear are changed, and the valve opening and closing time is incorrect. Second, the end of the cylinder compression temperature and pressure drop reasons: (1) cylinder, piston ring wear too much, the piston ring is installed incorrectly or lose elasticity resulting in cylinder leakage; (2) valve clearance is too small, easy to be hot car The top open, or valve ablation, carbon deposition caused the cylinder seal is not strict; (3) cylinder head and body, fuel injector and cylinder head joint leakage; (4) severe valve depression, piston and piston pin, piston pin and The small head of the connecting rod and the large gap between the connecting rod and the connecting rod journal make the volume of the combustion chamber increase and the compression ratio decreases. Third, diesel fuel atomization causes: (1) fuel injector pressure adjustment is too low; (2) fuel injector pressure spring break or issuing; (3) injector needle and valve seat coke, needle valve stuck Or wear too much; (4) fuel injection valve relief valve ring wear too much, so that the injector drip. 4. The reasons for the inconsistency in the time of fuel supply and the amount of fuel supply are: (1) the time of fuel supply is too late; (2) the initial pressure of the gas and temperature is low and the time of fuel supply is too early; (3) the injection pump plunger Increase the fuel supply stroke after the wear of the coupling piece. (4) The fuel pump adjusts the stroke of the gear rod or rod excessively, resulting in excessive oil supply. China Agricultural Network Editor