Why does the bus and truck emit black smoke?

1: The oil supply of each cylinder of the high pressure oil pump is not uniform or too large. Uneven oil supply will result in unstable speed and intermittent black smoke, which should be adjusted to make it balanced or within the specified range.

2: The problem of diesel itself. The diesel brand used is wrong, the viscosity is too large, or the quality of the diesel is too bad, it is not easy to catch fire, so that the exhaust gas emits black smoke, and the combustion chamber and the exhaust pipe are also easy to produce carbon deposits. The solution is to choose the appropriate formality. Diesel.

3: injector malfunction or damage, resulting in insufficient diesel atomization.

The main reasons are:

(1) The injector pressure adjustment is too low;

(2) The injector pressure regulating spring is broken or issued;

(3) The injector needle and the valve seat are carbon deposited, and the needle valve is stuck or worn excessively;

(4) The decompression ring of the fuel injection valve of the fuel injection pump is worn out too much, so that the injector is dripped. Solution: Disassemble or clean the injector or replace it directly.

4: The gap between the intake and exhaust valves is too large, so that the valve opening is reduced, or the parts of the accessory mechanism are loose, worn and deformed. The relative position of the camshaft gear and the crankshaft timing gear changes, and the valve opening and closing time is incorrect, resulting in the cylinder. There is not enough fresh air inside. Solution: Check valve clearance, valve spring and valve seal

5: Exhaust back pressure is too high or the exhaust pipe is blocked. This situation will result in insufficient intake air, which will affect the air and fuel mixture ratio, resulting in excessive oil. Solution: First, the exhaust pipe bends too much, should be minimized; second, the inside of the muffler is blocked by too much soot, it should be removed.

6: The plunger of the fuel injection pump is seriously worn, which makes the oil supply pressure rise slowly, which affects the normal oil supply time and prolongs the fuel injection process, which affects the quality of the injection atomization. Common faults in black smoke. Solution: The oil pump should be repaired in time.

7: Insufficient intake air or blocked intake pipe. In order to find out the cause, the following checks should be made: first, whether the air filter is blocked; second, whether the air intake pipe is leaking (if there is such a phenomenon, the engine will be accompanied by a harsher whistling sound due to the increase in load); Is the turbocharger damaged? Solution: Check whether the waste wheel and the booster wheel are damaged and whether the rotation is smooth and flexible. Fourth, whether the intercooler is blocked.

8: The cylinder liner and piston assembly are worn more seriously. When this happens, the piston ring is not tightly sealed, and the air pressure in the cylinder is seriously degraded, so that the diesel cannot be fully burned and black smoke is generated, and the engine power is drastically lowered. In severe cases, the engine will automatically turn off when the load is carried. Solution: Replace worn parts.

The phenomenon of black smoke will cause great damage to the engine, so after you discover it, you must repair it in time! The above is all the content, I hope everyone likes it! !

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