The main reason for the black smoke of the diesel engine caused by the intake system is that the air filter or the intake pipe resistance is too large. In general, the resistance of the intake pipe is constant, and the air filter resistance may change at any time.
(1) Air filter problem If the air filter is dirty or a poor quality air filter is used, it may cause a recent increase in resistance, reduce the amount of fresh air entering the cylinder, and cause the diesel engine to emit smoke. If the original diesel engine does not emit smoke and the smoke level increases after replacing the air filter element, it means that there is a problem with the quality of the air filter element.
(2) Intake pipe problem If the intake system is blocked or the pipe is too long, it may increase the intake resistance. Intake resistance is too large, will cause the diesel engine to emit black smoke. If the intake air temperature is too high, it will also cause the diesel engine to emit black smoke.
In addition to the black smoke caused by the diesel engine, the intake system failure has the following phenomena:
. Insufficient power of the diesel engine. The increase in fuel consumption of the diesel engine. The basic method to confirm whether the diesel engine emits black smoke due to the failure of the intake system is:
.Air filter resistance: start the diesel engine at low speed, remove the air filter (including paper core and felt core), and then observe the change of exhaust smoke. If the smoke of the diesel engine is reduced after the air filter is removed, it means that the air filter has a problem. If you confirm that there is no problem with the quality of the air filter, you can further check the resistance of the intake pipe.
. Intake pipe resistance: Disassemble the intake pipe interface outside the intake pipe of the diesel engine to allow air to directly enter the intake pipe of the diesel engine, and then start the low-speed operation of the diesel engine and observe the exhaust smoke. If the smoke level decreases, it means that the intake system resistance is too high.
. Intake air temperature: If the exhaust pipe is too close to the intake pipe, or the air leakage at the exhaust pipe interface may directly affect the intake air temperature. If the diesel engine is idling and idling without smoke, black smoke will be emitted after loading, and the greater the load, the more serious the black smoke. After excluding other factors, the influence of intake air temperature should be considered. Under normal circumstances, the intake air temperature must not exceed 45 ° C.
Elimination method: replace with new, high-quality air filter, dredge the intake pipe and eliminate the heating phenomenon of the intake pipe.
Special reminder: diesel engines can not run for a long time without air filter, especially when the outdoor environment is harsh.
