Q: The reasons for the engine work rough, how to deal with?
A: Rough work refers to the engine in the combustion process, the piston is located in the upper stop near the rapid combustion of diesel combustion during the period more, the pressure rise rate is higher resulting in a crisp metal knocking sound when the engine work, and produce vibration shaking, rapid acceleration rhythmless knocking sound intensified, while black smoke, high speed when the knocking sound weakened or disappeared. This phenomenon will greatly affect the service life of the engine.
(1) Cause
① Poor quality of diesel fuel, cetane number is too low.
② The injection advance angle is too large.
③ Injector is not sealed, fuel dripping, poor atomization of fuel injection.
④ Uneven fuel supply to each cylinder and excessive fuel supply to individual cylinders.
⑤ Insufficient air intake.
(2) Diagnosis and treatment method
① If the knocking sound is uneven, sometimes accompanied by shaking phenomenon, it means that the individual cylinder is not working well. In the warm-up, available single-cylinder oil reduction method, cold start can be used to sense the temperature method to find out the work of bad cylinder. For example, at the beginning of the start of a cylinder exhaust manifold hot fast, that the cylinder oil supply; conversely, the cylinder may be a small amount of oil supply or injector work poorly.
② remove the faulty injector, check to confirm the injector failure, the standard injector can also be used to replace the original injector test drive, if the sound disappears, the fault is in the injector.
③ If the standard injector after changing the knocking sound of the cylinder has not disappeared, it may be due to excessive oil supply, the available oil reduction method to determine the check. That is, a little lemon loose the cylinder injector into the fuel pipe connector, so that a small amount of diesel fuel sprayed outside the cylinder, reducing the fuel into the cylinder. If the knocking sound is eliminated after using this method, it can be confirmed that the fuel supply is too large, and the fuel supply uniformity of the injection pump should be checked.
④ If the knocking sound is more uniform, it means that the working condition of each cylinder is close, and the cause of the fault is related to the quality of diesel fuel, air inlet condition, injection timing and so on. You can check the air intake condition first.
Check and clean the filter. If the knocking sound is weakened or disappeared, it indicates that the engine exhaust black smoke and knocking sound caused by insufficient air intake. If the sound and exhaust smoke color does not change significantly, indicating that the air filter is good, should check the intake hose has no dent or delamination blockage.
⑤ If the air intake is normal, may be the diesel fuel grade is not suitable or injection is not correct, first should be appropriate to reduce the fuel supply advance angle, observe the engine smoke and sound changes. If the supply advance angle is reduced, the exhaust smoke color is normal, the knocking sound disappears, it means that is caused by improper fuel injection. If the fault is still not eliminated, it is possible that the diesel fuel grade is not correct.