Compared with the gasoline engine, diesel engine abnormal sound diagnosis is more difficult to grasp, this is decided by the structure characteristics and working characteristics of the diesel engine, such as compression ratio, thermal load, work is relatively rough, big noise, broken oil cannot instantly, and even some diesel oil at the opening of the position of the people not easy to close, to the diagnosis of abnormal noise also brings inconvenience. However, the abnormal sound of the diesel engine has its specific rules, as long as the analysis and comparison, look at the phenomenon of grasping the essence, it is possible to find out its regularity.
Cylinder ring
The engine cylinder is in the cylinder wall along the direction of movement of the piston groove appeared phenomenon, it can cause leakage and knock, power, economy becomes worse, serious when the piston stuck in the cylinder, the engine does not work. The piston is pulled by the piston will make the oil into the combustion chamber, too much carbon, fuel leakage to the oil pan to dilute the oil, and sometimes can be added from the oil inlet to observe the smell of oil fumes and breathing phenomenon.
The reason
The use of non-standard. The car running according to the provisions of the operation, and even make the engine high temperature, work overload, destruction of the lubricating oil film on the cylinder, piston ring and cylinder wall caused by melting strain, serious, so that the piston and the cylinder expansion is too large, a bite wound.
Maintenance is not standard. The coke on the piston ring is not removed in a timely manner, so that this loss of elasticity in the ring groove.
The coke scraping is not cleaned, the particles into the hard carbon cylinder gap, the formation of abrasive injury.
After maintenance, the clearance between the piston and the cylinder wall is too small, and the piston ring end gap is too small.
When the piston ring is broken, the piston pin circlip is off, so that the piston pin is pulled out of the cylinder.
The oil cooling nozzle failure, caused by poor lubrication and cooling.
The cold start or low temperature Meng throttle, poor fuel atomization, excessive fuel into the cylinder wall of the cylinder washing oil film.
Baotou beiben heavy truck parts connecting rod deformation to skew the pistons in the cylinder.
The diagnosis and treatment methods
The engine is running, if there is like knocking sound, and the sound of the engine with increasing temperature decreases, can determine the initial cylinder.
The demolition of Baotou beiben heavy truck parts of cylinder head, cylinder strain check, generally can be divided into early, middle and late three stages:
The initial cylinder engine noise is not very clear, but the oil into the combustion chamber, the coke increased. In addition, when the gas leakage into the crankcase compression, so that the deterioration of the oil, and in increasing the throttle or intermittent acceleration, from the oil inlet and crankcase ventilation pipe at the outlet of the oil fume.
For the early on, should take the piston check, cleaning, and change the oil and filter, cleaning the oil pan. After loading test, go, and after a period of time, the cylinder seal will be improved, but the power may be slightly worse.
The middle cylinder engine leakage serious, similar abnormal sound of knocking is clear, open and oil cover a lot of smoke, the rhythm of the smoke exhaust pipe, exhaust smoke concentration, while idling bad. When the oil is used, the noise is reduced. If the middle cylinder in multi cylinder, with oil method inspection, abnormal sound can weaken, but not disappear.
For the middle cylinder, if the cylinder wall stains is not deep, with oilstone polishing, put on the same model, the quality of the piston and the piston ring with the same specification, you can continue to use, will greatly reduce the abnormal sound.
Later, the cylinder was knocking and blow the sound power also decreased significantly. With the throttle to increase the noise will also increase, the sound of chaos, the engine jitter. Serious damage to the piston or cylinder.
For this situation must be replaced Baotou North heavy truck parts cylinder liner, piston and piston ring.