Cause judgment and elimination of abnormal noise o

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Cause judgment and elimination of abnormal sound of connecting rod bush of diesel engine

wd615 series diesel fatigue testing machine works according to the principle of electromagnetic resonance. As long as the main bearing bush and connecting rod bush pay attention to the brand of oil, maintain regularly and operate correctly, there will be no problems. However, due to improper use and maintenance, it will also cause abnormal noise of connecting rod bearing bush

the phenomenon of connecting rod shaft is called the abnormal sound of yield bearing:

① when the engine accelerates suddenly, there is a continuous and obvious knocking sound, which is crisp, short and solid. The sound increases with the increase of engine speed and load

② the sound changes little when the engine temperature changes

③ when idling and running at medium speed, you can hear the rattling sound

④ oil cut-off test, the sound is significantly reduced

the reasons for the failure are as follows:

① poor lubrication. The fit clearance between journal and bearing bush does not meet the standard. The electrical performance of the oil grade will also be greatly reduced. Adding ordinary diesel engine oil will cause poor lubrication, accelerate the wear of the bearing bush, and burn the bush. Then there is the problem of oil pipeline. There are a lot of leaks, causing the engine to burn

② the inner hole of the connecting rod big end is worn, the bearing bush goes round, the oil hole is blocked, the journal is elliptical, and the contact between the bearing bush and the journal is poor

③ the quality or installation problems of the bearing bush deform the bearing bush, causing the alloy to fall off and burn the bush

the judgment of abnormal noise of connecting rod bearing bush is as follows:

① cylinder by cylinder oil cut-off test. From idle speed to medium speed, shake the throttle, and the sound increases with the increase of engine speed. Gently shake the accelerator, you can hear the rattle sound, and the sound is prominent at the moment of refueling, the sound of oil cut-off is reduced, and the sound becomes larger at the moment of resuming oil supply. Hearing this sound, it can be judged that the connecting rod bearing bush rings

② remove the oil filler cap, and you can hear a strong knock

③ when the vehicle is running, increase the throttle or shift from low gear to high gear and refuel violently, we should provide free technical service and maintenance for all kinds of faults caused by the equipment's own reasons or shortcomings within the warranty period; A clanking sound

the above three conditions are the sound of bearing burning failure, but the crankshaft is not locked and can continue to rotate. If you suddenly hear the sound of chirp during the vehicle operation, it is the sound of burning due to the lack of lubrication of the bearing bush. You should stop immediately for treatment, otherwise the crankshaft will lock up, the difficulty of repair will increase, and the cost will increase

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