Abnormal sounding of agricultural machinery engines is mainly caused by the loosening, improper adjustment or improper use of internal mechanical parts. This indicates that the engine has major or minor faults and should be diagnosed promptly and effective maintenance measures should be taken.
First, the initial diagnosis, determine the impact of abnormal sound on the engine In many complex engine sounds, first of all should determine what is the normal sound, which is abnormal noise. Which of the abnormal noises has little effect on the working conditions of the engine is allowed to exist temporarily; which ones are not allowed to continue to exist, must be eliminated immediately, otherwise it will easily cause greater harm.
1. If the sound is slight and simple when the engine is running at low speed, the roar sounds smooth and even when it is running at high speed, and it looks like a smooth transition when it accelerates or decelerates. It is a normal sound.
2. If the sound is only present at idle speed, it will disappear after the speed increases, and there will be no obvious change in the sound during the entire use. This is an unusually noisy sound that allows for temporary existence and should be repaired at the appropriate time.
3. If the sound is suddenly accelerated or suddenly decelerates, and when the engine does not disappear during the medium and high-speed operation, and the organic parts vibrate at the same time, then this is an abnormal sound that is not allowed to continue to exist and should be checked immediately. Explain why and exclude it.
4. If the sound suddenly appears during the operation, and if it is more violent, it should not be continued or diagnosed by trial-and-error. It should be stopped immediately. Generally, the bottom shell is removed first, and then the cylinder head and the valve chamber cover are removed.
Second, conscientiously analyze, and then determine the location, cause and extent of abnormal noise on the emergence of abnormal sound and the continuous existence of time, abnormal sound generally exist in: idle or low-speed operation period, high-speed operation period or the entire driving period.
1. For abnormal noise during idle or low speed operation (1) First, check whether the abnormal noise is related to the working cycle, and further determine the location of the fault. If there is an association, it indicates that the failure occurred in the crank linkage mechanism or the valve distribution mechanism. According to the frequency of abnormal sounds, a preliminary determination can be made. All the sounds caused by the crank connecting rod mechanism are emitted by one working cycle twice, and the sound caused by the gas distribution mechanism is emitted once by one working cycle. Therefore, the crankshaft bearing Frequencies of abnormal sounds at places etc. are low, and frequencies of abnormal sounds at valves, etc. are high.
(2) Gradually increase the engine speed, hear whether there is any abnormal sound, and judge the degree of loss of the moving parts according to the change of the abnormal sound with the speed.
(3) Attention should also be paid to observing the effect of engine temperature changes on abnormal sound.
(4) For a multi-cylinder engine, first check whether the abnormal noise is related to the cylinder position by using a single-cylinder cut-off method. If there is a significant change in the abnormal sound after a cylinder breaks the oil and the fire breaks, it means that the fault is in this cylinder; if there is no obvious change in the abnormal sound after a cylinder breaks the oil and breaks the fire, it means that the abnormal sound is not related to the cylinder position.
Through the diagnosis of the above-mentioned several processes, the relationship between abnormal noise and engine load, work cycle, rotation speed and temperature can be basically ascertained. If the abnormal sound matches certain abnormal sound characteristics, a final diagnosis can be made.
2. For abnormal sounds during high-speed operation (1) Increase the engine speed gradually from low speed to high speed operation. In this process, pay attention to the timing of abnormal sound.
(2) When abnormal noise occurs, it is stable at this rotational speed and the abnormal noise is carefully observed. Sometimes abnormal sound may occur only in the case of sudden acceleration or sudden deceleration. The speed of the engine should be rapidly changed to find out when abnormal noise occurs.
(3) In the process of diagnosis, attention should also be paid to the accompanied phenomenon of changes in oil pressure, oil filling port, exhaust pipe, etc. to assist in diagnosing the malfunction and to reach a final diagnosis.
3, for abnormal sound during driving the engine abnormal noise in the traffic, generally can be in the engine after stopping to reflect the same speed, resulting in abnormal sound failure diagnosis conclusion. But sometimes there are exceptions, unusual noise in the car, after the stop, the engine running at the same speed, but no longer appear this abnormal sound, then you should change the speed of rapid changes, generally can make abnormal sound. Then find the reason and draw a final diagnosis.
Sometimes the abnormal sound in driving may not be abnormal noise of the engine, but may be the abnormal sound of other parts. You should press the clutch pedal or disengage the transmission gear, and then do the rapid acceleration test. If it disappears, it means that the abnormal sound is not in the engine but in the chassis or body part.
The diagnosis of abnormal engine noise is a highly empirical maintenance operation. Since the abnormal sound of the engine is various and intricate, the abnormal noises reflected by different faults may be similar, or the same fault may be due to different degrees. It reflects different sound characteristics. Normal sounds and abnormal sounds are mixed and difficult to distinguish. Diagnostic personnel can only master the regularity of their studies by conducting thorough studies and analyzing and distinguishing them, and then actively diagnose abnormal sounds.
First, the initial diagnosis, determine the impact of abnormal sound on the engine In many complex engine sounds, first of all should determine what is the normal sound, which is abnormal noise. Which of the abnormal noises has little effect on the working conditions of the engine is allowed to exist temporarily; which ones are not allowed to continue to exist, must be eliminated immediately, otherwise it will easily cause greater harm.
1. If the sound is slight and simple when the engine is running at low speed, the roar sounds smooth and even when it is running at high speed, and it looks like a smooth transition when it accelerates or decelerates. It is a normal sound.
2. If the sound is only present at idle speed, it will disappear after the speed increases, and there will be no obvious change in the sound during the entire use. This is an unusually noisy sound that allows for temporary existence and should be repaired at the appropriate time.
3. If the sound is suddenly accelerated or suddenly decelerates, and when the engine does not disappear during the medium and high-speed operation, and the organic parts vibrate at the same time, then this is an abnormal sound that is not allowed to continue to exist and should be checked immediately. Explain why and exclude it.
4. If the sound suddenly appears during the operation, and if it is more violent, it should not be continued or diagnosed by trial-and-error. It should be stopped immediately. Generally, the bottom shell is removed first, and then the cylinder head and the valve chamber cover are removed.
Second, conscientiously analyze, and then determine the location, cause and extent of abnormal noise on the emergence of abnormal sound and the continuous existence of time, abnormal sound generally exist in: idle or low-speed operation period, high-speed operation period or the entire driving period.
1. For abnormal noise during idle or low speed operation (1) First, check whether the abnormal noise is related to the working cycle, and further determine the location of the fault. If there is an association, it indicates that the failure occurred in the crank linkage mechanism or the valve distribution mechanism. According to the frequency of abnormal sounds, a preliminary determination can be made. All the sounds caused by the crank connecting rod mechanism are emitted by one working cycle twice, and the sound caused by the gas distribution mechanism is emitted once by one working cycle. Therefore, the crankshaft bearing Frequencies of abnormal sounds at places etc. are low, and frequencies of abnormal sounds at valves, etc. are high.
(2) Gradually increase the engine speed, hear whether there is any abnormal sound, and judge the degree of loss of the moving parts according to the change of the abnormal sound with the speed.
(3) Attention should also be paid to observing the effect of engine temperature changes on abnormal sound.
(4) For a multi-cylinder engine, first check whether the abnormal noise is related to the cylinder position by using a single-cylinder cut-off method. If there is a significant change in the abnormal sound after a cylinder breaks the oil and the fire breaks, it means that the fault is in this cylinder; if there is no obvious change in the abnormal sound after a cylinder breaks the oil and breaks the fire, it means that the abnormal sound is not related to the cylinder position.
Through the diagnosis of the above-mentioned several processes, the relationship between abnormal noise and engine load, work cycle, rotation speed and temperature can be basically ascertained. If the abnormal sound matches certain abnormal sound characteristics, a final diagnosis can be made.
2. For abnormal sounds during high-speed operation (1) Increase the engine speed gradually from low speed to high speed operation. In this process, pay attention to the timing of abnormal sound.
(2) When abnormal noise occurs, it is stable at this rotational speed and the abnormal noise is carefully observed. Sometimes abnormal sound may occur only in the case of sudden acceleration or sudden deceleration. The speed of the engine should be rapidly changed to find out when abnormal noise occurs.
(3) In the process of diagnosis, attention should also be paid to the accompanied phenomenon of changes in oil pressure, oil filling port, exhaust pipe, etc. to assist in diagnosing the malfunction and to reach a final diagnosis.
3, for abnormal sound during driving the engine abnormal noise in the traffic, generally can be in the engine after stopping to reflect the same speed, resulting in abnormal sound failure diagnosis conclusion. But sometimes there are exceptions, unusual noise in the car, after the stop, the engine running at the same speed, but no longer appear this abnormal sound, then you should change the speed of rapid changes, generally can make abnormal sound. Then find the reason and draw a final diagnosis.
Sometimes the abnormal sound in driving may not be abnormal noise of the engine, but may be the abnormal sound of other parts. You should press the clutch pedal or disengage the transmission gear, and then do the rapid acceleration test. If it disappears, it means that the abnormal sound is not in the engine but in the chassis or body part.
The diagnosis of abnormal engine noise is a highly empirical maintenance operation. Since the abnormal sound of the engine is various and intricate, the abnormal noises reflected by different faults may be similar, or the same fault may be due to different degrees. It reflects different sound characteristics. Normal sounds and abnormal sounds are mixed and difficult to distinguish. Diagnostic personnel can only master the regularity of their studies by conducting thorough studies and analyzing and distinguishing them, and then actively diagnose abnormal sounds.