Diesel generator set maintenance training of the diesel engine -p131-p135 diesel engine often ...

Diesel generator set maintenance training diesel engine articles -p131-p135 diesel engine common troubleshooting methods

Chapter V Diesel Engine Diesel Engine Common Faults Maintenance Methods

1 Introduce the principle of diesel engine fault judgment and elimination;

2 Introduce the main methods of diesel engine fault judgment;

3 Introduce troubleshooting examples of various types of diesel engines.

Diesel generator set diesel engine sometimes has one or more failures during its use. The phenomenon is various and the cause of failure is also very complicated. A failure can be manifested as one or more abnormal phenomena. For example, after the oil radiator (water-cooled) is damaged, the organic oil in the water radiator, there is water in the bottom of the oil: an abnormal phenomenon may also be The cause of one or more faults, such as the lack of diesel engine power, may be that the diesel fuel injection advance angle is not adjusted correctly, or the diesel engine inlet and exhaust valve seals may not be strict, or the injector may not be injected. It may also be that the wear gap between the diesel cylinder liner and the piston is too large and the compression force in the cylinder is reduced. From the perspective of finding the cause of the fault to troubleshooting, the search for the cause of the fault or the search for which component is faulty takes 70% of the entire repair time, and troubleshooting takes less than 30% of the time. Therefore, when the fault is judged, the maintenance personnel must not only be familiar with the structure and working principle of the diesel engine, but also master the general principles and methods for finding faults. Only in this way, through careful observation and correct analysis when actual problems are encountered, it is possible to quickly, accurately, and promptly troubleshoot.

Section 1 Principles and Main Methods for Judging and Eliminating Diesel Engine Failures by Diesel Generator Sets

First, the principle of diesel engine fault diagnosis and elimination

1. Judging from the overall analysis of the fault committee, troubleshooting has a comprehensive diesel engine backup system, parts, and parts are closely related to each other. A system, a component, or a component has a fault, and it will inevitably involve other systems. Parts or parts. Therefore, one failure phenomenon cannot be viewed in isolation, and it is necessary to analyze the cause of the failure as a whole and eliminate it in a timely manner.

2. When finding a diesel engine fault, dismantle it as much as possible.

When troubleshooting diesel engines, the parts of the diesel engine must not be dismantled blindly. The structure, working principle, and fault location of the diesel engine can only be disassembled in a scientific manner.

Must be disassembled on the basis of careful analysis prior to disassembly

For example, if a diesel engine is found to have a faulty phenomenon of burning oil during operation, if it is not determined what the cause is, or if any component is damaged, the engine parts are blindly removed, which will not only prolong the time for troubleshooting, but also have the potential to The relative position of other parts has changed. Therefore, when troubleshooting a diesel engine, it is important to make sure that parts or systems fail to be repaired after a fault occurs to prevent them from being blindly chaosed. Otherwise, sometimes not only does the problem not be resolved, but it causes other faults to appear. The correct approach is to disassemble the diesel engine parts as little as possible when troubleshooting.

3. Find faults carefully, combine them, listen. Modular, sniff, all-round inspection; observe the external characteristics of the diesel engine during operation, such as whether there is abnormality in the exhaust of the exhaust pipe, whether the color of the oil is normal, whether the fuel system has a leakage phenomenon, the cooling system and the lubrication system. Whether there is water leakage, oil leakage or other phenomena, whether the diesel engine's various meter indications are abnormal, whether the moving parts and fixed parts of the nuts are loose, whether the diesel starter circuit has open circuit, short circuit or incorrect connection.

Listening: It mainly listens to the abnormal sound of the diesel engine during operation, such as whether the explosion sound of the diesel fuel in the combustion chamber is even, whether the piston, the connecting rod, the impact sound of the crankshaft is abnormal during the operation of the diesel engine, and the intake and exhaust valves Whether there is abnormal noise in the movement, whether the diesel driving gear and the driven gear have abnormal noise during operation, and whether the valve spring in the valve chamber has abnormal noise or the like.

Touch: Check whether the temperature of the backup exhaust pipe of the diesel engine is the same, whether the temperature is the same, whether the temperature of the water pipe on the water pump and the water pipe are the same, whether the instructions of the oil temperature meter are the same, and whether the vibration of the machine body is abnormal.

Temperature of oil pipe or oil shell of external cylinder body of diesel generator set diesel engine and whether the diesel engine has burnt smell during use, such as whether the battery charging generator or regulator has burnt taste, battery charging line or starting control line Whether there is burnt smell, the starter has no burnt smell and so on.

4. When troubleshooting, the five major systems and two components of the diesel engine should be classified to find the diesel engine consists of two major components and five major systems. The two major components are fixed and relative moving components of a diesel engine. For example, cylinder heads, cylinder blocks, and cylinder liners are fixed components, while pistons, connecting rods, and crankshafts are relatively moving components. The five major diesel engine systems are:

1 fuel system. Its role is to ensure that a certain amount of pressure sprayed diesel fuel is injected into the combustion chamber in a regular and quantitative manner. If the diesel engine fuel system fails, the diesel engine will suffer from insufficient power, unstable rotation speed, or abnormal exhaust pipe exhaust.

2 lubrication system. Its role is to ensure that the friction surface of the relative moving parts of the diesel engine has a certain amount and a certain pressure of lubricating oil. If there is a problem with the lubrication system of a diesel engine, the probability of a failure is generally very high. Do not generate "watt-hold-up" accidents on the crankshaft and "cylinder-pulling" phenomena on the cylinder liners. The economic losses caused are generally large.

2 cooling system. Its role is to ensure that the amount of cooling water cools the combustor assembly and the oil, allowing the combustor assembly and the oil to work within the allowable temperature range. When the cooling system fails, the temperature of the diesel engine body will be too high, and the water radiator will appear to “open the pot” phenomenon. In severe cases, the cylinder gasket may be damaged.

4 gas distribution system. Its role is to open and close the intake and exhaust valves of each cylinder at regular intervals, so that the intake room is filled with sufficient air, the exhaust is clean, and the seal is good. After the gas distribution system malfunctions, the diesel engine will suffer from insufficient power and abnormal color of the exhaust pipe.

2 start and charging system. Its role is to ensure the normal start of the diesel engine and the normal charging of the battery.

When the start-up and charging system fails, the diesel engine will be difficult to start or the battery will not be charged properly.

The above two components of the diesel engine and the five systems cause the diesel engine to not work properly.

No matter which system or component fails,

Second, diesel generator sets to determine the main method of diesel engine failure

There are many ways to determine the fault of a diesel engine. At present, more methods are used to determine the failure of a diesel engine and instrument inspection methods.

Partition method

The partition method is to temporarily stop the fuel supply of a single cylinder or several cylinders of a diesel engine when determining the fault (open the high-pressure fuel pipe in the upper part of the high-pressure pump or remove the cover plate of the inspection port of the high-pressure oil pump with an open-end wrench, and then use a screwdriver. The wheel body of the high-pressure oil pump sub-pump, as shown in Figs. 5-1 and 5-2, is observed to observe the change of the working state of the cylinder before the fuel injection of the fuel injection pump and after the fuel supply is stopped. For example, when the exhaust pipe of a diesel engine is found to be black smoke, if the failure phenomenon disappears after the fuel supply to a certain cylinder is stopped, the fault is in the cylinder, and the cause of the cylinder failure should be further analyzed and found out. If the failure phenomenon disappears after each cylinder stops supplying oil, it means that it is not an individual cylinder failure, and it is necessary to continue to search for fault locations that affect the operation of each cylinder.

2. Comparison method

The comparative method is more commonly used when troubleshooting diesel engines. For example, if there is suspicion for a certain part, replace the good quality spare parts or find a same part on the diesel engine and compare them with each other, and then change according to the phenomenon of failure. Determine if the part is malfunctioning or identify where the failure occurred.

For example, when it is suspected that the injector of the sixth cylinder fails, it can be retrofitted with the squirt of another cylinder, as shown in Figure 5-3. If the fault is changed to another cylinder after the swap, it means that the injector originally installed in the sixth cylinder has a fault. If the fault phenomenon is not transferred to another cylinder, the fault is caused by other reasons.