Diesel engine fault judgment and elimination method 2015-12-27
Diesel engine in use process can appear sometimes failure of one kind or another, the phenomenon is varied, the cause of failure is also very complex. A kind of fault can be characterized by one or more abnormal phenomena, such as high pressure oil pump wear and tear, can show the start is difficult, also can show the output power is insufficient, can also be unstable phenomenon such as characterized by a low speed; A kind of abnormal phenomenon can also be caused by one or more of the cause of the problem, such as diesel engine power is insufficient, may be due to the diesel engine fuel injection pump failure, may also be a valve-train diesel engine and inlet and exhaust systems fault, also may be injector fuel injection, also may be not enough in a diesel engine cylinder compression pressure.
Fault diagnosis is complicated, the purpose of such change of various kinds of failure phenomenon, according to their occurrence, development and change process, by which a system or institution, is to determine the fault caused by the reason, in order to rule out timely and accurately, make the diesel engine running back to normal.
So in fault diagnosis, the turbine management not only should be familiar with the diesel engine structure principle, operation, debugging, but also to master to find general principles and methods of the fault, only in this way, when the actual problems, through careful observation and analysis, the right to ask the right processing method, to eliminate the fault.
Second, the abnormal phenomena after diesel engine failure
Diesel engine fault happens, often appear the following abnormal phenomenon:
1. The abnormal sound during operation. If not normal beat, put guns, boasting sound, friction of the exhaust noise, periodic, etc.
2. The abnormal operation. There was a violent vibration is not easy to start, such as diesel engine work, lack of power, speed is not stable, etc.
3. Abnormal appearance. Such as diesel engine exhaust pipe smoke, blue smoke, white smoke, each system in the oil, water, air, etc.
4. The temperature anomaly. Oil and cooling water temperature is too high, exhaust temperature, bearing temperature, etc.
5. Abnormal pressure. Oil, water and fuel pressure is too low, the compression pressure drop, etc.
6. Abnormal smell. Diesel engine is running, stink, focal flavour, such as smoke smell.
Diesel engine run time appear abnormal phenomenon, must find out the reasons of abnormal phenomenon seriously, so adept at analysis, reasoning, judgment, we look at essence through the phenomenon, and find out the cause of the failure parts, troubleshooting.
Third, the principle of diesel engine fault diagnosis and eliminate
Diesel engine failure, should keep calm, step by step is the destination for inspection and analysis, must not went blind inspections, random disassembly, should be based on the abnormal symptoms, signs, the noise of the fault, occurrence time, change rule to find the fault part, first of all, from the principle and the structure level of a detailed analysis of reasoning, to make the right judgment to find the cause of the problem.
Determine the general principles of the diesel engine fault are: combining structure, contact principle, make clear phenomenon, practical, simple to the complex, situated in, press section, find the reason.
1. The judge fault from the overall analysis, troubleshooting to be comprehensive
Diesel engine of each system, components and parts are closely related, between a component or a system or a component fails, will inevitably involve other components or parts of the system. So, to view, as a fault phenomenon cannot be isolated from the overall analysis of the cause of the failure and troubleshooting as soon as possible.
2. Look for diesel engine fault should minimize the disassembly
In troubleshooting, can not blindly remove the diesel engine parts, must first understand before disassembling the structure principle of diesel engine, such as the failure positions, only to establish on the basis of the scientific, careful analysis can be dismantled.
3. The malfunction to careful, see, hear, touch, smell, comprehensive inspection
In the case of does not have the advanced testing equipment, generally use direct feeling diagnosis method for fault diagnosis, can be divided into: see, hear, touch, smell, try.
See: external characteristics in the running process of diesel engine, such as exhaust smoke situation whether there are abnormal; The oil color is normal; Fuel system whether there is a leak diesel parts; Cooling system and lubricating system whether there is leakage, oil leakage phenomenon; The instruments of diesel engine indicate whether there is abnormal; If there's any loose for the moving parts of nut; Whether the diesel engine vibration, etc.
Listen: mainly to diesel engine abnormal noise in the operation process, according to the nature and the location of a sound to judge the fault. Such as diesel fuel in the combustion chamber combustion explosion is uniform, Diesel engine piston, connecting rod, crankshaft, in the process of operation of impact whether there are abnormal; Inlet and exhaust valve and timing gear for diesel engine abnormal sound, etc.
Momo: try to touch by hand. As the pulsation of the tubing, unit seismic shaking; The oil tube or shell oil temperature and oil thermometer indicates whether or not the same, etc.
Smell: thanks to diagnose the fault area of smell. In the working process of diesel engine presence of focal flavour; If there is a burning diesel oil flavor, etc.
Test: test validation. Diagnosis such as cease-fire with single cylinder diesel engine abnormal sound, etc.
Above methods according to the characteristics of different fault, flexible application specific, objective through thinking, analysis and reasoning of the fault analysis, find out the cause of the problem and eliminate measures are put forward.
Four, the main method of diesel engine fault
Partition method 1.
Doubt and analysis of the failure is caused by a work place, can make the part of the local stop working, observe whether failure phenomenon is disappeared, which can be concluded that the fault location. Partition method is to stop a single cylinder diesel engine work or stop them one by one several or all of the cylinder oil, diesel engine and stop work changes before and after injection. Use this method to check the working condition of each cylinder, especially check each cylinder exhaust color is the most effective. , such as diesel engine smoke analysis is a poor cylinder injector atomization, the cylinder can be stop working right now, if the black smoke disappear, can think right.
2. The comparison method
After comparison with the more common, diesel engine failure, if have doubt on which a component or system, change a good quality parts or a normal system, observe whether the fault is eliminated, if the failure phenomenon disappears, prove that failure occurs in the component or the system.