If a diesel engine malfunctions during operation, the basic components will be damaged, and heavy machinery accidents will occur. Under normal circumstances, before the failure of the diesel engine, its speed, sound, exhaust, water temperature, oil pressure and other aspects will show some abnormal signs, that is, the characteristics of the symptoms of the failure. Therefore, operators should promptly make correct judgments based on the characteristics of the signs and take decisive measures to avoid accidents. 1. "Speed" Fault Predicts that the characteristic speed suddenly rises, and that it is getting faster and faster. It is not controlled by the throttle. The sound is abnormal and harsh. The exhaust pipe emits a lot of blue smoke or black smoke. "Speeding" belongs to overspeed idling. It will not happen under load. It will only happen if the load is suddenly removed or reduced during the start-up or work. The main reason for the "carriage" is that the regulator system has failed and caused the oil supply to be out of control or the sump oil is excessive. There are signs of "speed racing". If emergency measures are not taken immediately, it will eventually lead to major accidents such as blow-by-cylinder and broken shafts. Treatment measures are mainly to achieve the purpose of extinction by cutting off oil or gas. The emergency measures that can be taken are: First, stop the fuel supply to stop the accelerator and step on the brake; second, block the intake pipe and cut off the air; third, quickly release the high pressure fuel pipe to stop the fuel supply; and 4) use the diesel engine during walking. High-grade heavy load (brake) makes the engine turn off due to insufficient torque. 2. Viscous cylinder failure symptoms The characteristic speed is reduced, the operation is weak, the sound is boring, the water temperature is extremely high, and its indication with a water temperature gauge exceeds 100°C. At this point, sprinkle some water on the parts and quickly evaporate. The main reason is the severe lack of water and the failure of the water cooling system. If the flameout is stopped immediately, a sticky cylinder may be produced. Treatment measures Idle speed for a period of time or turn off the crankshaft to help cool, so that the water temperature is reduced to about 40 °C, and then slowly add cooling water. Be careful not to add cooling water immediately, otherwise it will cause the parts to be deformed or cracked due to the sudden drop in local temperature. 3. The characteristics of the cylinder bore fault are characterized by a “click†sound in the crankcase, and a sound like a small hammer tapping a hard floor, which is commonly known as the “knock cylinder sound†oil pressure drop, is more pronounced when the rapid acceleration. Cylinder is a destructive mechanical failure, the main reason is due to the loose connecting rod bolts or bolts stretching telescopic neck, connecting rod shaft with the gap is too large, resulting in loose bolts or broken due to. If there is a knocking sound, but the oil pressure is normal, it is not a sign of boring. It should be considered from the adjustment of the fuel advance angle. The measures are immediately shut down for maintenance and replacement of new parts. 4. The characteristics of the burned tiles indicate that the characteristic sound is boring, as if the load suddenly increases and the speed decreases, the oil pressure drops, and the exhaust gas emits black smoke. Burning tiles will cause the bushes and journals to lock and extinguish due to the fact that the lubricant film on the surface of the bearing bush is damaged, the bearings and the metal on the surface of the journal are in direct contact with each other, the friction temperature rises rapidly, and the surface is glued. Immediately stop the treatment measures, remove the cover and check the connecting rod bearings, find out the reasons, and repair and replace. 5. Axis fault pre-diagnosis characteristic The boring knocking sound occurs in the crankcase. When the sensational throttle sounds, the knocking sound becomes louder. When the idling speed is running, the parts are shaken seriously, and the exhaust gas emits black smoke. The broken shaft is caused by mechanical fatigue at the crankshaft neck shoulder and has a gradual change from cracking to breaking. When the latent fission occurs, the characteristics of the omens are not obvious. As the cracks expand, the features of the omens become more and more obvious, and finally the axis breaks down. If there is a throttle, such as a throttle, or when the knock frequency matches, it may be at the critical point of the broken axis. At this point, the cover is inspected and the flywheel is pushed by hand. If the axial clearance is large, and the pushing is effortless, it indicates that the crankshaft has been broken. The treatment measures found that the omen was immediately checked for shutdown and it was found that the crankshaft should be replaced in time.