Preface
The mechanical failure of diesel engine during operation will result in damage to the base parts. Before the failure of the diesel engine, there will be some abnormal signs, such as speed, sound, exhaust, water temperature and oil pressure, that is, the characteristics of fault precursor. Therefore, operators should quickly make accurate judgments based on the characteristics of omens, and determine acceptance measures to avoid accidents.
Diesel engine
fault
1, "flying car" failure
Omen feature
The speed rises suddenly, and is faster and faster. It is not controlled by throttle. The sound is abnormal and harsh, and the exhaust pipe is full of blue smoke or black smoke.
The "flying car" belongs to the overspeed. It will not happen under the load. It is possible to appear when the load is suddenly disappeared or lighten in the start or work. The main reason is that the governor system fails, resulting in the loss of control or excessive oil in the sump. There is a "flying car" warning. If no urgent measures are taken immediately, it will eventually lead to serious accidents such as tamping cylinders and broken shaft.
Disposal measures
The main purpose is to extinguish the fire by cutting off the oil or cutting off the gas. The emergency measures can be taken as follows: one is to shut the oil door to contain the oil supply and step down the brake; two is the infarction intake pipe, the air is cut off; the three is to quickly release the high-pressure oil pipe to stop the oil supply; the four is to use the advanced heavy load (brake) in the vehicle diesel engine, so that the engine is flameout because of the shortage of torsional gas.
2, the malfunction of the visco cylinder
Omen feature
The speed drops, the running is weak, the voice is boring, the water temperature is very high, and the indication with the water temperature gauge exceeds 100 degrees. At this point, sprinkling some water into the machine will evaporate quickly. The main reason is the serious shortage of water and the failure of the water cooling system. If the flameout is stopped immediately, a visco cylinder may occur.
Disposal measures
Idle operation for a period of time or stalling and rotating crankshaft auxiliary cooling, so that the water temperature dropped to about 40 degrees, and then slowly add cooling water. Be careful not to add cooling water immediately, otherwise it will cause the parts to deform or crack due to sudden drop in local temperature.
3. Malfunction of ramming cylinder
Omen feature
The crankcase has "clatter" sound, like the sound of a small hammer tapping on the hard floor, commonly known as "knock on the cylinder". The pressure drop of the oil is more obvious when it is accelerated. The ramming cylinder is a destructive mechanical fault, mainly due to the loosening of the connecting rod bolts or the tensile necking of the bolt, and the excessive clearance of the connecting rod shaft, resulting in the loosening or breaking of the bolt. If there is a knock on the cylinder, but the oil pressure is normal, it is not a harbinger of tamping cylinder. We should consider the adjustment of the oil supply advance angle.
Disposal measures
Stop overhaul immediately and replace new pieces.
4. Failure of burning tile
Omen feature
The sound is stuffy, as if the load suddenly increased, the speed decreased, the oil pressure decreased and the exhaust smoked. The main reason is the destruction of the lubricating oil film on the surface of the axle bush, the direct contact between the axle bush and the surface of the neck of the axle, the rapid rise of the friction temperature, and the bonding to the axle.
Disposal measures
Shut down immediately, remove the cover, check the connecting rod and bearing bush, find out the reason, repair and replace.
5. Fault shaft fault
Omen feature
There was a dull knocking in the crankcase, the throttle increased, and the engine shakes badly when it was idle, and the exhaust blows black smoke. The broken shaft is caused by mechanical fatigue at the shoulder of the crankshaft neck, and there is a gradual process from splitting to breaking. When the latent fission occurs, the characteristics of the precursor are not obvious. With the enlargement of the crack, the characteristics of the precursor become more and more obvious. If the throttle and other trembling or knocking frequency coincide, the shutdown may be at the critical point of the broken shaft. At this time, the cover is checked and the flywheel is pushed by hand. If the axial clearance is large, and the driving is not hard, the crankshaft is broken.
Disposal measures
It is found that the stop is checked immediately, and the crankshaft should be replaced in time.
