There are many reasons for the failure of diesel engine burning. The shortage of oil is one of the main reasons for diesel burning. The diesel engine will be run without engine oil, but the diesel engine may also burn when it is not short of oil. This paper mainly analyzes the causes of the non-normal damage of the shaft, which is the damage caused by both the oil pressure and the amount of oil in the oil.

Analysis of the cause of failure

The basic cause of diesel engine failure is:

Diesel engine in the process of normal work, baotou north toward the heavy card parts of the crankshaft journal and the bearing has a certain gap between oil film and exist, formation fluid lubrication, in this way, small friction loss and the heat generated by the friction is small, heat from the oil away, at normal operating temperature. If direct contact with the bearing and shaft neck, form part of the state of dry friction, the friction power consumption will increase sharply, produce a large number of frictional heat by the bearing bush is sending out, and was taken away by the oil heat, and heat accumulation within the bearing shell, temperature rising, when the temperature exceeds melting point alloy on the surface of the bearing, bearing surface begins to melt, to produce loss, led to the diesel engine is not running.

2, the factors that cause the failure

A, the oil is too hot or too low

When the oil temperature is too low, lubricating oil viscosity is too large, less liquid, especially in the cold machine start-up stage, into the crankshaft oil quantity is less, easy to make direct contact with the crankshaft journal bearing, speed up the bearing wear and damage; When the oil temperature is too high, the viscosity of the lubricating oil is too low, the oil film is weak, and the thickness of the oil film is thinned, and it is also easy to cause the early wear and tear of the shaft. It is generally believed that the temperature of the diesel engine lubricating oil up to 130 ℃. But in order to fully extend the service life of bearing, the commonly used temperature should be kept in the range of 95 ~ 105 ℃.

Improper clearance of the bearing assembly

To improve the existing diesel engine main bearing lubrication state, prevent the loss, should be strictly in accordance with the requirements for the operation manual of diesel engine control the clearance between the crankshaft journal and bearing. Change when bearing shell, should check the roundness and cylindricity of crankshaft journal, if the overrun should be grinding, lest cause journal and bearing shell to reduce the contact area, pressure per unit area; In addition, the crankshaft axial clearance should be controlled, and if the wear exceeds the limit, it should be repaired in time.

C, lubricating oil is inferior

Generally speaking, the lubricating oil in use process, as a result of the diesel engine cylinder liner, piston ring wear, and the change of the piston ring gap and open position, make into the crankcase mixture increase in high temperature and high pressure, which not only cause lubricating oil temperature rise, but also accelerated the oxidation and polymerization of lubricating oil; Coupled with diesel engine combustion products into at the same time, external dust and metal abrasive dust with, as well as the additive in lubricating oil consumption, the lubricating oil degradation, deterioration of accelerated dramatically, which not only increased diesel lubrication part of the friction pair wear and corrosion, but also the main cause of bearing damage.

D, the lubricating oil quality is not good, the diesel engine in the use the process USES the inferior lubricating oil or the fake high quality lubricating oil. If the quality grade of the lubricant does not meet the requirements of the diesel manufacturer, it also causes the diesel engine to produce a burning failure.

E, the shaft quality problem

If the use of inferior materials, baotou north toward the heavy card parts bearing high temperature resistance and bearing capacity is insufficient, even if the oil pressure is normal, oil amount, will also cause the tile burning failure.

F, the diesel engine is vibrating too much during the operation

Because of the dampening or other causes, the engine is vibrating too much during operation. It is also possible that the damping component of the crankshaft itself is damaged, causing the crankshaft to vibrate too much. The long run may cause the shaft to loosen and cause a burning or a slip.

G, diesel engine temperature is too high, due to the failure of the cooling system or other reason is that the overall diesel engine temperature and oil temperature is too high, long run lead to produce tile burning diesel engine fault.

Diesel engines use caution

(1) to maintain regularly, to clean the machine, to unplug the oil, to add or replace the oil, to prevent the oil from getting old or dirty, and to block the oil way.

(2) use lubricants which conform to the requirements of the diesel manufacturer, and carry out serious maintenance according to the requirements.

(3) before the diesel engine is launched, the lubricating oil quantity should be checked carefully before the diesel engine is started.

(4) when the cold car starts, it should be idle for three to five minutes at the idle load, then gradually transition to high speed or heavy load.

(5) the diesel engine is strictly forbidden to operate for long periods of time and avoid urgent acceleration. If the oil pressure alarm lamp is detected, the reason should be determined and the rear can be run.

(6) be careful to check the parts of the lubrication system when repairing. The important parts cannot be used (for example, if the wire is not replaced by iron wire). Use clean oil when assembling.

(7) when replacing the new axle of the baotou north, check the length of the shaft, and the shaft is too short to ensure that it can be properly attached to the shaft neck and that it can heat the shaft. When the shaft is too long, the contact is distorted and causes the gnawing.

(8) check the cooling effect of the diesel engine cooling system, pay attention to the cooling fluid and in a timely manner when tight or replacement of fan belt, ensure that the cooling system is in good condition.