Reasons for cylinder pulling of diesel generator sets and how to prevent

Cylinder pulling of diesel engine is a common fault, which is manifested by scratches and groove-like strains on the surface of the cylinder wall. In severe cases, the piston and the cylinder wall are stuck, the piston is stuck, and the piston ring is locked by the pull card. As a result of cylinder pulling, Zhao Cheng’s engine power performance is often severely reduced, difficult to start, severe blow-by oil and increased oil consumption, and even cause the piston to hold the cylinder and the engine to go out and fail to work.
1. Cylinder pulling mechanism of diesel engine
1. There are two types of diesel engine pull cylinders: one is powder wear. The abrasive formed by mechanical impurities entering the cylinder, attached to the surface of the cylinder, causes the cylinder wall to be parallel to the cylinder axis, causing the cylinder wall to be pulled or coarsely strained; the other is fusion wear. It is a more destructive wear. It is because the oil film between the piston, piston ring and cylinder wall is not easy to form or be destroyed for some reasons, resulting in dry friction on the local surface, resulting in a large number of friction surfaces that melt into a rough surface , Thereby increasing the wear and tear, resulting in cylinder pulling.
2. Pull cylinder refers to the serious surface damage caused by the interaction between the cylinder and the piston or piston ring relative moving surface. It usually happens in the early stage after a new machine or overhaul. After the cylinder is strained, the lubricating oil will escape into the combustion chamber, and blue and black smoke will be discharged from the exhaust pipe, causing a large amount of carbon deposits in the combustion chamber. At the same time, combustible gas leaks into the crankcase, which will dilute the lubricating oil. In severe cases, it can be seen from the lubricating oil filler mouth that there is a phenomenon of “gasp” and oily smoke will burst out. At the same time, the piston of the internal combustion engine has a knocking sound, and the power of the internal combustion engine is insufficient.

2. Analysis of the cause of cylinder pulling of diesel engine
There are many reasons for the cylinder pulling of a diesel engine. I mainly focus on the following reasons:
1. There is air resistance in the cooling system of the cold water diesel engine
After the diesel engine is installed, the cooling system is installed with a secondary water tank to communicate with the atmosphere. Therefore, there is a problem of air obstruction in the cooling system. However, for non-vehicle diesel engines and thermal tests on the bench, the cooling system must be installed before the thermostat is activated. The cooling system is basically in a completely closed state, and the cooling water pump is forced to perform circulating cooling. In this state, if the air in the system is not clean, the air will form air resistance in such a closed and forced system. Under the forced action of the water pump, the resistance will move in the system (move towards a lower instantaneous pressure), and the air resistance will cause insufficient partial cooling of the parts or even failure. In this case, the diesel engine will overheat and cause cylinder pulling.
2. Operational reasons
The cylinder pulling caused by improper operation is mainly manifested in the following aspects:
(1) Drive with insufficient oil. When the diesel engine is operated under the condition of insufficient oil supply (the oil level is too low), the lubrication parts can not realize normal lubrication, and the surface of each mechanical part is friction and wear is aggravated, causing failures such as cylinder pulling and tile burning.
(2) Run the diesel engine when the oil pressure is too low. The oil pressure is too low. The lubrication system cannot realize normal oil circulation and pressure lubrication, and cannot reliably supply sufficient oil to the friction surface of each part so that each lubricated part can be fully lubricated, resulting in wear, cylinder pulling, and tile burning. malfunction.
(3) Overspeed load operation. Frequent over-speed and overload operation will cause the diesel engine to operate under excessive load for a long time, which will cause the diesel engine to burn roughly, cause the diesel engine to overheat, and increase the thermal load and mechanical load of the cylinder liner, piston, etc., which is easy to cause mechanical parts Damage and failure of pulling or holding cylinder.
(4) Long-time no-load operation or long-term high-speed and high-load operation during the running-in period. Long-time no-load operation during the running-in period, because the fuel dilutes the oil on the cylinder wall, it may cause cylinder pulling, but excessively rapid load operation will be more likely to occur. When running at high speed or load for a long time, the oil film is easily damaged and local If the metal contact parts are not cooled in time, the cylinder will be pulled.
(5) The cold start immediately increases the load without passing through the heater. Due to the low oil temperature, high viscosity and poor fluidity at the beginning, the oil cannot fully flow to the lubrication parts, and the oil supply of the oil pump is small. At the same time, the oil on the original cylinder wall flows down along the cylinder wall after stopping, making the wall surface at the moment of starting. The lack of lubrication during operation causes the inner wall of the cylinder liner and the piston assembly to friction and wear sharply, resulting in cylinder pulling failure.
(6) The amount of cold water is insufficient for driving. Insufficient cooling water (too low water surface) will affect the cooling effect, causing the diesel engine to work too high, causing the main heated parts such as cylinder liners and pistons to overheat, resulting in a decrease in mechanical properties such as strength and toughness. The increase in the amount of deformation destroys the normal state of technical coordination, which intensifies wear, and in severe cases, causes the piston to over-expand and become stuck in the cylinder. In addition, overheating of the diesel engine will cause the oil temperature to be high and the viscosity to decrease. The lubricating oil film on the surface of each friction pair is not easy to form and maintain, which deteriorates the lubrication conditions of the cylinder liner and piston assembly and other main friction surfaces, causing abnormal wear and cylinder pulling and burning. Failure of tile and axle holding.
3. Reasons for maintenance
This is mostly manifested in maintenance according to regulations. Mainly have the following and aspects:
(1) If the oil filter is not cleaned in time, it will cause excessive resistance or even blockage of the oil filter, causing the oil to pass through the bypass valve without passing through the filter element, and use unfiltered oil to lubricate the inner wall surface of the cylinder liner. It is extremely easy to cause serious wear and strain on the cylinder liner and piston assembly.
(2) Checking and adjusting the fuel supply advance angle is not timely. This will cause the diesel engine’s advance angle to be too large, causing the diesel engine to work rough, increase the thermal load and mechanical load of the cylinder liner and piston, and easily cause the failure of cylinder holding and cylinder pulling.
(3) Poor maintenance of the air filter. Dust, sand, etc. in the air will be sucked into the cylinder with the air due to poor maintenance of the air filter or air leakage in the intake system, forming harmful abrasives, which adhere to the inner wall surface of the cylinder liner, making the cylinder liner and the piston The friction surface of the component is subject to intense particle wear and strain.
(4) If the engine oil is not added or changed in time, or the engine oil is not added in time, the above-mentioned lack of engine oil will occur. During the continuous operation of the diesel engine, the engine oil will be contaminated by the dust drawn from the air and the combustion products and wear products of the diesel engine itself, and will gradually deteriorate under the influence of high temperature, and eventually make the lubrication performance and lubrication effect less than the use requirements If it is not replaced in time, not only the mechanical impurities in the oil will aggravate the wear of the parts, but also make the lubrication worse and even cause the oil pipes and oil passages to be blocked, causing failures such as cylinder pulling and tile burning.
(5) If the engine oil of the specified quality and the specified label is not selected, and the engine oil that is not for diesel engine or whose performance does not meet the requirements is added to the diesel engine, a complete oil film with a certain thickness can be established on the friction surface, which is a change in lubrication performance. Poor, it is easy to cause failure of cylinder pulling and tile burning. If the oil with too low viscosity is used, when the temperature is high, the oil film on each friction surface is difficult to form and maintain; if the oil with too high viscosity is used, the fluidity is poor and it is not easy to transport to the friction surface gap of each part, so it is impossible to achieve Reliable lubrication of lubrication parts will also cause failures of cylinder pulling and tile burning.

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con rod, Cylinder Head, Diesel Engine, engine pulling, Fuel Pump, oil pump, Piston, problem

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