Causes and prevention of cylinder wear of Jinan scrap car engine

First, the cause of early wear and tear of the cylinder

1. The new or overhauled engine is put into operation without a rigorous running-in test, causing early wear of cylinders and other parts.

2. Long-term overload operation. Due to the long-term overload operation of the engine, the machine temperature rises, the lubricating oil becomes thinner, and the lubrication is poor, which accelerates the wear of the cylinder liner, the piston and the piston ring. Moreover, due to the rise of the oil, the inflation coefficient is lowered, the ratio of the fuel to the air is out of balance, the combustion is incomplete, and the carbon deposits of the cylinders and the like are increased, causing the cylinder to malfunction, thereby accelerating the early wear of the cylinder.

3. Run for a long time. When the engine is running at idle speed for a long time, the machine temperature is too low, the lubrication is poor, the combustion is incomplete, and the carbon deposit is generated, which accelerates the early wear of the cylinder. Moreover, due to the low temperature of the machine, acidic substances are easily generated in the cylinder, thereby corroding the cylinder, causing spalling of the pitting, causing early wear of the cylinder.

4. Frequent starting. After the engine is turned off, the oil in the lubricating oil circuit will quickly flow back into the oil sump, so frequent starting will cause the surface of the cylinder liner, piston and piston ring to be in dry or semi-dry friction, which will inevitably accelerate the cylinder liner. Wear and tear.

5, do not pay attention to the maintenance of the air filter, resulting in a serious blockage of the air filter element, the air without the filter directly into the cylinder. The various dust impurities contained in the air, in which silica accounts for more than half, and its hardness exceeds that of steel, so the air entering the cylinder accelerates cylinder wear.

6. Change the oil from time to time. After the oil has been used for a certain period of time, it gradually deteriorates and loses its lubricating effect, and at the same time, some mechanical impurities are mixed to cause abrasive wear.

7. Fuel is supplied during engine warm-up period. When the temperature of the multi-cylinder diesel engine is lower than 5 °C, it must be fully preheated before the oil can be supplied to the cylinder. However, during the preheating period, the oil is supplied, which is not only difficult to start, but also the fuel injected earlier is incompletely calcined. The increase has accelerated the wear of the cylinder.

8. After the engine is started, it will be put into operation without preheating. Because the machine temperature is too low, the throttle will be increased immediately, the combustion will be incomplete, and the cylinder deposit will increase, which will accelerate the cylinder wear.

9, the engine is sick. For example, the connecting rod is bent, twisted, and the fitting parts are loose or too tight.

10, the choice of lubricants do not pay attention to specifications.

11, "Humping the throttle." Some operators blew a few throttles before stopping, trying to burn the remaining oil in the cylinder. In fact, it is counterproductive. Because the throttle is too big and small, the fuel and air mix unevenly, the combustion is incomplete, and the carbon deposit is more, which accelerates the cylinder. abrasion.

Second, Jinan scrap car engine http:// prevent cylinder early wear and tear measures

1. The new or overhauled diesel engine must be subjected to strict running-in test operation before it can be officially put into operation.

2. Regularly inspect and maintain the air filter, oil filter, and diesel filter to make it work under good technical conditions. This is to prevent dust impurities from entering the cylinder from the air, fuel and oil passages, and to reduce cylinder wear. An important measure to extend the life of the engine.

3. Regularly replace the oil sump oil, and the added oil must meet the requirements of the manual. When replacing the oil sump oil, the oil sump and the lubricating oil circuit should be carefully cleaned by first disposing of the modified oil, using the same amount of clean diesel oil, pouring into the oil sump, starting the engine, and idling for 3-5 minutes. Clean the diesel oil, then clean the oil pan, clean the oil filter, and finally add the specified amount of oil.

4. It is forbidden to add water after starting, otherwise it will make the cylinder quench and crack.

5. Always keep the engine working at normal temperature. If it is too high, the oil will be diluted and the lubrication conditions will be deteriorated. If it is too low, acid corrosion will occur, causing the pitting to peel off. A suitable operating temperature is 70-80 ° C, and the evaporative engine can be slightly higher.

6. When starting the engine, pay attention to pre-lubrication, because when the engine is turned off, most of the oil in the lubrication system will flow to the oil pan, and the surface of each moving pair will be dry friction and semi-dry friction. If it starts immediately, the cylinder will be intensified. When the parts wear speed, the crankshaft is first turned to tens of turns during starting, so that the surface of the moving pair is lubricated in advance.

7. Warm up for a period of time after starting the engine. Because the engine temperature is low at this time, the cylinder and other parts have not been fully lubricated, otherwise the cylinder liner, piston, piston ring, journal and bush are worn out. When the engine temperature starts at 40 °C, 60 °C is officially put into operation.

8. It is forbidden to overload the machine for a long time.

9. It is forbidden to run the engine for a long time. Because the engine is running at a rapid speed for a long time, the nozzle is poorly atomized, the fuel and air are not uniformly mixed, the combustion is incomplete, and the cylinder is prone to coke formation, which intensifies the cylinder wear. In addition, long-term idle operation also accelerates wear and tear.

10. Start properly and minimize the number of starts. If the machine stops for less than 15 minutes, do not turn off the fire to reduce the number of starts. When starting the engine, do not put the throttle to the maximum position forcibly starting, otherwise the diesel fuel injected into the cylinder will be too much, which will cause the start to fail. Even if it can be started, the combustion will be incomplete due to excessive fuel in the cylinder, which will cause carbon deposit and increase wear. . Generally speaking, when the temperature is below 15 °C, do not add the throttle at the start of the start, idling the crankshaft several times, feel relaxed and then add a small throttle to start.

11. It is strictly forbidden to bombard the throttle. The bombing not only causes deformation of the connecting rod and the crankshaft, but even the crankshaft is broken, and the combustion is incomplete.

12. It is strictly forbidden to carry sick work. Maintenance should be strengthened and repaired in time. If the gap of the piston ring is kept in compliance with the regulations, the piston ring that does not meet the requirements should not be used to reduce the carbon deposit of the cylinder; the piston “offset cylinder” should be inspected according to the engine assembly process. If it does not meet the requirements, it should be checked in time. Reasons to be excluded; regularly check the high-speed valve clearance and the fuel supply advance angle, so that the fuel and air are evenly mixed, the combustion is normal, and the carbon deposition is reduced; when the connecting rod and the crankshaft are bent and twisted, it should be corrected in time, and the axial direction of the crankshaft is ensured. The clearance meets the technical requirements.

13. It is not allowed to abrupt the throttle when working. If the throttle is changed due to the change of working load, it should also be carried out slowly.

14. Establish a sense of cleanliness. During maintenance, care should be taken to keep the body, tools and parts clean so as not to bring abrasive particles, mud and sand into the cylinder and cause early wear of the cylinder.