1. Maintenance and maintenance of engine fuel system
(1) Choose diesel oil with low freezing point and good fluidity. At low temperature, the viscosity of the fuel increases, the fluidity becomes poor, and the atomization is poor. Therefore, the freezing point of diesel oil should be 3~5°C lower than the lowest ambient temperature to ensure that it does not freeze at the lowest temperature. the
(2) The climate is dry in winter, especially in the north where there is a lot of wind and sand, so the maintenance of air filters, fuel tanks and diesel coarse and fine filters should be strengthened to prevent dust pollution and accelerate the wear of parts. the
(3) For severe cold regions, diesel oil can also be preheated during engine operation. There are two main ways to preheat diesel oil: one is to use exhaust gas to preheat, that is, connect a pipe from the exhaust pipe of the engine to pass through the diesel tank, and use the exhaust waste heat to heat the diesel oil; the other is to use circulating water to preheat, that is, to use a pipe to pass the engine circulating water through the diesel tank, or use a sandwich fuel tank to fill the inner layer with oil and the outer layer to contain circulating water to heat the diesel oil. When diesel oil is used for preheating, low-condensation-point diesel should be used to start the engine first. After the preheated diesel oil flows out, high-condensation-point diesel should be used for operation. When the engine is turned off, low-condensation-point diesel should be used for 10-20 minutes to ensure that the high-condensation-point diesel in the fuel supply system is exhausted, preventing the diesel oil from condensing and blocking the oil passage after shutdown. the
2. Maintenance and maintenance of engine lubrication system
(1) Release the lubricating oil of the engine. After cleaning, add engine oil with a lower viscosity to improve the lubrication conditions; secondly, strengthen the cleaning of the coarse and fine filters of the engine oil to reduce the resistance of the lubricating oil. For construction machinery used under dusty conditions, the replacement cycle of lubricating oil should be appropriately shortened. the
(2) When some diesel engines enter winter (generally when the temperature is lower than 5°C), the switch on the filter seat should also be turned to the "winter" season use position.
3. Maintenance and maintenance of engine cooling system
(1) Remove scale and unblock the pipeline. Remove the scale inside the engine water jacket to prevent excessive scale accumulation and block the pipeline. If the scale blocks the water discharge switch, it will cause dirty water discharge. the
(2) Check all parts of the cooling system to ensure that they are complete and in good condition. The louvers of the engine radiator, the starting insulation curtain and the engine cover should be in good condition, and an insulation cover should be installed on the engine cover and radiator cover. The thermostat should be in good working condition to prevent the engine water temperature from being too low or too high. When the engine is working normally, in order to keep the engine in a good technical state, the air temperature under the hood should be kept between 30~40°C, and the cooling water temperature should be kept between 80~90°C. the
(3) When the construction machinery stops running for a long time, in order to prevent the engine cooling water from freezing, it is necessary to start at intervals to maintain the machine temperature, and the water should be released in time after the operation (all water discharge switches must be turned on). In order to prevent deformation or cracking of the engine block and cylinder head, the cooling water should not be released until the engine temperature drops to 50~60°C. the
(4) Add antifreeze. When the air temperature is too low and conditions permit, antifreeze can be used, and the cooling system should be thoroughly cleaned before use. There are two commonly used antifreeze fluids, one is synthesized from industrial ethylene glycol and distilled water, and the other is synthesized from alcohol and water. Since the thermal expansion coefficient of antifreeze is larger than that of water, in order to prevent the antifreeze from overflowing after thermal expansion, the antifreeze added should be 6%~8% less than the volume of the cooling system. the
4. Engine starting at low temperature
(1) Preheating is required before starting to reduce the starting resistance of the engine, improve the atomization and evaporation of fuel during starting, form a good combustible mixture, and facilitate starting. The easiest and easiest method is hot water preheating, which is to inject cooling water into the cooling system after heating. When adding hot water to the cooling system, turn on the drain switch and turn it off when the temperature of the water flowing out of the drain switch reaches 30-40°C, stay there for 10-15 minutes, and start the engine when the water temperature in the engine water jacket is gradually consistent with the temperature of the cylinder block. If you use charcoal fire to bake the oil pan to heat the engine oil or add heated engine oil (≤70~80℃), the effect will be better. the
(2) For diesel engines equipped with electric preheating device and decompression device, try to preheat and decompress as much as possible when starting. the
(3) For a diesel engine without a preheating device, the air filter can be removed, and the engine can be heated with a blowtorch at the air inlet (pay attention to prevent sundries from being sucked into the cylinder), so that the engine can inhale the flame while inhaling. the
(4) When starting at low temperature, due to the high viscosity of the engine oil, the lubricating oil will not be sufficient for a short time and cannot spread all over the lubrication points. At this time, if the engine is running at high speed, the wear of the crankshaft, camshaft and rocker shaft will increase, and serious accidents such as cylinder scuffing and tile burning will occur. Therefore, after the engine is started, it should run at idle speed for a period of time, and then work under load after the water temperature is normal.
