Several contents easily neglected in maintenance of diesel generator set
2022-04-19
I believe that many users of diesel generator sets have such doubts. I have done every maintenance. Why do the equipment still fail frequently or the service life is not long? According to the summary of laines' communication and interaction with customers over the years, this is actually largely related to everyone falling into the misunderstanding of maintenance and neglecting some small details. To sum up, I only did XXX and ignored XXX. Let's take a look at some contents that are easy to be ignored in maintenance:
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1、 Only replace the plunger and nozzle, ignoring the technical state of the oil outlet valve. After the oil outlet valve is worn, the residual pressure of the high-pressure oil pipe will be too high, resulting in incomplete oil cut-off and oil dripping of the fuel injection nozzle, resulting in exhaust smoke, cylinder knocking and unstable operation of the diesel engine. The method is to check the oil outlet valve and detect it with a pressure gauge with a range of 0-600 kg / cm2. When the gauge needle decreases from 200 kg to 180 kg / cm2, the pressure holding time should be greater than 15 seconds, otherwise the oil outlet valve should be replaced; Or pump out the diesel oil with the high-pressure oil pipe opening upward to make the oil level flush with the pipe opening, put the throttle back to the stop supply position, suddenly reverse the traveling wheel for half a turn, and it is qualified if the diesel oil at the high-pressure oil pipe opening is not sucked back, otherwise the oil outlet valve shall be replaced.
2、 Only adjust the valve clearance and ignore the valve timing. Most people just adjust the valve clearance according to the value specified in the manual, but ignore checking whether the valve timing is correct. Especially for the aging machine, due to the change of geometry after cam wear, the valve opens late and closes early, which will lead to insufficient intake, unclean exhaust, increased fuel consumption and reduced power. Therefore, when adjusting the valve clearance of aging diesel engine, the valve clearance value should be appropriately reduced according to the engine conditions to make up for the error of valve timing. For example, for S195 diesel engine, the valve timing changes by 3 degrees for every 0.1mm reduction in valve clearance. However, the valve clearance shall not be less than 0.2mm, otherwise the valve will not be tightly closed due to expansion. If the valve clearance is already 0.2mm, and the valve timing error is still more than 5 degrees, and the working condition of the diesel generator set is obviously deteriorated, the camshaft shall be replaced.
3、 Only look at the oil volume of the oil pan and ignore the oil quality. Many people only supplement the engine oil, never check the quality of the oil or replace it. As everyone knows, the waste engine oil to be replaced contains a large amount of oxidizing substances and metal chips, which reduces the lubrication performance, intensifies the wear of parts and shortens its service life. Therefore, the quality of engine oil in the machine should be checked at any time. The general method is to grind the oil by hand. If you feel that there are mechanical impurities or insufficient viscosity, you should replace it in time. Another inspection method is to drop the used engine oil on the white paper. If the black spot is small and the color is light, and the Yellow moist mark around is large, it can continue to be used; If the spot is black and large and there is no yellow stain around, it should be replaced.
4、 Only know how to maintain the air filter and ignore the air short circuit. There are many reasons for air short circuit, such as improper welding of the air filter fixed on the three wheel frame, no sealing gasket at the joint of the air inlet pipe, loose insertion of the air inlet pipe into the rubber pipe without clamp, undetected rupture of the air inlet rubber pipe, lack of rubber ring in the air filter, which will cause air short circuit, make unfiltered air enter the cylinder, and aggravate the wear of cylinder, piston, piston ring, valve and other parts.
5、 Only clean the oil filter screen and ignore the cleaning of the purified oil chamber. The connecting rod journal of most diesel generator sets is hollow and there are oil plugs at both ends, which is called purification chamber. Under the action of centrifugal force, the impurities of the engine oil lubricating the connecting rod bearing bush adhere to the cavity wall, so as to improve the lubrication quality. Generally, the oil plug of diesel generator set shall be removed every 500 hours, and the impurities in the purified oil chamber and oil passage shall be removed according to the specified methods.
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1、 Only replace the plunger and nozzle, ignoring the technical state of the oil outlet valve. After the oil outlet valve is worn, the residual pressure of the high-pressure oil pipe will be too high, resulting in incomplete oil cut-off and oil dripping of the fuel injection nozzle, resulting in exhaust smoke, cylinder knocking and unstable operation of the diesel engine. The method is to check the oil outlet valve and detect it with a pressure gauge with a range of 0-600 kg / cm2. When the gauge needle decreases from 200 kg to 180 kg / cm2, the pressure holding time should be greater than 15 seconds, otherwise the oil outlet valve should be replaced; Or pump out the diesel oil with the high-pressure oil pipe opening upward to make the oil level flush with the pipe opening, put the throttle back to the stop supply position, suddenly reverse the traveling wheel for half a turn, and it is qualified if the diesel oil at the high-pressure oil pipe opening is not sucked back, otherwise the oil outlet valve shall be replaced.
2、 Only adjust the valve clearance and ignore the valve timing. Most people just adjust the valve clearance according to the value specified in the manual, but ignore checking whether the valve timing is correct. Especially for the aging machine, due to the change of geometry after cam wear, the valve opens late and closes early, which will lead to insufficient intake, unclean exhaust, increased fuel consumption and reduced power. Therefore, when adjusting the valve clearance of aging diesel engine, the valve clearance value should be appropriately reduced according to the engine conditions to make up for the error of valve timing. For example, for S195 diesel engine, the valve timing changes by 3 degrees for every 0.1mm reduction in valve clearance. However, the valve clearance shall not be less than 0.2mm, otherwise the valve will not be tightly closed due to expansion. If the valve clearance is already 0.2mm, and the valve timing error is still more than 5 degrees, and the working condition of the diesel generator set is obviously deteriorated, the camshaft shall be replaced.
3、 Only look at the oil volume of the oil pan and ignore the oil quality. Many people only supplement the engine oil, never check the quality of the oil or replace it. As everyone knows, the waste engine oil to be replaced contains a large amount of oxidizing substances and metal chips, which reduces the lubrication performance, intensifies the wear of parts and shortens its service life. Therefore, the quality of engine oil in the machine should be checked at any time. The general method is to grind the oil by hand. If you feel that there are mechanical impurities or insufficient viscosity, you should replace it in time. Another inspection method is to drop the used engine oil on the white paper. If the black spot is small and the color is light, and the Yellow moist mark around is large, it can continue to be used; If the spot is black and large and there is no yellow stain around, it should be replaced.
4、 Only know how to maintain the air filter and ignore the air short circuit. There are many reasons for air short circuit, such as improper welding of the air filter fixed on the three wheel frame, no sealing gasket at the joint of the air inlet pipe, loose insertion of the air inlet pipe into the rubber pipe without clamp, undetected rupture of the air inlet rubber pipe, lack of rubber ring in the air filter, which will cause air short circuit, make unfiltered air enter the cylinder, and aggravate the wear of cylinder, piston, piston ring, valve and other parts.
5、 Only clean the oil filter screen and ignore the cleaning of the purified oil chamber. The connecting rod journal of most diesel generator sets is hollow and there are oil plugs at both ends, which is called purification chamber. Under the action of centrifugal force, the impurities of the engine oil lubricating the connecting rod bearing bush adhere to the cavity wall, so as to improve the lubrication quality. Generally, the oil plug of diesel generator set shall be removed every 500 hours, and the impurities in the purified oil chamber and oil passage shall be removed according to the specified methods.
