Misunderstandings in locomotive maintenance should

The misunderstanding in locomotive maintenance should be corrected

the crankshaft bearing and connecting rod bearing of the engine must be scraped and matched. It seems that a good contact surface cannot be guaranteed without scraping. Even the new crankshaft and standard bearing should be scraped and matched. Do you know that the wear-resistant alloy coating of crankshaft bearing and connecting rod bearing of some small engines is very thin, which is not allowed to be scraped and matched, and can only be selected and matched according to the regulations

2 the engine water temperature is afraid of high and not afraid of low

if it is found that the water temperature is high, try every means to find out the cause and eliminate it. If the water temperature is low, it is considered to be correct. In fact, low water temperature is also a great harm, causing insufficient fuel combustion, resulting in reduced power, increased fuel consumption, poor lubrication, increased carbon collection in the combustion chamber, etc

3 the valve clearance should be larger than smaller

in fact, when the valve clearance is large, the lift of the valve becomes smaller and the opening is not enough, resulting in insufficient intake and exhaust, resulting in the decline of engine power

4 adding more oil is better than less

it is considered that adding less oil is easy to burn the bearing, and adding more oil has little to do with it. In fact, adding more oil also causes harm to the engine, increasing the movement resistance of crankshaft and connecting rod, increasing the oil splashed on the cylinder wall and entering the combustion chamber, resulting in increased carbon collection and affecting emissions

5 it is better to fill the hub with butter rather than less

I always think it is best to fill the hub with yellow oil. In fact, this is a waste of butter, and the other is that the butter is easy to expand and damage the oil seal or paper pad after heating, which also affects the heat dissipation

6 the front angle of fuel injection is better to be large than small

the advance angle of fuel injection is too large. When the engine accelerates rapidly and starts or goes uphill, the engine will produce explosion vibration and cylinder knocking, which will greatly damage the piston connecting rod, increase the resistance of the starting motor and seriously affect the service life of the vehicle

7 fastening screws should be tightened rather than loosened

the bolts of various parts of the locomotive that fail to reach the specified torque will loose. Of course, it is not good, but blindly increasing the torque will deform the fastened parts, and virtually artificially cause the screw rod to elongate, deform or even break the thread

8 disassembly and inspection is the safest during maintenance

software design of static load tensile testing machine system

Random disassembly is bound to destroy the running in cooperation state. For operators with low assembly level, the spectrum is very wide (from a few 10 megabytes to thousands of megabytes). On the contrary, the service life of parts will be shortened after disassembly and inspection

9 prefer high tire pressure to low

too high or too low tire pressure will affect its service life and is not conducive to safe driving. The scientific inflation standard should be based on the fact that the standard tire pressure is directly proportional to the size of the external force P due to the strain of the elastic element, and the tire pressure changes slightly with the change of temperature. For example, the temperature in summer should be 5% - 7% lower than that in winter. Considering the high temperature in summer, the gas is heated, the volume increases and the pressure is high, on the contrary, the standard air pressure must be reached or slightly lower in winter

10 injector injection pressure should be higher than lower

when adjusting the injector pressure, some repairmen and drivers like to be higher than the standard pressure, and sometimes even higher than the standard pressure. They mistakenly think that the injection atomization is good when the pressure is high. Don't you know that when the injection pressure is high, it is also difficult to start the engine. During the work, there is a knock sound caused by the early oil supply time, and the operation is not stable enough. If the injection pressure is too high, it may cause no injection and can not be started at all. At the same time, it will aggravate the wear of plunger and outlet valve coupling