磨:即磨合,是延长柴油机使用寿命的基础,无论是新的还是大修后的柴油机,都必须按规定进行磨合后方能投入正常作业。净:即油净、水净、气净和机车净。柴油是发动机的主燃料,若柴油不净,会使精密偶件磨损,配合间隙增大,滴油、漏油和供油压力不足,燃烧恶化,功率下降。同样,若机油不净,会使轴颈和轴瓦间产生磨料磨损,间隙变大,油压降低,甚至造成油道堵塞、抱轴烧瓦等严重事故。若空气含有大量尘土,将会加速缸套、活塞和活塞环的磨损,缩短使用寿命。若冷却水不净, Grinding: run-in, that is to extend the service life of diesel engines, whether it is new or overhaul of the diesel engine, must be carried out in accordance with the provisions of the run-in before they can put into normal operation. Net: that the net oil, water net, net air and locomotive net. Diesel is the main fuel of the engine. If the diesel is not clean, it will wear the precision coupling parts, increase the clearance, reduce the pressure of the oil drip, oil spill and fuel supply, deteriorate the combustion and reduce the power. Similarly, if the oil is not clean, there will be abrasive wear between the journal and the bearing, the gap will become larger, the hydraulic pressure will be reduced, and even cause the blockage of the oil passage and the serious problem of the axle burning bush. If the air contains a lot of dust, will accelerate the cylinder liner, piston and piston ring wear and reduce service life. If the cooling water is not clean