The working environment of underground loader is relatively bad, so it will cause all kinds of problems after a long time of use, especially the engine which plays a decisive role in the loader. The early wear of engine of underground loader refers to the phenomenon that the power of diesel engine is greatly reduced and the fuel consumption is increased due to the wear of main moving pairs in a short period of time, so that the diesel engine can not continue to work effectively. The main reasons for the early wear of diesel engine are as follows:

①新机不经过磨合就大负荷运行。冷车起动后，应在小油门状态下暖车3～5分钟才能起步行车，起初运行时，应小负荷工作一段时间，待温度升高后再大负荷作业。

① The new machine runs at a high load without running in. After cold start, warm up the car for 3-5 minutes under the condition of small throttle, and then start driving. At the beginning of operation, work with small load for a period of time, and work with large load after the temperature rises.

②空气滤清器失效。

② Air filter failure.

③使用保养不当，机油质量差。

③ Improper use and maintenance, poor oil quality.

④燃烧不好，使气缸积炭过多。发动机刚起动后，机器温度低，柴油燃烧不完全。此时，若加大油门，增加供油量，多余的没燃烧柴油就会形成积炭，使发动机排放加剧。此外，多余的柴油还可能沿气缸壁流入曲轴箱，影响气缸壁润滑，并会稀释油底壳的机油，降低润滑性能，减少发动机的使用寿命。

④ Poor combustion causes excessive carbon deposition in the cylinder. After the engine is just started, the temperature of the machine is low, and the diesel combustion is incomplete. At this time, if you increase the throttle and fuel supply, the extra unburned diesel will form carbon deposit, which will aggravate the engine emissions. In addition, the excess diesel may flow into the crankcase along the cylinder wall, affecting the lubrication of the cylinder wall, diluting the oil in the oil pan, reducing the lubrication performance and the service life of the engine.

对于装有废气涡轮增压器的发动机，更应注意暖车。如果起动后立即加大油门，涡轮的转速升高，而机油来不及到达各润滑部位表面，形不成良好润滑，很容易产生涡轮转轴卡死的现象，造成故障。

For the engine with exhaust turbocharger, more attention should be paid to warm up. If the accelerator is increased immediately after starting, the speed of the turbine will increase, and the oil will not reach the surface of each lubricating part in time, which will lead to bad lubrication. It is easy to cause the turbine shaft to jam and cause failure.