论文部分内容阅读
一台挖掘机匹配6135柴油机,在工作中有冒烟现象,经检查,气门间隙过大引起发动机冒烟。气门间隙经正确调整后烟度消失。但是工作几个班次后又有冒烟现象。再次检查调整气门间隙,烟度再次消失。周而复始。 拆开检查,发现气门挺杆弯曲。气门挺杆弯曲会引起气门间隙变化。气门挺杆为什么会弯曲?根据常规推测是配气相位错或气门顶活塞。可是配气相位经检查正确无误。同时活塞顶部亦没有碰撞印迹,这说明挺杆的弯曲原因不在于此。进一步详细检查,发现挺杆弯曲的部位都是在挺杆下半部,并在上半部有磨损的印痕,而且靠外面。由此看来挺杆有倾斜的现象。根据这种现象我们认为是气门调整螺丝座孔不垂直于缸盖上平面,而是偏于外倾,因而当气门开启最大位置时,气门调整螺丝外倾角增大因而将挺杆推动倾斜角度也就越大,甚至将挺杆上端挤压在挺杆孔上边缘,形成挺杆下部向内弯曲。由于挺杆弯曲,气门间隙就随之变大。造成气门不能按时开启。气缸内形成过浓混合气,燃烧不完全而冒烟。把挺杆校直后,更换了标准摇臂故障排除。
An excavator matching 6135 diesel engine, smoke at work, after inspection, the valve clearance is too large to cause the engine to smoke. After the valve clearance is properly adjusted, the smoke disappears. However, after a few shifts in work there was a smoke phenomenon. Check again to adjust the valve clearance, smoke disappears again. Cycle again and again. Open the inspection and found that the valve tappet bending. Valve lifter bending can cause valve clearance changes. Why valve tappet bending? According to the conventional guess is the valve with the wrong phase valve or valve piston. However, with the gas phase check correct. At the same time, there was no impact imprint on the top of the piston, which indicated that the reason for the bending of the tappet was not that. Further examination revealed that the tappet was bent at the lower half of the tappet, with impressed marks on the upper half, and on the outside. It seems that the tappet tilted phenomenon. According to this phenomenon, we think that the valve seat screw hole is not perpendicular to the cylinder head plane, but partial to the camber, so when the valve is opened to the maximum position, the valve camber angle increases and thus push the tappet tilt angle The bigger it is, and even the upper end of the tappet is pressed against the upper edge of the tappet hole to form a bent lower part of the tappet. As the tappet bending, valve clearance will become larger. Cause the valve can not be opened on time. Cylinder to form a thick mixture, incomplete combustion and smoking. After the tappet alignment, replace the standard rocker troubleshooting.