活塞顶坏了。
If necessary extend the probe of the dial gauge until you can definitely take measurements on the piston crown.
如有必要，延长百分表的探针，直到可以明确测量活塞顶为止。
This paper studies the fracture mechanics of piston crown crack by means of finite element method and photoelastic method.
本文应用有限元法和光弹性试验对活塞顶的裂纹进行断裂力学分析。
Also the valve heads will be liable to be burnt by the passing hot gases, and there is the likelihood of the piston crown touching an open valve, which can seriously damage the engine.
而且气门头部容易被经过的高温气体烧蚀，活塞顶部也可能会碰到气门使发动机严重损坏。
Also the valve heads will be liable to be burnt by the passing hot gases, and there is the likelihood of the piston crown touching an open valve, which can seriously damage the engine.
此外气门头易于被通过的热气体燃烧，这有可能使活塞频繁冲击打开的气门，使发动机严重损坏。
The piston head or "crown" is the top surface against which the explosive force is exerted.
活塞头部或“冠部”是整个活塞的最上端，处在燃烧室里要承受爆炸燃烧产生的力。
The crown diameter of eutectic al Si alloy piston has increased suddenly in twice, but the hyper eutectic al Si alloy piston only once.
共晶铝硅合金活塞顶部直径有两次突然长大，而过共晶铝合金活塞仅有一次。
This paper introduced a four-body contact model of steel crown-the nodular cast-iron skirt-piston pin-connecting bolt for the steel-crown aluminum-skirt composite piston of locomotive diesel engines.
本文以机车柴油机钢顶铝裙组合活塞为对象，建立组合活塞钢顶铝裙连接螺栓-活塞销的四体接触计算模型。
This paper introduced a four-body contact model of steel crown-the nodular cast-iron skirt-piston pin-connecting bolt for the steel-crown aluminum-skirt composite piston of locomotive diesel engines.
本文以机车柴油机钢顶铝裙组合活塞为对象，建立组合活塞钢顶铝裙连接螺栓-活塞销的四体接触计算模型。
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