一、一项QC课题的确定内燃机各运动机件都以高速运转,所以,工作条件是十分苛刻的。以CA10B发动机为例,其进排气门的上下往复的运动频率,高速时达1400rpm。在气门弹簧力的作用下,气门也以每分钟1400次的频率拍打、敲击气门的座圈即气门口。这里讨论的是气门口在气门的碰撞力作用下易产生的松动和脱落现象,俗称“掉气门口”。我单位以往在处理这类故障时,单纯地采用加大气门口与气门口承孔的配合过盈量的措 First, a QC project to determine the internal combustion engine parts are moving at high speed, so the working conditions are very harsh. To CA10B engine, for example, up and down the reciprocating motion of the intake and exhaust frequency, high speed up to 1400rpm. Under the action of the valve spring force, the valve beats at a frequency of 1400 times per minute, knocking on the valve seat of the valve. Discussed here is the valve easy to produce under the action of the impact of the valve loosening and shedding, commonly known as “out of breath door.” My unit in the past in dealing with such failures, simply increase the valve seat and valve port with the amount of interference measures