In this paper, kinematics of upper air valve unit is analyzed. The displacement, velocity and acceleration of air valve are calculated by accurate and approximate methods.

对顶置式气门机构进行了运动学分析，通过平底推杆的运动规律求得气门的升程、速度和加速度，分别给出了精确解和近似解。

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But it also had some non-original parts, including Model A cranks and rods, an overhead valve unit built for 1920s dirt-track racing and dual carburetors from the 1930s.

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The dealership diagnosed it as a faulty valve body unit (mechatronic unit in VW speak) and replaced it.

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But then at 4:00 a.m. on Mar. 28, 1979 a cooling valve got stuck at the Three Mile Island Nuclear Generating Station's Unit 2.

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