Natural frequencies are very important characteristics of a valve train system. From the measured natural frequencies of a valve train the following can be determined: will the system have acceptable dynamic behavior, is one valve train system design superior to another, and is a dynamic model of the system properly setup. The three most important modes of vibration of a valve train system are the fundamental mode of vibration of the entire linkage (system natural frequency), translation of the valve spring, and torsion of the camshaft. Valve trains are nonlinear systems due to varying system geometry throughout the lift event. It is important to have a natural frequency measurement technique that accommodates the nonlinearity of the valve train and that takes out as much subjectivity in determining the natural frequencies as possible. In this discussion, three different natural frequency measurement techniques are reviewed, which characterize one or more the three most important modes of vibration of the valve train. A significant part of the work done for this thesis project is on the development of a step input method for measuring valve train natural frequencies. Also discussed in this thesis are the effects of system nonlinearity and two nearby frequencies of one system on the frequency analysis results. The differences between low and high natural frequency systems are also discussed.
Library of Congress Subject Headings
Valves; Vibration--Measurement; Engines
Department, Program, or Center
Mechanical Engineering (KGCOE)
Greene, Cynthia, "Valve train natural frequency measurement and analysis" (1997). Thesis. Rochester Institute of Technology. Accessed from
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