Fundamentals of IC engine torsional vibration
Fluctuations in IC engine cylinder pressure are an obvious source of torsional vibration excitation, although the details of the coupling from cylinder pressure to torque on the crankshaft are complicated. A second, less obvious source of torsional excitation is the effect of variable inertia associated with the engine slider-crank mechanism. This is a tutorial paper, intended to show the relation between, on the one hand, the actual engine slider-crank mechanism subject to combustion gas pressure and, on the other hand, the models commonly used for torsional vibration analysis that involve constant inertias subject to torques expressed by Fourier series. As such, it uses some new approaches to reach previously known results with a greater degree of physical insight. The presentation is in terms of a single cylinder, two stroke engine with load, and makes clear the roles of piston mass, connecting rod mass and moment of inertia, and crank inertia as they affect both the effective inertia and the effective torque. The determination of natural frequencies and the forced vibration response calculation are briefly described to complete the analysis. The development of a Fourier series representation for the effective torque, including both the cylinder pressure and inertia variation is also discussed. The various components for the response are identified, in an effort to clarify the meaning of terms such as ''zero frequency mode,'' ''rigid body mode,'' and ''twisting mode.''
- OSTI ID:
- 5330624
- Report Number(s):
- CONF-880104-
- Resource Relation:
- Conference: 11. annual energy-sources technology conference and exhibition, New Orleans, LA, USA, 10 Jan 1988; Other Information: Technical Paper 88-ICE-6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
INTERNAL COMBUSTION ENGINES
CYLINDERS
MECHANICAL VIBRATIONS
CALCULATION METHODS
FOURIER TRANSFORMATION
FREQUENCY ANALYSIS
PRESSURE DEPENDENCE
TORSION
ENGINES
HEAT ENGINES
INTEGRAL TRANSFORMATIONS
TRANSFORMATIONS
330100* - Internal Combustion Engines
330603 - Vehicle Design Factors- Engine System