Effect of the torsional vibration depending on the number of cylinders in reciprocating engines

1995 ◽

Vol 209 (1) ◽

pp. 11-15 ◽

Cited By ~ 11

Author(s):

D C Hesterman ◽

B J Stone

Keyword(s):

Literature Review ◽

Recent Work ◽

Current Literature ◽

Torsional Vibration ◽

Angular Position ◽

Inertia Effect ◽

Secondary Resonance ◽

Inertia Effects ◽

Reciprocating Engines ◽

The Subject

It has been known for some time that the torsional vibration of reciprocating engines and pumps cannot be modelled accurately by representing the reciprocating mechanism by a constant inertia. There have been many publications describing better models than those that use constant inertia and these indicate that the effective inertia of a reciprocating mechanism varies with angular position. The major component of this variation is a twice per revolution cyclic effect—hence the term ‘secondary inertia’. The consequences of this secondary inertia effect can be serious for torsional vibration causing ‘secondary resonance,’ and even instability. This paper contains a review of the current literature on the subject and introduces some recent work by the authors.

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Nonlinear Aspects of the Performance of Centrifugal Pendulum Vibration Absorbers

Journal of Engineering for Industry ◽

10.1115/1.3670529 ◽

1964 ◽

Vol 86 (3) ◽

pp. 257-263 ◽

Cited By ~ 42

Author(s):

D. E. Newland

Keyword(s):

Torsional Vibration ◽

Large Amplitude ◽

Vibration Absorbers ◽

Aircraft Engines ◽

Reciprocating Engines ◽

Centrifugal Pendulum Vibration Absorbers ◽

Large Amplitude Motion

Centrifugal pendulums have been used for many years to limit the torsional vibration of reciprocating engines. Recently small pendulums, designed to swing through amplitudes of about 45 deg, have been tested for lightweight aircraft engines. These have not functioned properly, and have been found to swing through much larger angles than expected, damaging the stops limiting motion of the pendulum counterweight. This paper investigates the large-amplitude motion of centrifugal-pendulum vibration absorbers.

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A Systems Approach to the Torsional Vibration of Multi-Cylinder Reciprocating Engines and Pumps

Proceedings of the Institution of Mechanical Engineers Part C Journal of Mechanical Engineering Science ◽

10.1243/pime_proc_1994_208_145_02 ◽

1994 ◽

Vol 208 (6) ◽

pp. 395-408 ◽

Cited By ~ 11

Author(s):

D C Hesterman ◽

B J Stone

Keyword(s):

Time Domain ◽

Torsional Vibration ◽

Natural Frequencies ◽

Systems Approach ◽

Angular Position ◽

Rotary Inertia ◽

Rotating Systems ◽

Simulation Techniques ◽

Reciprocating Engines ◽

The Time Domain

The systems approach for the vibration analysis of complex systems requires that the receptances of the sub-systems are available. For the torsional vibration of rotating systems including reciprocating engines and/or pumps it has been the practice to represent the reciprocating mechanism by a constant rotary inertia. This paper describes the derivation of the receptance for such reciprocating mechanisms, which includes the effects of non-constant rotary inertia. It is then shown how the natural frequencies for torsional vibration vary with angular position and how this in turn affects the vibration in the time domain. The significance of the effects indicated by these simulation techniques is then demonstrated by comparing with results obtained from an experimental investigation.

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Effect of Gas Forces on Parametrically Excited Torsional Vibrations of Reciprocating Engines

Journal of Ship Research ◽

10.5957/jsr.2001.45.4.262 ◽

2001 ◽

Vol 45 (04) ◽

pp. 262-268

Author(s):

M. S. Pasricha

Keyword(s):

Torsional Vibration ◽

Parametrically Excited ◽

Inertia Effects ◽

Resonance Effects ◽

The Past ◽

Secondary Resonances ◽

Reciprocating Engines ◽

Marine Diesel ◽

Crankshaft Rotation ◽

Engine Systems

In the past the effects of ignoring the variable inertia characteristics of reciprocating engines on the accuracy of torsional vibration calculations were considered to be negligible. The associated secondary resonances tended to be dismissed by most engineers as interesting but of no importance. The situation changed in recent years, since there was evidence of the existence of the secondary inertia effects, which could have contributed to a number of otherwise inexplicable crankshaft failures in large multi-cylinder marine diesel engine systems. In view of these facts, a mathematical model is derived with key nondimensional parameters for the analysis of the effect of gas forces on the motion of the variable inertia system. The complex waveform responses are examined in detail within the range of speeds of engine rotation at which adverse effects are known to have occurred in practice. The effects on the parametrically excited motion of the system are investigated at a particular speed of the crankshaft rotation due to the action of external excitations with respect to changes in phase angle and inertia ratio. It is shown that under certain circumstances, interaction of secondary resonance effects with the excitations can be serious for torsional vibration. General comments on Draminsky's work in the light of present investigations are included.

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Torsional Vibrations in Reciprocating Engines

Journal of Ship Research ◽

10.5957/jsr.1976.20.1.32 ◽

1976 ◽

Vol 20 (01) ◽

pp. 32-39

Author(s):

M. S. Pasricha ◽

W. D. Carnegie

Keyword(s):

Torsional Vibration ◽

Mean Value ◽

Engineering Practice ◽

Torsional Vibrations ◽

Secondary Resonance ◽

Reciprocating Engines ◽

Marine Engines ◽

The Subject ◽

Theoretical Results ◽

Crank Mechanism

In the case of reciprocating engines, there are certain critical speeds of running at which the torsional vibrations in the shaft become large in amplitude and introduce an element of danger into the system. Fairly simple methods have been devised for the practical calculations to predict the torsional vibration characteristics from the constants of the machinery. The torsional vibration phenomenon in the running gear of reciprocating machinery is usually dealt with by considering a series of constant inertias connected by sections of massless shafting. In recent years several cases of fractures in the crankshafts of large marine engines have been attributed to the phenomenon of secondary resonance, which is explained from the fact that the effective inertia of each slider-crank mechanism varies about a mean value in relation to the position of the crank. Simplified theories predicted these designs of diesel engines as safe in practice. In view of the importance of the subject of torsional vibrations in engineering practice, the effects of variation in inertia on the torsional vibration of the system are examined in detail in the present paper. A comparison of theoretical results with Goldsbrough's experimental results is included.

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