Efficient modelling and analysis for crankshaft three-dimensional vibrations under firing conditions

Abstract

The three-dimensional vibrations of an engine crankshaft system under firing conditions were investigated by simple modelling and analysis using the dynamic stiffness matrix method (DSMM). In the analyses, the authors took account of the dynamic behaviour of cylinder block, oil film and torsional damper. To simplify the analyses, the crankshaft was idealized by a set of jointed structures consisting of simple round rods and simple beam blocks of rectangular cross-section. The main journal bearings were idealized by a set of linear springs and dash-pots, and the flywheel was modelled by finite elements. Then the dynamic stiffness matrix (DSM) was derived in closed form for each constituent member.

To eliminate the complicated finite element method (FEM) analysis for a cylinder block of complicated structure [1,2], the authors derived the dynamic stiffness matrix from the inverse matrix of the compliance matrix. Here, the compliance matrix was derived in analytical form from the modal parameters obtained from a series of hammering tests. Finally, the dynamic stiffness matrix was constructed for the total engine system consisting of the crankshaft system and the cylinder block.

The three-dimensional vibrations of the crankshaft system and cylinder block surface vibrations near the main bearings under firing conditions were calculated for an automobile diesel engine in which five kinds of solid pulley, each with different masses and moments of inertia, and a torsional damper were attached to the crankshaft. The calculated results were compared with the experimental results.

Keywords

forced vibration vibration of rotating body modelling automobile engine crankshaft dynamic stiffness matrix method

Get full access to this article

View all access options for this article.

References

Martin

I. T.

Low

Prediction of crankshaft and flywheel dynamics. In Proceedings of IMechE Conference Autotech ′89, November 1989, paper C382/046.

Priebsch

H. H.

Affenzeller

Kuipers

Structure borne noise prediction techniques. SAE paper 900019, 1990.

Okamura

Shinno

Yamanaka

Suzuki

Sogabe

A dynamic stiffness matrix approach to the analysis of three-dimensional vibrations of automobile engine crankshaft: Part 1—Background and application to free vibrations. In Proceedings of Vehicle Noise, ASME, NCA-Vol. 9, 1990.

Morita

Okamura

A dynamic stiffness matrix approach to the analysis of three-dimensional vibrations of automobile engine crankshaft: Part 2—Application to firing conditions. In Proceedings of Vehicle Noise, ASME, NCA-Vol. 9, 1990.

Okamura

Morita

Influence of crankshaft-pulley dimensions on crankshaft vibrations and engine-structure noise and vibrations. SAE paper 931303, 1993.

Den Hartog

J. P.

Mechanical Vibrations, 1956, pp. 184–185 (McGraw-Hill).

JSME

Data Book on the Static and the Dynamic Characteristics of the Journal Bearings (in Japanese), 1984 (Japan Industrial Publication).

Morita

Okamura

Analysis of crankshaft three-dimensional vibrations in a rotating coordinate system. SAE paper 951292, 1995.

Housner

G. W.

Hudson

D. E.

Applied Mechanics Dynamics, 2nd edition, 1959, pp. 38–47 (Van Nostrand).

10.

Marion

J. B.

Classical Dynamics of Particles and Systems, 1965, pp. 342–348 (Academic Press).

11.

Juvinall

R. C.

Marshek

K. M.

Fundamentals of Machine Component Design, 2nd edition, 1991, pp. 490 (John Wiley).

12.

Shigley

J. E.

Mischke

C. R.

Mechanical Engineering Design, 5th edition, 1989, pp. 484 (McGraw-Hill).

13.

Prentis

J. M.

Leckie

F. A.

Mechanical Vibrations: An Introduction to Matrix Methods, 1963, Section 4.3 (Longmans).

14.

Klosterman

A. L.

A combined experimental and analytical procedure for improving automotive system dynamics. SAE paper 720093, 1972.

15.

Klosterman

A. L.

McClelland

W. A.

Dynamic analysis of complex system. SDRC, Seminar Supplementary Literature, 1972.