Robust predictions of engine vibration are important for preliminary design of new engines and new vehicles, and in setting component tolerances. Vibration modeling of internal combustion engines is commonly based on a one-way-coupling assumption between the engine’s moving internal components and the vibrating engine block. This assumption causes Coriolis and gyroscopic interactions to be neglected, and leads to a vibration model that does not properly conserve energy. This paper presents a new seven-degree-of-freedom model for low frequency engine vibrations that does not utilize the one-way-coupling assumption. The model is based on fully coupled rigid-body dynamics for the pistons, connecting rods, crankshaft, flywheel, and engine block. Predictions from the new model are compared to those from an equivalent one-way-coupled model for poorly balanced (one-cylinder) and well-balanced (inline six-cylinder) engines. Predicted mount forces are dissimilar for the poorly balanced engine but are nearly the same for the well-balanced engine. In addition, the new model is found to properly conserve energy and account for gravitational forces.

Issue Section:
Internal Combustion Engines
Keywords:
internal combustion engines, vibrations, flywheels, vibration isolation
Topics:
Cylinders, Dynamics (Mechanics), Engines, Internal combustion engines, Vibration, Pistons, Model development
1.
Norling, R. L., 1978, “Continuous Time Simulation of Forces and Motion Within an Automotive Engine,” SAE paper No. 780665.
2.
Butsuen, T., Okuma, M., and Nagamatsu, A., 1986, “Application of Direct System Identification Method for Engine Rigid Body Mount System,” SAE Paper No. 860551.
3.
Okuma, M., Ohara, T., and Nagamatsu, A., 1989, “Application of a New Experimental Identification Method to Engine Rigid Body Mount System,” SAE Paper No. 891139.
4.
Pol, P. S., 1989, “Dynamic Loads in Engine Test Benches,” 1989 ASME 12th Biennial Conference on Mechanical Vibration and Noise, Montreal, Quebec, Canada, DE-Vol. 18-4 ASME, New York, pp. 155–159.
5.
Shiao
,
Y.-J.
,
Pan
,
C.-H.
, and
Moskwa
,
J. J.
,
1994
, “
Advanced Dynamic Spark Ignition Engine Modeling for Diagnostics and Control
,”
Int. J. Veh. Des.
,
15
, pp.
578
–
596
.
6.
Snyman
,
J. A.
,
Heyns
,
P. S.
, and
Vermeulen
,
P. J.
,
1995
, “
Vibration Isolation of a Mounted Engine Through Optimization
,”
Mech. Mach. Theory
,
30
, pp.
109
–
118
.
7.
Suh, C.-H., and Smith, C. G., 1997, “Dynamic Simulation of Engine-Mount Systems,” SAE paper No. 971940.
8.
Hoffman, D. M. W., and Dowling, D. R., 1999, “Modeling Fully Coupled Rigid Engine Dynamics and Vibrations,” SAE Paper No. 1999-01-1749, Proceedings, 1999 SAE Noise and Vibrations Conference, Vol. 2, Traverse City, MI, Society of Automotive Engineers, Warrendale, PA, pp. 747–755.
9.
Hoffman, D. M. W., 1999, “In-Line Internal Combustion Engine Dynamics and Vibration,” Ph.D. thesis, University of Michigan, Ann Arbor, MI.
10.
Winton (Hoffman
),
D. M.
, and
Dowling
,
D. R.
,
1997
, “
Modal Content of Heavy-Duty Diesel Engine Block Vibration
,”
SAE Trans.
,
106
, Section 6, Part 2, pp.
2802
–
2811
.
11.
Hoffman
,
D. M. W.
, and
Dowling
,
D. R.
,
1999
, “
Limitations of Rigid Body Descriptions for Heavy-Duty Diesel Engine Vibration
,”
ASME J. Eng. Gas Turbines Power
,
121
, pp.
197
–
204
.
12.
Hoffman
,
D. M. W.
, and
Dowling
,
D. R.
,
2001
, “
Fully Coupled Rigid Engine Dynamics and Vibrations—Part II: Model Experiment Comparisons
,”
ASME J. Eng. Gas Turbines Power
,
123
, pp.
685
–
692
.
13.
Kane, T. R., and Levinson, D. A., 1985, Dynamics: Theory and Applications, McGraw-Hill, New York.
14.
Greenwood, D. T., 1988, Principles of Dynamics, 2nd ed., Prentice-Hall.
15.
Himelblau, H., and Rubin, S., 1961, “Vibration of Resiliently Supported Rigid Body,” Shock and Vibration Handbook, 2nd ed., C. Crede and C. Harris, eds., McGraw-Hill, New York, Chapter 3.
16.
Smollen
,
L. E.
,
1966
, “
Generalized Matrix Method for the Design and Analysis of Vibration-Isolation Systems
,”
J. Acoust. Soc. Am.
,
40
, pp.
195
–
204
.
17.
Fox
,
G. L.
,
1977
, “
Matrix Methods for the Analysis of Elastically Supported Isolation Systems
,”
Shock Vib. Bull.
,
46
, Part 5, pp.
135
–
145
.
18.
Den Hartog, J. P., 1985, Mechanical Vibrations, 4th ed., Dover Publications, New York.
Copyright © 2001
 by ASME
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