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Vibration behavior of a crankshaft in operation is complicated and difficult to simulate because of oil effects on journals, coupled vibration of crankshaft system parts, combustion and inertia acting on the crankshaft. Particularly, the stiffness and damping of oil film vary with crank angles and thus the numerical analysis must deal with nonlinear vibration. This oil film effects also diversify the vibration modes of the crankshat; the vibration modes in an actual operation differs from that in statically experiment modal analysis. This paper describes a new method developed by the author to analyses, predict, and reduce noise and vibration using several techniques including numerical simulation, finite element method, Sommerfeld concept on oil film effects, and modal frequency response.

Eight kinds of the spot-welded test specimens were studied to obtain the basic fatigue data on steel sheets for car bodies. Analytical methods such as the strain amplitude at outside and inside plates close to the nugget, the maximum nominal stress and Kθmax criteria of fracture mechanics were used. The authors propose that the ratio of strains at two points around the nugget can provide evaluation of the bending load and estimation of the fatigue strength.

This paper describes the characteristics and mechanism of crankshaft impact noise that radiates from the cylinder body at full load medium engine speeds, based on the mechanism for axial vibration of crankshaft coupled with torsional vibration of crankshaft.

Experiment results were compared with computation analysis results for torsional vibration on a crankshaft system with/without a torsional viscous damper on a six-cylinder in-line type turbocharged diesel engine and a V type ten-cylinder naturally-aspirated diesel engine respectively. At first, the boundary conditions for boundary element method (BEM) model were determined to estimate the torsional stiffness of the crank-throws of the crankshafts. Then, the estimated stiffness was used to calculate the natural frequencies of the torsional vibration without the damper by dynamic stiffness matrix method. As a result, the calculated natural frequencies approximately agreed with the measured ones. Finally, the torsional vibration with the damper was analyzed by using the dynamic stiffness matrix method and complex viscous damping coefficients for the damper. The calculated torsional amplitudes and resonant engine speeds agreed with the experiment results.

Countour Induction Hardening (CIH) method is in the limelight as a new possible surface refining method for gears as it reduces quenching distortion considerably and increases compressive residual stress. Also, Double Shot Peening (DSP) method, especially its advanced technique of using extensively small shots (less than 100 m) at the secondary peening, enables increased compressive residual stress under the surface of the gears. Therefore, the new Compound Surface Refining Method of using CIH + DSP is expected to give much higher compressive residual stress than the conventional methods. On studying the application of this new method, the authors evaluated their surface-refining characteristics and the fatigue limits.

There is ever an increasing need for weight reduction and high performance of engine (clean smoke and improving fuel economy) To achieve this, recently aluminum castings are used for engine parts such as cylinder heads that construct combustion chamber and are required thermal resistance. This paper describes thermal fatigue tests of aluminum castings that are made under various conditions of cooling rate during solidification, heat treatment, and chemical compositions. It further investigates the influence of material (such as cooling rate, chemical conmposition and heat treatment) and mechanical properties (such as σB, δ, E ) on thermal fatigue life of aluminum castings.

Two working groups in the JSAE Committee of Fatigue–Reliability Section1 are currently researching the issue of fatigue life by both experimental and the CAE approach. Information regarding frequent critical problems on arc–welded structures were sought from auto–manufacturers, vehicle component suppliers, and material suppliers. The method for anti–fatigue design on arc–welded structures was established not only by a database created by physical test results in accordance with the collected information but also with design procedure taking Fracture–Mechanics into consideration. This method will be applied to vehicle development as one of the virtual laboratories in the digital prototype phase. In this paper, both the database from bench–test results on arc welded structures and FEA algorithm unique to JSAE are proposed some of the analysis results associated with the latter proposal are also reported.

A simple and easy calculation may be performed, using a three-mass vibration system model, to study the influence of an engine mounting on automobile vertical vibration. The advantage of an engine mounting of high damping rubber is confirmed by this calculation, and is further verified by using power and cross spectral analysis of an automobile random vibration. The validity of the three-mass vibration system is shown.