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To improve the accuracy of engine vibration analysis, the bolt model which fastens an engine head and an engine block had been developed. In the conventional method of engine vibration analysis, the bolt was modeled with a rigid bar. However, it is seen that the power plant rigidity becomes higher in proportion to the rigid bar bolt length. So, to precisely predict the vibration property of engine parts, the elastic deformation of the bolt was considered in this paper. It is known that the parameters, which are Young's modulus, the length of bolts, the distance between bolts, the area of contact plane, the tightening torque and so on, have a great influence on the performance of the engine vibration model. This paper describes a study of FE bolt model to correlate eigenvalue and mode shapes with the test result. The effects of following parameters were investigated: 1) Bolt model with elastic material 2) Rigidity of bolted-connection in tightening plane.

This paper discusses the prediction method of engine mount vibration using multi body simulation (MBS) with FE models in power plant assembly. In this analysis, some parts of the power plant were modeled with shell type elements and solid type elements, and modal parameters from FEA were imported into MBS, which method is called “Component Mode Synthesis”. For this analysis, the computational models of Suzuki 660cc in-line 3-cylinder engine with 4-speed automatic transmission were used. The flexibility of some engine parts was considered using FE models regarding the cylinder block, the crankshaft, the transmission case, etc. Also the properties of stiffness and viscous damping of the engine mount bushings were considered and the properties of the hydrodynamic oil film at the journal bearings were modeled with “Enhanced Short Bearing Model”. Accelerations at each engine mount were calculated.

The Mechanical CVT is mainly used for small size motorcycle called “scooter”, which has a 250 cc or less engine capacity. The speed characteristics of the Mechanical CVT are decided by engine speed and load-torque on driven pulley. In few papers, these characteristics are studied under full-load or no-load condition [1]-[2]. However, the characteristics at part-load condition are not well known. To develop a motorcycle with low fuel consumption, it is important that the characteristics at part-load condition are considered in driving cycle. Driving cycle simulation is needed to estimate CVT ratio at design stage. This research proposes equations representing the speed characteristics of the Mechanical CVT at part-load condition. Driving cycle simulation is also developed for estimation of the fuel consumption at optional driving cycles and the dynamic behavior of the CVT system. It could be a CVT design tool to makes sure whether its performance is achieved for design targets.