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Simulation technology that enables the holding limit of a tensioner to be predicted in advance was developed, and the effect of the tensioner on the chain clarified. The simulation model was constructed using multi-body dynamics. For the analysis, a link-by-link method was used, and a hybrid model of the tensioner consisting of multiple masses and oil was created. In comparing the tensioners, the main viewpoint was the difference between the spring type and hydraulic tensioners. The effect of each tensioner on the chain load and the chain behavior was clarified through this analysis, and as a result it was possible to predict the optimum chain system design by simulation.

To develop ideal oil circuits, it was necessary to establish technology that would accurately predict lubrication oil pressure and flow rates. Therefore, the oil flow rate was predicted by applying load fluctuations, calculated using multi body dynamics, to an oil film model. In addition, the pressure loss of complex oil passages was obtained using 3-dimensional computational fluid dynamics (hereafter, “3D-CFD”). Furthermore, the pressure loss of the oil pressure switching valves and other parts that are difficult to predict using 3D-CFD were measured as single parts, and these results were linked with one-dimensional internal flow analysis to develop a prediction method for lubrication oil pressure and flow rate distributions. Verification tests were ultimately performed using a completed engine, and the results confirmed that this simulation method accurately reproduces the oil pressure and oil flow rate in each part.

An increasing number of chain systems have used low cost blade tensioners. However, its functional mechanism had not been logically figured out. One reason for this is that a blade tensioner generates large transversal vibration. Consequently, in the case of the longitudinal model, the load prediction accuracy was inadequate. Accordingly, a link-by-link model was created, allowing transversal vibration to be taken into account. As a result, the features of a chain system using a blade tensioner were clarified, thus enabling the chain load and behavior to be predicted with a higher degree of accuracy than before.