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The engine's inevitable trend to higher output and speed has involved a lot of perplexing problems to be solved in valve gear design. Among all these problems, in modern engines, valve linkage separation has grown to be of particular interest, since the engine's great reliability at operation beyond the rated speed has come to be the first requirement. Thus valve ‘jump’ and valve ‘bounce’ are now not the valve linkage separation phenomena that might occur beyond the maximum engine speed, but those that should be expected within the speed ranges where the engines are driven with a considerable probability. This paper deals with the new simulation model, basically composed of a double mass system, which is conceived for sound reflection of such intricate valve train behaviors at the higher speed range of operation.

It is important to improve the sealing performance of bolted flanged joints subjected to internal pressure. Recently, bolted joints with flexible flanges of stamped steel have been used in an oil-pan structure of automobile from a lightweight viewpoint. However, it is difficult to improve the sealing performance of flexible bolted flanged joints due to the reduction of the interface pressure. In this paper, a liquid sealant is applied to a box-shaped flexible bolted flanged joints such as oil-pan structures subjected to internal pressure in order to improve the sealing performance. In the experiments, an internal pressure when a leakage occurred was measured in the case where box-shaped bolted flanged joints in which liquid sealant was applied to the interfaces between aluminum flexible flanges (the upper) with thickness of 1 and 3mm and the steel (aluminum) flange with 10mm thickness (the lower) and where the bolt positions are changed.

It is important to improve the sealing performance of bolted flanged joints subjected to internal pressure. Recently, bolted joints with flexible flanges of stamped steel have been used in an oil-pan structure of automobile from a lightweight viewpoint. However, it is difficult to improve the sealing performance of flexible flanged bolted joints due to the reduction of the interface pressure. In this paper, a liquid sealant is applied to a box-shape flexible flanged bolted joints subjected to internal pressure in order to improve the sealing performance. In the experiments, a leakage is observed when a box-shape flanged joints in which liquid sealants are applied to the interfaces between aluminum flexible flanges with thickness of 1 and 3 mm and the steel (aluminum) flange with 10 mm thickness. Experiments are also conducted on bolted joints with asbestos gaskets. In addition, the effects of the adjacent bolt distance and bolt preload on the sealing performance are examined.