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Engine balance refers to those factors in the design, production, engine tuning, maintenance and the operation of an engine that benefit from being balanced. Major considerations are: * Balancing of structural and operational elements within an engine * Longevity and performance * Power and efficiency * Performance and weight/size/cost * Environmental cost and utility * Noise/vibration and performance This article is currently limited to structural and operational balance within an engine in general, and balancing of piston engine components in particular. ==Overview== Piston engine balancing is a complicated subject that covers many areas in the design, production, tuning and operation. The engine considered to be well balanced in a particular usage may produce unacceptable level of vibration in another usage for the difference in driven mass and mounting method, and slight variations in resonant frequencies of the environment and engine parts could be big factors in throwing a smooth operation off balance. In addition to the vast areas that need to be covered and the delicate nature, terminologies commonly used to describe engine balance are often incorrectly understood and/or poorly defined not only in casual discussions but also in many articles in respected publications. Internal combustion piston engines, by definition, are converter devices to transform energy in intermittent combustion into energy in mechanical motion. A slider-crank mechanism is used in creating a chemical reaction on fuel with air (compression and ignition), and converting the energy into rotation (expansion). The intermittent energy source combined with the nature of this mechanism make the engine naturally vibration-prone. Multi-cylinder configuration and many of the engine design elements are reflections of the effort to reduce vibrations through the act of balancing. This article is organized in six sections: * "Items to be balanced" :: lists the balancing elements to establish the basics on the causes of imbalance. * "Types of vibration" :: lists different kinds of vibration as the effects of imbalance. * "Primary balance" :: discusses the term "Primary balance". * "Secondary balance" :: explains what Secondary balance is, and how the confusing terminologies 'Primary' and 'Secondary' came into popular use. * "Inherent balance" :: goes into engine balance discussions on various multi-cylinder configurations. * "Steam locomotives" :: is an introduction to the balancing of 2-cylinder locomotives and includes the wheel hammer effect unique to steam locomotives. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「engine balance」の詳細全文を読む スポンサード リンク
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