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Multiple-ribbed V belts have been widely used in automotive accessory drive systems to transmit power from crankshaft to power steering pump, alternator, and air conditioning (A/C) compressor. Overload under severe environmental conditions can lead to excessive slippage in the belt pulley interface in poorly designed accessory drive systems. This can lead to undesirable noise that increases warranty cost substantially. The mechanisms of this tribology phenomenon, noise features and system response are of utmost interest to the accessory drive system engineers. As accessory belt systems are usually used in ambient condition, the presence of water or moisture on belt is unavoidable under rainy or highly humid conditions. It has been found that the wet friction with negative coefficient of friction (cof)-velocity slope can lead to self-excited vibrations and squeal noise.

This paper studies the dynamics and noise of timing belt. A comprehensive theoretical contact dynamics model for belt tooth-sprocket tooth pair is developed. The general belt dynamics model in conjunction with the contact model is used to quantify the impact-sliding process of belt tooth. The effect of tooth meshing process is illustrated which results in the vibrations of belt span and tooth vibrations. The structural borne noise consists of structural impact portion and friction-induced portion. The relationship between system parameters and noise is quantified. The air borne noise due to air-pumping is investigated based on Lighthill's equation. A comprehensive model is developed and the spectrum signatures of the air-pumping noise are illustrated.

Serpentine belt system has been widely used to drive automotive accessories like power steering pump, alternator, and A/C compressor from a crankshaft pulley. Overload under severe conditions can lead to excessive slippage in the belt pulley interface in poorly designed accessory systems. This can lead to undesirable noise that increases warranty cost substantially. The mechanisms and data of these tribology performance, noise features and system response are of utmost interest to the accessory drive designers. As accessories belt systems are usually used in ambient condition, the presence of water on belt is unavoidable under the raining weather conditions. The presence of water in interface induces larger slippage as the water film in interface changes the friction mechanisms in rubber belt-pulley interface from coulomb friction to friction with mixed lubrication that has negative slope of coefficient of friction (cof) - velocity.

In this paper, a nonlinear dynamic model for automotive cushion-human body combined structure is developed based on a nonlinear seat cushion model and a linear ISO human body model. Automotive seat cushions have shown to exhibit nonlinear characteristics. The nonlinear seat cushion model includes nonlinear stiffness and nonlinear damping terms. This model is verified by a series of tests conducted on sports car and luxury car seats. The transfer functions from the tests for human body sitting on an automotive seat changes with the vibration platform input magnitudes. This indicates that the combined structure possesses nonlinear characteristics. The nonlinear model is validated by the transfer functions from the test. The paper discusses the influence of the parameters of the nonlinear structure on the design of seat and assessment of human body comfort.

This paper presents an experimental study of automotive V-ribbed belt slip noise under cold condition. In this study, a set of experiments was conducted to investigate the properties of the belt noise and friction using a self developed rig. The belt friction under cold condition is found to have higher value than that in room condition. The belt noise under cold condition is found to have much higher squeal frequency than that in room condition. This study is expected to provide accessory drive designers some fundamental understanding of belt startup noise under cold conditions.

This paper introduces a cumulative effort on the phenomenon of exhaust flow exited noise. The mechanisms of engine combustion noise via the exhaust system and flow excited noise are analyzed. Engine combustion noise contributes most to tailpipe noise at lower engine speed while flow excited noise dominates the tailpipe noise at high engine speed. WAVE model, a one dimension CFD and Acoustics model, is used to distinguish the engine combustion noise and flow excited noise. Both CAE and tests based results are used to draw conclusions. The influence of single system and quasi-dual system on the tailpipe noise is compared with each other. The paper analyzes the balance of different diameter pipes to achieve the desired sound at different rpm range. The evaluation balance between interior sound and tailpipe noise is described.

This book gives readers a working knowledge of vehicle vibration, noise, and sound quality. The knowledge it imparts can be applied to analyze real-world problems and devise solutions that reduce vibration, control noise, and improve sound quality in all vehicles—ground, aerospace, rail, and marine. Also described and illustrated are fundamental principles, analytical formulations, design approaches, and testing techniques. Whole vehicle systems are discussed, as are individual components. The latest measurement and computation tools are presented to help readers with vehicle noise, vibration, and sound quality issues. The book opens with a presentation of the fundamentals of vibrations and basic acoustic concepts, as well as how to analyze, test, and control noise and vibrations. The next 2 chapters delve into noise and vibrations that emanate from powertrains, bodies, and chassis.