Hanger Location Design and Vibration Isolation of an Exhaust System

Chen, Xiaoxun; Yu, Zhang; Zhang, Yunqing; Jiang, Ming

doi:10.4271/2014-01-1708

Cited by 6 publications

(1 citation statement)

References 8 publications

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“…The excitation is assumed to be single point drive. According to the modal analysis theory of multi-degree of freedom system, the response function between the response point l and exciting point p can be described as following [4]:…”

Section: Addofd Methodsmentioning

confidence: 99%

Analysis on Hanger Location and Hanger Isolator of an Exhaust System with Powertrain

Liu¹,

Zhang²,

Du³

et al. 2014

Proceedings of the 2014 International Conference on Mechatronics, Electronic, Industrial and Control Engineering

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To improving the NVH (Noise, Vibration and Harshness) performance of vehicles, the NVH performance of exhaust system must be considered. As hanger is the main vibration transfer path and hanger isolator is the crucial vibration isolation components, it is necessary to study hanger location and stiffness of vibration isolation. About the study of exhaust system is executed in four steps. Firstly, according the free modal analysis of the exhaust system, the ADDOFD (Average Driving Degree of Freedom Displacement) is acquired, and the suitable location of hanger is confirmed soon. Secondly, studied the powertrain influences to the vibration performance of exhaust system, the constrained modal frequencies must avoid the engine idle resonant frequency. Thirdly, the dynamic analysis of the exhaust system is researched based on the second step, in which way 100000N•mm sinusoidal excitation is applied at the powertrain's barycenter in the crankshaft rotation direction, and then the response reaction force (less than 5N) of the hanger are gained. Finally, the relationship between the bending and torsional modes of exhaust system and the stiffness of the hanger isolator are inquired. It is of great engineering significance.

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Section: Addofd Methodsmentioning

confidence: 99%

Analysis on Hanger Location and Hanger Isolator of an Exhaust System with Powertrain

Liu¹,

Zhang²,

Du³

et al. 2014

Proceedings of the 2014 International Conference on Mechatronics, Electronic, Industrial and Control Engineering

View full text Add to dashboard Cite

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Influence of Exhaust Aftertreatment System on Powertrain Vibration Behavior

Sarna,

Singh,

Kumar

et al. 2024

SAE Int. J. Commer. Veh.

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<div>NVH refinement of commercial vehicles is the key attribute for customer acceptance. Engine and road irregularities are the two major factors responsible for the same. During powertrain isolators’ design alone, the mass and inertia of the powertrain are usually considered, but in practical scenarios, a directly coupled subsystem also disturbs the boundary conditions for design. Due to the upgradation in emission norms, the exhaust aftertreatment system of modern automotive vehicles becomes heavier and more complex. This system is further coupled to the powertrain through a flexible joint or fixed joint, which results in the disturbance of the performance of the isolators.</div> <div>Therefore, to address this, the isolators design study is done by considering a multi-body dynamics model of vehicles with 16 DOF and 22 DOF problems, which is capable to simulate static and dynamic real-life events of vehicles. Design indicators are thoroughly analyzed and validated through the rigid body modes and real field events of the vehicle. As most of the research is done for four-point mounting powertrain systems by considering 6 DOF or 12 DOF in commercial vehicles but a novel approach with a 22 DOF model is proposed in this study to predict the impact of the inclusion of the exhaust aftertreatment system on torque roll axis and rigid body modes decoupling.</div> <div>The results of the proposed system show that the rigid body mode decoupling of the powertrain system improved and consequently the overall NVH performance of the vehicle in real life is further improved. Therefore, it is suggested from the study that ignoring the inclusion of the exhaust aftertreatment system in the powertrain mounting system design reduces the NVH performance of the vehicle, hence it is recommended to include it in the early phase of design.</div>

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Unique Approach of Modern Automotive Exhaust System Mountings Design for NVH Improvement

Sarna,

Singh,

Kumar

et al. 2024

SAE Int. J. Commer. Veh.

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<div>Minimizing vibration transmitted from the exhaust system to the vehicle’s passenger compartment is the primary goal of this article. With the introduction of regulatory norms on NVH behavior and emissions targets, it has become necessary to address these issues scientifically. Stringent emissions regulations increased the complexity of the exhaust system resulting in increased size and weight. Exhaust system vibration attenuation is essential not only from the vehicle NVH aspects but also for the optimized functionality of the subsystems installed on it. Based on earlier studies, this work adopts a more thorough strategy to reduce vehicle vibration caused by the exhaust system by adjusting it to actual operating conditions.</div> <div>To achieve this, a complete vehicle model of 22 DOF is considered, which consists of a powertrain, exhaust system, chassis frame, and suspension system. A method for evaluating static and dynamic vibration response is proposed. Through the use of the vehicle’s rigid body modes and actual field events, design indicators are carefully analyzed and validated. Based on actual operating conditions, the two main load cases that are taken into consideration are idling and the sweet spot operating zone. To define the sweet spot zone of the dominant vehicle/engine-operating scenario, the vehicle duty cycle is monitored experimentally.</div> <div>The baseline 22 DOF model results show a degradation in exhaust vibration performance in both load cases as its yaw and bounce modes are falling into the resonance region of the idle and sweet spot operating zone load cases, respectively. The acceleration reduction of nearly 10–20 dB in static events, and nearly 10 dB in dynamic events can be evident in the proposed model. The proposed system’s outcomes demonstrate an improvement in the eigenvalues of the yaw and bounce modes, which in turn enhances the vehicle’s overall NVH performance in both static and dynamic load cases. Thus, the study suggests that designers should consider the real field events’ load cases for modern exhaust system-mounting optimization to achieve improvement in NVH behavior, fuel efficiency, emissions performance, and durability aspects of the vehicle.</div>

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Hanger Location Design and Vibration Isolation of an Exhaust System

Cited by 6 publications

References 8 publications

Analysis on Hanger Location and Hanger Isolator of an Exhaust System with Powertrain

Analysis on Hanger Location and Hanger Isolator of an Exhaust System with Powertrain

Influence of Exhaust Aftertreatment System on Powertrain Vibration Behavior

Unique Approach of Modern Automotive Exhaust System Mountings Design for NVH Improvement

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