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. 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. 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.
{"title":"Unique Approach of Modern Automotive Exhaust System Mountings Design\u0000 for NVH Improvement","authors":"Amitabh Sarna, Jitender Singh, Navin Kumar, Vikas Sharma","doi":"10.4271/02-17-03-0015","DOIUrl":"https://doi.org/10.4271/02-17-03-0015","url":null,"abstract":"Minimizing vibration transmitted from the exhaust system to the vehicle’s\u0000 passenger compartment is the primary goal of this article. With the introduction\u0000 of regulatory norms on NVH behavior and emissions targets, it has become\u0000 necessary to address these issues scientifically. Stringent emissions\u0000 regulations increased the complexity of the exhaust system resulting in\u0000 increased size and weight. Exhaust system vibration attenuation is essential not\u0000 only from the vehicle NVH aspects but also for the optimized functionality of\u0000 the subsystems installed on it. Based on earlier studies, this work adopts a\u0000 more thorough strategy to reduce vehicle vibration caused by the exhaust system\u0000 by adjusting it to actual operating conditions.\u0000\u0000 \u0000To achieve this, a complete vehicle model of 22 DOF is considered, which consists\u0000 of a powertrain, exhaust system, chassis frame, and suspension system. A method\u0000 for evaluating static and dynamic vibration response is proposed. Through the\u0000 use of the vehicle’s rigid body modes and actual field events, design indicators\u0000 are carefully analyzed and validated. Based on actual operating conditions, the\u0000 two main load cases that are taken into consideration are idling and the sweet\u0000 spot operating zone. To define the sweet spot zone of the dominant\u0000 vehicle/engine-operating scenario, the vehicle duty cycle is monitored\u0000 experimentally.\u0000\u0000 \u0000The baseline 22 DOF model results show a degradation in exhaust vibration\u0000 performance in both load cases as its yaw and bounce modes are falling into the\u0000 resonance region of the idle and sweet spot operating zone load cases,\u0000 respectively. The acceleration reduction of nearly 10–20 dB in static events,\u0000 and nearly 10 dB in dynamic events can be evident in the proposed model. The\u0000 proposed system’s outcomes demonstrate an improvement in the eigenvalues of the\u0000 yaw and bounce modes, which in turn enhances the vehicle’s overall NVH\u0000 performance in both static and dynamic load cases. Thus, the study suggests that\u0000 designers should consider the real field events’ load cases for modern exhaust\u0000 system-mounting optimization to achieve improvement in NVH behavior, fuel\u0000 efficiency, emissions performance, and durability aspects of the vehicle.","PeriodicalId":507563,"journal":{"name":"SAE International Journal of Commercial Vehicles","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141817332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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