China
Africa
Explore chapters and articles related to this topic
Modelica as a Platform for Real-Time Simulation
Published in Katalin Popovici, Pieter J. Mosterman, Real-Time Simulation Technologies, 2017
John J. Batteh, Michael M. Tiller, Dietmar Winkler
To illustrate this point, a vehicle modeling example is considered. There are many compliant elements in a vehicle drivetrain, and these elements can lead to significant noise, vibration, and harshness (NVH) issues in the driveline as excited under various driving conditions. Capturing the NVH effects in the drive-line necessitates the modeling of the key compliances in the system and results in higher-order dynamics in the vehicle drivetrain. These higher-order dynamics are, in fact, the focus of the NVH modeling effort. In addition to the NVH model, another class of vehicle models is focused on the simulation of vehicle performance and fuel economy. Performance and fuel economy models are typically simulated over long time scales, including drive cycles that can be thousands of seconds in length. On this time scale, the higher-frequency NVH effects do not typically impact the vehicle-level results significantly. Thus, the idealization of the drivetrain as rigid is a perfectly reasonable assumption for a performance and fuel economy model.
Lightweight Thermoset Foams in Automotive Applications
Published in Omar Faruk , Jimi Tjong , Mohini Sain, Lightweight and Sustainable Materials for Automotive Applications, 2017
Numaira Obaid, Mark T. Kortschot, Mohini Sain
One of the most important properties to consider in the design of automotive components is noise, vibration, and harshness (NVH), which is mitigated by the use of materials that attenuate noise and vibrations. Materials selected for interior components must be able to attenuate vibrations caused by the rotation of the engine and by the travel over uneven surfaces [40]. These mechanical vibrations can also produce sounds that must be dissipated to improve the experience of passengers. Measures must be taken to either dampen these sounds or attenuate the vibrations themselves.
Vehicle Validation
Published in Vivek D. Bhise, Automotive Product Development, 2017
There are three subattributes of NVH that are generally evaluated during the validation phase: 1.BIW NVH: The body-in-white (BIW) of the vehicle should be tested for the range of frequencies expected during driving. The BIW is tested on a testing machine where it is subjected to external excitations, and its NVH levels are measured from different seating locations.2.Powertrain NVH: The noise and vibrations created by the powertrain and within the powertrain by external forces are measured by a testing machine. The simulator in the testing machine simulates the external forces experienced by the vehicle chassis from various sources (e.g., road surface roughness), and the test equipment measures the NVH levels in the engine and driveline components. The NVH levels should be lower than the target value set by the vehicle attribute requirements.3.Other sources of NVH: Generally, there are a number of parts in a vehicle that are bolted, spot welded, or even joined using snap fits. These parts should not produce any squeaky noise (usually generated by rubbing of adjacent moving components) or any kind of rattling noise (generally created by loose or moving components) throughout the operation of the vehicle. These sources of NVH are tested using standard company procedures (under predefined input conditions related to road surfaces, wind gusts, powertrain, braking system operation, and so forth). The resulting NVH outputs in the vehicle must meet the subattribute requirements, which are typically based on customer perception and acceptance of the annoyance and/or discomfort caused by the NVH-related issues.
Uncertainty analysis and optimization of automotive driveline torsional vibration with a driveline and rear axle coupled model
Published in Engineering Optimization, 2018
Y. D. Hao, Z. C. He, G. Y. Li, Eric Li, Y. Y. Huang
To cope with increasing market competition and growing user requirements, automotive manufacturers are striving to produce high Noise, Vibration, and Harshness (NVH) performance vehicles. The need for lightweight and fuel-efficient engines is often contradictory to customer expectations, however, which is putting increasing pressure on NVH design engineers. NVH performance design is a vehicle level issue which includes sub-topics such as body NVH, acoustic package, engine NVH, driveline NVH, and abnormal sound control. Among them, driveline torsional vibration is one of the most significant issues, especially in rear-wheel drive vehicles with manual transmission.
Nonintrusive parametric NVH study of a vehicle body structure
Published in Mechanics Based Design of Structures and Machines, 2022
F. Cavaliere, S. Zlotnik, R. Sevilla, X. Larrayoz, P. Díez
The noise, vibration and harshness (NVH) performance of a vehicle has an ever increasingly stronger impact on the customer perception of ride comfort and brand quality, and it has become one of the most prioritized attributes when purchasing a new car. To be competitive in the global market, car manufacturers need to improve the NVH properties of their products without deteriorating other targets, often conflicting, such as crashworthiness, light-weight, safety, ecological impact and styling.