Vehicle NVH Performance Research Articles

Cause Analysis of Whole Vehicle NVH Performance Degradation under Idle Conditions

Cause Analysis of Whole Vehicle NVH Performance Degradation under Idle Conditions

Optimization of Vehicle Powertrain Mounting System Based on Generalized Inverse Cascade Method under Uncertainty

This paper presents a summary of the optimization design process for a multi-objective, two-level engineering problem, utilizing the generalized inverse cascade method under uncertainty. The primary objective is to enhance the vibration isolation performance of a mounting system, considering the influence of uncertain factors on its stiffness. The focus is on determining the value range of the design variables at the bottom layer, ensuring that the design goal is met with a specified confidence level. To illustrate the application of this methodology, the optimization design of a powertrain mount is used as a case study. A data-driven approach is adopted, establishing a quantitative mapping relationship between mount stiffness, force transmission rate, modal decoupling rate, and other design indicators. This is achieved through the development of a CRBM-DBN approximate model, which combines Conditional Restricted Boltzmann Machines (CRBMs) and a Deep Belief Network (DBN). Additionally, an intelligent optimization algorithm and interval search technology are employed to determine the optimal design interval for the mount stiffness. Simulation and experimental verification are conducted using selected parameter combinations. The results demonstrate notable improvements in the vibration isolation performance, modal decoupling rate, and vehicle NVH performance when compared to the original state. These findings provide valuable insights for the interval optimization design of similar multi-objective, as well as two-level engineering problems, serving as useful references for future research and applications.

RENAULT Smart Cocoon Technology CAE

RENAULT was the first OEM to introduce mass production Battery Electric Vehicles in Europe with the ZOE in 2012. With the new Megane ETECH, RENAULT set the NVH comfort to higher level to match the customer expectations on BEV vehicles. One of the components that contributes to the silence of Megane is the "Smart Cocoon Technology". This innovative solution has been developed to transform the battery into an acoustically active element. An insulation foam has been embedded between the body floor and the battery casing in order to use the battery mass to improve the floor transparency and damping, and subsequently the Transmission Loss. To support further developments of this technology RENAULT and its CAE partners are developing a simulation methodology to achieve simultaneously three goals: predict the behavior of the smart cocoon technology on the whole vehicle NVH performance, optimize the performance and weight of the insulation package, and secure the assembly process. This paper presents in detail each step of this process. Non-linear simulations of the battery assembly process are used to capture the preloading effects in foam and body panels. The vehicle high frequencies NVH performance is then simulated for vehicle rolling conditions. In a last part of the paper, CAE results are compared with the test measurements on the Megane prototype.

A comparative study of properties of natural rubber and polyurethane-based powertrain mount on electric vehicle NVH performance

A comparative study of properties of natural rubber and polyurethane-based powertrain mount on electric vehicle NVH performance

A comparative study of properties of natural rubber and polyurethane-based powertrain mount on electric vehicle NVH performance

A comparative study of properties of natural rubber and polyurethane-based powertrain mount on electric vehicle NVH performance

Analysis of the control strategy of range extender system on the vehicle NVH performance

With focus on NVH performance, this paper studies the range extender system control strategy such as the initial start speed, operating points, speed up and down control method between operating points of the range extender, etc. At the same time, the confirmation of the operating points of the range extender based on the full vehicle frequency distribution and vibration and noise level of key points (seat rail, driver’s inner ear) was performed. Finally, we conducted objective test and compared the test data with benchmark vehicles.

Vibration and noise analysis of heavy-duty trucks based on powertrain lightweighting

Vehicle lightweighting has been considered as one of the most important solutions to improve fuel economy and reduce harmful emissions. Considering the PowerTrain System (PTS) lightweighting of a heavy-duty truck tractor, cast iron of which the transmission shell was made is replaced with aluminum. Such weight reduction caused the irrationality of the natural frequency matching and the vehicle NVH performance become worse. In order to evaluate the influence of PTS lightweighting on the vibration and noise, the theoretical analysis and experimental tests have been done. The Genetic Algorithm (GA) method was adopted for the Powertrain Mounting System (PMS) optimization. Considering the installation position of PMS, the limitations of package space, cost and available time, the mounting stiffness was chosen as the design variables. One combination of the main vibration energy distribution of PMS was selected as the objective function of optimization design. After optimization, the vehicle experimental study was carried out to investigate the vibration and noise performance of the PMS at idle and Whole Open Throttle (WOT). The test results show that the optimization of PMS had a significant improvement on the vehicle vibration and noise performance.

The Application of the Finite Element in the Vehicle NVH Field

The articles establish the dynamic model of the vehicle with the finite element software, and simulate the structural modes, acoustic modes, driving the NHV performance of ride comfort, and proposed improvement program. Practice has proved that the application of finite element analysis software can simulate the vehicle NVH performance and provide fast and accurate basis to improve its performance.

Experimental and finite element analyses of a sliding-tube-type driveshaft-induced vehicle vibration

Driveline noise, vibration, and harshness (NVH) has become an integral attribute in defining how the vehicle NVH performance is perceived by the customers of the automotive industry. The driveshaft component design requirements need to make sure that the designed driveline system is robust and reliable in order to achieve the vehicle NVH targets. They also need to ensure that the system maintains its durability performance as well. A slip mechanism in the driveline system is needed to accommodate the movements caused by the rear axle and rear suspensions when the vehicle travels on a rough road or accelerates/ decelerates abruptly. One design option to accommodate the slip mechanism is to use a press-fitted sliding-tube design. This slip mechanism causes the fluctuation of the contact forces in the tubes, particularly in the vehicle coast down course, and becomes a non-linear contact force phenomenon. This paper uses experimental and finite element method linear tools to explain the non-linear behaviour of the sliding-tube driveshaft, and to provide design options to prevent vehicle vibration issues created by the current sliding-tube driveshaft design.

Pushing the NVH Performance Envelope of Rubber Components

Engineering a vehicle's NVH performance is one of the most demanding challenges in automotive design, especially when it comes to deciding which materials and parts to use, how to shape the components and where to position them. The NVH expertise gained during decades of developing innovative and effective anti-vibration rubber products helped Tokai Rubber Industries (TRI) to successfully take up this new supplier role. Continuous investments in rubber material research and the deployment of a simulation-driven product development enable TRI to regularly introduce new design concepts and efficiently retrieve the most promising design alternatives. Throughout the development process, LMS simulation and testing solutions assist TRI engineers in shaping new products that further improve NVH performance and reduce production cost.