Analysis and Optimization of Low‐Speed Road Noise in Electric Vehicles

Abstract

When a certain electric vehicle is driving at a constant speed of 40 km/h on the rough asphalt road, the rear passenger can obviously feel the ear pressure, which seriously affects the comfort. Through the analysis of objective data, it was found that the problem was caused by the road excitation, which leads to the coupling between the mode of the backup door and the mode of the acoustic cavity, and causes the resonance of the car cavity, thus causing the ear pressure sensation. To solve this problem, this paper optimizes the backup door by means of experiment and simulation, increases the dynamic vibration absorber, makes its modal frequency avoid the acoustic cavity modal frequency, and achieves the purpose of reducing the interior noise. After optimization, the vehicle noise is reduced by 8 dBA at 42 Hz under 40 km/h working condition of rough road surface, and the ear pressure sensation is reduced at the same time, thus improving the NVH (noise, vibration, and harshness) performance of the vehicle.

Strategies for Reducing Booming Noise Generated by the Tailgate of an Electric Sport Utility Vehicle

“…Park and Hwang [23] explored the booming noise originating from the rear cross member due to road-induced vibrations and introduced methods to construct a model for system-level analysis. Liao et al [24] and Yu [25] conducted respective studies on the tailgates of sedans and sport utility vehicles (SUVs), and Liao et al [26] conducted a similar study focusing on the noise generated from the roof and floor of hybrid vehicles. Various methods have been explored to reduce this booming noise.…”

“…Acoustic metamaterials were incorporated based on the band gap theory into the finite-element analysis model of the vehicle's tailgate to diminish the booming noise arising from the thin sheet metal components of the tailgate [24]. A carefully designed approach incorporating resonators to decouple the interaction between the body modes and internal acoustics was proposed to reduce booming noise and was subsequently validated through experimental confirmation [25]. The internal noise distribution inside the vehicle was acquired to reduce the noise generated by vibrations on the roof and floor of the vehicle [26].…”

“…The aforementioned studies appear to cover the entirety of research conducted in this domain. As mentioned earlier, Liao et al [24] proposed noise reduction methods involving attaching acoustic metamaterials to the tailgate, whereas Yu [25] studied the tailgate but faced limitations involving additional weight and cost owing to the use of dynamic absorbers. Instead of introducing extra components such as absorbers, modifying the design of the tailgate panel and adjusting the boundary conditions between the panel and vehicle chassis, thus improving the system itself, presents a more efficient solution to mitigate booming noise with relatively less time and expense.…”

“…Additionally, our research facilitated the investigation of booming noise by creating a finite-element model of the tailgate during the preliminary design stage, a step before the finalization of the entire model. While previous research emphasized the necessity of models for pre-analyzing booming noise [12], most studies attempted problem analysis by interpreting finite-element models encompassing the entire vehicle and tailgate [8,12,24,25]. Although modeling methods that target the entire completed system have the advantage of precision, they consume a significant amount of time and resources.…”

Vibration Analysis of a Roller Bearing Condition Used in a Tangential Threshing Drum of a Combine Harvester for the Smooth and Continuous Performance of Agricultural Crop Harvesting

“…Wide vibration analysis techniques and their applications are very popular in automobile industries [15][16][17][18], however, these have few implementations concerning the threshing unit of combine harvesters. Most vibration analyses are conducted in the cabin area of the harvester and focus on driver safety and comfort [19,20], simulated vibration analysis [21], and under laboratory conditions [22].…”