Browse Topic: Noise

Items (5,937)

Innovative High-Performance Active Dampers for Effective Mitigation of Helicopter Main Rotor Vibrations

2025-01-0163To be published on 05/02/2025

Helicopter vibrations, primarily generated by the main rotor-gearbox assembly, are a major source of concern due to their impact on structural integrity, cockpit instrument durability, and crew comfort. These vibrations are mainly transmitted through the gearbox’s rigid support struts to the fuselage, leading to increased cabin noise and potential damage to critical components. This paper presents a solution for vibration mitigation which involves replacing traditional gearbox support struts with low-weight, high-performance active dampers. Developed by Elettronica Aster S.p.A., these active dampers are designed as electro-hydraulic actuators embedded within a compliant structure. The parallel nested configuration of the system enables high power densities and effective vibration control, significantly reducing the transmission of harmful vibrations to the fuselage. The comprehensive model-based design process is detailed, describing the development and use of a high-fidelity physics

Bertolino, Antonio Carlo, Sorli, Massimo, Porro, Paolo Giovanni, Galli, Claudio

A Methodology for Minimizing Liftgate-Induced Low-Frequency Boom Noise in Vehicles

2025-01-8617

04/01/2025

The significance of the liftgate's role in vehicle low-frequency boom noise is highlighted by its modal coupling with the vehicle's acoustic cavity modes. The liftgate's acoustic sensitivity and susceptibility to vehicle vibration excitation are major contributors to this phenomenon. This paper presents a CAE (Computer-Aided Engineering) methodology for designing vehicle liftgates to reduce boom risk. Empirical test data commonly show a correlation between high levels of liftgate vibration response to vehicle excitations and elevated boom risk in the vehicle cabin. However, exceptions to this trend exist; some vehicles exhibit low boom risk despite high vibration responses, while others show high boom risk despite low vibration responses. These discrepancies indicate that liftgate vibratory response alone is not a definitive measure of boom risk. Nonetheless, evidence shows that establishing a vibration level control guideline during the design stage results in lower boom risk. The

Abbas, Ahmad, Haider, Syed

Machine Learning-Based Lane Detection and Lateral Offset Estimation Model for Vehicle Following Applications

2025-01-8020

04/01/2025

Precisely understanding the driving environment and determining the vehicle’s accurate position is crucial for a safe automated maneuver. vehicle following systems that offer higher energy efficiency by precisely following a lead vehicle, the relative position of the ego vehicle to lane center is a key measure to a safe automated speed and steering control. This article presents a novel Enhanced Lane Detection technique with centimeter-level accuracy in estimating the vehicle offset from the lane center using the front-facing camera. Leveraging state-of-the-art computer vision models, the Enhanced Lane Detection technique utilizes YOLOv8 image segmentation, trained on a diverse world driving scenarios dataset, to detect the driving lane. To measure the vehicle lateral offset, our model introduces a novel calibration method using nine reference markers aligned with the vehicle perspective and converts the lane offset from image coordinates to world measurements. This design minimizes

Karuppiah Loganathan, Nirmal Raja, Poovalappil, Aman, Naber, Jeffrey, Robinette, Darrell, Bahramgiri, Mojtaba

A Proactive System to Anticipate and Store the Damage Information on a Parked Car Using Machine Learning Algorithm

2025-01-8211

04/01/2025

Vehicle ADAS Systems majorly comprises of two functions: Driving and Parking. The most common form of damage to the vehicle which goes unnoticed with unidentified cause are parking damages. A vehicle once parked at a certain location may get damaged without knowledge of the user. In this work developed a solution that not only pre-warns the driver but also prepares the vehicle beforehand if it suspects a damage may occur. This eliminates the latency between damage and information capture, detects small damages such as scratches, classifies the type of damage and informs the user beforehand. This is solution is different from our competitors as the existing solutions informs the user about the scratches/damages, but these solutions are expensive, have high response time, and the damage information is captured after the damage has occurred. The solution consists of the following check blocks: Precondition, Sensor Control and Action Module. The Precondition Module observes the vehicle

Debnath, Sarnab, Patil, Prasad, Belur Subramanya, Sheshagiri, Govinda, Shiva Prasad

Research on Motor Harmonic Injection Control in Hybrid System to Suppress the Torsional Vibration

2025-01-8515

04/01/2025

Based on the harmonic current injection method used to suppress the torsional vibration of the electric drive system, the selection of the phase and amplitude of the harmonic current based on vibration and noise has been explored in this paper. Through the adoption of the active harmonic current injection method, additional torque fluctuations are generated by actively injecting harmonic currents of specific amplitudes and phases, and closed-loop control is carried out to counteract the torque fluctuations of the motor body. The selection of the magnitude of the injected harmonic current is crucial and plays a vital role in the reduction of torque ripple. Incorrect harmonic currents may not achieve the optimal torque ripple suppression effect or even increase the motor torque ripple. Since the actively injected harmonic current is used to counteract the torque ripple caused by the magnetic flux linkage harmonics of the motor body, the target harmonic current command is very important

Jing, Junchao, Zhang, Junzhi, Liu, Yiqiang, Huang, Weishan, Dai, Zhengxing

Research on Noise Optimization Control Based on the New Dead Zone Compensation in Dual Motor Hybrid System

2025-01-8516

04/01/2025

In a three-phase voltage source inverter, in order to prevent the direct short circuit of the upper and lower tubes of the bridge arm and ensure the normal operation of the inverter, microsecond-level dead time needs to be added when the power devices are turned on and off. However, due to the dead-time effect, slight distortion may occur in the inverter within the modulation period, and this distortion will eventually lead to harmonic components in the output current after accumulation, thereby generating torque ripple. Against the above background, implementing dead-time compensation strategies is very important. To compensate for the voltage error caused by the dead-time effect, current polarity determination is required first. Then, the dead time is compensated, thereby indirectly compensating for the voltage error caused by the dead-time effect. Regarding the dead-time compensation time, without changing the hardware, this paper proposes a solution to turn off the dead-time

Jing, Junchao, Zhang, Junzhi, Zuo, Botao, Liu, Yiqiang, Yang, Tianyu, Zhu, Lulong

Vehicle Interior Audio System Noise Prediction Based on Inverse Acoustic Approach and Directivity Pattern

2025-01-8640

04/01/2025

Automotive audio components must meet high quality expectations with ever-decreasing development costs. Predictive methods for the performance of sound systems in view of the optimal locations of loudspeakers in a car can help to overcome this challenge. Use of simulation methods would enable this process to be brought up front and get integrated in the vehicle design process. The main objective of this work is to develop a virtual auralization model of a vehicle interior with audio system. The application of inverse numerical acoustics [INA] to source detection in a speaker is discussed. The method is based on truncated singular value decomposition and acoustic transfer vectors The arrays of transfer functions between the acoustic pressure and surface normal velocity at response sites are known as acoustic transfer vectors. In addition to traditional nearfield pressure measurements, the approach can also include velocity data on the boundary surface to improve the confidence of the

Baladhandapani, Dhanasekar, Thaduturu, Sai Ravikiran, Du, Isaac

Aeroacoustic Noise Prediction of Passenger Car HVAC by Using CFD and Validation with Test Result

2025-01-8629

04/01/2025

The advancement of automotive industry demand compact size of HVAC with better cabin comfort. To achieve this, HVAC has to be optimized in all the aspects such as in shape & size, thermal comfort as well as in noise comfort. from an HVAC perspective, aeroacoustics noise is more significant due to its intensity at higher speeds and frequencies. Since HVAC is mounted inside the cabin, noise can transfer directly inside cabin. To avoid this, noise reduction or noise controlling is of very important. This is possible with HVAC design and simulation at the initial level and acoustic prediction after the CFD/CAA analysis. The present paper describes the aeroacoustic simulation of one of the HVAC to predict the noise during face mode. For that, 1-D simulation has been done initially to find the porosity of heat exchangers and coupled with a CFD solver. STAR CCM+ software is used for the CFD analysis. Transient simulation is performed with compressible fluid using a moving mesh approach. To

Kame, Shubham, Parayil, Paulson, Goel, Arunkumar

Analysis and Validation of Torque Ripple Cancellation to Reduce Electric Motor Noise for Electric Vehicles

2025-01-8573

04/01/2025

The electric motor is a significant source of noise in electric vehicles (EVs). Traditional hardware-based NVH optimization techniques can prove insufficient, often resulting in trade-offs between motor torque or efficiency performance. The implementation of motor control-based torque ripple cancellation (TRC) technology provides an effective and flexible solution to reduce the targeted orders. This paper presents an explanation of the mathematical theory underlying the TRC method, with a particular focus on the various current injection methods, including those that allow up to 4DOFs (degrees-of-freedom). In the case study, the injection of controlled fifth or seventh order current harmonics into a three-phase AC motor is shown to be an effective method for cancelling the most dominant sixth order torque ripple. A dedicated feedforward harmonic current generation module is developed the allows the application of harmonic current commands to a motor control system with adjustable

He, Song, Gong, Cheng, Chang, Le, Peddi, Vinod, Zhang, Peng, GSJ, Gautam

Experimental Case Study of Sonic Perception of a First-Generation Electric Truck

14-14-02-0008

02/24/2025

The sound generated by electric propulsion systems differs compared to the prevalent sound generated by combustion engines. By exposing listeners to various sound situations, the manufacturer can start understanding which direction to take to achieve compelling battery electric vehicle trucks from a sound perspective. The main objective of this study is to understand what underlying aspects decide the experience and perception of heavy vehicle–related sounds in the context of electrified propulsion. Using a thematic analysis of data collected at a listening experiment conducted in 2020, factors affecting the perception of novel sounds generated by a first-generation electric truck are investigated. A hypothesis is that the experience of driving or being a passenger in electric trucks will affect the rating and response differently compared to listeners not yet experienced with this sound. The results show that the combination of individual preference and experience, hearing function

Nyman, Birgitta, Fagerlönn, Johan, Nykänen, Arne

Enhancing Disc Brake Performance: Investigating Squeal Noise, Wear, and the Application of Functionally Graded Materials in Brake Rotors

2025-28-0162

02/07/2025

Disc brakes play a vital role in automotive braking systems, offering a dependable and effective means of decelerating or halting a vehicle. The disc brake assembly functions by converting the vehicle's kinetic energy into thermal energy through friction. The performances of the brake assembly and user experience are significantly impacted by squeal noise and wear behaviour. This paper delves into the fundamental mechanisms behind squeal noise and assesses the wear performance of the disc brake assembly. Functionally graded materials (FGMs) are an innovative type of composite material, characterized by gradual variations in composition and structure throughout their volume, leading to changes in properties such as mechanical strength, thermal conductivity, and corrosion resistance. FGMs have emerged as a groundbreaking solution in the design and manufacturing of brake rotors, addressing significant challenges related to thermal stress, wear resistance, and overall performance. These

C V, Prasshanth, S, Gurumoorthy, Bhaskara Rao, Lokavarapu, S, Sridhar, S, Badri Narayanan, Kumar, Ajay, Biswas, Sayan

A reduced-order beam modelling approach of BIW for torsional and bending stiffness optimization

2025-28-0187

02/07/2025

Noise, Vibration, and Harshness (NVH) simulations of vehicle bodies are crucial for assessing performance during the design phase. However, these simulations typically require detailed computer-aided design (CAD) models and are time-consuming. In the early stages of vehicle development, when only high-level vehicle sections are available, designing the body-in-white (BIW) structure to meet target values for bending and torsional stiffness is challenging and often requires multiple iterations. To address these challenges, this study deploys a reduced-order beam modelling approach. This method involves identifying the beam-like sections and major joints within the BIW and calculating their sectional properties (area, area moments of inertia along the plane’s independent axes, and torsion constant). These components form a simplified skeleton model of the BIW. Load and boundary conditions are applied to the suspension mount locations at the front and rear of the vehicle, and torsional and

Khan, Mohd Zishan Ali, Thanapati, Alok, Deshmukh, Chandrakant

Analysis and Refinement of Road Boom Noise in Electric Vehicle

2025-28-0057

02/07/2025

Customers are expecting higher level of refinement in electric vehicle. Since the background noise is less in electric vehicle in comparison with ICE, it is challenging for NVH engineers to address even minor noise concerns without cost and mass addition. Higher boom noise is perceived in the test vehicle when driven on the coarse road at a speed of 50 kmph. The test vehicle is rear wheel driven vehicle powered by electric motor. Multi reference Transfer Path Analysis (TPA) is conducted on the vehicle to identify the path through which maximum forces are entering the body. Based on the findings from TPA, solutions like reduction in the dynamic stiffness of the suspension bushes are optimized which resulted in reduction of noise. To reduce the noise further, Operational Deflection Shape (ODS) analysis is conducted on the entire vehicle to identify the deflection shapes of all the suspension components and all the body panels like floor, roof, tailgate, dash panel, quarter panel and

S, Nataraja Moorthy, Rao, Manchi Venkateswara, Raghavendran, Prasath, Selvam, Ebinezer

NVH Optimization of Mounts for Reduction of Structure Borne Motor and Road Noise in Electric Vehicle

2025-28-0072

02/07/2025

Due to stringent emission norms, all OEMs are shifting focus from Internal combustion engine (ICE) to Electric vehicle (EV). NVH refinement of EVs is challenging due to less background noise in EVs in comparison with ICE vehicles. Motor whine noise is perceived inside cabin till the speed of 20 kmph. Vehicle is powered by electric powertrain (EPT). Electric powertrain is connected to the subframe with the help of three powertrain mounts. Subframe is connected to the body with the help of four mounts. With the help of Transfer Path Analysis (TPA), it is identified that the noise is structure borne and the dominant path is identified. By optimizing the stiffness of the EPT mounts, the structure borne noise levels are reduced. But reducing the stiffness of EPT mount deteriorated the road noise levels. The reason behind deterioration of road noise is investigated. The performance of double isolation of EPT is compared with single isolation of EPT with respect to both road and motor noise

S, Nataraja Moorthy, Rao, Manchi Venkateswara, Raghavendran, Prasath, Selvam, Ebinezer

Research on Noise Optimization of Exhaust System for Hydrogen Fuel Cell Vehicles

2025-01-7003

01/31/2025

This paper presents a strategy to reduce exhaust noise in fuel cell vehicles. It focuses on optimizing the exhaust system. The innovation is an integrated muffler device. It combines a vapor separator and an absorptive-reactive muffler. The vapor separator removes moisture from exhaust gases. This prevents damage to sound-absorbing materials. It keeps mufflers functional for longer. Fuel cell vehicles produce noise across a wide frequency range. This makes noise reduction challenging. The absorptive-reactive muffler improves noise attenuation. It works across the full frequency spectrum. The combination of the separator and muffler enhances noise reduction. Simulations show high transmission loss. They also confirm acceptable back pressure. Real-vehicle testing supports these results. The optimized system reduces idle noise by 22.1 dB(A). This is a 32.4% reduction. Blowdown noise is reduced by 46.3 dB(A), or 40.1%. Full-throttle noise drops by over 20 dB(A), a 17.2% decrease. The

Zhou, Jiawang, Jiang, Xiaokun, Qiu, Yongjin, Chen, Jiyuan, Feng, Pengfei, Xie, Qiguang, Xie, Xiaoping, Tan, Ligang

Research on the Characteristics of an Integrated Thermoelectric Generation, Catalytic Conversion, and Noise Suppression System

2025-01-7062

01/31/2025

In the context of global energy shortages and increasing environmental pollution, improving energy efficiency in automobiles has become a key area of research. Traditional internal combustion engines exhibit low energy conversion efficiency, with a significant portion of fuel energy wasted as exhaust heat. To address this issue, this paper proposes an integrated thermoelectric generation, catalytic conversion, and noise suppression system (ITGCMS) aimed at recovering waste heat from vehicle exhaust, while optimizing emissions and noise reduction through the combination of a catalytic converter and a muffler. A three-dimensional model was established using COMSOL software to thoroughly analyze the system's thermoelectric generation, catalytic conversion, and acoustic performance. The study found that Model B demonstrated the best thermoelectric performance, with an average surface temperature of 300.2°C and a more uniform temperature distribution across the thermoelectric modules

Wu, Ji-Xin, Su, Chu-Qi, Wang, Yi-Ping, Yuan, Xiao-Hong, Liu, Xun

Airborne Noise Mitigation for Roof-Mounted Air-Conditioning Unit Using Simulation-Based Flow-Induced Noise Detection Approach

2025-01-5002

01/23/2025

In the current world of automobiles, the air-conditioning system plays a crucial role in passenger comfort. Thermal comfort for the passengers, which was earlier a luxury, has now become a basic necessity. This thermal comfort, coupled with ventilation, brings along with it the symbiotic association of flow-induced noise. The subjective prominence of airborne noise from air-conditioning systems increases with higher refinement or masking of structure-borne noise and/or engine noise sources. These systems for commercial vehicles are higher in capacity, complex, and generally placed directly above the passenger seats. Flow-induced noise refinement for such systems is generally difficult and involves multiple physical trials. In the current work presented for a commercial van, the airflow delivery of the air-conditioning system was in line with the requirement. The location of the system, however, resulted in higher noise levels at the passenger ear location. To address this issue, an

Nomani, Mustafa, Kandekar, Ambadas, Latane, Santosh, Manoji, Akash, Tadigadapa, Suresh

Method for Predicting Lateral Attenuation of Airplane Noise

AIR5662 (Current)

01/09/2025

This document describes analytical methods for calculating the attenuation of the level of the sound propagating from an airplane to locations on the ground and to the side of the flight path of an airplane during ground roll, climbout after liftoff, and landing operations. Both level and non-level ground scenarios may be modeled using these methods, however application is only directly applicable to terrain without significant undulations, which may cause multiple reflections and/or multiple shielding effects. This attenuation is termed lateral attenuation and is in excess of the attenuation from wave divergence and atmospheric absorption. The methods for calculating the lateral attenuation of the sound apply to: turbofan-powered transport-category airplanes with engines mounted at the rear of the fuselage (on the sides of the fuselage or in the center of the fuselage as well as on the sides) or under the wings propeller-driven transport-category or general-aviation airplanes

A-21 Aircraft Noise Measurement Aviation Emission Modeling

Model Based Emissions and NVH Optimization

2024-36-0059

12/20/2024

Throughout the years, the legislations which drive the vehicle development have experimented constant evolutions. Especially when it comes about pollutant emissions and NVH ( Noise, Vibration & Harshness). However, it is complex to understand which calibration strategy promotes the best balance about lowest levels of emissions, vibrations, and noise if considered the number of inputs to be explored, becoming the searching for the optimum calibration a huge challenge for the development engineering team. This work proposes a methodology development in which complex problems can be solved by model based solutions regarding the best balance finding of emissions reduction and noise attenuation. The methodology is based in machine learning approach which provides a virtual behavior of engine phenomena making possible a wider comprehension of the problem and hence the opportunity to explore enhanced solutions. The study case scenario used to apply the method was a 6.4 liters engine which

Ruiz, Rodrigo Peralta Moraes, Santos, Lucas Resende, Nascif, Gabriel Nobre Alves, Oliveira Ribeiro, Douglas, Pereira, Willyan

Sound Level Determination for Snowmobiles under Typical Trail Operating Conditions

J3120_202412 (Current)

12/06/2024

This SAE Recommended Practice establishes the method to determine Sound Level of a snowmobile under typical trail operating conditions. Snowmobiles have different engine power levels that depends on the model.

Snowmobile Technical Committee

A Comprehensive Analysis of Electromagnetic NVH in Electric Powertrain

2024-28-0136

12/05/2024

In this paper, a comprehensive analysis of NVH in electric powertrains due to electromagnetic sources is presented. The spatial harmonics model of the traction motor, which is dependent on the motor design structure, rotor poles, stator teeth, and slots, is used for the analysis of the electromagnetic forces from the motor in the electric powertrain. The time harmonics model of the injected current of the motor dependent on the drive electrical circuit and control strategy is also considered for the electromagnetic force calculation. A complete workflow of this electromagnetic NVH analysis for electric powertrain covering the spatial harmonics and time harmonics model is presented. The spatial harmonics model result is presented as flux linkage with respect to dq-axes current and rotor position. The time harmonics are also presented by the injected current of the motor. In addition, a set of operating points on the torque-speed boundary of the traction motor is selected and results are

Joshi, Nakul, Kumar, Vinit, Tsoulfaidis, Antonios, Huang, Zhenhua, Schmaedicke, Marcel, Fialek, Gregory, Zhang, Dapu, Wimmer, Joe

An Approach to Reduce Noise Generated by Thermal Management Systems in Electric Vehicles

2024-28-0211

12/05/2024

Electric vehicles are transforming the future of transportation for the world while achieving the goal of sustainable development. While the concept and use of battery-powered vehicles has also penetrated the logistics and supply chain industry, it has also brought upon new challenges during its development. As OEMs strive to develop BEVs with extended range, the components within the propulsion and drivetrain system tend to demand a higher power output from the energy storage systems. This results in BEVs generating higher levels of thermal heat energy, which must be dissipated / rejected for optimal performance and safety. Consequently, to reject this heat, BEVs must utilize thermal management systems with higher capacities. This increase in size is accompanied by the inclusion of many parts that generate noise and contribute to increased noise levels in BEVS. In today’s market, optimization of noise levels is a significant factor when ensuring passenger comfort, while also showing

Shedge, Atharva Vikas, Shalgar, Sandeep, Srivastava, Sarvesh, Nagarhalli, Prasanna V

A Design Synthesis Approach to Improve HVAC Acoustic Performance of Passenger Vehicles

2024-28-0221

12/05/2024

Noise induced by the Heating, Ventilation and Air conditioning (HVAC) system inside a vehicle cabin can cause significant discomfort to passengers and, in turn, affect the brand image in a competitive automotive market. HVAC acoustic performance has become more prominent with the ongoing transformation from Internal Combustion (IC) to Electric Vehicle (EV) segments. For this reason, acoustic quality is increasingly prioritized as a key design issue throughout the entire development process of the HVAC system. This paper covers the design synthesis considering air handling unit-induced airborne and structure-borne noise of a dashboard-mounted HVAC system to achieve better NVH refinement inside vehicle while maintaining thermal performance. This study began by analysing HVAC-induced blower motor, impeller, air ducts, vents, and recirculation suction noise from the vehicle level to subsystem level and eventually at the component level. At the subsystem level, major noise source

Titave, Uttam Vasant, Naidu, Sudhakara, Kalsule, Shrikant

Duct Anechoicity Based on the Acoustic Black Hole Principle

2024-01-7006

11/15/2024

As a novel passive control method, the acoustic black hole (ABH) structure demonstrates achieve energy aggregation efficiently and has the characteristics of lightweight and wide-band noise reduction. This study applies ABH theory to aircraft ducts by incorporating an additional ABH structure into the inner wall design. The spiral structure is specifically engineered to increase the characteristic length of the black hole and lower the cutoff frequency. To validate the effectiveness of this ABH structural design, finite element analysis was conducted to investigate structural frequency response, acoustic energy concentration characteristics, as well as damping and energy dissipation effects. Simulation results indicate significant energy accumulation on the inner wall with ABH structure in frequencies above 800Hz. Additionally, through acoustic-structure coupling analysis, far-field acoustic radiation characteristics were determined for this structural design followed by a

Guo, Yaning, Lv, Peng, Liu, Pengfei, Ning, Donghong

Investigation of Mid-Frequency Interior Noise due to Tyre-Road Interaction

2024-28-0005

10/17/2024

Over the past twenty years, the automotive sector has increasingly prioritized lightweight and eco-friendly products. Specifically, in the realm of tyres, achieving reduced weight and lower rolling resistance is crucial for improving fuel efficiency. However, these goals introduce significant challenges in managing Noise, Vibration, and Harshness (NVH), particularly regarding mid-frequency noise inside the vehicle. This study focuses on analyzing the interior noise of a passenger car within the 250 to 500 Hz frequency range. It examines how tyre tread stiffness and carcass stiffness affect this noise through structural borne noise test on a rough road drum and modal analysis, employing both experimental and computational approaches. Findings reveal that mid-frequency interior noise is significantly affected by factors such as the tension in the cap ply, the stiffness of the belt, and the properties of the tyre sidewall.

Subbian, Jaiganesh, M, Saravanan

Acoustical Considerations for Aircraft Environmental Control System Design

AIR1826A (Current)

10/03/2024

This Aerospace Information Report (AIR) is limited in scope to the general consideration of environmental control system noise and its effect on occupant comfort. Additional information on the control of environmental control system noise may be found in 2.3 and in the documents referenced throughout the text. This document does not contain sufficient direction and detail to accomplish effective and complete acoustic designs.

AC-9 Aircraft Environmental Systems Committee

HVAC Kinematic Noise Prediction by Using Multi Body Simulation

2024-28-0070

09/19/2024

HVAC is one of the main components on AC system on passenger car. Air flow distribution through the HVAC duct outlet as well as foot outlet is controlled mainly through HVAC kinematic mechanism. Kinematic mechanism mainly controls the air flow distribution and also temperature linearity at the outlet. Blower assembly as well as Kinematic mechanism is mainly two moving components inside HVAC system. Apart from the blower noise, another important noise generating area is kinematic noise. Due to poor cam profile and pin reaction force inside cam profile, there is high reaction force and hence produce noise. Due to different kinematic mode travel (face, foot and defrost), the pin has to be moved inside the cam profile, so pin movement & interference due to the stroke length travel leads a higher noise. The present paper describes the noise prediction based on simulation methodology of HVAC kinematic mechanism and damper (Doors) movement. First kinematic simulation of baseline model is

Parayil, Paulson, Kame, Shubham, Goel, Arunkumar

Characterization of HVAC Noise and its Dynamic Interplay within the Vehicle's Environment

2024-28-0113

09/19/2024

Vehicle HVAC noise performance is an important vehicle design validation criterion since it significantly links the brand image of a vehicle. It affects the customer’s buying decision and the business of selling vehicles because it directly affects driving comfort. Customers expect continuous improvement in HVAC noise without compromising cooling performance. The process of cascading vehicle-level acoustic performance to subsystem and component levels becomes an important factor in the vehicle NVH development process. It was found that the component-level [HVAC unit without duct] performance of an HVAC system measured in an anechoic chamber was at par when compared to targets, whereas the subsystem-level performance [HVAC unit with duct and dashboard] was on the higher side of the targets. Advanced NVH tools were used to identify the source of noise at the subsystem level. It helped to locate the source and its transfer path. A design modification done at the transfer path location

Titave, Uttam Vasant, Kalsule, Shrikant, Naidu, Sudhakara

Investigation of Thermal Influences on Wear Behavior in Geared Transmissions

2024-24-0032

09/18/2024

Geared automotive and aerospace transmissions are one of the most critical systems regarding wear. Limiting wear is of paramount importance to improve sustainability by reducing replacements that lead to increased waste and energy consumption for re-manufacturing. Simulation of gears including the wear effect can be very useful for the design of new more efficient and compact gears. Thermal effects may play a decisive role in the wear phenomena and should be included in the models used for simulations. In this study, some tests are conducted on a pin-on-disk apparatus under varying temperatures to assess its influence on steel-to-steel wear rate. A modified Archard law is used for wear estimation which includes the experimentally derived parameters accounting for thermal effects. This model is then coupled with a loaded tooth contact analysis (LTCA) tool to obtain accurate predictions of the contact pattern, as well as the instantaneous load shared by the mating teeth pairs during the

Grabovic, Eugeniu, Ciulli, Enrico, Artoni, Alessio, Gabiccini, Marco

Evaluation and Prediction of Vibration Comfort in Engineering Machinery Cabs Using Random Forest with Genetic Algorithm

10-08-04-0027

09/11/2024

Vibration comfort is a critical factor in assessing the overall performance of engineering machinery, with significant implications for operator health and safety. However, current evaluation methods lack specificity for construction machinery, impeding accurate prediction of vibration comfort and hindering the optimization of noise, vibration, and harshness (NVH) performance. To address this challenge, this article proposes a model that combines a random forest with a genetic algorithm (GA-RF) to enable rapid and accurate prediction of vibration comfort in construction machinery cabins. The approach begins with an improved objective evaluation methodology for extracting key features from vibration signals at five measurement points: seat, floor, back, and left and right armrests. Additionally, subjective evaluation technology, combining semantic differential and rating scales, is employed to capture operators’ personal comfort perceptions. The implementation of the GA-RF model

Zhao, Jian, Yin, Yingqi, Chen, Jiangfei, Zhao, Weidong, Ding, Weiping, Huang, Haibo

Analysis of Stick-slip Phenomenon During Creep Groan Using Acoustic Emission Sensing

2024-01-3033

09/08/2024

When the brakes are released and the vehicle starts, the brakes and suspensions vibrate and the car body resonates at 10 to 300 Hz, which is called brake creep groan. This low-frequency noise is more likely to occur in high-humidity environments. As vehicles become quieter with the introduction of EVs, improving this low-frequency noise has become an important issue. It is known that the excitation force is the stick-slip between the brake rotor and pads, but there are few studies that directly analyze stick-slip occurring in a vehicle. Acoustic emission (AE) is a phenomenon in which strain energy stored inside a material is released as elastic stress waves, and AE sensing can be used to elucidate the friction phenomena. In this study, the AE sensing is used to analyze changes in the stick-slip occurrence interval and generated energy when creep groan occurs. As a result, it was confirmed that the AE signal increased with high humidity. Furthermore, the friction phenomena during creep

Toyoda, Hajime, Yazawa, Yusuke, Arai, Shinichi, Ono, Manabu, Hara, Yasuhiro, Hase, Alan

Piston and Guide-Pin Rattle Noise Mitigation in Electro-Mechanical Brake Caliper

2024-01-3032

09/08/2024

Brake caliper commonly utilizes rubber or spring components to maintain specific clearance range for sliding characteristics, rendering them susceptible to rattle noise. The Electro-Mechanical Brake (EMB) caliper has attracted attention for its advantageous features such as reduced brake drag, optimized vehicle layout, and precise brake control. However, the inclusion of additional components related to the dry-type pressurizing system results in increased caliper weight and susceptibility to rattle noise. This study thoroughly examines rattle noise characteristics in our prototype EMB caliper, identifying primary noise sources on the piston and guide-pin sides. Implementing piston seals and guide-pin boots tightening force proves the effectiveness in improving rattle noise characteristics. Collisions between the piston and ball-screw head can be mitigated by piston inner seal, significantly reducing rattle noise. The effectiveness of the piston outer seal is limited and can be

Yoon, Boram, Jeon, Kyeong Hun, Boo, Sangpil, Shin, Choongsik, Kim, Tae Hoon

Moisture Adsorption and Compression Deformation Behavior of Semimet vs. NAO Brake Pads: Effect of Pad Cure Temperatures and Moisture Adsorption on Low-Speed Friction

2024-01-3056

09/08/2024

Moisture adsorption and compression deformation behaviors of Semimet and Non-Asbestos Organic brake pads were studied and compared for the pads cured at 120, 180 and 240 0C. The 2 types of pads were very similar in moisture adsorption behavior despite significant differences in composition. After being subjected to humidity and repeated compression to 160 bars, they all deform via the poroviscoelastoplastic mechanism, become harder to compress, and do not fully recover the original thickness after the pressure is released for 24 hours. In the case of the Semimet pads, the highest deformation occurs with the 240 °C-cure pads. In the case of the NAO pads, the highest deformation occurs with the 120 0C-cure pads. In addition, the effect of pad cure temperatures and moisture adsorption on low-speed friction was investigated. As pad properties change all the time in storage and in service because of continuously changing humidity, brake temperature and pressure, one must question any

Rhee, Seong Kwan, Rathee, Aman, Singh, Shivraj, Sharma, Devendra

Low-Speed Stop and Near Zero-Speed Start-to-Move Brake Noise: Effect of Moisture Adsorption, Prior Braking and Deceleration Rate

2024-01-3057

09/08/2024

The influence of moisture adsorption, prior braking, and deceleration rate on the low-speed braking noise has been investigated, using copper-free disc pads on a passenger car. With increasing moisture adsorption time, decreasing severity of prior braking or increasing deceleration rate, the noise sound level increases for the air-borne exterior noise as well as for the structure-borne interior noise. The near-end stop noise and the zero-speed start-to-move noise show a good correlation. Also, a good correlation is found between the noise measured on a noise dynamometer and on a vehicle for the air-borne noise. All the variables need to be precisely controlled to achieve repeatable and reliable results for dynamometer and vehicle braking groan noise tests. It appears that the zero-speed start-to-move vehicle interior noise is caused by the pre-slip vibration of the brake: further research is needed.

Sriwiboon, Meechai, Rhee, Seong Kwan, Sukultanasorn, Jittrathep, Kunthong, Jitpanu

Analysis of Disc-Brake Squeal Considering Lining Wear

2024-01-3036

09/08/2024

Brake squeal is a phenomenon caused by various factors such as stiffness of brake components, mode coupling, friction coefficient, friction force variation, pressure, temperature and humidity. FEA simulation is effective at predicting and investigating the cause of brake squeal, and is widely used. However, in many FEA simulations, models of brake lining are mostly a brand-new shaper, so that the change of pressure distribution or pad shape, which can occur due to the lining wear, are not taken account. In this research, brake squeal analysis was conducted with consideration of lining wear, applying Fortran codes for Abaqus user subroutine. The brake assembly model for the analysis is created by using a 3D scanner and has a close shape to the real one. The wear patterns calculated by the analysis are similar to those of brake pads after a noise test. The complex eigenvalue analysis shows two unstable modes at the frequency of squeal occurred in the noise test. One is out-of-plane

Ikegami, Tokunosuke, Millsap, Tom, Yamaguchi, Yoshiyuki

Everyday Life, Improved by Light: GRYPHON’s Photonic Discoveries

TBMG-51468

09/01/2024

Radio frequency (RF) and microwave signals are integral carriers of information for technology that enriches our everyday life – cellular communication, automotive radar sensors, and GPS navigation, among others. At the heart of each system is a single-frequency RF or microwave source, the stability and spectral purity of which is critical. While these sources are designed to generate a signal at a precise frequency, in practice the exact frequency is blurred by phase noise, arising from component imperfections and environmental sensitivity, that compromises ultimate system-level performance.

Unique Amplifier Could Change Optical Communication

TBMG-51421

09/01/2024

Researchers at Chalmers University of Technology have developed an optical amplifier that they expect will revolutionize both space and fiber communication. The new amplifier offers high performance, is compact enough to integrate into a chip just millimeters in size, and crucially, does not generate excess noise.

Photonics-Based Wireless Link Breaks Speed Records for Data Transmission

TBMG-51398

09/01/2024

Researchers worldwide are currently working on the next evolution of communication networks, called “beyond 5G” or 6G networks. To enable the near-instantaneous communication needed for applications like augmented reality or the remote control of surgical robots, ultra-high data speeds will be needed on wireless channels. In a study published recently in IEICE Electronics Express, researchers from Osaka University and IMRA AMERICA have found a way to increase these data speeds by reducing the noise in the system through lasers.

Investigation of Vibration and Acoustic Analysis of Spark-Ignition Engine with Petrol and Compressed Natural Gas Using ADXL 335 Accelerometer and Fast Fourier Transform Algorithm

2024-01-5083

08/20/2024

Vibrations in IC engines have a widespread effect on the operations of consumer and commercial vehicles, which not only affect the life and efficiency of the vehicle but also affect user comfort and nervous system of human body. This paper focuses on the comparative analysis of vibration and acoustic characteristics while utilizing fuels such as petrol and CNG. ADXL 335 3-axis accelerometer was employed to measure acceleration vs time data, which was then processed using MATLAB to obtain FFT and PSD plots. These plots thus obtained gave insights on dominating frequency as well as frequencies with maximum energy. Six different cases with different engine speeds and loading conditions are studied with analysis of all the different parameters such as sound pressure levels and mean and max cylinder pressure.

Anasune, Aditya

Prediction and Improvement of Structure-Borne and Airborne Whines of an Electric Vehicle for Virtual Development

2024-01-5072

07/18/2024

Many sources and paths cause interior cabin noise. Some noise from an electric vehicle is unique and different from a vehicle with an internal combustion engine. Especially, whine noise occurs due to the particular orders of the electromagnetic force of an electric motor and transmission gears, which is tonal and usually reaches high frequencies. This paper covers structure-borne (SB) and airborne (AB) aspects to estimate whine, and the difference between the two characteristics is distinguished. The focus lies mainly on the process of virtual vehicle development and application for performance improvement. First, to predict SB whine, an e-powertrain is modeled as a finite element model (FEM), and electromagnetic (EM) forces are calculated. A vehicle model is also modeled as an FEM, in which interior sound packages are carefully modeled as they play an important role in the medium-frequency region. The e-powertrain and vehicle models (being simulated separately) are combined to obtain

Yoo, Ji Woo, Chae, Ki-Sang, Choi, JaeHyuk, Kim, Myunggyu, Cho, Seunghyeon, Coster, Christophe, Van Gils, Anneleen

NASA’s Noise-Testing Tool Finds Applications Beyond Aircrafts

TBMG-51070

07/03/2024

Airplane manufacturers running noise tests on new aircraft now have a much cheaper option than traditional wired microphone arrays. And it’s sensitive enough to help farmers with pest problems. The wireless microphone array that one company recently created with help from NASA can locate crop-threatening insects by listening for sound they make in fields. And now, it’s making fast, affordable testing possible almost anywhere.

Reduction of Flow-Induced Noise in Refrigeration Cycles

2024-01-2972

07/02/2024

In electrified vehicles, auxiliary units can be a dominant source of noise, one of which is the refrigerant scroll compressor. Compared to vehicles with combustion engines, e-vehicles require larger refrigerant compressors, as in addition to the interior, also the battery and the electric motors have to be cooled. Currently, scroll compressors are widely used in the automotive industry, which generate one pressure pulse per revolution due to their discontinuous compression principle. This results in speed-dependent pressure fluctuations as well as higher-harmonic pulsations that arise from reflections. These fluctuations spread through the refrigeration cycle and cause the vibration excitation of refrigerant lines and heat exchangers. The sound transmission path in the air conditioning heat exchanger integrated in the dashboard is particularly critical. Various silencer configurations can be used to dampen these pulsations. This paper compares the acoustic and thermodynamic performance

Saur, Lukas, Heidegger, Patrick, Naeger, Christoph, Becker, Stefan

Harmonic Injection Method for NVH Optimization of Permanent Magnet Synchronous Motors Considering the Structural Characteristics of the Machine

2024-01-3015

07/02/2024

Noise, vibration and harshness (NVH) is one of the most important performance evaluation aspects of electric motors. Among the different causes of the NVH issues of electrical drives, the spatial and temporal harmonics of the electrical drive system are of great importance. To reduce the tonal noise of the electric motors induced by these harmonics, harmonic injection methods are applied in many applications. However, a lot of existing researches focus more either on improving the optimization process of the harmonic injection parameter settings, or on the controller design of the harmonic injection process, while the structural dynamic characteristics of the motor are seldom considered. A lot of literature shows that the harmonic injection strategies can more effectively influence the mode 0 (M0) radial forces than the higher spatial orders, so it is more efficient to apply such methods at the frequencies/orders where the effect of mode 0 forces are dominant with respect to the

Fu, Tongfang, Xu, Zhipeng, Günther, Marco, Pischinger, Stefan, Böld, Simon

Decentralized Control for CACC Systems Accounting for Uncertainties

2024-37-0010

06/12/2024

Traditional CACC systems utilize inter-vehicle wireless communication to maintain minimal yet safe inter-vehicle distances, thereby improving traffic efficiency. However, introducing communication delays generates system uncertainties that jeopardize string stability, a crucial requirement for robust CACC performance. To address these issues, we introduce a decentralized model predictive control (MPC) approach that incorporates Kalman filters and state predictors to counteract the uncertainties posed by noise and communication delays. We validate our approach through MATLAB/Simulink simulations, using stochastic and mathematical models to capture vehicular dynamics, Wi-Fi communication errors, and sensor noises. In addition, we explore the application of a reinforcement learning (RL)-based algorithm to compare its merits and limitations against our decentralized MPC controller, considering factors like feasibility and reliability.

Seifoddini, Arash, Azad, Arefeh, Musa, Alessia, Misul, Daniela

Roadnoise Reduction through Component-TPA with Test and Simulation Convergence Using Blocked Force

2024-01-2952

06/12/2024

While conventional methods like classical Transfer Path Analysis (TPA), Multiple Coherence Analysis (MCA), Operational Deflection Shape (ODS), and Modal Analysis have been widely used for road noise reduction, component-TPA from Model Based System Engineering (MBSE) is gaining attention for its ability to efficiently develop complex mobility systems. In this research, we propose a method to achieve road noise targets in the early stage of vehicle development using component-level TPA based on the blocked force method. An important point is to ensure convergence of measured test results (e.g. sound pressure at driver ear) and simulation results from component TPA. To conduct component-TPA, it is essential to have an independent tire model consisting of wheel-tire blocked force and tire Frequency Response Function (FRF), as well as full vehicle FRF and vehicle hub FRF. In this study, the FRF of the full vehicle and wheel-tire blocked force are obtained using an in-situ method with a

Park, Junmin, Park, Sangyoung

Comparing the NVH Behaviour of an Innovative Steel-Wood Hybrid Battery Housing Design to an All Aluminium Design

2024-01-2949

06/12/2024

The production of Electric Vehicles (EVs) has a significant environmental impact, with up to 50 % of their lifetime greenhouse gas potential attributed to manufacturing processes. The use of sustainable materials in EV design is therefore crucial for reducing their overall carbon footprint. Wood laminates have emerged as a promising alternative due to their renewable nature. Additionally, wood-based materials offer unique damping properties that can contribute to improved Noise, Vibration, and Harshness (NVH) characteristics. Compared to conventional materials such as aluminium, wooden structures exhibit significantly higher damping properties. In this study, the potential of lightweight wood composites, specifically steel-wood hybrid structures, is investigated as a potential composite material for battery housings for electric vehicles. Experiments have been performed in order to determine the modal parameters, such as natural frequencies and damping ratios. These parameters where

Wagner, Markus, Baumann, Georg, Lindbichler, Lukas, Klanner, Michael, Feist, Florian

Definition and Application of a Target Cascading Process on a Fully Trimmed Body, from Vehicle Objectives to Component Objectives

2024-01-2916

06/12/2024

Finite element (FE) based simulations for fully trimmed bodies are a key tool in the automotive industry to predict and understand the Noise, Vibration and Harshness (NVH) behavior of a complete car. While structural and acoustic transfer functions are nowadays straightforward to obtain from such models, the comprehensive understanding of the intrinsic behavior of the complete car is more complex to achieve, in particular when it comes to the contribution of each sub-part to the global response. This paper proposes a complete target cascading process, which first assesses which sub-part of the car is the most contributing to the interior noise, then decomposes the total structure-borne acoustic transfer function into several intermediate transfer functions, allowing to better understand the effect of local design changes. This transfer functions decomposition opens the door to cascading full-vehicle objectives, which typically consists of achieving a maximal noise level in the cabin

de Walque, Cyril, Yoo, Ji Woo, Jeong, ChanHee, Kong, Taesik

Transmission of Sound under the Influence of Various Environmental Conditions on Short Distances

2024-01-2933

06/12/2024

Electric vehicles, being inherently quiet without the typical combustion noises, pose a potential safety concern, especially at low speeds. Consequently, an Acoustic Vehicle Alerting System (AVAS) is mandatory in many countries worldwide to warn pedestrians of approaching electric vehicles. The development of AVAS sounds involves conducting measurements on an outside noise test track to verify compliance with regulations. Various environmental parameters on the test track can influence the transmission of sound from the car’s AVAS speaker to the measurement microphones. This research delves into understanding the relationship between the transmission of sound over short distances and environmental parameters. Over a one-year period, 122 measurements were conducted using a specially designed dolly setup. The frequency response function, which characterises the sound transmission, was calculated to determine the dependencies and correlations with environmental parameters. The findings

Schönfeld, Nils, Gsell, Stephan, Müller, Gerhard

Application of a Seat Transmissibility Approach to Experience Measured or Predicted Seat-Rail Vibration in a Multi-Attribute Simulator

2024-01-2962

06/12/2024

Computer modelling, virtual prototyping and simulation is widely used in the automotive industry to optimize the development process. While the use of CAE is widespread, on its own it lacks the ability to provide observable acoustics or tactile vibrations for decision makers to assess, and hence optimize the customer experience. Subjective assessment using Driver-in-Loop simulators to experience data has been shown to improve the quality of vehicles and reduce development time and uncertainty. Efficient development processes require a seamless interface from detailed CAE simulation to subjective evaluations suitable for high level decision makers. In the context of perceived vehicle vibration, the need for a bridge between complex CAE data and realistic subjective evaluation of tactile response is most compelling. A suite of VI-grade noise and vibration simulators have been developed to meet this challenge. In the process of developing these solutions VI-grade has identified the need

Franks, Graham, Tcherniak, Dmitri, Kennings, Paul, Allman-Ward, Mark, Kuhmann, Marvin

A Low-Cost System for Road Induced Tire Cavity Noise Control (RTNC)

2024-01-2961

06/12/2024

The transition from ICE to electric power trains in new vehicles along with the application of advanced active and passive noise reduction solutions has intensified the perception of noise sources not directly linked to the propulsion system. This includes road noise as amplified by the tire cavity resonance. This resonance mainly depends on tire geometry, gas temperature inside the tire and vehicle speed and is increasingly audible for larger wheels and heavier vehicles, as they are typical for current electrical SUV designs. Active technologies can be applied to significantly reduce narrow band tire cavity noise with low costs and minimal weight increase. Like ANC systems for ICE powertrains, they make use of the audio system in the vehicle. In this paper, a novel low-cost system for road induced tire cavity noise control (RTNC) is presented that reduces the tire cavity resonance noise inside a car cabin. The approach is cheap in terms of computational effort (likewise ICE order

Sues, Micha, Nojavan, Aidin, Kirchhof, Jan, Schirmacher, Rolf

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