Browse Topic: Parts and Components

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Improving Gearbox Acoustics Through Elastomer-Based Bearing Damping2025-01-0323To be published on 07/02/2025
This study analyses the effect of external damping of roller bearings on the acoustic behaviour of gearboxes in electric powertrains. The increasing adoption of electric vehicles has increased the importance of mitigating gearbox noise, as the lack of masking noise from internal combustion engines and the higher operating speeds of electric motors exacerbate the acoustic challenges. Gearbox noise, which is primarily caused by tooth mesh excitation and its transmission through shafts and bearings, requires strategies to minimise its impact on vehicle comfort and performance. External damping is introduced via adapters integrated into the outer bearing ring, which are used to modify the vibrational behaviour of the bearing assembly and reduce both structure-borne and airborne noise emissions. A systematic approach using Design of Experiments (DoE) methodology is used to quantify the effects of this damping. This approach allows the analysis of critical parameters including material
von Schulz, Kai, Linde, Tilmann, Jäger, Steffen
Technical Paper
Noise Management in Electric Vehicle Compressors for Superior Cabin Comfort2025-01-0191To be published on 06/16/2025
“This research addresses the issue of noise, vibration, and harshness (NVH) in electric buses, which can hinder their widespread adoption despite their environmental benefits. With the absence of traditional engines, NVH control in electric vehicles focuses on auxiliary components like the air compressor. In this study, the air compressor was identified as a major source of vibration, causing harsh contact between its oil sump and mounting bracket. Analyzing the vibrations revealed that the sump and bracket were not moving freely, increasing noise. Modifying the bracket design to allow more movement between the components successfully reduced both noise and vibration. The paper details the experimental process, findings, and structural damping methods to mitigate NVH in electric buses”.
Paroche, Sonu, Patel, Shubhanshi, Patidar, Ashok Kumar
Technical Paper
NVH Improvement of Transmission Electric Oil Pump with Uneven Pitch Control2025-01-0252To be published on 06/16/2025
Acoustic noise and vibration are always main issues to overcome in electric oil pumps for gearboxes in HEV and BEV. This paper introduces a noise reduction control method of electric oil pump in wet-type dual clutch transmissions. This paper proposes an uneven pitch control for electric oil pumps. For the noise reduction of vane pumps, mechanical arrangements of uneven pitch vain angle are widely used. However, the tooth angle of gear-type pumps should be even mechanically. The proposed uneven pitch control provides similar effects of the mechanical uneven pitch arrangement by instantaneous motor torque controls of the electric oil pump which cannot have uneven pitch mechanically. The magnitude of motor torque for each pump tooth is determined by an uneven pitch formula which is widely used for mechanical vane pumps in previous study and patents. A formula for the shape of motor torque is proposed by analyzing pressure fluctuations of pump as a combination of trigonometric and
Choi, Chinchul, Kim, Jongbeom
Technical Paper
Investigating lubricants base oils reactivity in ammonia/hydrogen engines via accelerated aging2025-01-0240To be published on 06/16/2025
As a carbon-free molecule, ammonia is more and more considered as a relevant fuel for long distance and off-road applications. However, this gas has different combustion characteristics compared to conventional fuels, challenging the suitability of lubricants to such engines. In this work, the evolution of lubricants under conditions mimicking ammonia combustion was assessed. Mineral and polyester lubricant base oils were exposed to oxygen, nitrogen oxides, and ammonia in a pressurized reactor under stirring. Oil aliquots were sampled at regular intervals, and characterized using Fourier Transform Infrared Spectroscopy (FTIR), viscosity and total oxygen and nitrogen contents measurements. Exposure to air containing nitrogen oxides resulted in quicker accumulation of oxidation products compared to neat air, for both the mineral and complex polyester base oil. Besides, exposure to gaseous ammonia in air resulted in a slower oxidation rate for both oils, compared to neat air. A global
Doncoeur, Carole, Giarracca, Lucia, Cologon, Perrine, Rousselle, Christine
Technical Paper
Commercial Vehicle’s Exhaust Front Pipe Reliability Improvement through Virtual Simulation and Experimental Validation2025-01-0209To be published on 06/16/2025
The exhaust front pipe is a critical structural component in commercial vehicles, ensuring the leak-proof flow of exhaust gases into the exhaust after-treatment system while withstanding engine and frame vibrations. To isolate these vibrations, the front pipe is equipped with a flex connector capable of enduring various displacements at frequencies between 8-25 Hz. The position of the flex connector relative to the engine crank axis significantly impacts its structural reliability over its service life. This paper compares the existing design, which features a horizontally positioned flex connector, with a modified design that positions the flex connector vertically and changes the material from SS-304 to SS-321. Finite element analysis was conducted using Nastran software. The fatigue life of the existing flex connector design is approximately 1015 cycles. In contrast, the improved design demonstrates a fatigue life of 1727 cycles, representing a 70% increase in durability compared to
Chandel, Kushal, Paroche, Sonu, Namdev, Akhilesh, Jain, Shailendra, Patil, Keyur
Technical Paper
Morphology Experiment of Icing Effect on Spray Propagation2025-01-0222To be published on 06/16/2025
The working conditions of combustion systems have been going extreme under the desire of human beings exploring the unknown. Cold environments can be a significant impact on the spraying of fuel not only by changing the fuel properties including viscosity and surface tension, but also by freezing the parts. In the present study, methanol spray from a commercial injector is studied via high-speed imaging, with the liquid fuel being frozen to sub-zero degrees at the injector tip. It is observed that water components from the environment will freeze at the injector tip, creating crystal structures on the surface. During the injection, the ice components will be flushed by the liquid, and the spray morphology of the starting cycle will be strongly altered, resulting in wider spray angles, much shorter penetrations, and particle structures can be observed in the downstream of the flow field. The results of the experiment provide a clear view and quantified evaluation of the freezing impact
Zeng, Tingxi, Wang, Shangning, Zhang, Yijia, Hung, David, Xu, Min
Technical Paper
Numerical Simulation and Parametric Optimization of Engine/Powertrain Mounts: Identifying Key Design Variables to Reduce NVH Noise2025-01-0251To be published on 06/16/2025
Abstract: Introduction: Engine and powertrain mounts are vital for isolating vibrations and reducing the transmission of Noise, Vibration, and Harshness (NVH) from the engine to the vehicle structure. Despite technological advancements, addressing NVH issues related to tribological factors continues to pose significant challenges in automotive engineering. Aim: This study aims to systematically identify and optimize design parameters of engine/powertrain mounts to minimize NVH levels using CAE tools and parametric optimization techniques in Abaqus and Isight, respectively. Purpose: The purpose of this research is to investigate the correlation between various design parameters of powertrain mounts and their impact on NVH characteristics. Specific attention is focused on noises such as clunking, banging, or thumping that emerge from the engine bay under dynamic conditions like acceleration, braking, or turning. These sounds often occur as the engine moves excessively due to worn mounts
Ganesan, Karthikeyan
Technical Paper
New system for the measurement of sound-insertion loss on small samples: a comparison with ASTM-E2611 and ASTM E90 test procedures2025-01-0116To be published on 05/05/2025
This article follows a companion article presented at the SAE NVC 2021, in which a new system for the measurement on small samples of the normal-incidence Insertion Loss (IL) of multilayers used for the manufacturing of automotive sound package parts was first introduced. In addition to simplifying the evaluation of the sound-insulation of multi-layers used to produce sound-package components, the system aims to overcome the limitations of the test procedure based on the ASTM E2611 standard. In this article, the latter point is demonstrated by comparing the insertion loss results obtained with the new system with those obtained with the test procedure based on the ASTM E2611 standard on a few multilayers commonly used for the manufacturing of automotive sound package parts. Results indicate that the results obtained by means of the newly developed system are more meaningful, practically usable and less prone to edge-effects, compared to those obtained according to the ASTM E2611 test
Ruggeri, Giulio, Bertolini, Claudio, Horak, Jan
Technical Paper
Vibration refinement of two wheeler sub chassis and aesthetic parts due to engine unbalanced excitation forces2025-01-0113To be published on 05/05/2025
Two wheelers are important and essential transportation mode in India. Designing a motorcycle with better riding comfort and minimal vibration are thus a major challenge for engineers now a day. Engine and road excitations are two sources of vibration acting on motor bike or scooter. These vibrations are transmitted to chassis, sub chassis, aesthetic parts and then to the rider and pillion. Unwanted vibrations will create discomfort to the rider/pillion as well as produces noises and hence needs to be minimized. This study is focused on diagnosis and control of output vibration responses of sub chassis/aesthetic parts due to engine unbalanced excitation forces. There are numerous parameters of motor bike/ scooter that govern the vibration responses of sub chassis/ aesthetic parts. Engine unbalanced inertia force characteristics and their transmission to rider and pillion has been studied and reported here. Environmental benefits demands for a complete NVH refinement for lesser
Khare, Saharash
Technical Paper
NVH improvement of the BEV transmission by altering bearing mounting arrangement.2025-01-0104To be published on 05/05/2025
As per metaphor, “The squeaky wheel gets the grease” the transmission of battery electric vehicle (BEVs) gets topmost attention in terms of NVH improvement. While the engine is getting replaced with an almost silent electric motor, the transmission noise appears persistent and demands more silent transmission. This has raised demand for improvement in design as well as manufacturing quality. Various innovations are being done to drive an improvement in the NVH. Following paper will discuss the improvement in NVH achieved through a design innovation in the way bearings are installed and demonstrated a significant amount of improvement. We have used SMT MASTA used as a simulation tool to predict the expected results and a Transmission Dyno test bench in an anechoic chamber to test the NVH performance on physical sample. The innovation was done on a small single speed two stage reduction gearbox coupled with a 100 NM, 14000 RPM battery electric motor. Though the bearings have
Pingale, Abhijeet, Soni, Jaldeep
Technical Paper
Virtual Gear Noise Analysis and Case Design Investigation for Concept Parallel Axis Drive Unit2025-01-0102To be published on 05/05/2025
For electric vehicles, it is critical to develop drive units that produce a minimal amount of noise while meeting efficiency needs for a given application. Modern computational resources and accumulated experience allow for engineers to evaluate gear noise early in the development process and influence the design of the drive unit. This paper documents a high-fidelity virtual engineering approach to evaluate gear noise in a concept parallel axis drive unit and provide learnings to influence design of the external structure to improve NVH performance. By using the latest simulation tools to calculate and visualize the noise and vibration characteristics of the drive unit, designers and developers can implement design changes in optimization iterations to reduce noise and vibration. Gear harmonic response is firstly analyzed through a system model which considers structural deflection and misalignment, then a FE housing model is incorporated which is used for noise radiation evaluation
Lima, Luiz, Shi, Zhenghong, Xu, Hai, Reynolds, Craig, Miller, John
Technical Paper
Asymmetric Gear Blank Optimization to Reduce Gear Noise for Electric Drive Units2025-01-0079To be published on 05/05/2025
Gear whine has emerged as a significant challenge for electric vehicles (EVs) in the absence of engine masking noise. The demand from customers for premium EVs with high speed and high torque density introduces additional NVH risks. Conventional gear design strategies to reduce the pitch-line velocity and increase contact ratio may impact EV torque capacitor or its efficiency. Furthermore, microgeometry optimization has limited design space to reduce gear noise over a wide range of torque loads. This paper presents a comprehensive investigation into the optimization of transfer gear blanks in a single-speed two-stage FDW electric drive unit (EDU) with the objective of reducing both mass and noise. A detailed multi-body dynamics (MBD) model is constructed for the entire EDU system using a finite-element-based time-domain solver. This investigation focuses on the analysis and optimization of asymmetric gear blank design features with three-slot patterns. A DOE methodology is employed to
He, Song, Bahk, Cheonjae, Li, Bo, Du, Isaac, Patruni, Pavan Kumar, Baladhandapani, Dhanasekar
Technical Paper
Snap-fits evaluation for minimizing the Squeak & Rattle in Automotives2025-01-0091To be published on 05/05/2025
The world of plastic products has been growing due to its versatile properties, which have become an intrinsic and fundamental part of the engineering of new products. The most important aspects contributing to this spectacular growth are the design and assembly, making sure that plastic parts are designed optimally. The safety requirements have been increased due to the safety ratings and thus interior parts must provide more absorption and protection to occupants. The main connection types used in the plastic parts are heat stakes and snap fits. The purpose of a good snap fit is not only to have a high retention effort but also to present ergonomic characteristics with low insertion and extraction effort because each part requires a different function. With the time-dependent loading the material will redistribute its internal energy thereby performing a time-related flow leading to reduced pretension thus decreasing stiffness. This paper presents an analytical and numerical method
Michael Stephan, Navin Estac Raja, C M, Mithun, Mohammed, Riyazuddin, R, Prasath
Technical Paper
Correlated Beamforming Based on Deconvolution Methods for Identified Vehicle Exterior Wind Noise Sources and Interior Noise2025-01-0025To be published on 05/05/2025
Sound source identification based on beamforming is widely used today as a spatial sound field visualization technology in wind tunnel experiments for vehicle development. However, the conventional beamforming technique has its inherent limitations. To improve the performance, three deconvolution methods CLEAN, CLEAN-SC and DAMAS were investigated. These algorithms were applied for the wind noise sources identification on a production car. After analysis of vehicle exterior wind noise sources distribution, to study the energetic contribution of identified exterior noise sources to interior noise, correlation analysis between them were conducted. The results show that, the algorithm CLEAN-SC based on spatial source coherence shows the outstanding capability to remove the sidelobes for the uncorrelated wind noise sources, while CLEAN and DAMAS which based on point spread function have definite limitations. In the application aspect, the main noise source outside vehicle is from the
He, Yinzhi, Shen, Henghao, Wu, Yu, Zhang, Lijun, Yang, Zhigang, Blumrich, Reinhard, Wiedemann, Jochen
Technical Paper
A Comprehensive Evaluation of PU Foam for EV NVH Performance2025-01-0120To be published on 05/05/2025
Low density polyurethane foam was first proposed as an alternative to expandable baffles and tapes for sealing vehicle body cavities towards the end of the last century. In spite of several inherent advantages for cavity sealing, the high equipment cost of dispensing amongst other reasons, this technology has not spread as widely as expected. With the advent of electric vehicles, there is an increased emphasis on controlling higher frequencies from motors, inverters and other components, and polyurethane foam can be a viable solution by providing more robust sealing. Polyurethane foam sealing is already being employed in the new breed of electric vehicles but its NVH advantages have not been fully studied or published in literature. Using an existing electric vehicle with conventional expandable baffles & tape sealing measures, a comprehensive evaluation of NVH performance using the closed-cell polyurethane foam solution was carried out. Testing included component level bench test on
Kavarana, Farokh, Guertin, Bill
Technical Paper
Improving the Sound Transmission Loss of Wire Harness Pass Throughs2025-01-0118To be published on 05/05/2025
Abstract Improving the Sound Transmission Loss of Wire Harness Pass Throughs For years the NVH community has known that openings in the dash sheet metal, such as holes to pass wire harnesses through, create an acoustical weak point that limits the potential noise reduction of the dash insulation system. These pass throughs can also be a source of water leaks into the vehicle’s interior. With the combustible engine and now electric inverter power plants, the need to seal this area is vital. By molding a lightweight barrier that draws through the fiber/absorber interior decoupler and dash sheet metal which mates to a secondary seal molded into an outer engine dash decoupler, the two opposing molded barriers meet in the engine compartment and compress together forming a seal around the wire harness. This male/female molded seal replaces the conventional snap in grommet and eliminates noise/water leaks. The system Sound Transmission Loss (STL) is equivalent to similarly insulated sheet
Check, James, Moritz, Charles
Technical Paper
A Study on Reduction of Gear Rattle Noise through Clutch Hysteresis Stabilization2025-01-0100To be published on 05/05/2025
Reducing gear rattle noise within the passenger cabin is a crucial objective in vehicle development due to its direct impact on customer comfort and driving experience. Gear rattle occurs when free gears collide during meshing, primarily driven by high torsional vibrations generated by engine fluctuations. These vibrations are transmitted through the clutch system to the transmission, amplifying noise inside the cabin. To address this issue, this study focuses on optimizing the clutch by stabilizing its hysteresis, which helps in minimizing the torsional vibrations transferred to the transmission input shaft, thereby reducing gear rattle. The investigation centers on a case where significant gear rattle was observed at high vehicle speeds, particularly under high engine torque conditions. A thorough root cause analysis identified that the primary contributor to the noise was a drop in the clutch hysteresis value at elevated engine torques. This drop increased torsional vibrations in
Awasthi, Mradul, Dhankhar, Dinesh Singh, Khare, Devendra Kumar, Rana, Deepak, Pandey, Anant
Technical Paper
Impact of tripod joint pressing load variation on drive shaft rattling in passenger car2025-01-0097To be published on 05/05/2025
In today’s fast changing and competitive automotive world, vehicle NVH plays an important role in customer’s perception of the brand. A silent cabin with lower noise levels is a desired attribute in a modern car. In such a scenario, abnormal noises arising because of manufacturing variations and tolerances of components can impact the brand image of any automotive company negatively. This paper presents an investigation into a noise issue arising from the right-hand (RH) drive shaft of an automotive vehicle while driving on rough roads at approximately 30 km/h. Various technical measurements, including rotational backlash and dimensional assessments, were conducted, all of which were found within specification. However, axial play between the tripod spline and the mid-shaft spline was identified during disassembly. Further analysis revealed that material localization was the only change point in the RH drive shaft manufacturing process. The fit interference between the tripod spline
Dhankhar, Dinesh Singh, Mishra, Ashish, Kirti, Viplav, Rana, Deepak, Bhardwaj, Ashish, Singh, Karanveer
Technical Paper
GPU-Accelerated Aeroacoustic Simulations of HVAC Duct Configurations2025-01-0133To be published on 05/05/2025
Large eddy simulations of two HVAC duct configurations at different vent blade angles are performed with the low-Mach (Helmholtz) flow solver ``Fidelity CharLES'' for comparison with aeroacoustics measurements conducted at Toyota Motor Europe facilities. The pressure fluctuation time history is recorded on a Ffowcs Williams-Hawking (FW-H) surface to predict the sound pressure level at specific locations, corresponding to the positions of four near-field and four far-field microphones. The A-weighted 1/3 octave band delta sound pressure level (SPL) between the two vent blades angle configurations is computed and compared to experimental data. Overall, the simulations capture the experimental trends and the LES spectra show good agreement with the experimental measurements over the frequency range of interest (i.e. 1000Hz to 5000Hz).
Besem-Cordova, Fanny M., Dieu, Donavan, Wang, Kan, Brès, Guillaume A., Delacroix, Antoine
Technical Paper
Road Noise Analysis Using Component TPA and FBS with Vehicle Component Modifications2025-01-0055To be published on 05/05/2025
Road noise caused by road excitation is a critical factor for vehicle NVH (Noise, Vibration, and Harshness) performance. However, assessing the individual contribution of components, particularly bushings, to NVH performance is generally challenging, as automobiles are composed of numerous interconnected parts. This study describes the application of Component Transfer Path Analysis (CTPA) on a full vehicle to provide insights into improving NVH performance. With the aid of Virtual Point Transformation (VPT), blocked forces are determined at the wheel hubs; afterward, a TPA is carried out. As blocked forces at the wheel hub are independent of the vehicle dynamics, these forces can be used in simulations of modified vehicle components. These results allow for the estimation of vehicle road noise. To simulate changes in vehicle components, including wheel/tire and mount bushings, Frequency-Based Substructuring (FBS) is used to modify the vehicle setup in a simulation model. In this
Kim, Jungu, Reichart, Ron, de Klerk, Dennis, Schütler, Willem, Malic, Mario, Kim, Hyeongjun, Kim, Uije
Technical Paper
The applications of Acoustic Black Holes to attenuation of Coach/Bus Frame Structure Vibrations2025-01-0065To be published on 05/05/2025
Abstract An acoustic black hole (ABH) is a structure whose cross-sectional thickness decreases exponentially to zero, and the phase velocity and group velocity of wave propagation in those structure acoustic black holes decrease as the thickness decreases until they are zero. ABH produce some very magical physical phenomena. For example, because the wave velocity decreases to zero, the wave can never reach the center of the ABH, so the wave propagation in the acoustic black hole has neither refraction nor reflection; that is to say the vibration wave will not go through the acoustic black hole. As a result, the wave energy is concentrated in the center of the ABH. The arrangements of those acoustic black holes in the structures could change the directions of the vibrational wave propagation in the structures at NVH engineers’ wills. These amazing phenomena could play a magical role in reducing structural vibration, structural noise radiation and structure-borne noise. Basic structures
Xu, Chuanyan, Wang, Jianjun, Xing, Qisen, Chen, Hengbin, Huang, Xianli
Technical Paper
Indirect Blocked Force Measurement of a Hydraulic Power Pack for Structural Vibration Transmission into an Airframe2025-01-0052To be published on 05/05/2025
Centralization of electrically driven hydraulic power packs into the body of aircraft have increased the attention on the noise and vibration characteristics of the system. A hydraulic power pack consists of a pump coupled to an electrical motor, accumulator, reservoir, and associated filter manifolds. In previous studies, the characteristics of the radiated acoustic noise and fluid borne noise were studied. In this paper, we focus on the structure borne forces generated by the hydraulic pump characterized through blocked force measurements. The blocked force of the pump was determined experimentally using an indirect measurement method. The indirect method required operation with part under test fixed to an instrumented receiver structure. Measured operational accelerations on the receiver plate were used in conjunction with transfer function measurements to predict the blocked forces. Blocked forces were validated by comparing directly measured accelerations to predicted
Smither, Matthew, Tuyls, Zachary, Patel, Pratik, Yan, Xin, Herrin, David
Technical Paper
Development of a Model to Predict Acoustic Emissions of Bent-Axis Pumps2025-01-0056To be published on 05/05/2025
This work presents a comprehensive procedure for predicting the acoustic emissions of mechanical systems, using a bent-axis pump as a case study. The procedure is developed as a workflow integrating multibody dynamics (MBD), harmonic structural analysis, and acoustic solvers. By modeling the mechanical system, we capture the pump’s dynamic response and the vibration behavior of the enclosure’s surface, enabling the estimation of equivalent radiated power (ERP) and the prediction of sound pressure level (SPL). To validate the simulation results, experimental investigations were conducted in a semi-anechoic chamber, where data was collected using a microphone placed at a specific distance from the pump. At the time of this publication, preliminary correlations between the simulation model and real-world measurements demonstrate promising accuracy and reliability. However, further investigation is needed to identify potential sources of discrepancies. Findings from this project offer
Kwarta, Michael, Banerjee, Bhaskar, Abdel Mallak, Zuher, Vallebrant, Per-Ola, Wiklund Lång, Marcus, Kayani, Omer
Technical Paper
Machine Learning-Based Vision Mapping and Planning for Flexibility in High-Mix Robotic Manufacturing2025-01-0157To be published on 05/02/2025
Industries that require high-accuracy automation in the creation of high-mix/low-volume parts, such as aerospace, often face cost constraints with traditional robotics and machine tools due to the need for many pre-programmed tool paths, dedicated part fixtures, and rigid production flow. This paper presents a new machine learning (ML) based vision mapping and planning technique, created to enhance flexibility and efficiency in robotic operations, while reducing overall costs. The system is capable of mapping discrete process targets in the robot work envelope that the ML algorithms have been trained to identify, without requiring knowledge of the overall assembly. Using a 2D camera, images are taken from multiple robot positions across the work area and are used in the ML algorithm to detect, identify, and predict the 6D pose of each target. The algorithm uses the poses and target identifications to automatically develop a part program with efficient tool paths, including
Langan, Daniel, Hall, Michael, Goldberg, Emily, Schrandt, Sasha
Technical Paper
Enhancing Efficiency in Aerospace Manufacturing through AI Agent Based Bearing Diagnostics System2025-01-0158To be published on 05/02/2025
Industrial bearings are critical components in aerospace manufacturing, where their failures can result in costly downtime. Traditional fault diagnosis typically depends on time-consuming on-site inspections conducted by specialized engineers. This research introduces an innovative Artificial Intelligence application that functions as a virtual maintenance technician, empowering on-site personnel to perform preliminary diagnoses. By reducing the dependence on specialized engineers, this technology aims to minimize downtime. The AI system leverages large language models to guide the inspection process, answer queries from a comprehensive knowledge base, analyze defect images, and generate detailed reports with actionable recommendations. Multiple deep learning algorithms operate as backend APIs to support this functionality. This study details the architectural design of the expert system and provides a real-time simulation of its workflow, demonstrating its potential to enhance
Chandrasekaran, Balaji
Technical Paper
Evaluation of Hybrid Aeroacoustics Models for HVAC Duct Noise Predictions2025-01-5032To be published on 05/01/2025
This study evaluates the effectiveness of two hybrid computational aeroacoustic methods—Lighthill wave model and perturbed convective wave model—in simulating HVAC duct noise in the automotive industry. Using component-level acoustic testing of a Ford HVAC duct, simulations were conducted at varying airflow rates to assess the accuracy of both models in predicting duct noise. The Lighthill wave model, suitable for noise analysis in regions outside turbulent flow areas, showed a good correlation with experimental data, especially in the frequency range of 100 Hz–5000 Hz, but sometimes struggled with pseudo-noise effects at low frequencies near turbulent regions. The perturbed convective wave model, which is suitable for noise analysis anywhere in the flow domain, underpredicted sound pressure levels at low frequencies as well. Both models underpredicted high-frequency noise (>5 kHz) due to insufficient mesh and time-step sizes. Despite these limitations, the Lighthill wave model
Nam, Jee-Whan, Mendel, Marc, Golberg, Igor
Technical Paper
Research on the Influence of Door and Window Sealing on Interior Wind Noise Based on Statistical Energy Analysis10-09-03-002604/24/2025
Wind noise is an important indicator for evaluating cabin comfort, and it is essential to accurately predict the wind noise inside the vehicle. In the early stage of automotive design, since the geometry and properties of the sealing strip are often unknown, the contribution of the sealing strip to the wind noise is often directly ignored, which makes the wind noise obtained through simulation in the pre-design stage to be lower than the real value. To investigate the effect of each seal on wind noise, an SUV model was used to simulate the cases of not adding body seals, adding window seals, and further adding door seals, respectively. The contribution of each seal to wind noise was obtained and verified by comparing it with the test results. The influence of the cavity formed at the door seal was also addressed. In the simulations, a CFD solver based on the lattice Boltzmann method (LBM) was used to solve the external flow field, and the noise transmitted into the interior of the
Zhang, Yingchao, He, Tengsheng, Wang, Yuqi, Niu, Jiqiang, Zhang, Zhe, Shen, Chun, Zhang, Chengchun
Journal Article
Research on Intake Sound Tuning Method by Valve Timing Modification for Enhance Sound Quality in V6 Outboard Engine2024-32-005904/18/2025
This paper explores methods to enhance the sound quality of V6 outboard engines. Previous research in the boat and outboard engine domain has underscored the importance of enhancing sound quality. Specific preferences and desired directions for outboard engine sound quality have been identified. It’s been suggested that controlling intake sound and gear noise is important to achieving desired sound quality according to customer preferences. However, there are few examples of methods for achieving this. This study aims to develop methods for enhancing sound quality by emphasizing low-frequency sounds through intake sound. Initially, various methods were evaluated, and intake valve timing modification was chosen. Simple simulations confirmed that delaying valve timing for some cylinders may introduce characteristics that are not present in conventional cases. Subsequent 1D simulations identified optimal intake valve timing, balancing intake pressure characteristics and horsepower
Muramatsu, Hideta, Matsumoto, Taro, Naoe, Gaku, Kondo, Takashi
Technical Paper
Study on the Optimal Pre-Chamber Geometry for Active Pre-Chamber Gas Engines2024-32-002304/18/2025
In a pre-chamber engine, fuel in the main-chamber is ignited and combusted by the combustion gas injected from the pre-chamber. Therefore, further fuel dilution is possible and thermal efficiency can be also improved. However, adding a pre-chamber to an engine increases the number of design parameters which have a significant impact on the main combustion and the exhaust gas. Then, in this study, the optimum geometry of the pre-chamber in an active pre-chamber gas engine was investigated. The considered parameters were the volume of pre-chamber, the diameter of a nozzle hole, and the number of nozzle holes. 18 types of pre-chambers with different geometries were prepared. Using these pre-chambers, engine experiments under steady conditions were conducted while changing the conditions such as engine speeds, mean indicated pressure and air excess ratio. Based on the experimental data, neural network models were constructed that predict thermal efficiency, NOx and CO emissions from the
Yasuda, Kotaro, Yamasaki, Yudai, Sako, Takahiro, Takashima, Yoshitane, Suzuki, Kenta
Technical Paper
Dynamic Analysis of Intake and Exhaust Valve Motion in a High-Performance 4-Stroke Engine. Part1 - Experimental Measurement of Valve Motion Using a High-Frequency Laser Sensor2024-32-008304/18/2025
The motion of the intake and exhaust valves plays a pivotal role in determining operational efficiency and performance, especially in high-specific power 4-stroke engines. At high rpm levels, the dynamic behavior of the valve may deviate from the kinematic model established during the design phase. This discrepancy arises due to the high accelerations and forces to which the valve and other components of the valvetrain system are subjected. Notably, under such conditions, the valve may detach from the cam profile at the conclusion of the opening stroke and can exhibit a bouncing behavior during the closing stroke. Moreover, the elasticity of all valvetrain system elements introduces additional complexities. Factors such as timing chain elongation, camshaft carrier deformation, and valve stem compression can contribute to a deviation in phase compared to the initially defined kinematics. Within this context, the direct measurement of the valves motion represents fundamental information
Grilli, Niccolò, Romani, Luca, Raspanti, Sandro, Bosi, Lorenzo, Ferrara, Giovanni, Trassi, Paolo, Fiaschi, Jacopo, Guarducci, Edoardo
Technical Paper
A Study on Optimal Combinations of Winding and Cooling Methods for Downsizing Power Units in Motorcycles2024-32-000704/18/2025
In commercially available electric motorcycles, there is a notable shift in the cooling method, moving from air cooling to water cooling, and in the winding method, moving from concentrated winding to distributed winding, as the output increases. This shift occurs around 8 to 10 kW. However, there is a paucity of empirical investigations examining these combinations to ascertain their optimality. In order to verify this trend, a verification model has been constructed which allows for the comparison of the capacity and weight of the motor and cooling system according to the vehicle’s required output and thermal performance. A comparison and verification of the combinations of winding methods (concentrated winding or segment conductor distribution winding) and cooling systems (water-cooled or air-cooled) was conducted using the model that had been constructed. In the motor designed for this study, when the maximum output of the vehicle was 35 kW or less (European A2 license), the total
Otaki, Ryota, Tsuchiya, Teruyuki, Sakai, Yu, Yamauchi, Takuya, Shimizu, Tsukasa
Technical Paper
Investigation on the Wear Regime of Plastic Gears Sliding Against Metal Gears2024-32-009904/18/2025
The use of plastic gears has expanded due to their lightweight properties, low noise emission, and cost-effective manufacturing. For instance, in the transportation equipment industry, some metal gears are being replaced with plastic gears. To achieve further size and weight reduction, gears must be able to withstand higher loads without damage. Gears have various modes of damage. Since there are different types of wear, each with different factors, it is important to identify the factors and take appropriate countermeasures. In gear meshing, there are many factors that affect wear, so restricted-factor tests are required to confirm the effectiveness of countermeasures. The purpose of this study is to elucidate the wear regime in high-load gear meshing and then to establish a simplified evaluation method replicating the meshing of gears for wear resistance focusing on the relative sliding between the two surfaces of metal and plastic. In the evaluation, changes in wear morphology over
Yamamoto, Jimpei, Suzuki, Takaharu, Ako, Natsuki, Iwasaki, Shinya, Kurita, Hirotaka
Technical Paper
Dependency of Gear Honing Machine Processing Accuracy on Machine Vibration and the Vibration Reduction Considering Contribution2024-32-002004/18/2025
In recent years, accurate gear processing is required for various products to improve efficient power transmission and small noise and vibration. On the other hand, the accuracy tends to be worse by high speed processing for increasing production efficiency. Therefore, we investigated relationship between gear honing machine vibration and the accuracy. The vibration acceleration of the honing machine was measured at various conditions, and the gear accuracy was measured after processing. As results, the accuracy was observed to be affected by both the original gear accuracy before honing processing and the gear secondary rotational vibration of the machine in operation. Subsequently, we applied transfer path analysis (TPA) to investigate which directional force in operation increased the vibration. As the results, the contribution from the input force at gear processing point along normal direction was the main contributor. Then, vibration transmission characteristics of the machine
Hanioka, Hiroaki, Ogawa, Yunosuke, Yoshida, Junji, Onishi, Yoichi, Kurokawa, Yasuhiro
Technical Paper
Recommended Wheel Tie Bolt Preload ProcedureARP5481A (Current)04/14/2025
This SAE Aerospace Recommended Practice (ARP) provides the recommended procedure for obtaining desired preloads in aircraft wheel tie bolts when mounting tires and assembling the wheel. It is generally referred to as the snug-angle bolted joint assembly procedure. It is also known as the “torque-turn” procedure in the heavy equipment ground vehicle industry.
A-5A Wheels, Brakes and Skid Controls Committee
Recommended Practice
Hose Assembly, Convoluted Polytetrafluoroethylene, Metallic Reinforced, Low Pressure, Up to 400 °F, AircraftAS1227C (Current)04/14/2025
This SAE Aerospace Standard (AS) defines the requirements for a convoluted polytetrafluoroethylene (PTFE) lined, metallic reinforced, hose assembly suitable for use in aerospace fluid systems at temperatures between -65 °F and 400 °F for Class 1 assembly, -65 °F and 275 °F for Class 2 assembly, and at operating pressures per Table 1. The use of these hose assemblies in pneumatic storage systems is not recommended. In addition, installations in which the limits specified herein are exceeded, or in which the application is not covered specifically by this standard, shall be subject to the approval of the procuring activity.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Technical Standard
Coupling Assemblies, Non-Locking Probe Style, Self-Aligning, Self-Sealing DisconnectsAS4251A (Current)04/14/2025
This specification establishes the requirements for a probe type self-sealing, self-aligning, non-locking coupling intended for aerospace hydraulic and cooling systems.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Technical Standard
NUT, PLAIN, HEXAGON, BOSS CONNECTION, SILVER PLATED, 347 CRES UNS S34700AS9201E (Current)04/14/2025
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Technical Standard
INSERT - CRES HELICAL COIL FINE THREAD, STRAIGHT STUD LOCKING, 2.5 DIA NOM LENGTHAS3082B (Current)04/14/2025
E-25 General Standards for Aerospace and Propulsion Systems
Technical Standard
FITTING, UNION, FLARED TUBE BULKHEAD AND UNIVERSAL, FOR SEAL RINGAS1100E (Current)04/14/2025
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Technical Standard
Aerospace Fluid Systems and Components – Pressure and Temperature ClassificationsAS2001B (Current)04/14/2025
This document establishes the temperature types and pressure classes that are commonly used in aerospace fluid systems. The temperature types and pressure classes are equivalent, but not identical, to the SI units defined in MA2001 (ISO 6771). For exact conversion use NAS 10000.
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Technical Standard
Detailed Specification for Aircraft Pressure Refueling NozzleAS5877C (Current)04/14/2025
This SAE Aerospace Standard (AS) prescribes requirements for the various types of nozzles that are used for the refueling and defueling of aircraft fitted with pressure fuel servicing systems. It is to be used as a replacement for MIL-N-5877 and MS29520 and for all commercial applications.
AE-5C Aviation Ground Fueling Systems Committee
Technical Standard
BOLT-CLUSTER FITTING SINGLE PORT-FLAREAS21949A (Current)04/14/2025
G-3, Aerospace Couplings, Fittings, Hose, Tubing Assemblies
Technical Standard
Assessment of Aircraft Wheel Sealing SystemsARP5146 (Current)04/11/2025
This SAE Aerospace Recommended Practice (ARP) is intended to provide guidance on verifying the integrity of inflation pressure sealing systems of aircraft wheel/tire assemblies.
A-5A Wheels, Brakes and Skid Controls Committee
Recommended Practice
CRIMPING TOOL AND ACCESSORIES, REMOTE CRIMP HEAD, HYDRAULIC, WIRE SIZE 8 TO 0000 FOR INSULATED AND UN-INSULATED CRIMP BARRELSAS5259/1B (Current)04/02/2025
AE-8C2 Terminating Devices and Tooling Committee
Technical Standard
Development of a New Concept Structure for 4-Way Electric Headrest Adjustment2025-01-862004/01/2025
At present, electric head restraints have been developed locally, so overseas mechanisms are used. In this study, two concept mechanisms were developed, and in addition, one patent for a wing-out head restraint mechanism was additionally applied. The new mechanism has had an excellent effect on cost reduction and improvement of operating noise compared to the current one.
Yu, Sanguk
Technical Paper
Dynamic Tailgate Water Management Simulation Using Smoothed Particle Hydrodynamics2025-01-862504/01/2025
Opening a tailgate can cause rain that has settled on its surfaces to run off onto the customer or into the rear loadspace, causing annoyance. Relatively small adjustments to tailgate seals and encapsulation can effectively mitigate these effects. However, these failure modes tend to be discovered relatively late in the design process as they, to date, need a representative physical system to test – including ensuring that any materials used on the surface flow paths elicit the same liquid flow behaviours (i.e. contact angles and velocity) as would be seen on the production vehicle surfaces. In this work we describe the development and validation of an early-stage simulation approach using a Smoothed Particle Hydrodynamics code (PreonLab). This includes its calibration against fundamental experiments to provide models for the flow of water over automotive surfaces and their subsequent application to a tailgate system simulation which includes fully detailed surrounding vehicle geometry
Gaylard, Adrian Philip, Weatherhead, Duncan
Technical Paper
Design Optimization of Electro-Hydraulic Valve Performance Through Simulation and Experimental Methods2025-01-864204/01/2025
The main purpose of the semi-active hydraulic damper (SAHD) is for optimizing vehicle control to improve safety, comfort, and dynamics without compromising the ride or handling characteristics. The SAHD is equipped with a fast-reacting electro-hydraulic valve to achieve the real time adjustment of damping force. The electro-hydraulic valve discussed in this paper is based on a valve concept called “Pilot Control Valve (PCV)”. One of the methods for desired force characteristics is achieved by tuning the hydraulic area of the PCV. This paper describes a novel development of PCV for practical semi-active suspension system. The geometrical feature of the PCV in the damper (valve face area) is a main contributor to the resistance offered by the damper. The hydraulic force acting on the PCV significantly impacts the overall performance of SAHD. To quantify the reaction force of the valve before and after optimization under different valve displacements and hydraulic pressures were simulated
Chintala, Paramesh, Hornby, Ryan
Technical Paper
A Sensitivity Study of Frequency Response Method for Setting Bearing Preload Due to Uncontrollable Parameters2025-01-852004/01/2025
A new method for bearing preload measurement has shown potential for both high accuracy and fast cycle time using the frequency response characteristics of the power transmission system. One open problem is the design of the production controller, which relies on a detailed sensitivity study of the system frequency response to changes in the bearing and system design parameters. Recently, an analytical model was developed for multi-row tapered roller bearings that includes all appropriate bearing and power transmission system design parameters. During the assembly process, some of the parameters related to the roller positions cannot be controlled. These parameters include the actual position of the first roller compared to the vertical axis, the relative position of the rollers between the bearing rows, and others. This work presents a sensitivity analysis of the effects of those uncontrollable parameters on the analytical model. The sensitivity study determines the percentage change
Gruzwalski, David, Mynderse, James
Technical Paper
A Review of Warm Forming for Steels: History, Methodology and Emerging Trends2025-01-881404/01/2025
Many manufacturing techniques and processes have been implemented over the years to improve the formability of sheet metals. Warm forming of sheet metals is one such established method. However, it is more commonly and successfully applied to aluminum grades. The re-evaluation of less-used metal forming technologies, such as warm forming and sheet hydroforming for steel are responses to the challenges posed by competitive processes like large castings and the geometry requirements of new BEV parts. By understanding the effects of elevated temperatures (above or below recrystallization temperatures) on different steel grades and the impact of various heating methodologies, the industry can adapt and optimize these proven techniques for modern applications. This paper is a thorough summary of the effect of elevated temperatures on various grades of steel. Different heating techniques, their cycle times and effects on final forming feasibility are contrasted. The effect of chemistry
Kella, Caroline, Wormald, Tom
Technical Paper
Research on the Gearshift Control in Dual Motor Hybrid System2025-01-851204/01/2025
This paper delineates a shift control approach for a dual motor structure incorporating a drum-type shift lever in a parallel mode, which can be approximately categorized into five stages. In the first stage, the torque of the dual motor and internal combustion engine is interchanged, and the engine side torque is reverted to zero within the capacity range, with the P3 motor compensating for the torque loss on the engine side. In the second stage, the vehicle control unit transmits a request for series connection to the powertrain control module and dispatches a request for the internal combustion engine gear position to be in neutral to the powertrain control module. The powertrain control module enters the sequence for the transition from parallel to series and undertakes the action of unloading the C0 clutch torque. Once the C0 clutch torque is completely disengaged, the actual mode is fed back as parallel, and the actual engine gear position is fed back as neutral. In the third
Jing, Junchao, Liu, Yiqiang, li, Dongfei, Zuo, Botao, Huang, Weishan
Technical Paper
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