bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Operation of Purge Valve to Reduce the H
2
Wastage in the Fuel Cell
Authors: Shah Saurabh , Bhat Adithya , Munirajappa Chandrashekara , Prasad P Shilpa , Choubey Ayush
Published: January 2024

A Proton Exchange Membrane Fuel Cell requires the input of Oxygen from the Cathode and Hydrogen from the anode. As atmospheric air is fed into the system for power generation, nitrogen molecules enter the fuel cell along with oxygen molecules. Over time, an accumulation of nitrogen inside the fuel cell leads to an increase in the effective impedance, which in turn leads to an increase in losses inside the fuel cell, hence reducing the fuel cell efficiency. To reduce the losses, most of the PEM fuel cells have a purge valve at the anode. This purge valve is operated frequently as the impedance increases to let out the nitrogen molecules. During the purging operation, some amount of Hydrogen is let out along with nitrogen, which cannot be recovered. In other words, loss of Hydrogen could also be considered in terms of reduction in system efficiency. Conventionally, nitrogen purging operation in fuel cell takes place reactively as voltage/ power drop across the electrode increases above a defined threshold. This paper proposes an optimization-based solution, which aims at operating the purge valve by predicting load on the vehicle. This can minimize the overall losses in a fuel cell that occur due to wastage of hydrogen and conduction losses due to the presence of water and contaminants like nitrogen inside fuel cell. The predicted energy loss due to the loss of Hydrogen and the predicted energy loss due to the accumulation of nitrogen is modelled, and an optimization algorithm is developed. Optimizer suggests the time instants when the purge valve should be opened which minimizes the hydrogen loss and conduction losses.
Hydrogen as a Carbon Neutral ICE Fuel for Future India
Authors: Bandyopadhyay Debjyoti , Sutar Prasanna S , Sonawane Shailesh Balkrishna , Rairikar Sandeep , Thipse Sukrut S , Jadhav Ajinkya
Published: January 2024

Researchers are under pressure to investigate and discover ways to improve the efficacy and reduce emissions from ICE due to the depletion of energy resources and the growing concern over global warming. Hydrogen is viewed as a promising fuel and has been investigated as a potential fuel in combustion because to several desirable qualities like carbon-less content and strong flammability limitations. When equated to other alternative fuels like LPG, CNG, LNG, etc., hydrogen has inimitable qualities because it lacks carbon, making it one of the promising alternatives fuels.

In order to achieve zero CO2 emissions for traffic applications in the near future, hydrogen being an automotive fuel in ICE is a solution. The ICE powered by hydrogen is prepared for that. The actual drawbacks of using hydrogen in ICE generally are manufacturing, storage, and development of the requisite infrastructure. Hydrogen can be produced in its many forms. Hydrogen storage is a significant barrier to the utilization of this renewable fuel; hence its transportation and storage are being researched. For ICE, hydrogen can be a fuel, and its required adaptations for the current ICE are currently being researched.

The characteristics and various fuel properties of a hydrogen ICE are studied. This study aims to comprehend the worldwide scenario of hydrogen and its emerging demand in the automobile market. The various challenges of using hydrogen as a fuel in India are identified, the possibility of on-site production of hydrogen and the pros and cons of using hydrogen as an ICE fuel are reviewed in this paper.
Fuel Cell Electric Metro Train Concept – Zero Emission Rail Transport Solution for Indian Cities
Authors: Emran Ashraf , Garg Shivam , Mertes Simon , Gautam Anirudh , Schmidt Marvin , Wick Maximilian , Walters Marius , Wagh Sachin , Sharma Vijay
Published: January 2024

Indian cities are among the most polluted in the world. The transportation sector is one of the major sources of gaseous pollutants. In recent years, also the effects of climate change and global warming have been felt across the globe. India has therefore committed at the CoP26 summit in 2021 to reduce its CO2 emissions by 45% till the year 2030. The Indian automotive sector is already addressing the problem with implementation of the Stage 2 BS VI norms, CAFÉ & Stage V standards and pursuing rapid electrification with application of zero emission vehicles.

India also has the largest rail network of Asia, and a significant proportion of greenhouse gases is emitted by this sector. Deployment of zero emission fuel cell trains would be one of the solutions to meet India’s emission reduction targets. Indian Railways has already started its journey towards zero emissions and has set a target to launch hydrogen fuel cell trains on some routes soon as part of the “Hydrogen for Heritage” initiative.

In this study, the application of fuel cell technology in an Indian metro train is investigated. The dimensioning of the major powertrain components like the fuel cell system, HV battery pack, and the hydrogen storage system for the fuel cell train are presented. Also, a retrofit approach will be developed, which includes a packaging study of the major powertrain components in the engine and passenger coaches of the existing train. System simulations with validated models allow an assessment of the system weight and costs for the new fuel cell metro train.
Indian Cooperative Intelligent Transport Systems
Authors: Rajak Vipin , Sandhu Jivraj Singh
Published: January 2024

In response to the growing need for increased mobility and road safety, India, like other developing nations, is placing a high focus on modernizing its transport infrastructure. This report performs a thorough technical analysis of the challenges and implementation issues that were encountered when deploying Intelligent Transportation Systems (ITS) in India. This paper provides valuable information about successful ITS deployment and the unique challenges faced in the Indian context, drawing on global research and case studies.

A detailed understanding of cutting-edge technologies and how they integrate with current infrastructure is essential for India's adoption of ITS to be successful. Collaboration with a range of stakeholders, including governmental organizations, transportation authorities, and technology businesses, is essential for effective deployment. Using examples from around the world, this study intends to find the best stakeholder management practices.
Evaluation of Automated Emergency Braking Systems for Collision Avoidance
Authors: K V Manoj , Kamikkiya P , Urs Hriday V.
Published: January 2024

From the past few years, there is a pressing need for implementation of automatic in-vehicle safety systems to avoid vehicle crashes and fatalities. Development of autonomous emergency braking systems (AEBS) to detect and avoid collisions in such critical moments is of paramount importance. In this paper, AEBS is developed for a four-wheeler system that aims to detect vehicles and controls the ego vehicle based on the expected stooping distance (ESD). This control system aims to react based on the real-time relative distance & speed of the ego vehicle to actuate appropriate braking force. Control systems developed in Altair Activate are co-simulated with CARLA, a virtual reality simulator for autonomous driving research. Various scenarios including low and high-speed car to car motion, urban high and low traffic density environments are simulated to study the robustness of the control system. Further, studies are conducted to evaluate the effectiveness of the systems by varying the activation threshold, distance etc. The results of this evaluation demonstrate the effectiveness of the AEB system in reducing the severity of collisions, and the system’s ability to function correctly in different scenarios. Later, suitable modification to the control system is suggested in case ESD is very high when compared to Stopping distance.
Geometry, Sizing and Optimization of Honeycomb Structures along with Embedded Metal Inserts on the Floor for Truck-Mounted Container Applications
Authors: Phukan Prerna , Dave Rajeev
Published: January 2024

With the rise of worldwide trends towards light weighting and the move towards electric vehicles, it is now more important than ever for the automotive industry to develop and implement lightweight materials that will result in significant weight reduction and product improvements. A great deal of research has been done on how to best combine and configure honeycomb cores with the right face sheets for Truck-Mounted Container Applications. Honeycomb structures possess the ability to bring about superior structural rigidity when the core parameters are selected and optimized based on the automotive application requirements. Through a variety of experimental tests for various combinations of the core parameters, the selection of the critical honeycomb core parameters to efficiently increase the compressive strength and panel rigidity of the entire container assembly has been evaluated and compared in order to determine the most effective combination to produce superior results for automotive applications specific to container segment.

The current study also describes the challenges that were faced when using honeycomb core structures for chassis installation as well as the extensive research that was done to identify the optimal option. As all loads and fastening will induce higher forces on the floor mountings, it became crucial to design appropriate metal inserts at these truck mounting locations in order to support these loads/forces and ensure proper distribution to the complete floor panel. Keeping this objective, various metal insert designs with different geometric characteristics were studied and experimental trials carried out in order to arrive at the optimum design sizing for best performance. The specifications of the metal insert built-in the floor panel to achieve the desired result of withstanding the container loads are also highlighted in the study.
Utilizing Computed Tomography for Cell Characterization, Quality Assessment, and Failure Analysis
Authors: Singh Sathya Prakash , Baidya Kapil Krishna , Adhale Pratik
Published: January 2024

Computed Tomography (CT) has become a potent instrument for non-invasive assessment of battery cell integrity, providing detailed insights into their internal structure. The present study explores the capabilities and advantages of employing CT for cell characterization through a systematic evaluation from various parameters. The evaluation results will be based on real-world experiments conducted on a standard battery cell, assessing the CT system’s ability to provide precise internal measurements, detect defects, and ensure the overall integrity of the cell. We outline a comprehensive framework that includes criteria such as system specifications, image quality, software capabilities, maintenance, service, and cost-effectiveness. This framework serves as a valuable guide for battery researchers and quality control professionals, enabling them to make informed decisions when selecting the most suitable CT solution for battery cell characterization, quality assessment, and failure analysis.
Headliner Composition Optimization without Compromising the Safety and Performance
Authors: D Gowtham , Vadla Vilas , Bhaskararao Pathivada , Sai Konduru , Bornare Harshad , Ritesh Kakade , Deoli Manish , Kakani Phani Kumar
Published: January 2024

Reducing material wherever there is a possibility in automobile industry is inevitable for weight and cost saving. This paper explains about the possibilities of optimizing the material composition of automotive Headliners (also called as Roof liners) without affecting the performance and safety criteria. In this paper, we are targeting at optimizing the individual constituents of a composite Headliner. A conventional Headliner comprises of many sandwich layers of which PU foam shares the major percentage of the composition contributing to 80% of the Headliner thickness. In this paper, we are discussing about the optimization done in Headliner sandwich constituents without affecting the core performance parameters of headliner such as curtain airbag deployment, ergonomic regulations, drop test etc.

By incorporating this change, without significant changes in other layers, overall weight reduction of ~24% and overall cost reduction of ~24% is achieved.
Scientific Approach for Pickup Cargo Weight Reduction
Authors: Mohan Aravind , Balasubramani Sritharkumar , Pandurangan Raman , Cornelio Ronald , Senrayaperumal Sakthivel , ved Kapil , Patel Mayank
Published: January 2024

In this study, the benchmarked-based statistical Light Weight Index (LWI) technique is developed for predicting the world in class optimum weight. For these four statistical Lightweight Index numbers are derived based on the geometrical dimensions. This strategy is used for the target setting. To achieve the target, the Value Analysis approach for Cargo assembly is to redesign and make Refresh Cargo assembly.

The organization also benefited directly by reducing the inventory cost and transportation costs because of the deletion of parts and minimizing the assemblies. Vehicle power-to-weight ratio and fuel economy also improved based on cutting weight.

The complete case study with details has been mentioned in the work. The weight benefit led to an increase in the profit margin and caters to the difficulty because of the daily increase in the price of raw materials.
Development of Advanced Signal Analysis Technique for Pass-by Noise Source Identification of Light Commercial Vehicle
Authors: Suresh Vineeth , Choudhari Yogeshwar , Kalsule Dhanaji , Athavale Prasad
Published: January 2024

The auto industry is one of the major contributors for noise pollution in urban areas. Specifically, highly populated heavy commercial diesel vehicle such as buses, trucks are dominant because of its usage pattern, and capacity. This noise is contributed by various vehicle systems like engine, transmission, exhaust intake, tires etc. When the pass by noise levels exceeds regulatory limit, as per IS 3028, it is important for NVH automotive engineer to identify the sources & their ranking for contribution in pass by noise. The traditional methods of source identification such as windowing technique, sequential swapping of systems and subsystems which are time consuming.Also advanced method in which data acquisition with a synchronizing technology like telemetry or Wi-Fi for source ranking are effective for correctness.However they are time and resource consuming, which can adversely impact product development timeline. This paper discusses about the advanced signal analysis technique that enables the synchronization of in-vehicle near source data with exterior pass-by noise microphone data without any external synchronization technology. The key element of this technique is the use of innovative signal processing technique to extract the vehicle engine rpm from exterior pass-by noise microphone noise color plot. Once the engine rpm at which the maximum pass-by noise occurred has been ascertained, octave analysis and contribution analysis can be carried out for source identification and ranking sources at critical engine rpm where higher pass by noise was recorded. This method was validated by identifying the transmission system as the primary contributor to higher pass-by noise in a light commercial vehicle. This exercise provides a method to synchronize and analyze data from 2 independent data acquisition systems without any external synchronizing equipment and also proves that transmission unit contribution to pass-by noise is significant and must be monitored closely.
A Universal Steering Grommet Design Approach to Enhance the Passenger Cabin NVH Performance
Authors: J Sadhish , Vijayarangan Deepak , S Senthil , Kole Shantinath
Published: January 2024

As a car OEM, we continuously strive to set the bar for competitors with every product. Consumer travel experiences are enhanced by increasing passenger cabin silence. There is only one steering system opening in the firewall panel, which is used for allowing intermediate shaft's fitment on the pinion shaft of the steering gear. The steering grommet is the sole component that covers the firewall cut-out without disrupting steering operations, which has a substantial impact on the NVH performance of the vehicle. It is typically used in cars to eliminate engine noise and dust entering to passenger compartment. The part is assembled inside the vehicle where the steering intermediate shaft passing through BIW firewall panel. We use a bearing, plastic bush, or direct rubber interference design in the steering grommet to accommodate the rotational input the driver provides to turn the automobile. However, occasionally noise may be produced due to uneven bearing or plastic bush loading or a lack of flexibility in the grommet. This paper covers all the factors that must be considered when designing a better steering grommet assembly, including the flexibility of the grommet during steering operations, maintaining concentricity between the intermediate shaft and the grommet at various steering column tilt positions, and efficient packaging.
The Science of Engine Mounts and its Multidimensional Impact on Noise and Vibrations in Passenger Car
Authors: Hazra Sandip , Mohare Gourishkumar
Published: January 2024

A robust process of specifying engine mounting systems for internal combustion engines (ICE) has been established through decades of work and countless applications. Vehicle vibration is a critical consideration in the early stage of vehicle development. Apart from comfort, it also affects the overall vehicle's performance, reliability, Buzz-squeak and rattle (BSR), parts durability and robustness.

The most dynamic system in a vehicle is the powertrain, a source of vibration inputs to the vehicle over the frequency range. The mounting system supports a powertrain in a vehicle and isolates the vibration generated from the powertrain to the vehicle. In addition, it also controls the overall dynamic movement of the powertrain system when the vehicle is subjected to road load excitations and avoids contact between the powertrain and other adjacent components of the vehicle.

This paper investigates the effect of the mounting position, stiffness, and progressivity on overall vehicle-level vibrations. This study is constructed around a case of a front-engine passenger vehicle with a transverse mounting system to support the Gasoline powertrain unit. The baseline and optimum systems are studied digitally and then compared physically. It explains a traditional and new approach for optimizing the mounting system. Further, a methodology to optimize the vehicle vibration characteristics with the help of a new approach for mounting layout optimization is proposed. A case study with vehicle-level NVH measurement data for baseline and optimum systems demonstrates the strength of the new methodology and its multidimensional impact on overall vehicle-level NVH. The driver seat rail (DSR), Key on/off (KOKO), Tip in/Tip out (TITO) and Judder measurement results show the robustness of the proposed mounting system over its manufacturing variation of +/-10% dynamic stiffness.
Intelligent Classification of Automotive Horn Sound Quality
Authors: Mollah Asfak , Mahanta Tapan K. , Balide Venkatesham
Published: January 2024

The primary function of an automotive horn is to alert pedestrians and other nearby vehicles to their safe passage on the road. Most of the human population is subjected to a certain amount of horn sound dosage daily. The study of automotive horn sound quality is equally important as their sound generation mechanism in passenger cars. The sound quality of automotive horns can be studied through subjective and objective test methods. In the present study, a subjective jury test and objective analysis using psychoacoustic parameters are conducted to classify car horn sound samples according to pleasantness. Twenty-two car horns, consisting of a disc and shell, are chosen for binaural sound recording. The recorded sound samples are used for subjective and objective analysis. Thirty members participated in the jury test, and a semantic differential method was used to collect the user response. The Tukey range test is used to classify the subjective test data. Six parameters, namely SPL (dBA), loudness, sharpness, roughness, fluctuation strength, and tonality, are obtained from the recorded sound samples of automotive horns using the Artemis suite and in-house-developed code for objective analysis. Mahalanobi's distance method and AI/ML-based intelligent classification techniques were further used to group the horn sounds using calculated objective parameters. Critical psychoacoustic parameters with the highest weightage on the classification of horn sound samples were identified and AI/ML models were reconstructed. Reconstructed models produce similar classification accuracy as compared to the original AI models. Horn sound classifications based on subjective tests, objective analysis and intelligent classification techniques are in good agreement. Developed models can be used to select a pleasant class of automotive horn for final deployment.
Refined Driveline Isolation in Bus Vehicles
Authors: Dhadiwal Nishant Surendra , Pathak Rahul , Bijwe Vilas , Gore Pandurang
Published: January 2024

NVH is of prime importance in buses as passengers prefer comfort.

Traditionally vehicle NVH is analysed post completion of proto built however this leads to modifications, increases cost & development time. In modern approach physical validation is replaced by CAE. There are many sources of NVH in vehicle however this article is focused about the methodology to improve NVH performance of bus by analysing and improving the stiffness and mobility of various chassis frame attachment points on which source of vibrations are mounted or attached. In this study chassis frame attachment stiffness of Engine mounts and propeller shafts is focused.
Crank-Train System Balancing and Crankshaft Optimization in Different Outlook
Authors: Mishra Pragya , Kolhe Vivek M , Ghotekar Sunil
Published: January 2024

IC (Internal Combustion) engines are evolved and refined over time to greater levels of technology in terms of emission, performance, NVH (Noise, Vibration & Harshness), and design philosophy. Crank-train generates a greater impact on NVH optimization due to its geometry and dynamics. Hence, more attention to mass balancing is required to minimize the negative impact on NVH.

The present work demonstrates the evaluation of balancing rate of crank-train system from the first principle of couple balancing. Calculations are conducted at the concept stage to estimate an internal rotating couple balancing of crank-train system due to counterweights and rotating masses. As crankshaft weighs approximately 10-12% weight of an engine and its counter weight plays a vital role in balancing, its optimization will result in a significant impact on NVH. Therefore, based on balancing rate, engines’ crankshaft was optimized and to validate the methodologies, forces on engine mount and main bearings were evaluated for both the base and optimized engine.

Conventionally, CAE analysis needs to be conducted at each iteration of optimization to evaluate the balancing of the system. However, using the mentioned approach, estimating balancing at a preliminary stage of design optimization proves to be effective in time-saving too. Forces on the crankcase and engine mounting arm evaluated as these are exciting forces for in cab NVH.
Challenges for Indian Road Traffic with Sound Alert Devices on Electric and ICE Vehicles
Authors: A Milind Ambardekar
Published: January 2024

For safety towards pedestrians and other road-vehicles, sound alert systems, like horns, have been in use since development of Automobiles. On the same line but with special purpose of preventing a Driver to sleep in a running vehicle, a Driver Monitoring System [DMS] is recently developed. For Electric Vehicles which are very quiet during starting and driving till 20 km/hr, Acoustic Vehicle Alert System (AVAS) is deployed in Europe and likely to be implemented in India soon.

For all these Alert Devices, there are Standard Regulations across the world: ECE R-28 for Horns and ECE R-138 for AVAS. They, however, define only lower and upper dBA limits of the sound radiated by them. For DMS, no such regulation exists till today. With this, there has been a long time debate on what an optimal dBA level should be there, for all road-users as well as for vehicle- users inside the cabin. It should be adequate, on one side, from detectability point of view and, on the other side, it should not cause human- discomfort & noise pollution to environment.

This paper discusses these two aspects in details and recommends solutions over the conflicting demands from these Sound Alert Devices based on experimental findings over a no. of passenger and commercial vehicles inside an anechoic chamber and on the test-track. This is supported by Jury Evaluation, too, with rankings given for their preference for both alertness of a passing vehicle and pleasantness of the alerting message.

Limitation of the sound as the only medium for alerting the road users is brought to notice for dense Traffic conditions in a highly populated country like India. Here, the sound of AVAS or horns could be weak in comparison with very high background noise levels in certain zones. Different design solutions are given to overcome this. At the same time, design guidelines are discussed for minimization of environmental noise pollution and for the right sound quality of all horns, AVAS and DMS assuring the best comfort inside cabin of the vehicles in running conditions.
Intake and Exhaust System Optimization of a Single Cylinder Engine Using 1D Simulation Approach
Authors: Paranjape Sumeet , Thakur Sunil , Emran Ashraf , Wagh Sachin , Sharma Vijay
Published: January 2024

Reducing vehicular noise has become a crucial step in product development to meet stringent legislation and improve passenger experience. Smaller vehicles like three-wheelers and compact cars are often powered by a single cylinder engine due to product cost, packaging and weight constraints. Unlike a multi-cylinder engine where cylinders fire one after another which helps to reduce noise levels by destructive interference of pressure waves, a single cylinder engine produces higher noise levels due to firing of a single cylinder. Intake and exhaust flow noise is one of the dominant sources of vehicular noise. This study focuses on using CAE tools to reduce intake and exhaust flow noise levels to meet target noise requirements. One dimensional (1-D) gas dynamics simulation provides a good trade-off between accuracy and run-time, allowing for evaluation of multiple design iterations with acceptable accuracy in a relatively short time frame. A system level optimization was performed on the intake and exhaust systems, requiring a larger number of design of experiments (DoE) to be performed, thus making 1-D simulation the preferred approach for this study. A compact car engine which was unable to meet the target noise levels was selected. A 1-D gas dynamics model was built and calibrated using test data. The calibrated model was used for intake system optimization by running DoE to evaluate the optimal air-filter and resonator parameters. Further optimization was performed on the exhaust system to determine the optimal muffler configuration. Multiple muffler designs were evaluated to optimize parameters such as pre and post muffler duct layout, muffler volume, baffle location, perforations and noise absorptive material placement. With the optimized intake and exhaust system recommendations about 17 dB(A) noise reduction was achieved on the exhaust side and about 7 dB(A) noise reduction was achieved on the intake side while meeting other performance targets.
Challenges in NVH Refinement of Electric Vehicle Built on ICE Platform
Authors: Channamaneni Rajesh Babu , MR Vikram
Published: January 2024

Electric car markets experience exponential growth. As per IEA battery electric vehicles sales exceeded 10 million in 2022 [1] . There is projection from IEA that EV sales will touch 40 million mark by 2030, major contribution from China (12 m) and Europe (13.3 m) regions [2]. This growth projection attributed to many global factors, government policies, automakers commitment, climate change, etc. There is a massive push from global institutions and automobile community for transition to electric mobility. There is a 66% likelihood that the annual average near-surface global temperature between 2023 and 2027 will be more than 1.5°C above pre-industrial levels for at least one year. There is a 98% likelihood that at least one of the next five years, and the five-year period, will be the warmest on record [3]. Hence transition is imperative to reduce greenhouse gases and adhere to climate change commitments.

Today EVs are not popular as ICE. As per WEF [4] there are three major reasons for that (a) high upfront costs of EVs (b) Limited access to charging infrastructure (c) concern about EV range. Last two are related to ecosystem, battery research and exploration. But first one is engineering challenge. To overcome this, especially emerging markets or cost sensitive markets, adopted strategy is to develop EVs from the traditional ICE vehicle design. Developing an EV from existing ICE vehicle design is found to be cost-feasible solution. At the same time, this strategy leads to new challenges. Some engineering issues, customer concerns not so prominent in ICE vehicle becomes very significant in EV. One of those discussed in this paper is NVH.

BEV developed from traditional ICE design generally has common top hat. Most of the parts are common. By this approach product is optimized for validation time and cost. However, the underbody needs to be redesigned for accommodating battery module and the electric powertrain. NVH challenges that could arise in such vehicle can be categorized into broadly two types. Firstly, electric vehicle specific challenges due to new underbody and electric powertrain. Secondly, issues that were not prominent in ICE version of the car, like road noise, wind noise, component noises, etc. Aim of this paper is to discuss about such challenges in meeting NVH performance of a battery electric vehicle built on a traditional ICE vehicle design. This includes performance targets, engineering issues, and approach to resolve those issues in the time and cost constraint of the market.
NVH Refinement of Small Commercial Vehicle
Authors: Yeola Yogesh , Kharpude Yogesh , Kalsule Dhanaji , Choudhary Aditya , Sonar Santosh , Nikam Avinash
Published: January 2024

In today's volatile market environment, and with the change of user priorities, NVH refinement results in silent, vibration-free vehicle. The commercial vehicle industry is also starting to embrace this development in NVH vehicle refinement. There are health concerns associated with the discomfort experienced by occupants. This calls for cabins with no boom noise and less tactile vibrations.

Noise within the vehicle is contributed by excitation from the Powertrain, Intake, Exhaust system, driveline, road excitations, suspension (structure borne noise) and its radiation into the air (air borne noise).

This paper discusses the approach used to reduce “In-cab boom” noise in the operating speed sweep condition and seat track vibration during engine IDLE condition to improve driver comfort. In this paper NVH refinement was carried out on small commercial vehicles.

Higher Seat track vibrations during IDLE and cabin boom noise during wide open throttle condition were observed during development of the product viz. small commercial vehicles.

One of the rigid body power train modes was coupled with IDLE excitation firing frequency in the vehicle. The use of optimized PT mounts stiffness, resulted into separation of PT rigid body mode from IDLE frequency excitation and thus reducing the seat track vibrations to acceptable level.

Another challenge was of In-cab noise with boom perception in speed sweep condition in customer driving pattern in another small commercial vehicle which was contributed by Exhaust and Intake noise. The exhaust engine firing orders were attributed to higher In-cab noise. Boom noise perception was reduced with silencer design optimization without affecting back pressure. The silencer design optimization was carried out through TL prediction.

Intake noise is mostly attenuated by passive control techniques. One of the technique is Helmholtz resonator. Helmholtz resonator was designed and evaluated on vehicle to address resonance at Intake system for the vehicle.

The journey involves various tasks including noise, vibration measurement and analysis, PT mounting stiffness tuning, virtual simulation and evaluation on the vehicle.

It was observed that the engine mounts with correct stiffness’s, seat track vibrations decreased by more than 50% during IDLE, optimised design of exhaust silencer & with Helmholtz resonator at Intake system, the cabin boom noise was reduced by 6 to 8 dB(A) resulted into the targeted NVH performance.
A Study on the Effect of an Acoustic Valve in the Exhaust Silencer for Noise Reduction in Automotive Application
Authors: Singh Har Govind , Khandagale Anup , Choudhari Yogeshwar , Kalsule Dhanaji , Petale Mahendra
Published: January 2024

Customer preference towards quieter vehicles is ever-increasing. Exhaust tailpipe noise is one of the major contributors to in-cab noise and pass-by-noise of the vehicle. This research proposes a silencer with an integrated acoustic valve to reduce exhaust tailpipe noise. Incident exhaust wave coming from the engine strikes the acoustic valve and generates reflected waves. Incident waves and reflected waves cancel out each other which results in energy loss of the exhaust gas. This loss of energy results in reduced noise at the exhaust tailpipe end. To evaluate the effectiveness of the proposed silencer on the vehicle, NVH (Noise, vibration, and harshness) performance of the proposed silencer was compared with the existing silencer which is without an acoustic valve. A CNG (Compressed natural gas) Bus powered by a six-in-line cylinder engine was chosen for the NVH testing. After NVH evaluation, it was found that when using the proposed silencer, overall exhaust tailpipe orifice noise is reducing by 4-5 dB throughout the engine rpm range. In-cab noise at DEL (Driver ear level) is reducing by 2 dB throughout the engine rpm range except for 1200-1400 rpm range. Pass-by noise is reducing by 1 dB when vehicle is running in 3rd gear and it is reducing by 3 dB when vehicle is running in 4th gear.
Solving Whine Noise in Electric Vehicles: A Comprehensive Study Using Experimental and Multiphysics Techniques
Authors: Cheerla Ganesh , Pulugundla Krishna Chaitanya , Kolla Kalyan Deepak , Sathyanarayana P.V.V.
Published: January 2024

This paper examines one of the approaches used to identify the root causes of sound quality issues in vehicles, including the direct impact of psychoacoustics on the human experience. Specifically, the absence of masking effects provided by traditional combustion engines has made noise and vibration from electric drives significant factors in decision-making processes, with high-pitched tonal noise from electric motors causing annoyance and sound quality concerns for electrified propulsion systems. During vehicle testing at different speeds, a whining noise was observed, leading to an NVH test to locate the noise source. The noise is traced to the transmission by the dominating order of input reduction along with the contribution from the casing resonance. A multi-physics-based e-NVH analysis was performed, and the test data were correlated. By optimizing transmission error (T.E.) and implementing modifications to enhance the drivetrain design’s stiffness, noise levels were reduced, resulting in enhanced EV sound quality and confirming the effectiveness of the approach.”
Clutch Pedal Pulsation and Vibration Tuning by Introducing a Unified Damper (LFF and HFF) in Clutch Release System
Authors: Kumar Sarvesh , AP Baaheedharan , Kanagaraj Pothiraj
Published: January 2024

In the current automobile era, weight, emission, and fuel efficiency were driving the overall powertrain development without compromising on the performance. Due to light weight and high-performance engines, the increased level of excitations in terms of torsional, axial, and bending frequency on crank shaft during combustion is inevitable. The axial and bending moment exerted from crankshaft during combustion causes vibration of the clutch diaphragm spring, in turn these vibrations are transferred through the hydraulic release system to clutch pedal which induces undesirable pedal pulsation and vibration during clutch pedal operation. The subjective perception on Noise Vibration and Harshness (NVH) becomes more essential in the Vehicle development process of modern high-performance vehicles. The clutch pedal pulsation in Idle rpm at 10% pedal travel with low frequency less than 80Hz and pedal vibration in higher rpm ranging between 1500 to 2500 RPM at 60% to 80% of total pedal travel with high frequency of 160Hz ~ 450Hz. To solve this concern, one Low Frequency Filter (LFF) and one High Frequency Filter (HFF) is a standard approach in automobile industry. However, the custom use of LFF and HFF dampers in clutch release hydraulic system will result in deterioration of the system efficiency thus increasing the gear shift impulse. This paper mainly focuses on integrating the LFF and HFF as a single unit with reduced volumetric expansion, thus addressing the pedal vibration at low and high frequency without affecting the system level efficiency and gear shift impulse.
Methodology for Jury Evaluation and Target Setting for Passenger Vehicle Operational Sound Quality
Authors: Somasundharam Sundaralingam , Manoj K Mridul , Raj Gaurav , Mohammed Riyazuddin , R Prasath
Published: January 2024

In automotive market, with competitive car prices, build quality of a car will be a major distinguishing factor. Consumer's need for acoustic comfort has evolved from the removal of annoying noises to perceived sound quality. Operational sounds from electromechanical systems like sunroof system, window regulator, door lock system, HVAC etc. directly interact with users’ senses. The perceived acoustics comfort of these sounds are direct indicators of vehicle character and can influence customer’s buying decision. With the reduction in product development time and stringent cost constraints, a proper structured target setting methodology to benchmark & evaluate these operational sounds is crucial. In this paper, such a target setting methodology is proposed and discussed for operational sound quality evaluation. Electromechanical noises from various vehicles are measured using binaural head measurement system. Using Simultaneous Categorical Scaling method, jury evaluation is performed with advanced binaurally corrected headphones. Cluster analysis along with Multivariate Linear Regression is performed to understand correlation between jury ratings and psychoacoustic metrics. Sound Preference Index (SPI) is derived based on the correlated psychoacoustic metrics. Using SPI, psychoacoustic metrics targets are derived to meet project requirements.
Driveline Vibration Reduction in Light Weight all Wheel Drive Vehicle
Authors: S Nataraja Moorthy , Rao Manchi , Raghavendran Prasath
Published: January 2024

The test vehicle is All Wheel Drive (AWD) vehicle which is powered by four-cylinder engine. The power is transferred from the powertrain to the wheel through power transfer unit (PTU), propeller shaft, flexible rubber coupling and Integrated Rear Differential Assembly (IRDA) . Higher boom noise and vibration levels are observed when driving the vehicle in 4th gear WOT conditions. NVH levels are dominant between 1150 rpm to 2100 rpm and at 2200 rpm in 2nd order and 4th order respectively. Operational deflection shape (ODS) analysis is carried out on entire vehicle to identify the location where maximum deflection is observed at the problematic frequency. It is identified that higher torsional excitation from the powertrain is exciting the IRDA pitching mode and the propeller shaft bending mode which is the reason for higher 2nd order and 4th order NVH levels. The driveline forces are entering the body through the IRDA and rear cradle bushes. The dynamic stiffness of IRDA bushes is reduced which resulted in reduction of 2nd order vibration levels by ~ 7 dB at 2100 rpm. Further reduction of vibration is achieved by using mass dampers on IRDA and by reducing the stiffness of rear cradle bushes. Modal analysis is done on the propeller shaft to identify the mode shape at the problematic frequency. Various solutions like increasing the propeller shaft dynamic stiffness and tuned mass dampers on propeller shaft are investigated and the optimum solution which provides the best performance is selected. Stiffness of the rubber coupling used in driveline is modified to reduce the torsional excitation on the IRDA and various methods of reducing torsional excitation in driveline are discussed. With all the countermeasures, the boom noise is eliminated and vibration levels are reduced by ~ 10 dB.
Motorcycle Engine Vibrations Prediction for Inertia Loads Using Multi Body Dynamics Calculations
Authors: Kumar Virender , Joshi Gaurav , Garg Ankit
Published: January 2024

Motorcycles are a preferred means of transportation in most of the countries due to its economic factor and ease in travelling. Rider comfort is an important aspect while designing a vehicle. Rider comfort is often compromised by unwanted vibrations experienced at human interface points also called as tactile points. These unwanted vibrations also affect rider’s motorcycle control and overall health. There are two major source of vibrations in a motorcycle that is engine & road inputs.

In current study, a method is being explored to predict engine induced vibrations. Engine induced vibrations at various locations are simulated through multi body dynamics (MBD) and finite element (FE) simulation methods at vehicle level. Motorcycle model comprising of engine, frame and subassemblies are modeled in FE tool and then condensed to be used in MBD tool. Piston assembly, connecting rod, bearings and engine mounts are modeled in MBD tool. Vibration response resulting from unbalanced inertia forces and moments are simulated at engine locations. Simulated vibration levels are correlated with test results to confirm robustness of proposed method.
Resonator Design Study to Reduce Pressure Pulsation from CNG Injector
Authors: Meena Deepesh , Sharma Rohan , Khandelwal Abhishek , Jadhav Praveen Singh , Pai Devananda
Published: January 2024

With the advent of upcoming stringent automobile emission norms globally, it is inevitable for original equipment manufacturers (OEMs) to shift towards greener alternatives. Use of compressed natural gas (CNG) is a preferred solution as it is a relatively clean burning fuel and it doesn’t have significant loss in vehicle efficiency and performance. Modern day customers are more aware and sensitive towards vehicle noise, vibration and harshness (NVH). Hence, OEMs must cater to this demand through optimized design and layout. In a passenger vehicle, CNG is stored at high pressure and delivered to injectors after pressure reduction at a regulator. During engine idling, the opening and closing motion of the CNG injector generates back pulsation and these pulsations cause vibrations which may propagate through other components in the delivery path and perceived as noise inside vehicle cabin. To identify the frequencies involved in pressure pulsation, a 1-D simulation of CNG fuel system is performed using commercially available simulation software GT-Suite through which excitation frequencies and pressure pulsation peak amplitude has been identified. To validate the model, actual pulsation measurement testing has been performed and pressure peaks amplitude are compared with simulation. Based on correlation with actual testing, multiple resonator designs are created to dampen the identified excitation frequencies range. These designs have been virtually validated for pressure peak reduction by simulating resonators with fuel system layout in GT-Suite.
A Study on Effect of Regenerative Braking on Vehicle Range and Axle Life
Authors: S Srivatsa , Pethkar Shivanand , Ghosh Sandeep
Published: January 2024

This paper aims at analysing the effect of regeneration braking on the amount of energy harnessed during vehicle braking, coasting and its effect on the drive train components like gear, crown wheel pinion, spider gear & bearing etc. Regenerative braking systems (RBS) is an effective method of recovering the kinetic energy of the vehicle during braking condition and using this to recharge the batteries. In Battery Electric Vehicles (BEV), this harnessed energy is used for controlled charging of the high voltage batteries which will help in increasing the vehicle range eventually. Depending on the type of the powertrain architecture, components between motor output to the wheels will vary, i.e., in an e-axle, motor is coupled with a gear box which will be connected with differential and the wheels. Whereas in case of a central drive architecture, motor is coupled with gearbox which is connected with a propeller shaft and then the differential and to the wheels. All the components between motor output to the wheels has to be designed and validated for taking the regenerative torque during braking & coasting.
An Optimum Solution to Meet the Thermal Load Challenge in a High Mobility Military Vehicle
Authors: AT Shajahan , Kiran Nalavadath , Rao Bonthala
Published: January 2024

Military vehicles are intended to operate at rugged terrains in adverse environmental conditions. Unlike a regular truck, these vehicles are powered by a much bigger engine and transmission to meet the vehicle performance parameters. Thermal systems in these vehicles are challenging. With the adverse climatic condition and driving terrains, the criticality of Engine cooling system is intensified. In this paper, a Cooling system is finalized for a high mobility military vehicle with higher power engine, Automatic transmission and a hydraulic retarder. Thermal load cases are different for each. Modelling is done in thermal simulation software KULI. A steady state simulation is done for engine and automatic transmission where-as transient simulation is performed for retarder. The aim is to finalize a cooling system circuit consisting of radiator, oil to air cooler and oil to water cooler which are interconnected to meet the heat load demand of engine, transmission and retarder together.