Browse Topic: Engine mounts

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In-situ Decoupling and Stiffness Optimization of Resiliently Coupled Assemblies Using FRF-Based Substructuring2026-01-02274/7/2026
Resilient mounts are critical in controlling vibration transfer from sources such as engines, motors, and suspension to the vehicle structure. Conventional optimization methods rely on finite element analysis (FEA), which, while accurate, is computationally intensive and limits iterative NVH development. This paper introduces a Frequency Response Function Substructuring (FBS)-based approach that decomposes the system into substructures characterized by FRFs, significantly reducing computational cost without compromising accuracy. Key contributions include: (1) recovering subsystem FRFs from coupled system data in-situ for mount optimization, (2) extending FBS to handle enforced motion, and (3) proposing an alternative strategy for cases with unknown or unmeasurable loads. The methodology is demonstrated on a mid-size pickup truck model to optimize seat track response under a Four post shake load by refining body mounts. These advances broaden the applicability of FBS for efficient NVH optimization in complex systems.
Haider, Syed, Abbas, Ahmad, Jahangir, Yawar, Maddali, Ramakanth
Electromagnetically Levitated Engine Mount2026-26-03421/16/2026
In the evolving landscape of the automotive industry, enhancing passenger comfort and ride quality has become a key differentiator for manufacturers. While suspension systems have traditionally received significant attention, powertrain isolation through engine mounts plays an equally critical role in controlling noise, vibration, and harshness (NVH). Engine mounts are not only responsible for supporting the powertrain’s weight but also for mitigating the transmission of unbalanced engine forces to the vehicle body. Modern engine mount designs aim to eliminate any metal-to-metal contact between the powertrain and chassis, thereby achieving optimal vibration isolation. This study proposes a refined approach to completely decouple the powertrain from the vehicle structure, ensuring minimal vibration transfer and thereby extending the operational life and performance of the engine mount system.
Hazra, Sandip, Naik, Sarang Pramod, More, Vishwas
Comprehensive Evaluation and Development of a Single Cylinder Engine Vehicle for Refinement of NVH Characteristics2026-26-03081/16/2026
The scale of worldwide population presents its own set of difficulties, especially in densely populated cities. Almost every individual has some form of personal transport, which leads to congestion and limited parking space. Automotive manufacturers are scaling down the size of vehicles to resolve these issues to some extent. This paper is based on the NVH development of a single cylinder diesel engine vehicle. It provides an insight into the comprehensive vehicle level NVH refinement approaches adopted. The NVH characteristics of benchmark two-cylinder diesel and baseline vehicle were measured and analyzed for target setting. The performance of each subsystem such as engine mounting, vehicle structure, intake and exhaust was evaluated, and gap analysis was performed against set targets. It was found that the engine mounting system and vehicle structure were inefficient in isolating the excitation forces. The design and location of the mounting system was evaluated using CAE and modified to improve modal performance and force isolation. The vibrations were evident at tactile locations and found to correlate with engine excitation frequency at certain locations. Hence, cradle and body structure analysis were carried out to reduce vibration transfer. Additional stiffeners and channels were added to vehicle structure which helped in eliminating problematic frequencies and noise levels. The acoustic pack of the vehicle was updated to reduce airborne transfer of noise and improve sealing of vehicle. The intake system was evaluated and the air filter with resonator size and position were modified to improve noise levels. Similarly, the exhaust muffler design was analyzed and modified to improve noise levels. Each modification was implemented and evaluated for its individual contribution in improving noise and vibration by validating on mule vehicle. After implementation of all feasible updates, the noise and vibration targets were achieved for the new vehicle.
Ghale, Guruprasad Chandrashekhar, Baviskar, Shreyas, Bendre, Parag, Kamble, Pranit, Bhangare, Amit, THAKUR, SUNIL, Kunde, Sagar, Wagh, Sachin
Adaptive Control Algorithms for Active Mounts on Diesel Powertrains in Passenger Cars2026-26-03241/16/2026
Diesel powertrains are inherently characterized by high vibration levels and low-frequency excitations, which are extremely demanding for passenger comfort and vehicle refinement. Conventional passive engine mounts often fall short in mitigating such vibrations effectively across a wide range of operating conditions. Passive mounts are inadequate for effectively isolating vibrations in powerful, lightweight vehicles or those without a balancer shaft 3-cylinder engine ordiesel engines. Consequently, this has prompted the consideration of active engine mounts as an alternative solution for solving NVH (Noise, Vibration, Harshness)-related issues. This paper explores the application of adaptive control algorithms in active engine mount systems for diesel powertrains in passenger vehicles. Through the integration of real-time feedback loops with smart control strategies the system adaptively controls mount stiffness and damping to minimize engine-induced vibrations. The study presents simulation and experimental results showing enhanced vibration isolation, better ride quality, and lower transmitted forces to the vehicle chassis. In addition, the adaptive control ensures high robustness under varying driving conditions, such as load variations and engine transients. This trend opens up the future for next-generation diesel vehicle NVH solutions with a comfort-performance-fuel efficiency balance.
Hazra, Sandip, Khan, Arkadip Amitava, more, Vishwas
Value-Engineered Design Optimization of a Recycled Plastic Bracket to Meet Natural Frequency Targets in Passenger Vehicles2026-26-03551/16/2026
Engine mount brackets are a primary structural components of passenger vehicles that supports the powertrain to the chassis via engine mounts. These brackets are important to control vibrations and the transmission of noise into the cabin as well as vehicle stability. Since they support the engine mounts, these brackets play a role in determining ride comfort and load distribution on the mounts and the engine. While traditionally made from steel, cast iron and aluminum, we are trying to redesign engine mount brackets with recyclable engineering plastics to fit current demands of light-weighting, cost efficiency, and sustainability. The present work is concerned with the design of a plastic engine mount bracket, which aims to hit specified natural frequency targets in order to avoid resonance and fulfill strict NVH (Noise, Vibration, and Harshness) requirements. Because of the superior mechanical strength, thermal stability, and vibration-dampening properties, PPS, glass-fiber reinforced polyamide (PA66-GF50), PEEK (polyether ether ketone), and other high-performance reinforced plastics like polyphenylene sulfide were taken into consideration. These materials can be used in structural automotive applications in place of metals. Through the Finite Element Analysis, modal analysis, CAE based durability simulations and vehicle-level testing the optimized bracket proven to meet structural and dynamic performance specifications. The findings confirm that, in the form of plastic bracket, recyclable designs can be technically feasible and sustainable alternatives to metal designs, which help reduce vehicle weight, increase fuel efficiency and vehicle manufacturability without sacrificing durability and safety.
Hazra, Sandip, Gupta, Deepak, Khan, Arkadip, Gite, Yogesh
Contradictions of Automotive NVH and TRIZ Tools for Innovative Problem Solving2026-26-03471/16/2026
Balance towards various Vehicle attributes often faces design contradictions, particularly in Noise, Vibration, and Harshness (NVH) optimization. Traditional approaches rely on trade-offs, but TRIZ (Theory of Inventive Problem Solving) offers a structured methodology to resolve contradictions innovatively. This paper presents TRIZ-based solutions for 2 key NVH challenges: (1) exhaust systems requiring noise reduction while maintaining low engine back-pressure, (2) engine mounts requiring both softness for vibration isolation and hardness for durability & vehicle stability, By applying TRIZ principles such as separation, mechanics change, etc. and using Thinking Tools such as thinking in time & scale, novel solutions are proposed to achieve superior performance without traditional compromises. These case studies demonstrate how TRIZ enhances automotive NVH refinements by enabling systematic innovations. This also explores benefits of Frugal Engineering for profitable launch of new vehicles in the market without sacrifice of customer satisfaction. At the same time, new innovative solutions are generated using past-present-future prediction models.
A, Milind Ambardekar
An Engineering Perspective on Cradle and Saddle Mount Configurations2026-26-03131/16/2026
The evolution of electric vehicles (EVs) also demands the evolution of powertrain mounting systems to achieve superior Noise, Vibration, and Harshness (NVH) performance. This study presents a comparative evaluation of cradle, saddle and ladder mounting systems in EV applications. Examples of experimental modal analysis and vehicle-level vibration tests were performed in order to evaluate structure-borne noise transmission as well as airborne noise transfer under operating conditions. Important parameters like mount stiffness, isolation efficiency and dynamic load distribution were performed. These findings provide valuable guidance for selecting optimal mount strategies to enhance occupant comfort and acoustic quality in future EV designs. Recommendations for mount system improvements considering evolving EV architectures are also discussed. This work provides a crucial, experimentally-validated framework for selecting optimal mounting architectures, addressing a key gap in the transition from ICE-based intuition to EV-specific design principles.
Hazra, Sandip, more, Vishwas, Naik, Sarang Pramod
Optimization of Electric Powertrain Mounting for Vibration Isolation in EV Powertrains Using Multibody Dynamics2026-26-00801/16/2026
With growing significance of electric vehicles (EVs), their powertrains – while naturally quieter than internal combustion engine (ICE) powertrains – pose new NVH (Noise, Vibration, Harshness) challenges. These are triggered mainly from high-frequency disturbances caused by electric motors and gear interactions. Isolation of such excitations is essential for securing cabin refinement and customer expectations for acoustic comfort. This paper offers a simulation-based approach to optimal placement of the electric drive unit (EDU), which houses the electric motor and gearbox, with the objective of reducing vibration transfer to the chassis of the vehicle. The methodology explores the effect of spatial mount repositioning under actual dynamic load conditions through multibody dynamics (MBD) modeling and integrated optimizer using advanced multibody dynamics simulation software – Virtual Dynamics. The suggested workflow helps in effective investigation of mount positioning within packaging constraints, and NVH performance. Simulation analysis illustrates that optimized shifting of mount locations is capable of achieving quantifiable reductions in transmitted vibrations and dynamic response. The research showcases the potential of virtual prototyping enabling early-stage layout optimization, and outlines a feasible guide to enhance NVH performance in future EV powertrains without hardware iteration.
Shah, Swapnil, Mane, Prashant, Back, Arthur, Emran, Ashraf
Design of a McPherson Strut Based Split Link Front Suspension for a Higher Rear to Front Weight Ratio SUV with Least Turning Circle Diameter2026-26-00921/16/2026
Generally, in an electric sports utility vehicle with rear mounted powertrain the mass distribution is greater in the rear compared to front. This higher rear to front weight distribution results in oversteer behavior during high-speed cornering deteriorating vehicle handling & risking passenger safety. To compensate this inherent oversteer nature of such vehicles & produce understeer behavior, the steering rack is placed frontwards of the front wheel center for toe-out behavior due to lateral compliance during cornering. This compensation measure results in lower Ackermann percentage resulting in higher turning circle diameter deteriorating vehicle maneuverability. This paper proposes a design to obtain ideal understeer gradient with minimal turning circle diameter through utilization of split link technology with a McPherson Strut based suspension framework & frontwards placed steering rack. This suspension is utilized in our Mahindra Inglo platform. This paper elaborates on how through split links, variable knuckle length arm can be achieved which helps in achieving greater outer to inner wheel steering turn angle rate effectively improving Ackermann percentage & minimizing turning circle diameter. Apart from that the design mentioned herein allows greater manipulation of longitudinal & lateral compliance due to partial decoupling of both by split links. This overall improves longitudinal compliance resulting in better plushness during bumps improving ride without compromising handling characteristics of the vehicle. The suspension design is also optimized for wheel travel of 185mm, higher than benchmarks to provide enough wheel traction as well as comfort on hilly terrains & city roads of India.
Nadkarni, Ameya Ravindra, Mhatre, Nitij, Patnala, Avinash, NAYAK, Bhargav
High-Frequency Dynamic Stiffness Measurements of Automotive Elastomers for Electric Vehicles2026-26-03121/16/2026
The increasing adoption of electric vehicles (EVs) has intensified the demand for advanced elastomeric materials capable of meeting stringent noise, vibration and harshness (NVH) requirements. Unlike internal combustion engine (ICE) vehicles, EVs lack traditional masking noise generated by the powertrain. In the automotive industry, the dynamic stiffness of elastomers in internal combustion engines has traditionally been determined using hydraulic test rigs, with test frequencies limited to a maximum of 1,000 Hz. Measurements above this frequency range have not been possible and are conducted only through computerized FE or CAE calculation models. Electric drive systems, however, generate distinct tonal noise components in the high-frequency range up to 10,000 Hz, which are clearly perceptible even at low sound pressure levels. Consequently, the dynamic stiffness characteristics of elastomers up to 3,000 Hz are critical for optimizing NVH performance in EVs. This study focuses on high-frequency dynamic stiffness testing of automotive elastomers using a specialized high-frequency test rig. According to ISO 10846-1 [1], there are two methods for determining the dynamic stiffness of elastomers: the direct method (part 2) and the indirect method (part 3). This paper presents measurements carried out using the direct method, employing an electrodynamic shaker and applying static preload conditions. The objective is to accurately determine the frequency-dependent dynamic stiffness and damping properties of elastomeric components, such as engine mounts, bushings, and isolators, which play a crucial role in mitigating structure-borne noise and vibrations.
Bohne, Christian, Gröne, Michael
Analysis and Mitigation of Parasitic Noise in Hydraulic Engine Mounts: Addressing Cavitation and Membrane Hitting2026-26-03351/16/2026
Hydraulic engine mounts are widely used in automotive applications to reduce vibration and noise transmission from the engine to the vehicle body by providing high damping at low frequencies and low damping/stiffness at higher frequencies. This is achieved by allowing sufficient clearance between components inside the hydro mount, activating hydraulic damping only with sufficient amplitude inputs. However, this inherently leads to the generation of parasitic noises emanating from hydraulic engine mounts which significantly degrade the Noise, Vibration, and Harshness (NVH) performance of vehicles, presenting a considerable challenge in the automotive industry. This encompasses phenomena such as cavitation, arising from the formation and subsequent collapse of vapor bubbles within the working fluid due to localized pressure drops below the vapor pressure, and membrane hitting, resulting from the dynamic interaction between the fluid and the elastic membrane within the mount. Both noise sources are often difficult to trace back to the engine mount. This paper details a systematic approach for both detecting and mitigating these parasitic noise sources specifically in decoupled hydraulic mounts. This methodology is grounded in an investigative analysis conducted on a passenger car. The outcomes of this investigation offer practical strategies for pinpointing the fundamental causes of both cavitation and membrane hitting noise in hydraulic engine mounts and implementing effective solutions to improve overall vehicle NVH characteristics.
Agrawal, Adheesh, Vineeth, Sekharan, Ghosh, Chiranjit, Saxena, Akshansh, Parmar, Aashish, Seenivasan, Gokulram, Nandal, Abhishek, Dhankhar, Dinesh Singh, Khan, Prasenjit
Prediction of Trimmed Body Noise Transfer Function Based on BIW Response Using Machine Learning2026-26-06401/16/2026
This work focuses on the prediction of Trimmed Body Noise Transfer Function (NTF) using Glazed BIW (body in white) structural model characteristics by leveraging Machine Learning (ML) technique. Inputs such as Glazed BIW (GBIW) attachment dynamic stiffness, Body Panel Vibration Transfer Functions (VTF) and Driver Ear level NTFs are employed to predict Trimmed Body NTF for a particular hard point. An iterative process of performing design modifications on the BIW to verify its effect on BIW performance and therefore on Trimmed body NTF is undertaken. BIW geometric parameters are varied in an organized manner to generate hundreds of data points at GBIW level which are provided as input to the train the ML model to predict the trimmed body level NTF. The outcome provides crucial insights of how the trimmed body NTF is closely related to the GBIW design characteristics. This ML approach of predicting trimmed body NTF based on GBIW characteristics provides critical insight about GBIW design during early stages of product evolution, which benefits in quick decision making rather than the conventional approach of evaluating complex trimmed body simulations.
Kulkarni, Prasad Ramesh, Bijwe, Vilas, Kulkarni, Shirish, Sahu, Dilip, Inamdar, Pushpak
Machine Learning based Engine Mount NVH Life Health Monitoring System2026-26-03591/16/2026
Noise, Vibration, and Harshness performance refinement and long-term vehicle reliability are rapidly evolving in today’s automotive industry and becoming a basic need considering comfort. Engine mounts play a central role in isolating powertrain-induced vibrations. Their deterioration can significantly affect cabin comfort, powertrain integrity, and customer satisfaction. Prior work in this area has primarily focused on direct mount sensors and physical inspection at service centre after failure. While effective in controlled environments, such methods are not scalable, add system complexity and increase vehicle cost due to sudden breakdowns. This paper introduces a novel indirect health monitoring method that leverages a driver seat rail-mounted accelerometer to capture driver specific vibrational responses. By analysing these signals using machine-learning models placed by AIML ECU and domain-specific analytical features, engine mount health is inferred without requiring sensors on the all three mounts. We developed and validated this approach using a combination of real-world vehicle data, controlled degradation cases, and extensive testing across varied operating conditions. Feature engineering supervised learning techniques and anomaly detection algorithms were applied to distinguish subtle variations in engine Noise Vibration and Harness behaviour at driver seat linked to mount degradation. The system demonstrated excellent predictive accuracy with reliable detection of degraded mounts without intruding on existing vehicle systems. This OEM-friendly, scalable solution enables cost-effective, real-time diagnostics and supports predictive maintenance.
Iqbal, Shoaib, Dusane, Mangesh
TOC99-07-06-0TOC12/2/2025
TOC
Tobolski, Sue
Uncertainty Optimization of Vibration Characteristics in Engineering Machinery Powertrain Mounting Systems Using Monte Carlo and Genetic Algorithms10-10-01-000611/22/2025
With the rising demand for high performance and reliability in engineering machinery, the vibration isolation performance and robustness of the powertrain mounting system (PMS) have become critical to overall machine performance. However, during service, rubber mounts are prone to environmental influences, causing significant stiffness deviations that render traditional optimization and analysis methods inadequate. To address this, this article proposes an uncertainty optimization strategy combining Monte Carlo and genetic algorithm (MC-GA), applied to design optimization accounting for stiffness uncertainty due to mount aging, to enhance vibration isolation robustness under large-scale stiffness fluctuations. The study first establishes a Monte Carlo analysis framework based on the statistical characteristics of retired mount stiffness and a dynamic model, systematically evaluating the impact of varying stiffness deviations on vibration characteristics under the original PMS configuration. On this basis, using initial mount stiffness as the optimization variable and considering extreme aging conditions, the MC-GA method is employed for uncertainty optimization of vibration characteristics. Real-vehicle test results demonstrate the method’s strong engineering applicability: in the scenario with a 50% increase in initial stiffness, the decoupling rate improved by an average of 4.2%, effectively reducing system vibration coupling; the vibration isolation rate from chassis to powertrain in the 20–80 Hz range during operation decreased by an average of 4.3 dB, effectively reducing the vibration transmitted to the powertrain.
Xiang, Xingyu, Yi, Hongwei, Hou, Jie, Peng, Cheng, Huang, Haibo, Huang, Xiaorong
Isolation of Engine Vibrations from 3 Cylinder Engines on Off-Highway Machines2025-28-029211/6/2025
The new Stage 5 emission regulation requires several changes on engines as well as design and development of new auxiliary systems. These changes affected the engine dynamics and NVH characteristics. These changes are validated for various operating conditions on engine test cell in a controlled environment where engine is mounted on test cell with dyno. Further, this engine will be used by other machine forms, hence NVH performance needs to be evaluated for all the applications. Isolation of three-cylinder engines is challenging since it has to deal with inherent imbalance forces while providing the isolation to meet the durability requirements of heavy applications from off highway machines. This paper covers the methods used for verification of engine isolation performance. NVH tests are conducted for integration of three-cylinder engine with roadbuilding machine. An analytical model is developed to identify rigid body modes and mount transmissibility. Results from this analytical model were verified with a physical experimental modal analysis. Vibration transmissibility at each mount is measured to ensure sufficient vibration attenuation. Vibration levels on machine frame and cab seat are evaluated in various operating conditions. These evaluations helped to select suitable isolators for machine NVH performance.
Pawar, Sachin M., Mandke, Devendra Laxmikant, KASABE, SANDEEP, Jadhav, Vijay
Numerical Simulation and Parametric Optimization of Engine/Powertrain Mounts: Identifying Key Design Variables to Reduce NVH Noise2025-01-02516/16/2025
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. 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. 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, making unintended contact with other components and producing impact noises. This study explores these interactions, with a particular emphasis on tribological factors within the mount systems. The research utilizes Abaqus for detailed finite element simulations to model the dynamic behavior of engine mounts under operational loads. Isight is used for parametric optimization, where key variables such as mount geometry, stiffness, damping properties, and material specifications are adjusted. A multi-objective optimization function is developed to find an optimal balance between reducing NVH levels and ensuring mount durability and performance. The study includes a sensitivity analysis to prioritize the most impactful design variables, followed by optimization algorithms to refine the mount design for optimal NVH mitigation.
Ganesan, Karthikeyan, Seok, Sang Ho
Designing Rubber Flaps for Resonance Management: High-Frequency Tuning in Electric Vehicles Using AI/ML Approaches2025-01-01255/5/2025
High-frequency whine noise in electric vehicles (EVs) is a significant issue that impacts customer perception and alters their overall view of the vehicle. This undesirable acoustic environment arises from the interaction between motor polar resonance and the resonance of the engine mount rubber. To address this challenge, the proposal introduces an innovative approach to predicting and tuning the frequency response by precisely adjusting the shape of rubber flaps, specifically their length and width. The approach includes the cumulation of two solutions: a precise adjustment of rubber flap dimensions and the integration of ML. The ML model is trained on historical data, derived from a mixture of physical testing conducted over the years and CAE simulations, to predict the effects of different flap dimensions on frequency response, providing a data-driven basis for optimization. This predictive capability is further enhanced by a Python program that automates the optimization of flap dimensions using a linear combination formula. The automation ensures that the desired frequency response is achieved efficiently and systematically. By combining the insights from ML with the linear combination formula, the method not only addresses the dynamic peak during frequency sweeps but also mitigates resonance issues through the principles of dual dynamic absorber theory. This comprehensive approach improves the acoustic environment within the vehicle cabin and serves as a preventative measure against potential resonance problems, ultimately contributing to a higher-quality user experience.
Hazra, Sandip, Khan, Arkadip
Crash Performance Improvement: The Impact of Engine Mount Crash Plates on Achieving a 5-Star Safety Rating2025-01-00855/5/2025
Electric vehicles (EVs) differ from internal combustion engine (ICE) vehicles in that they lack a conventional engine and feature an electric drive unit, leading to distinct dynamic behaviours in the powertrain. Additionally, the arrangement of auxiliary components in EVs often differs from that in traditional ICE vehicles, which can sometimes significantly impact safety ratings. This paper examines a case study of a critical failure during a crash test, where displacement of an engine mount arm caused substantial structural intrusion and reduced the vehicle’s safety rating. To address this issue and enhance crashworthiness, a “crash plate” was designed and integrated into the mount system. This solution effectively constrained the mount arm’s movement during impact, preventing the intrusion observed in previous tests. The paper provides a detailed analysis of the crash plate’s dimensions and its relationship to the engine mount, demonstrating its potential for broader application in passenger EVs. This innovative and cost-effective approach significantly improved the vehicle’s crash performance, resulting in a higher safety rating and presenting a new method for enhancing vehicle safety through targeted design improvements.
Hazra, Sandip, Khan, Arkadip, Mohare, Gourishkumar
The Accelerated Roughness Noise Optimization of One PHEV Vehicle2025-01-00875/5/2025
To optimize the noise that heard like ‘kalakala’ produced by the plug hybrid electric vehicle when accelerating with a small accelerated pedal opening while in the charging state of series modal. The LMS test device was used to acquire the noise of the driver's outer ear. Through filtering and playback analysis, it was confirmed that the noise is mainly contains the frequency bands of 250-400Hz and450-700Hz. The frequency bands of the noise were used as carriers for Hilbert transform, and their envelopes were obtained for Fourier transform analysis. It was found that the modulation order of the noise is 0.5 times of the engine ignition order, and the modulation frequency is 20-30Hz, which let the customer hears like roughness. Regarding the spectral characteristics of this noise, firstly, at the excitation source, selected a reasonable moment of inertia and frequency of the Crank torsional damper, to decrease the torsional excitation of the engine. Secondly, investigated the structural propagation path of the noise systemically, and effectively reduces the propagation path of the noise by increasing the dynamic stiffness of the powertrain mount’s passive bracket and tuning a reasonable front driveshaft damper. Finally, based on the universal characteristics and the pressure rise rate map of the engine, as well as the targets of the attribute of the vehicle economy and power, different calibration strategies were attempted, and a calibration strategy that balances the three attributes was selected. By the above measures, the energy of two resonance bands of acceleration roughness sound were reduced by 9dB (A), and 3dB (A) respectively. After optimization, the noise inside the car is almost inaudible.
Shouhui, Huang, Zhongxun, Hu, Zhao, Yun, Shanyin, Ren, Ruifeng, Dong, Teng, Charlie, Changshui, Zhou, Xu, Ling
Evaluating Powertrain Mount Decoupling: Insights from Simulation, Experimental Results, and Analytical Calculations2025-01-00225/5/2025
Powertrain mounts are vital for isolating vibrations and enhancing vehicle ride comfort and performance, making their dynamic behavior critical for effective design. This study provides a comprehensive analysis of powertrain mount decoupling by integrating virtual simulations, physical testing, and analytical calculations. In our approach, we first derived stiffness data through analytical calculations, which were validated through multi-body dynamics (MBD) simulations that modeled interactions within the powertrain mounts. By adjusting bush stiffness parameters within the MBD framework, we predicted decoupling frequencies and analyzed kinetic energy distribution. The iterated stiffness values from simulations were then confirmed through physical testing, ensuring consistency in decoupling frequencies and energy distribution. This alignment between virtual and experimental data enhances the reliability of our findings and helps identify overlapping frequencies across vehicle systems, crucial for avoiding resonance. A key novelty of our approach is its application in the early design phase. Unlike conventional methods that rely on optimization in later stages, our methodology allows for the positioning and orientation of powertrain mounts to be optimized from the outset. This enables the creation of more realistic powertrain mounts during the conceptual design phase, facilitating high-accuracy optimization of secondary ride and vibration performance and providing a "first-time-right" solution from the concept stage. The results demonstrate strong correlations across all three methods, offering a well-rounded understanding of powertrain mount dynamics. This research advances design methodologies, highlights the benefits of virtual testing, and improves powertrain mount performance in automotive applications.
Shende, Kalyani, Shingavi, Shreyas, Rane, Vishesh, Hingade, Nikhil
Hybrid RLDA Methodology for Passenger Car Engine Mount Applications2025-01-00955/5/2025
In the development of engine mounting systems for passenger cars, accurately capturing dynamic loads during real-world driving conditions is crucial for optimizing performance, durability, and NVH (Noise, Vibration, and Harshness) characteristics. This paper introduces an innovative approach that integrates load cell and strain gauge technologies for Road Load Data (RLD) acquisition, specifically designed for engine mounting applications. By combining load cells and strain gauges, this method offers a comprehensive solution for measuring both direct forces and the resulting strains on engine mounts, providing a more detailed understanding of the load profiles. Load cells capture the overall forces exerted on the engine mounts, while strategically placed strain gauges measure local deformations and stress distributions within the mounts. This dual-method approach enables precise correlation of force and strain data, enhancing the accuracy of load calculations under various driving conditions. The data collected from this combined methodology is then used to refine the design and material selection of engine mounts, ensuring they can withstand the complex and varying loads encountered in passenger vehicles. By integrating these two measurement techniques, the study demonstrates a significant improvement in the reliability of load data, which is critical for developing more effective and durable engine mounting systems. In conclusion, the hybrid use of load cell and strain gauge-based RLD provides a robust and accurate method for engine mount load analysis in passenger cars, contributing to improved NVH performance and extended component life. This approach represents a valuable advancement in automotive engineering, offering insights that could lead to the development of next-generation engine mounts optimized for real-world conditions.
Hazra, Sandip, Khan, Arkadip Amitava, Mohare, Gourishkumar
Evaluation of Invariant Structural and Acoustic Loads Estimation Methods to be Used in Vehicle Platform Development Independent to the Boundary Conditions of Load Generation2025-01-00535/5/2025
Platform based vehicle development is standardized at John Deere. The challenges of frontloading the integration of individual components within different platforms using predictive methods is key to shortening the development cycle. Components are individually characterized on test benches and results cannot directly be used to evaluate system performance. Invariant characterization is needed instead, which is possible through techniques such as blocked loads estimation. To evaluate the applicability of such methods, the component-based loads and vehicle in-situ operational loads need to be compared. The confident use of these methods for obtaining structural and acoustic loads enables the use of hybrid system models, enhancing early NVH response predictions. The objective of this work was to enable the confident use of test stand measurements in predictive models across various vehicle platforms. This study compares a powertrain characterization in a vehicle against a test stand to assess the invariance of the operating mount structural loads as well as operating acoustic loads. The following milestones are discussed: 1 Perform in-situ Component Transfer Path Analysis (C-TPA) in an agricultural tractor to compute engine acoustic loads and engine mount structural invariant loads. 2 Perform C-TPA on the same model engine in a dynamometer test cell to compute engine acoustic loads and engine mount structural invariant loads. 3 Compare acoustic and structural loads in both test scenarios for their invariance and study sensitivity of variables in two test scenarios. 4 Discuss lessons learned throughout the process for implementation in the development of complex machines.
Vesikar, Prasad Balkrishna, Edgington, Jason, Drabison II, John
A Comparative Study of Optimization Algorithms for 6DOF Design in Electric Vehicle Powertrain Mounting Systems2025-01-86504/1/2025
Optimizing engine mounting systems is a complex task that requires balancing the isolation of vehicle vibrations with controlling powertrain movement within a limited dynamic envelope. Six Degrees of Freedom (6DOF) optimization is widely used for mounting stiffness and location optimization. This study investigates the application of various optimization algorithms for 6DOF analysis in engine mount design, where the system’s stochastic behaviour and probabilistic characteristics present additional challenges. Selecting an appropriate optimization framework is essential for achieving accurate and efficient NVH results. Recent advancements in research have introduced several 6DOF optimization algorithms to determine the optimal stiffness and location of engine mounts. The study evaluates a range of optimization methods, including Simultaneous Hybrid Exploration that is Robust, Progressive and Adaptive (SHERPA), Quadratic Programming (QP), Genetic Algorithm (GA), Particle Swarm Optimization (PSO), Non-dominated Sorting Genetic Algorithm III (NSGA-III), Nelder-Mead Simplex (NMS), Multi-Start Local Search (MSLS), Response Surface Method (RSM), and Simulated Annealing (SA). This paper conducts a comparative analysis of these algorithms through a detailed case study, focusing on key parameters required to achieve convergence. By systematically comparing these optimization methods based on criteria such as time efficiency, accuracy, data generation, and robustness, this paper provides comprehensive guidelines for selecting the optimal approach to engine mount design. The findings contribute significantly to mounting system design, offering efficient solutions for enhancing vehicle performance, comfort, and durability.
Hazra, Sandip, Khan, Arkadip
A Comparative Study of Strain Gauge and Load Cell-Based RLD Methods for Assessing Structural Durability Loads in Engine Mounts2025-01-82574/1/2025
In the ongoing Road Load Data Acquisition (RLDA) for engine mounts, a load cell arrangement is being utilized, where the load cell must be placed between the mount arm and an engine mount bracket or an additional tower bracket. This configuration required the design of a custom mount arm with a crank in the Z direction, secured with a single bolt to accommodate the load cell. However, this method has revealed significant load coupling in the X and Z directions, resulting in incorrect load prediction for engine mount testing. This happens due to the architectural packaging of the engine mount on the long member to meet NVH requirements. To mitigate these issues, an alternative strain gauge-based RLDA approach was investigated. The optimal locations for strain gauge placement were determined using the inverse matrix method with the assistance of Computer-Aided Engineering (CAE) analysis. Strain gauges were then installed at these identified locations on the mount arm. The engine mount, now equipped with strain gauges, was tested in a real vehicle under standardized driving conditions and tracks. The strain data obtained was subsequently converted into load signals through the inverse method, demonstrating a substantial reduction in coupling effects compared to the load cell arrangement. This method not only provided more accurate load data but also presented a reliable alternative for RLD collection in engine mounts. A detailed case study is included to illustrate the correlation and effectiveness of this newly proposed RLDA process.
Hazra, Sandip, Khan, Arkadip, Mohare, Gourishkumar
Analysis of Frequency at Minimum Dynamic Stiffness for a Hydraulic Engine Mount with Floating Decoupler under High Frequency Excitation2025-01-82644/1/2025
The primary functions of mounts include providing structural support, sound insulation, and vibration damping. Dynamic stiffness and loss angle are critical metrics for evaluating their NVH (Noise, Vibration, and Harshness) performance. This paper examines a floating decoupler hydraulic mount featuring a long decoupler membrane track. A nonlinear lumped parameter model is developed to calculate the dynamic stiffness and loss angle. The model incorporates fluid flow in the lower chamber and variations in the support reaction force of the decoupler membrane under switching conditions. Parameters of the nonlinear lumped parameter model, including rubber stiffness, equivalent piston area, and volumetric compliance of the fluid chamber, were analyzed and calculated using the finite element method. The influence of different decoupler membrane track structures on the frequency corresponding to the minimum high-frequency dynamic stiffness was investigated based on the established model. The results demonstrate that, under high-frequency and small-amplitude conditions, increasing the decoupler membrane track length and decreasing its cross-sectional area result in a lower frequency at which the minimum high-frequency dynamic stiffness occurs. Conversely, under low-frequency large-amplitude conditions, alterations in the decoupler membrane track structure have negligible impact on the dynamic characteristics. A comparison between simulation and experimental results confirms that the developed lumped parameter model accurately represents the dynamic behavior of the hydraulic mount.
Li, Shenghao, Zhang, Shenglan, Yu, Chao, Tu, Xiaofeng, Shangguan, Wenbin
Advanced Methodology for Accelerated Durability Block Cycle Testing of Automotive Rubber Suspension Bushings and Powertrain Mounts2025-01-82364/1/2025
In the field of automotive engineering, the performance and longevity of suspension bushings and powertrain mounts are critical. These components must endure fatigue loads characterized by their variable amplitude, multi-axial nature, and out-of-phase oscillations. The challenge lies in comprehensively characterizing these service loads during the early stages of vehicle production to foresee potential issues that may arise during later stages. Additional complexity in this analysis is introduced by the nonlinear hyperelastic deformation exhibited by natural rubber, a common material used in these components. To address these challenges, original equipment manufacturers (OEMs) and suppliers employ Computer-Aided Engineering (CAE) techniques for fatigue life predictions. These predictions are complemented by physical testing involving what are known as block cycles. However, the results obtained from these approaches often fail to fully represent the real loading conditions that a vehicle encounters. Consequently, late changes are applied to component design, leading to unnecessary delays in product launches and additional tooling costs. This study examines the drawbacks present in the existing methodologies and offers an innovative solution. The proposed approach involves the development of a new block cycle method, which is based on the calculation of cyclic damage on a critical plane for each proving ground event. It utilizes efficient interpolation mapping to convert multi-channel load-displacement histories into stress-strain histories suitable for a nonlinear elastic finite element model. Fatigue life prediction includes the analysis of strain history by using crack energy density parameter, Rainflow event identification and linear damage rule. This method maintains a specified percentage of damage within the confines of test time limits for the complete proving ground damage. This is achieved by establishing a reverse relationship from critical plane approach damage to nominal load-time history, defining an accelerated block cycle. The efficacy of this novel block cycle methodology was tested by employing a heavy-duty car engine mount. Through systematic testing in a component lab setup, the initiation location of cracks and the life regime of the elastomeric component were monitored. The results gave satisfactory correlation between the damage incurred in the laboratory and performance of the same component within a vehicle under proving ground conditions. In conclusion, this study introduces an innovative and efficient block cycle methodology to address the challenges associated with fatigue life predictions for automotive elastomeric components. The methodology improves predictive accuracy and exhibits a strong correlation with real-world component performance, serving as a valuable tool for automotive engineers and manufacturers.
Zarrin-Ghalami, Touhid, Datta, Sandip
Optimization Method for Powertrain Mounting Systems Based on Enhanced Genetic Algorithms2025-01-86444/1/2025
A methodology for optimizing natural properties of a powertrain for an electric vehicle has been presented. A model with six-degree-of-freedom was proposed utilizing ADAMS, and the natural frequencies and energy distribution of the powertrain are estimated using the proposed model. The calculated natural frequencies and energy distribution shown that the initial design of mount stiffness does not meet requirements of natural frequency and decoupling ratio, and vibration isolation standards. To overcome the limitations of conventional optimization techniques, a non-dominated sorting genetic algorithm (NSGA) was adopted for the enhancement optimization the mounts parameters. The optimization objectives included the refinement of the decoupling rates and frequency distribution at all mounting directions. Stiffness parameters of the mounts were optimized via the NSGA. The optimized results confirmed significant improvements for powertrain natural characteristics. This study presented an effective optimization approach for design of electric vehicle powertrain mounting systems.
Jin, Yang, Li, Dewei, Zhao, Yang, Xiao, Lei, Guo, Yiming
NVH Optimization of Mounts for Reduction of Structure Borne Motor and Road Noise in Electric Vehicle2025-28-00722/7/2025
Due to stringent emission norms, all OEMs are shifting focus from Internal combustion engine (ICE) to Electric vehicle (EV). NVH refinement of EVs is challenging due to less background noise in EVs in comparison with ICE vehicles. Motor whine noise is perceived inside cabin till the speed of 20 kmph. Vehicle is powered by electric powertrain (EPT). Electric powertrain is connected to the subframe with the help of three powertrain mounts. Subframe is connected to the body with the help of four mounts. With the help of Transfer Path Analysis (TPA), it is identified that the noise is structure borne and the dominant path is identified. By optimizing the stiffness of the EPT mounts, the structure borne noise levels are reduced. But reducing the stiffness of EPT mount deteriorated the road noise levels. The reason behind deterioration of road noise is investigated. The performance of double isolation of EPT is compared with single isolation of EPT with respect to both road and motor noise. Modal criteria which needs to be considered for EPT and subframe mount development in design stage with respect to road noise and structure borne motor noise is also discussed.
S, Nataraja Moorthy, Rao, Manchi Venkateswara, Raghavendran, Prasath, Selvam, Ebinezer
A Study on Powertrain Modes for Optimizing the NVH Performance2024-28-018712/5/2024
The stiffness and positioning of engine mounts are crucial in determining the powertrain rigid body modes and kinetic energy distribution. Therefore, optimizing these mounts is essential in the automotive industry to separate the torque roll axis (TRA) and minimize vibration. This study aims to enhance mount locations by isolating the engine rigid body modes and predicting the inter-component force (ICF) and transfer function of the vehicle. The individual ICFs for engine mountings are calculated by applying a unit force at the bearing location. Critical frequencies are identified where the amplification exceeds the unit force at the mounting interface between the engine and the frame. The transfer function approach is utilized to assess the vibration at the handlebar. Both ICF and transfer functions analyze the source and path characteristics linked to critical response frequencies. This understanding aids in enhancing mounting positions to minimize vibration levels, thereby enhancing NVH performance.
Jha, Niraj Kumar, Yeezaku, Antony Neomin, Victor, Priyanka Esther, Krishnamurthy, Govindasamy
Modelling and Simulation Approach for Fiber-Reinforced Polymer Components in Passenger Car Engine Mounting Brackets2024-28-001610/17/2024
The functionality of the Powertrain mount is to securely anchor the engine and gearbox within a vehicle, and effectively absorb vibrations, while simultaneously shielding the vehicle's body from powertrain movements and road irregularities. The mounts are supported by engine mount brackets, which serve as connectors between the engine mount and the vehicle's body-in-white (BIW), providing a structural link that secures the engine and gearbox assembly. Conventionally made with materials such as aluminum, sheet metal, or cast iron, a recent surge has been seen toward using a viable substitute in Fiber Reinforced Polymer (FRP). This transition is driven by the potential to reduce weight and cost, while also improving Noise, Vibration, and Harshness (NVH) characteristics. This study aimed to evaluate the relative strengths of existing brackets compared to those made of FRP, with a focus on their modal response and crash resistance. Due to the absence of a standardized method for modelling orthotropic materials in powertrain mounting brackets, a systematic approach to address this gap is proposed in this paper. By conducting a comprehensive literature review, FRP was examined and contrasted with other conventional materials currently utilized. Subsequently, a series of stress-strain and eigenmode finite element method (FEM) analysis was performed to assess the performance of various materials and material models. Moreover, an analysis to determine the maximum injection pressure and maximum clamp force was conducted, serving as an integral part of validating manufacturability. To validate the results, physical components were produced based on simulation outcomes and recommendations, followed by testing to confirm the correlation. A case study is presented as an illustrative demonstration of this methodology.
Hazra, Sandip, Khan, Arkadip
Research on the Strength Calculation Method of Rubber Mount Housing for Heavy Truck Powertrain2024-01-50808/14/2024
A method of overall modeling and step-by-step solution was proposed to verify and analyze the strength of the mount shell. First, a reliable finite element simulation model was established based on testing of the mechanical properties of rubber materials, constitutive model construction, and stiffness tests of the mounts. Second, the displacement of the mount system under preloading and crash loads was calculated separately through the modeling of the powertrain mount simulation, which provided accurate load conditions of the mount for the following work. Finally, the strength calculation and evaluation of the mount shell was completed with the quasi-static solution method. This calculation method could consider the influence of complex factors comprehensively, such as assembly load distribution, large deformation of rubber, and contact nonlinearity on the stress distribution of the mount shell. In addition, the calculation method could solve the problem of balance between solution quality and efficiency in modeling and solving complex structural mount systems.
Li, Keliang, Chen, Guozheng, Sun, Wanyu, Yan, Shanheng, Li, Ming, Liu, Baoguo
Optimization of Idle Vibration Characteristics of Powertrain Mounting System10-08-03-00185/30/2024
To address the issue of engine jitter at idle conditions in a specific vehicle model, an initial test of the inertial parameters of the powertrain mounting system was conducted. Utilizing the Adams software, a system model was constructed and subjected to modal analysis. The stiffness of the mounting components was selected as the optimization variable. A deterministic multi-objective optimization was performed on the system’s decoupling rate, natural frequencies, and minimum dynamic reaction force, employing the multi-island genetic algorithm. sensitivity analysis regarding the stiffness of the mounts was conducted based on DOE method. The optimized stiffness values were then re-entered into the Adams software. The results of the deterministic optimization indicated a significant enhancement in the decoupling rate of the powertrain mounting system in the primary direction of concern, a reduction in the natural frequencies, and a decrease to 43.5% of the original scheme in the minimum dynamic force transmitted to the vehicle body. A comparative analysis was conducted on the acceleration amplitude–frequency curves before and after optimization in the Z-direction under idle conditions, and the dynamic reaction force amplitude–frequency curves in three dimensions, both demonstrating a notable attenuation post-optimization. In addition, vibration isolation tests were performed on the powertrain mounting system, comparing the comprehensive isolation rates before and after optimization under idle conditions, with the results fulfilling corporate standards. Finally, based on the stiffness values post-deterministic optimization, robust optimization was conducted employing the 6σ methodology. A robustness analysis of the powertrain energy decoupling rate was performed utilizing the Monte Carlo simulation method, effectively mitigating the tremor issue of the vehicle model under idle conditions.
Zheng, Bao Bao, Guo, Yiming, Xiao, Lei, Zheng, Di, Li, Guohong, Shangguan, Wen-Bin, Rakheja, Subhash
Engine Crank Stop Position Control to Reduce Starting Vibration of a Parallel Hybrid Vehicle2024-01-27844/9/2024
Engine off control is conducted on parallel hybrid vehicles in order to reduce fuel consumption. It is efficient in terms of fuel economy, however, noise and vibration is generated on engine cranking and transferred through engine mount on every mode transition from EV to HEV. Engine crank position control has been studied in this paper in order to reduce vibration generated when next cranking starts. System modeling of an architecture composed of an engine, P1 and P2 motors has been conducted. According to the prior studies, there exists correlation between crank vibration level and the crank angle. Thus a method to locate pistons on a specific crank angle which results in a local minimum of vibration magnitude could be considered. The P1 motor facilitates this crank position control when engine turns off, for its location directly mounted on a crankshaft allows the system model to obtain more precise crank position estimation and improved linearity in torque control as well. For the sake of robustness, a position-speed controller considering active damping has been designed, and verified by simulations on frequency and time domains analyses. The controller suggested in this paper shows better response to load disturbance compared to conventional P-PI position-speed controller, and is able to operate robustly on fluctuating static and dynamic friction of an engine. Vehicle tests have been conducted to prove the control performance, which resulted in 50% reduction of vibration magnitude in average.
Park, Jihyun, Yang, Byunghoon, LIM, Jongkyong, Kim, SungKyu
High Pressure Hydrogen Injector Sizing Using 1D/3D CFD Modeling for a Compression Ignition Single Cylinder Research Engine2024-01-26154/9/2024
With the aim of decarbonizing the vehicles fleet, the use of hydrogen is promising solution. Hydrogen is an energy carrier, carbon-free, with high calorific value and with no CO2 and HC emissions burning in ICE. Hydrogen use in spark ignition engines has already been extensively investigated and optimized. On the other hand, its use in compression ignition engines has been little developed and, therefore, there is a lack of information regarding the combustion in ultra-lean conditions, typical of diesel engines. Several applications employ dual fuel combustion for the easy management of the PFI injection system to be applied in addition to the DI Common Rail system. However, this mode suffers from several problems regarding the management of the maximum flow rate of hydrogen into the intake. In particular, to avoid throwing hydrogen into the exhaust, injection must be started after the valve crossing. Furthermore, it is not possible to introduce gaseous fuel into the engine when the compression phase begins. In fact, the hydrogen can find favorable autoignition conditions, giving rise to unwanted combustion processes in the manifold. For these reasons, a direct hydrogen injection system that could be easily applied to the head of the production engine has been designed and realized. In the head of 1.9l GM engine mounted on a single cylinder research engine, the adapter in place of the pre-heating glow plug has been modified to accommodate a commercial injector for the hydrogen direct injection up to 100 bar. Hydrogen is provided by a bottle at 200 bar via a secured line and a rail prior to reach the injector. In the design stage, attention has been paid to the correct assessment of the optimum diameter of the injection system. A 1D Fanno flow based model has been developed to determine in a quick way the mass flow rate and total pressure losses for several possible diameters. In particular, in order to have the desired hydrogen quantity entering into the cylinder a probe featured by a diameter of 2 mm and length of 137 mm has been identified. To confirm the validity of the 1D result, the CAD model of injection system has been designed and analyzed by means of computational fluid-dynamic simulations, which have shown a good agreement with the 1D outcomes. Thus, the 1D Fanno model can be considered a fast and reliable tool for the preliminary design of injection systems for gaseous fuels.
Mancaruso, Ezio, Catapano, Francesco, Rossetti, Salvatore, Anaclerio, Giuseppe, Camporeale, Sergio, Episcopo, Domenico, Laera, Davide, Torresi, Marco
Optimization Methods to Enhance Performance of a Powertrain Mounting System at Key on and Key off2024-01-23894/9/2024
To enhance the transient vibration performance of the vehicle at key on and key off, a method for optimizing mount parameters of a powertrain mounting system (PMS) is proposed. Uncertainties of mount parameters widely exist in a PMS, so a method for optimizing mount parameters of a PMS, which treats the mount parameters of a PMS as uncertain, is also proposed in this paper. Firstly, a 13 degrees of freedom (DOFs) model including car body with 3 DOFs, a PMS with 6 DOFs and unsprung mass with 4 DOFs is established, and the acceleration of the active side of mounts is calculated. An experiment is carried out to measure the accelerations located at active and passive sides of each mount and the accelerations of seat track. A comparison is made between the measured and estimated accelerations, and the proposed model is validated. Two optimization methods for the PMS are proposed based on the developed 13 DOFs model. One method treats mount parameters as deterministic variables, while another one treats them as interval variables. Vibration dose value (VDV) of longitudinal acceleration of a powertrain is defined as one of optimization objectives, and natural frequencies (NFs) placement and energy distributions of a powertrain in different directions are also defined as optimization objectives. The ranges of powertrain uncertain responses are obtained through the perturbation center difference method (PCDM) and are validated using the Monte Carlo method (MCM). The optimized upper and lower bounds of powertrain responses are also given. Finally, key on/off experiments with optimized mount parameters are carried out to validate the proposed methods.
Lin, Shuo, Yin, Zhi-Hong, Jiang, Yong-Feng, Song, Yan-Ping, Shangguan, Wen-Bin
Influence of Exhaust Aftertreatment System on Powertrain Vibration Behavior02-17-02-00113/1/2024
NVH refinement of commercial vehicles is the key attribute for customer acceptance. Engine and road irregularities are the two major factors responsible for the same. During powertrain isolators’ design alone, the mass and inertia of the powertrain are usually considered, but in practical scenarios, a directly coupled subsystem also disturbs the boundary conditions for design. Due to the upgradation in emission norms, the exhaust aftertreatment system of modern automotive vehicles becomes heavier and more complex. This system is further coupled to the powertrain through a flexible joint or fixed joint, which results in the disturbance of the performance of the isolators. Therefore, to address this, the isolators design study is done by considering a multi-body dynamics model of vehicles with 16 DOF and 22 DOF problems, which is capable to simulate static and dynamic real-life events of vehicles. Design indicators are thoroughly analyzed and validated through the rigid body modes and real field events of the vehicle. As most of the research is done for four-point mounting powertrain systems by considering 6 DOF or 12 DOF in commercial vehicles but a novel approach with a 22 DOF model is proposed in this study to predict the impact of the inclusion of the exhaust aftertreatment system on torque roll axis and rigid body modes decoupling. The results of the proposed system show that the rigid body mode decoupling of the powertrain system improved and consequently the overall NVH performance of the vehicle in real life is further improved. Therefore, it is suggested from the study that ignoring the inclusion of the exhaust aftertreatment system in the powertrain mounting system design reduces the NVH performance of the vehicle, hence it is recommended to include it in the early phase of design.
Sarna, Amit Kumar, Singh, Jitender, Kumar, Navin, Sharma, Vikas
The Science of Engine Mounts and its Multidimensional Impact on Noise and Vibrations in Passenger Car2024-26-02031/16/2024
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.
Hazra, Sandip, Mohare, Gourishkumar
An Experimental Approach to Investigate the FEAD Cover Failure & Its Design Optimization2024-26-03711/16/2024
In automotive Front End Accessory Drives (FEAD), the crankshaft supplies power to accessories like alternators, pumps, etc. FEAD undergoes forced vibration due to crankshaft excitation, dynamic tension fluctuations can cause the belt to slip on the accessory pulleys. By considering the criticality of the system, when engine mounting is longitudinally to the vehicle which makes it directly exposed to the air flow containing foreign particles which may cause the damage to the FEAD system and deteriorate the intended functionality. FEAD cover is introduced in the system to enhance belt-pully system functionality by restricting the entry of foreign particles during engine operation. This paper contains a study of FEAD cover failure and provides the stepwise approach to capture such issue during novel model development for 4 cylinder naturally aspirated engine during engine bench testing. The failure mechanism was studied using various methodology such as CAE and G-Load measurement to identify the root cause. CAE analysis was done with near to bench boundary conditions and correlation has been established with strain measurement data of failure zone in FEAD cover on the engine test bench. Countermeasures identification directed towards design optimization and product has been implemented, validated in the engine bench testing successfully.
Patel, Hardik Manubhai, Kumar, Nitish, Chand, Subhash, Gupta, Vineet
Crank-Train System Balancing and Crankshaft Optimization in Different Outlook2024-26-02091/16/2024
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.
Mishra, Pragya, Kolhe, Vivek M, Ghotekar, Sunil
Design Optimization of Engine Mount Bracket to Reduce Various Gear Noises in the Passenger Car Cabin2024-26-02081/16/2024
With the advancement of regulatory norms in automobile industry, there is a challenge to meet performance efficiency targets, especially with a lightweight platform, while providing superior driving experience to customers. The shift towards weight optimization, makes the vehicle structure more susceptible to transfer a diverse range of noise and vibrations through body. Although most undesirable noises perceived inside the cabin can be reduced by superior technology engine mounts and NVH packaging, all such solutions lead to cost addition. Intelligent considerations in part design can be used to supplement predictable transfer paths to quell the unwanted vibrations. One such case is of the gear whine noise in certain rpm bands caused by inherent gear meshing frequency coinciding with natural frequency of an engine mounting bracket. This paper demonstrates two methodologies to counter such a phenomenon, either through engine mount bracket natural frequency optimization or addition of a dynamic damper. However, the focus is on frequency and mobility optimization approach. Another case is of gear “JAA” noise originating from the rattling of remaining freely engaged gears. This kind of gear induced vibration tends to transfer along dynamically weaker structural parts and become audible inside the cabin. This is countered by reducing the mobility of transfer path viz. engine mounting brackets.
Ghosh, Chiranjit, Agrawal, Adheesh, Karmakar, Sudipto, Srivastava, Shubham, Khan, Aamir
Application of Hydraulically Controlled Rear Mount to Mitigate Key on/off Requirement of Passenger Car2024-26-02101/16/2024
Key on/off (KOKO) Vibration plays a vital role in the quality of NVH (Noise Vibration and Harshness) on a vehicle. A good KOKO experience on the vehicle is desirable for every customer. The vibration transfer to the vehicle can be refined either by reducing the source vibrations or improving isolation efficiency. For the engine mounting system of passenger cars, the mounts are an isolating element between the powertrain and receiver. Various noise, Vibration, and harshness criteria must be fulfilled by mounting system performance like driver seat rail vibration (DSR), tip-in/tip-out, judder performance, DSR at idle and Key on/off Vibration. Out of these requirements, in the paper, the investigation is done on KOKO improvement without affecting other NVH parameters related to mount performance. Higher damping is required to isolate Vibration generated during the Key-on event, and lower damping is required during the idle condition of the vehicle. These contradictory damping requirements can only be fulfilled by something other than conventional rubber mounts. The proposed solution is designed to have different damping during Key on and idle vehicle conditions. Increasing the mounting system damping can decrease the KOKO vibration by absorbing the energy during the event. As a result, the hydraulically controlled switchable rear mount is proposed, which can provide high damping during KOKO events but switches to lower damping to isolate vibrations under idle conditions. The level of damping is controlled by the proper design of the bypass channel and piston movement. The effect of damping is validated at the rig level to get the required performance at the vehicle level. The physically prototyped performance is demonstrated on the vehicle, which this paper explains.
Hazra, Sandip, More, Vishwas
NVH Refinement of Small Commercial Vehicle2024-26-02191/16/2024
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.
Yeola, Yogesh, Kharpude, Yogesh, Kalsule, Dhanaji, Choudhary, Aditya, Sonar, Santosh, Nikam, Avinash
Motorcycle Engine Vibrations Prediction for Inertia Loads Using Multi Body Dynamics Calculations2024-26-02321/16/2024
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.
Kumar, Virender, Joshi, Gaurav, Garg, Ankit
Development of System Level Testing Method for Passenger Car Engine Mounts2024-26-03241/16/2024
Engine mount is an integral part of any Internal Combustion engine. It is the medium which isolates the vibrations coming from engine being transferred to the chassis or body. Engine or power plant is the main source of unbalanced vibrations. The major role of an engine mount is to reduce those vibration levels, improve ride comfort and increase the life of an engine and its parts [1]. This work determines the Test methodology development for passenger car engine mounts in the Laboratory by using Multi-axial environment [2]. This explains the details of truly Multi-axial test rig development, Drive file creation and the Durability Testing with the maintained vehicle conditions by simulating field conditions in the laboratory. The Multi-axial test rig developed with incorporation of vehicle’s both Front Drive shafts torques and One Propeller shaft which simulates the Front wheel drives and the rear prop shaft torque. Drive file generation done by using MTS controller using rpc software. Durability testing for the identified engine mounts carried out by maintaining the actual vehicle conditions.
Tormal, Uday Bapurao, Satale, Sunil, V Dhage, Yogesh, Shinde, Vikram V.
Refined Driveline Isolation in Bus Vehicles2024-26-02051/16/2024
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.
Dhadiwal, Nishant Surendra, Pathak, Rahul, Bijwe, Vilas, Gore, Pandurang
Case Study: Power Hop Improvement by Rear Mount Redesign - Small Passenger Car2023-36-00601/8/2024
This Paper has as objective to describe the powertrain mount system and its relation with the Power Hop phenomenon. It will be present the Powertrain mounts stiffness characteristics and how the mounts manage the loads inputs. In this study, we will review a summary about powertrain mounts main characteristics to help the understanding how to establish the static and dynamic characteristics, with the engine torque applied over the system. It will be present how the Powertrain mounts shall manage the loads inputs. As a Case Study, it was applied one small passenger vehicle as hardware. This vehicle presents the powertrain mounts system as pendulum three points configuration. In addition, this vehicle presents the Power Hop phenomenon mainly in Reverse take off flat road. The required load data was collected through load cells installed on the powertrain mount system. The Power Hop phenomenon is mainly impacted by the rear mount, so the load data is related to rear mount direction X. The solution was developed around the rear mount design. Its current design (Load deflection curve) was compared to competitor design that does not present the Power Hop phenomenon. The vehicle under study has a constrain related to engine package that was considered for solution development. The study conclusion allows to comprehend the loads sensitivity against the rear mount rubber stiffness variation. The current scenario and proposed scenario were both subjectively (According to customer point of view) evaluated by NV&H specialists.
Barbetti, Marcos Rogerio Sanches
Driveline System Effects on Powertrain Mounting Optimization for Vibration Isolation under Actual Vehicle Conditions02-16-04-00268/4/2023
Vehicle vibration is the key consideration in the early stage of vehicle development. The most dynamic system in a vehicle is the powertrain system, which is a source of various frequency vibration inputs to the vehicle. Mostly for powertrain mounting system design, only the uncoupled powertrain system is considered. However, in real situations, other subsystems are also attached to the powertrain unit. Thereby, assuming only the powertrain unit ignores the dynamic interactions among the powertrain and other systems. To address this shortcoming, a coupled powertrain and driveline mounting system problem is formulated and examined. This 16 DOF problem is constructed around a case of a front engine-based powertrain unit attached to the driveline system, which as an assembly resting on other systems such as chassis, suspensions, axles, and tires. First, the effect of a driveline on torque roll axis and other rigid body modes decoupling is examined analytically in terms of eigensolutions and frequency responses. It is observed from the analysis that when the optimized uncoupled powertrain system is introduced in real vehicle conditions, the vibration isolation level of the powertrain mountings gets degraded. Then, a new improved approach of considering coupled powertrain and driveline systems in the initial design phase itself is proposed. The mounting system parameters such as mount location, mount orientation angle, and stiffness rate are optimized and redesigned for the proposed system. The results of the redesigned system show that the decoupling of the rigid body mode parameters is improved and consequently powertrain vibration performance is also improved in static and dynamic conditions of the vehicle. Overall, the findings of this study suggest that considering the driveline along with the powertrain as a coupled system at the early phase of the mounting system design itself improves the vibration performance of the vehicle during real-life situations.
Singh, Jitender, Sarna, Amit Kumar, Kumar, Navin, Sharma, Vikas
Vehicle Idle Vibration Development with DFSS Method2023-01-10735/8/2023
This paper describes idle vibration reduction methods using a Stellantis vehicle as a case study. The causes of idle vibration are investigated using the NVH source, path, and receiver method. The torque transfer path into a vehicle has shown to be very important in determining vehicle idle vibration response. New electronic control enablers that affect idle vibration are tested and discussed, including Neutral Idle Control (NIC), Transfer-case Idle Control (TIC,®), and Switchable Engine Mounts (SEM). The Design For Six Sigma (DFSS) analysis method is used to arrive at an optimized result for vehicle idle vibration. This paper also discusses the results confirming TIC’s capability of reducing idle vibration on all-wheel drive vehicles. Transfer-case Idle Control is a new idle vibration control enabler developed by Stellantis and a patent was awarded by the United State Patent and Trademark Office.
Yuan, Wei, Nakkash, Gary, Roco, Rob, Orzechowski, Jeff, Bowen, Brooke, Sanders, Mark
Analysis of Noise of Hydraulic Mounts from Decoupler-Cage Hitting2023-01-11515/8/2023
In this paper, the influence of the decoupler-cage structure on the hitting noise of the hydraulic mount is studied, the abnormal noise of the hydraulic mount is mainly caused by the collision impact between the decoupler and the cage, the hitting noise was simulated and evaluated using calculation and experiment. a finite element model of the collision impact between the decoupler and the cage is developed, and an explicit finite element analysis is performed to obtain the time history of the vibration acceleration of the model, which is used as the boundary condition of the noise analysis. The acoustic boundary element method is used to analyze the impact noise of the decoupler-cage, and the frequency domain distribution characteristics of the impact sound pressure are obtained. The influence of different decoupler structure on the hitting noise is studied, and the recommended values for each parameter for a structure are given. The structure of a decoupler with hitting noise is improved, and the design is validated to solve the problem of abnormal noise of the hydraulic mount.
Zong, Kaihua, Zhao, Kegang, Shen, Dongming, Tu, Xiaofeng, Shangguan, Wenbin, Ren, Yan
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