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Technical Paper

Automated Charging Methodology for Fleet Operated EV Buses to Reduce Down Time and Increase Safety at Charging Station

2024-01-16
2024-26-0112
Prime concern for electric vehicle where the application of the vehicle is public transport, is the charging of vehicle and operation of its infrastructure. Such an example of operating the EV buses is under the GCC (gross cost contract) model, with high operation time and comparatively lesser time for charging. It is challenging to meet these requirements. To counter this situation in fleet operated busses it is proposed to adapt an automated charging method which involves minimum man power intervention and automated mechanism to connect & disconnect the charging connectors. This paper proposes an automated pantograph mechanism based method of charging EV buses, meeting requirements as per SAE J3105 & ISO 15118 standards, which would be an ideal way to resolve the current situation.
Technical Paper

A Study on Traction Battery Mounting Arrangements in Different EV Buses

2024-01-16
2024-26-0121
Adaption of EV powertrains in existing vehicle architecture has created many unique challenges in meeting performance, reliability, safety, ease of manufacturing & serviceability at optimum cost. Mounting of large size battery packs in existing vehicle architecture is one of them. Specific energy & the energy density of Lithium ion batteries are very lower compared to Diesel & Petrol, which requires high volume & weight for equivalent energy storage. For movement of many passengers and to ensure sufficient range EV buses typically needs large amount of energy and for storage of same bigger size battery packs are required. These large size batteries directly affect vehicle architecture, seating layout, ease of assembly & serviceability. Moreover the heavy mass of batteries directly influences vehicle dynamics & performance characteristics such as vehicle handling, roll & NVH. The most important consideration in design of EV vehicles in general and buses in specific is safety.
Technical Paper

A Comparative Analysis and Novel Powertrain Topology for FCEVs, Integrating Ultra-Capacitor and Batteries

2024-01-16
2024-26-0168
This paper addresses challenges in current Fuel Cell Stack Buses and presents a novel Fuel Cell Electric Vehicle Bus (FCEV-Bus) powertrain that combines fuel cells, ultra-capacitors, and batteries to enhance performance and reliability. Existing Fuel Cell Stack Buses struggle with responsiveness, power fluctuations, and cost-efficiency. The FCEV-Bus powertrain uses a Fuel Cell stack as the primary power source, ultra-capacitors for quick power response, and batteries for addressing power variations. Batteries also save costs in certain cases. This combination optimizes power management, improves system efficiency, and extends the FCEV-Bus's operational life. In conclusion, this paper offers an innovative solution to overcome traditional fuel cell system limitations, making FCEV-Buses more efficient and reliable for potential wider adoption.
Technical Paper

Development of Advanced Signal Analysis Technique for Pass-by Noise Source Identification of Light Commercial Vehicle

2024-01-16
2024-26-0201
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.
Technical Paper

A Detailed Study to Evaluate Sporty Sound Character of Passenger Cars

2024-01-16
2024-26-0207
Sound signature design is gaining more importance within global auto manufacturers. ‘Sportiness’ is one of the important point to consider while designing a sound character of a car for passionate drivers and those who love aggressive driving. Nowadays automobile manufacturers are more focused in developing a typical sound signature for their cars as a ‘unique design strategy’ to attract a niche segment of the market and to define their brand image. Exhaust system is one of the major aggregate determining the sound character of ICE vehicles which in turn has the direct influence on the customer perception of the vehicle and the Brand image and also the human comfort both inside and outside the cabin. This research work focuses on novel approaches to identify frequency range and order content by a detailed study of subjective feelings based on psycho-acoustics. Sound samples of various benchmark sporty vehicles have been studied and analyzed based on sound quality parameters.
Technical Paper

Refined Driveline Isolation in Bus Vehicles

2024-01-16
2024-26-0205
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.
Technical Paper

Utilizing Computed Tomography for Cell Characterization, Quality Assessment, and Failure Analysis

2024-01-16
2024-26-0189
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.
Technical Paper

A Design Approach to Optimize Suspension Clunking Noise in Passenger Vehicles

2024-01-16
2024-26-0226
Designing a Passenger vehicles suspension system is a key challenge for all OEMs because balancing buzz, squeak, and rattle (BSR) acoustic performance at low-speed driving and improving ride quality at high-speed driving conditions are bet challenging. Suspension noise deteriorates in-cab acoustic quietness and overall vehicle performance. For this reason, optimizing these noises is becoming increasingly prioritized as a key design issue throughout the development process of suspension system. This paper studies the various components of suspension system and their noises in Passenger vehicles. Based on customer voice index and drive pattern, suspension anomalous Clunking noise was identified in Passenger vehicles. This noise phenomenon was cascaded from the vehicle level to BSR rig and eventually to the suspension rig for root cause analysis.
Technical Paper

Crank-Train System Balancing and Crankshaft Optimization in Different Outlook

2024-01-16
2024-26-0209
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.
Technical Paper

Simulation Techniques for Liquid Gasket Sealing Performance Prediction

2024-01-16
2024-26-0267
In the automotive industry, silicon adhesive has become increasingly popular due to its benefits in ease of assembly and cost savings associated with material and manufacturing processes. To meet the imperative of minimizing both time and expenses during the project's development phase, it becomes essential to select the appropriate gasket material and an optimal flange design at the outset of the design process. In order to achieve stringent emission standards such as Real Driving Emission (RDE) and Corporate Average Fuel Economy (CAFE) norms, a better sealing performance is an essential parameter. Various types of liquid gaskets such as silicon rubber based Room Temperature Vulcanizing (RTV) sealants and thermoset plastic based Anaerobic sealants are widely used in an Internal Combustion engine. They are commonly used for the components such as oil sump, bedplate, and gearbox housings, etc.
Technical Paper

Fatigue Assessment & Test Correlation of Seam Welded Joints Using Force Based Equivalent Structural Stress Solid Weld Approach

2024-01-16
2024-26-0268
The stress concentration at welded joints and small crack propagation from some pre-existing discontinuities at notched regions control the fatigue life of typical welded structures. There are numerous FEM stress-based weld fatigue assessment approaches available commercially which unify FEM stresses with various fatigue software codes embedded with international weld standards. However, FEM stress-based approaches predict extensively conservative results. Considerable efforts & subjective decision making is required to arrive at desired level of weld life correlation with physical test results, in terms of weld life and failure location. This is majorly because of inconsistency & inaccuracy in capturing the hot spot stress results due to stress singularities occurring at the notched regions owing to the mesh sensitivity, modeling complexity.
Technical Paper

CAE Based Benchmarking of Shaft Deflection for Transmission Gear Rattle Noise

2024-01-16
2024-26-0245
Vehicle transmission gear rattle is one of the most critical NVH irritants for refined vehicles. It is perceived more dominantly in lower gears of vehicle running. It depends on various design parameters like engine input torque amplitude & fluctuations, driveline torsional vibrations, gear micro & macro geometry, shaft flexibility, etc. Establishing exact contribution of each of these parameters to transmission rattle, thru experimental or simulation technique, is very challenging. Current paper explains the NVH CAE benchmark approach deployed to understand difference in rattle behavior of two transmission designs. Paper focuses on simulation of gear impact power and its sensitivity to transmission shaft deflections.
Technical Paper

Simulation Methodology Development for Vibration Test of Bus Body Structure Code AIS-153:2018

2024-01-16
2024-26-0249
A bus is integral part of public transportation in both rural and urban areas. It is also used for scheduled transport, tourism, and school transport. Buses are the common mode of transport all over the world. The growth in economy, the electrification of public transport, demand in shared transport, etc., is leading to a surge in the demand for buses and accelerating the overall growth of the bus industry. With the increased number of buses, the issue of safety of passengers and the crew assumes special importance. The comfort of driver and passenger in the vehicle involves the vibration performance and therefore, the structural integrity of buses is critically important. Bus safety act depicts the safety and comfort of bus operations, management of safety risks, continuous improvement in bus safety management, public confidence in the safety of bus transport, appropriate stakeholder involvement and the existence of a safety culture among bus service providers.
Technical Paper

Enhanced Development Process for UPDs – Digital Approach

2024-01-16
2024-26-0239
Underrun Protection devices (UPDs) are specially designed barriers fitted to the front, side, or rear of heavy trucks. In case of accidents, these devices prevent small vehicles such as bikes and passenger cars going underneath and thus minimizing the severity of such accident. Design and strength of UPD is such that it absorbs the impact energy and offers impact resistance to avoid the vehicle under run. Compliance to UPD safety regulations provides stringent requirements in terms of device design, dimensions, and its behavior under impact loading. Since accuracy of Computer Aided Engineering (CAE) predictions have improved, numerical tools like Finite element method (FEM) are extensively used for design, development, optimization, and performance verification with respect to target regulatory performance requirements. For improved accuracy of performance prediction through FEA, correct FE representation of sub-systems is very important.
Technical Paper

“Test Methodology Development for Rig Level Validation of Light Weight Stabilizer Link of EV Bus Suspension”

2024-01-16
2024-26-0357
In the modern and fast growing automotive sector, reliability & durability are two terms of utmost importance along with weight & cost optimization. Therefore it is important to explore new technology which has less weight, low manufacturing cost and better strength. The new technology developed always seek for a quick, cost effective and reliable methodology for its design validation so that any modification can be made by identifying the failures. This paper presents the rig level test methodology to validate and to correlate the CAE derived strain levels, life cycle & failure mode of newly developed light weight stabilizer link for EV Bus suspension
Technical Paper

Design Implementation through Computational Fluid Dynamics (CFD) Analysis to Reduce Fuel Filling Time in NGVs

2024-01-16
2024-26-0309
In the past few decades CNG (Compressed Natural Gas) fuel growing as an alternate fuel due to its more economically as compared to Gasoline & Diesel fuels by vehicle running cost in both passenger as well as commercial vehicles, additionally it is more environment friendly & safer fuel with respect to gasoline & diesel. At standard temperature & pressure fuel density of Natural Gas (0.7-0.9 kg/m3) is lower than Gasoline (715-780 kg/m3), Diesel (849~959 kg/m3), therefore CNG fuel require higher storage space as compared to Gasoline & Diesel & also it stores at very high pressure (200-250 bar) to further increase the fuel density 180 kg/m3 (at 200 bar) and for 215 kg/m3 (at 250 bar) in CNG cylinders so that max fuel contains in the cylinders and increase the vehicle running range per fuel filling & reduces its fuel filling frequency at filling stations.
Technical Paper

Tweaking Elastomer by Addition of Nano Silica in Formulation

2024-01-16
2024-26-0197
The art of rubber formulation science always has a scope for fine-tuning with changing the parameters like base polymer grade selection, filler selection, curing system/cross link density, manufacturing methods, and many. Hence forth the filler manufacturer arrived differentiation of the filler already, this paper provides a description of rubber formulation tuning for damped vibration automotive applications. Acicular spiky spherical and hollow spherical nano silica selected as filler. With the thorough knowledge of elastomeric formulation and with doping different new selected silica grades, an optimized DOE was done. New formulation development was focused on isolation characteristics without affecting other necessary properties. The different inputs for finite element calculations was studied with the effects of doping different fillers and also studied the resultant virtual output in damping coefficients.
Technical Paper

Advanced Material Modelling for Failure Prediction of ISOFIX Anchorages

2024-01-16
2024-26-0300
ISOFIX anchorage plays a critical role in restraining child occupants during crashes. Effective design of ISOFIX anchorages is essential for achieving controlled child occupant kinematics. CAE simulations are extensively used for the development of ISOFIX anchorages. Comprehensive material characterization of ISOFIX wires play a vital role for achieving desired prediction accuracy. This paper covers the detailed process of ISOFIX material characterization for material failure prediction. ISOFIX wires are case hardened to exhibit required strength characteristics. Due to its material characteristics, the conventional material models don't give desired prediction accuracy for failure prediction. Therefore, advanced material models are developed in LS Dyna environment, which can accurately predict plastic and fracture behavior of ISOFIX wires.
Technical Paper

Dynamic Stress-Strain and Fatigue Life Estimation Using Limited Set of Measured Accelerometer Data on Exhaust System Using System Equivalent Reduction and Expansion Process (SEREP)

2024-01-16
2024-26-0251
The dynamic response of structures to operating or occasional loads is crucial for design considerations, as it directly impacts the cumulative fatigue life. In practice, accurately discerning the precise loads and structural conditions, which involve considerations such as boundary conditions, geometry, and mechanical properties, can be quite challenging. Significant efforts are invested in identifying these factors and developing suitable prediction models. Nonetheless, the estimated forces and boundary conditions remain approximations, leading to uncertainties which affects the overall predictions and the analysis of how stress and strain develop in the structure during subsequent evaluations. Many researchers frequently employ a method where they estimate the forces acting on the system based on measurement data obtained at limited number of locations over the structure.
Technical Paper

Estimation of Gear Utilization and Durability Test Specifications through Virtual Road Torque Data Collection for Light Commercial Vehicles

2024-01-16
2024-26-0257
The automotive world is rapidly moving towards achieving shorter lead time using high-end technological solutions by keeping up with day-to-day advancements in virtual testing domain. With increasing fidelity requirements in test cases and shorter project lead time, the virtual testing is an inevitable solution. This paper illustrates method adopted to achieve best approximation to emulate driver behavior with 1-D (one dimensional) simulation based modeling approach. On one hand, the physical testing needs huge data collection of various parameters using sensors mounted on the vehicle. The vehicle running on road provides the real time data to derive durability test specifications. One such example includes developing duty cycle for powertrain durability testing using Road Torque Data Collection (RTDC) technique. This involves intense physical efforts, higher set-up cost, frequent iterations, vulnerability to manual errors and causing longer test lead-time.
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