Browse Topic: Six Sigma

Items (252)
Thermal runaway in high-voltage lithium-ion battery modules should focus on critical safety and design challenges in electric vehicle applications, which need predictive methods that enhance passenger safety and support regulatory compliance. The primary purpose of a lithium-ion battery in an electric vehicle is to provide reliable energy storage while maintaining safe operation under different operating conditions. This study proposes a Design for Six Sigma (DFSS) methodology to virtually predict and correlate thermal runaway and its propagation in an 800V high-power lithium-ion battery pack module. Conventional propagation analysis relies heavily on physical testing, whereas the DFSS-based virtual framework enables cost-effective evaluation at early design stages. Input factors included are heat transfer pathways, which are sensitive to the temperature changes, as well as thermal propagation time. Control factors are the design or process parameters that engineers use to establish the functional performance of a system. The noise factors capture material variability and manufacturing tolerances affecting thermal properties. Output responses included the maximum cell temperature Versus time, thermal propagation time to adjacent cells, and total propagation duration across the module, measured in minutes. The validated 1D GT-SUITE model shows strong correlation with experimental data, confirming its reliability to predict thermal propagation time and supporting safer, thermally optimized battery pack designs. The validated model can be integrated into system (battery pack) level 1D thermal simulations, offering a calibrated model for future pack level propagation studies and supporting the development of safer, thermally optimized battery architectures.
Dixit, ManishRaja, VinayakGudiyella, Soumya
Non-uniform temperature distribution within lithium-ion battery cells is a critical challenge that accelerates degradation, compromises safety, and reduces pack-level performance in electric vehicles (EVs). This work focuses on modeling and minimizing these thermal gradients through the structured optimization of a liquid-based Battery Thermal Management System (BTMS). A one-dimensional transient thermal model is developed to capture the axial temperature differentials (ΔT) in a cylindrical cell under dynamic drive-cycle loading, incorporating detailed heat transfer from the cell interior through thermal interface materials (TIM) and an aluminum cooling plate to the coolant. Using a Design for Six Sigma (DFSS) approach with an L18 orthogonal array, key control factors—including coolant flow rate, inlet temperature, TIM properties, and plate geometry—are systematically analyzed to identify configurations that optimally balance low average temperature with minimal internal temperature variation. The results provide a data-driven framework for designing robust cooling systems that mitigate the risks of localized hotspots and thermal runaway, thereby enhancing the durability and safety of EV battery packs.
El-Sharkawy, AlaaAsar, MonaSerpento, StanSheta, Mai
Battery thermal runaway is a major safety concern in electric vehicles because of the extreme heat and hazardous gases released during cell failure. These venting events can quickly raise the temperature of the battery enclosure and cabin floor, threatening occupant safety. To address this challenge, this study employs the Design for Six Sigma (DFSS) methodology to design and optimize a thermal protection system that delays and limits heat transfer to the cabin. A physics-based transient heat-transfer model was combined with DFSS principles to systematically evaluate insulation materials, shield layouts, surface emissivity, and layer geometry. An L-18 orthogonal array was used to identify key parameters and quantify their influence on thermal robustness. The optimized architecture reduced cabin-floor temperature rise under severe runaway conditions (600–900 °C vent gas), meeting occupant-egress safety requirements. Findings confirm DFSS as an effective framework for developing high-robustness EV thermal protection systems under uncertainty and extreme boundary conditions.
El-Sharkawy, AlaaAsar, MonaTaha, NahlaSheta, Mai
This study presents the results of applying a Lean Six Sigma-based analytical approach to optimize the manufacturing of automotive coatings, specifically in a PU primer filling process. Through production flow mapping and the Define, Measure, Analyze, Improve, and Control (DMAIC) methodology, unplanned stoppages in the filling line were significantly reduced, addressing critical inefficiencies in automotive coating production. The research was driven by the need to enhance manufacturing productivity and ensure process reliability in the production of coatings used in the automotive sector. To achieve this, Quality Management tools, such as Pareto Analysis and the Cause-and-Effect Diagram, along with Lean Manufacturing techniques, including Kaizen Blitz, were applied. These methods facilitated the identification and mitigation of key causes of unplanned downtime, improving process efficiency and reliability. The results demonstrated a significant reduction in downtime, enhanced operational efficiency, and an increase in Overall Equipment Effectiveness (OEE). Furthermore, the implementation of Reliability-Centered Maintenance (RCM) practices contributed to process stability and improved failure prediction, ensuring higher consistency in automotive coating production. This study highlights that integrating lean methodologies with data-driven analysis is a highly effective strategy for improving manufacturing performance in the automotive industry, reducing operational costs, and strengthening supply chain resilience for automotive coating manufacturers.
Filho, William Manjud MalufRodrigues, Mateus FerreiraCarriero, Emily AmaralYoshimura, Sofia LucasMarini, Vinicius KasterSiqueira, GonçaloAlves, Marcelo Augusto Leal
The steering system is one of the most important assemblies for the vehicle. It allows the vehicle to steer according to the driver’s intention. For an ideal steering system, the steering angle for the wheel on the left and right side should obey the Ackman equation. To achieve this goal, the optimization method is usually initiated to determine the coordinates of the hard points for the steering system. However, the location of hard points varies due to the manufacturing error of the components and wear caused by friction during their working life. To decrease the influence of geometry parameter error, and system mass, and improve the robust performance of the steering system, the optimization based on Six Sigma and Monte Carlo approach is used to optimize the steering system for an off-road vehicle. At last, the effect is proved by the comparison of other methods. The maximum error of the steering angle is decreased from 7.78° to 2.14°, while the mass of the steering system is reduced by 3.15%. Thus, the vehicle handling performance and fuel efficiency are improved.
Peng, DengzhiDeng, ChaoZhou, BingbingZhang, Zhenhua
A continuous effort to improve reliability and efficiency of processes is at the forefront of any successful business. One methodology that can have a crucial impact in this effort is Lean Six Sigma (LSS), which aims to reduce variability and wasteful activities within a company’s processes, in turn leading to improvements in areas such as customer satisfaction, employee morale, regulatory compliance, and profitability. In the medical device industry, where a seemingly minor error could be life-threatening, LSS can play a pivotal role in patient safety. This article presents a case study illustrating the benefits of LSS for a medical device manufacturing company, as well as one of its key customers.
In automotive engineering, seam welds are frequently used to join or connect various parts of structures, frames, cradles, chassis, suspension components, and body. These welds usually form the weaker material link for durability and impact loads, which are measured by lab-controlled durability and crash tests, as well as real-world vehicle longevity. Consequently, designing robust welded components while optimizing for material performance is often prioritized as engineering challenge. The position, dimensions, material, manufacturing variation, and defects all affect the weld quality, stiffness, durability, impact, and crash performance. In this paper, the authors present best practices based on studies over many years, a rapid approach for optimizing welds, especially seam welds, by adopting Design For Six Sigma (DFSS) IDDOV (Identify, Define, Develop, Optimization, and Verification) discrete optimization approach. We will present the case testimony to show the approach throughout each phase of IDDOV. Three case studies are presented in this paper to demonstrate that the presented DFSS approach provides efficient, effective, and reliable practices to improve the robustness of weld designs over conventional design methodologies. This practice approach is scalable not just within the automotive industry but across other industries applying welded components.
Qin, WenxinLi, FanPohl, Kevin J.Pentapati, Venkat
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 BaoGuo, YimingXiao, LeiZheng, DiLi, GuohongShangguan, Wen-BinRakheja, Subhash
With globalization, vehicles are sold across the world throughout different markets and their automotive brake systems must function across a range of environmental conditions. Currently, there is no current standardized test that analyzes brake pads’ robustness against severe cold and humid environmental conditions. The purpose of this proposed test method is to validate brake system performance under severe cold conditions, comparing the results with ambient conditions to evaluate varying lining materials’ functional robustness. The goal of this paper is to aid in setting a standardized process and procedure for the testing of automotive brakes’ environmental robustness. Seven candidate friction materials were selected for analysis. The friction materials are kept confidential. Design of experiment (DOE) techniques were used to create a full-factorial test plan that covered all combinations of parameters. The test script involves brake applications at 5, 10, 15, and 20 bar, at both ambient/non-humid and cold/humid conditions. Each brake application collects the stop time and coefficient of friction (COF) values throughout the stop. Failure modes are subjectively long braking times and failed brakes. The test results verify that brake pad effectiveness is dependent on friction lining, braking pressure, and environmental conditions. Other than at the lowest tested braking pressure, the COFs appear to be consistent across the tested braking pressures. Each material was evaluated for robustness against cold conditions by calculating their signal-to-noise (S/N) ratio, a common method used during design for six sigma (DFSS) robust optimization analysis. The braking time S/N is calculated using smaller the better (STB) analysis, whereas the COF S/N is calculated using the larger the better (LTB) analysis. Using the S/N ratio, it can easily be determined which brake pad friction lining material is the most robust against environmental conditions. Friction designation A was consistently calculated to be the most robust friction material against the cold environmental conditions. All friction linings had extended stopping times in cold conditions when compared to ambient conditions. In some cases, the lining materials reached critical failure in severe cold environments. Additionally, the collected friction values gave insight into potential extreme pad wear rates.
Passador, Stephen Daniel AustinBoudreau, Douglas BarretCapacchione, Christopher James
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, WeiNakkash, GaryRoco, RobOrzechowski, JeffBowen, BrookeSanders, Mark
In research and development of any automotive industry the main challenge is to virtually simulate probable failures rather than relying on physical testing which consumes time and resources. It is even more challenging when it comes to failure prediction of ABS plastic parts due to its complexity in material, behavior and assembly variations. ABS material is used extensively in automotive vehicles especially in motorcycles and scooters due to its visual and structural benefits at moderate cost. In this paper, the work showcases a methodology to predict failure of ABS parts. In order to do so, understanding the shortcomings in the current system is necessary. With the help of testing database history of various vehicles on proving grounds, root causes and drawback with respect to current simulation process are identified for failure of ABS parts. The input excitations from proving ground are probabilistic, thus, random vibration fatigue process is then introduced to calculate life. By correlating the simulation predicted life with testing, the required factor of safety to include residual stresses, assembly stresses are calculated and passing limit in terms of stress is derived for ABS parts to further reduce the simulation run time. Using six sigma methods, the accuracy in simulation is improved with which cycle time, prototype cost and testing time is reduced.
Jawahar, Nagarjun
The automotive industry is moving towards larger SUVs and also electrification is a need to meet the carbon neutrality target. As a result, we see an increase in overall gross vehicle weight (GVW), with the additional weight coming from the HV battery pack, electric powertrain, and other electrical systems. Tow-eye is an essential component that is provided with every vehicle to use for towing during an emergency vehicle breakdown. The tow-eye is usually connected to the retainer/sleeve available in the bumper system and towed using the recovery vehicle or other car with towing provision. Therefore, the tow-eye should meet the functional targets under standard operating conditions. This study is mainly for cars with bumper and tow-eye sleeves made of aluminum which is used in the most recent development of vehicles for weight-saving opportunities. Tow-eye systems in aluminum bumpers are designed to avoid any bending or buckling of the sleeve during towing for whatever the GVW loads. So that the vehicle doesn’t face any tow-eye system failure, which would prevent another car from towing the breakdown vehicle and would need special roadside assistance to take it for servicing. This paper uses the Design For Six Sigma (Taguchi Method) approach to identify the potential control factors (from the benchmarking study) to optimize the tow-eye sleeve to withstand higher GVW load without functional loss. Furthermore, this approach proved that the selected optimum design is less sensitive to noise factors such as aluminum property variation, bumper beam thickness variation, and load direction variation. The learnings from this paper will help to reduce the development time and cost by implementing the robust sleeve design in the early stage of the program.
Fahir, AhamedChoudhari, SatishMichalowski, Krzysztof
Ford CEO Jim Farley exposed significant product-development lapses during his company's fourth-quarter-2022 earnings call on February 2. Ford's 4Q profit performance was no-excuses dismal. Its causes, he stated, run deep. So, in front of investors and media, Farley boldly lifted Ford's PD skirt to reveal alarming management and process issues behind the dysfunction. The fire had to be lit. “We didn't know that our wiring harness for Mach-E was 1.6 kilometers longer than it needed to be,” Farley stated on the call. “We didn't know it's 70 pounds heavier and that that's [worth] $300 a battery. We didn't know that we underinvested in braking technology to save on the battery size.” Credit to CNN's Chris Isidore for roping these EV-specific details into a Feb. 3 story.
Brooke, Lindsay
Cargo box is one of the indispensable structures of a pickup truck which makes it capable of transporting heavy cargo weights. This heavy cargo weight plays an important role in durability performance of the box structure when subjected to road load inputs. Finite element representation for huge cargo weight is always challenging, especially in a linear model under dynamic proving ground road load durability analysis using a superposition approach. Any gap in virtual modeling technique can lead to absurd cargo box modes and hence durability results. With the existing computer aided engineering (CAE) approach, durability results could not correlate much with physical testing results. It was crucial to have the right and robust CAE modeling technique to represent the heavy cargo weight to provide the right torsional and cargo modes of the box structure and in turn good durability results. As there are multiple variables owing to heavy cargo weight, Design for Six Sigma (DFSS) methodology was used to develop a robust CAE modeling technique. This project was defined with multiple key control factors considering geometrical and material properties of cargo along with the multiple ways to connect cargo ballast with the box floor bed. The manufacturing variability of box panels was considered as a noise factor. L18 Orthogonal Array matrix was chosen to optimize the variables based on factorial effects of signal to noise (S/N) ratio. Finally, the validation was done for the achieved optimum solutions using numerical tests. This paper describes the DFSS project in detail, and emphasizes on how the DFSS approach could be very effective to predict the influential control factors and how the combination of these factors was utilized to find out the optimum solution. This paper also highlights how the optimized/proposed CAE modeling technique improves the accuracy of the cargo box modal and durability results.
Pankaj, Ananta VijayaNazir, FazilZhang, WeidongGuo, Mingchao
In the modern practice of the vehicle crashworthy design development and its impact performance validation, virtual full vehicle crash models have been widely and successfully utilized as the analysis tool by many safety CAE engineers. Recently, a typical full-vehicle front impact model has grown in size up to over 3 million finite elements to enable analysis of highly localized and transient responses of vehicle structure deformation under the impulsive loads. This full vehicle model takes 10~15 computer hours per run even on a fast Massively Parallel Process (MPP) server. The CPU time will increase if the full-vehicle model is applied for analysis of the offset-barrier events in which the test vehicle receives barrier impact loading for a longer duration. Furthermore, for a design optimization task running a large Design of Experiment (DOE) variation matrix, the total turn-around time including CPU hours taken for the DOE model iterations could rise significantly depending on the number of the control parameters and levels of choice. At an early stage of developing a vehicle safety design strategy and direction, a DOE variance study is necessary to provide an adequate size of safety design data for quicker gaining insight and informed decision-making about the effectiveness and unseen risks of the potential safety design options. As this task usually proceeds before a full vehicle model build, a virtual analysis tool, simple but reliable as a full scale model, is required. Hence, this study has developed a simplified vehicle impact model using nonlinear springs and mass elements to enable a single analysis run in a few minutes. To demonstrate the usefulness of the simplified model, a DFSS optimization of the vehicle Small Overlap Rigid Barrier (SORB) impact performance via the simplified model has been conducted and its results are compared with a full vehicle analysis.
Park, Sae U.Hor, HassanRajagopalan, RajkumarKleinhoffer, StaceyWestra, Michael
In the vehicle front closure development process, it is very important to meet the durability functional attributes such as Fit and finish, slam event and ease of closing effort. Conventionally softer seal & bump-stop stiffness properties are required for better flushness, but a stiffer seal & bump-stop will help to arrest the hood over travel during the slam event. It is always a challenging and iterative process to arrive at an optimum combination of these design parameters to meet both the flushness and slam targets. This paper highlights the six sigma approach to identify the effect of various control factors like Seal & Bump stop stiffness, latch position, bump-stop design clearance to meet the durability functional attributes. This approach suggests optimum design which is less sensitive to noise factors such as build tolerances on the latch position and the bump-stop design clearance. The learnings from this paper will help to improve design at the early stages of the product development cycle and thereby reducing overall cost and time.
VS, KrishnarajGolla, Rama Raju
The design and development of electric vehicles involves many unique challenges. One such challenge involves accurately predicting driveline abuse torque loads early in the design cycle to aid with sizing drive-unit and driveline components. Since electrified drivelines typically lack a torque-limiting “fuse” element such as a torque converter or slipping clutch, they can be vulnerable to sudden transient events involving high wheel acceleration or deceleration. Component sizing must account for the loads caused by such events, and these loads must be accurately quantified early on when vehicle parameters haven’t been finalized yet. Early load predictions can be made by completing abuse maneuver simulations where key parameters are varied to gauge their influence on simulated loads. Understanding how these parameters impact loads allows for better risk assessment during the design process, as these parameters will inevitably change until a final design is iterated upon. This paper discusses simulations of an aggressive driveline abuse maneuver, and then identifies the key design parameters that affect the predicted loads through a Design for Six Sigma (DFSS) study.
Ilunga, RalphOrtner, AlexanderCelentano, MatthewChinta, BalakrishnaFreiman, David
CAE Modeling and Automation on High Performance ComputingSAE-PP-002433/4/2022
CAE modeling is rapidly improving and becoming more efficient to reduce the cost of physical testing and cut time to make parts in record time. CAE engineers are under pressure to reduce turnaround time and find solution with more precision. There can be two different paths to achieve this task by either increasing headcount or do CAE automation. Increasing the head count is not desirable as it will erase the benefit of using CAE technique. Whereas, doing automation help engineer to focus more on problem solving to find the best solution rather than repeatedly building the CAE models where they can make mistakes. CAE Automation process has been proposed and demonstrated design optimization on a driveline component that is collapsible spacer. Collapsible spacer is very complex engineering design because it should provide sufficient preload to two bearing inner race and at the same time be structurally strong to withstand the fatigue loading. In this paper automation procedure has been explained to optimize the spacer design more efficiently and accurately using High performance Computing (HPC). Hyperstudy has been used as CAE automation software where it was integrated with meshing software Simlab, analysis software Abaqus and fatigue software FEMFAT. Analysis was performed on HPC to improve efficiency. Optimization technique GRSM was used to find the best solution that improved the fatigue life significantly higher than original design and preload was sufficient to meet the minimum preload criteria.
Singh, Sushil
Climate change and global warming are the main threats to our planet. CO2 emissions contribute vastly to climate change and automobiles contribute to CO2 emissions. We can reduce the CO2 emissions from vehicles by various measures, out of which shredding weight is one of the solutions, and even for hybrid or electric vehicles there will be a need for weight reduction for the control of global CO2 emission. We can shred the weight of the automobiles by replacing the components with lighter materials or by optimizing the components by removing excessive material. It is not always possible to change the materials due to its mechanical, thermal properties, manufacturability etc. This leads to the other method which is removing excessive material. Today, we use different simulation tools like ANSYS for topology or shape optimization. During the traditional optimization, we perform the simulation, based on the available design limits and propose the best optimized design to the customer. This method doesn’t consider any uncertainty like manufacturing tolerances, material irregularities etc in the model. Hence the proposed design may not be said as a robust design. The proposed Robust Optimization Methodology takes into account the uncertainties and proposes the robust optimized design. Robust optimization has two stages. In the first stage, we need to calculate the standard deviation (sigma) of output results based on the uncertainty in input parameters. In the second stage, we use the calculated sigma and modify the optimization target based on the required confidence level (for e.g., 3*Sigma (σ) ➔ 99.73% Confidence level). In this paper we demonstrate the robust optimization methodology on a clutch damper drive plate and propose robust design which resulted in 15% reduction in weight.
Bhatta, Hari Venkata SantoshV, NaveenkumarKhajamohideen, Abdur-RasikCouturier, BenoitGanesan, Rajeshkumar
The Bharat Stage VI emission norms in India is driving the use of more complex after treatment systems for diesel engines, to meet the stringent emission limits. The after-treatment system typically includes theSelective Catalytic Reduction (SCR) catalyst and the Diesel Oxidation Catalyst (DOC) - Diesel Particulate Filter (DPF) systems to reduce engine out emissions of Nitrogen Oxides (NOx), hydrocarbons (HC), and particulates respectively. For a durable functioning of the aftertreatment system, cleaning of these components at regular intervals is required, the process termed as ‘regeneration’. The most common industry technique for regeneration is to use the existing injectors in the engine, to dose the extra fuel which is burnt in the DOC for regeneration. This has been a cost effective and simpler technique compared to the external hydrocarbon dosing system. But the tradeoff involved with this in-cylinder dosing technique is the risk of fuel in oil (FIO). The extra fuel injected impinges the cylinder wall and eventually get mixed with engine oil thereby diluting it. The diluted oil increases the risk of early wear and impacts the durability of the engine. This paper emphasizes on parameters impacting fuel in oil dilution due to regeneration, associated tradeoffs and some system level analysis of the same. Through six sigma, the various factors impacting FIO is studiedexperimentally using a mid-range diesel engine in an engine dynamometer. Study also considers impact of regen frequency and application level impact on oil drain interval for some on-highway commercial vehicle applications. A system level approach is formulated to understand FIO which can be used in the early phase of design and calibration of aftertreatment system.
Vinay P, AshwynVerma, UtkarshGoswami, ImonSuresh, Swathy
Aerostructures assembly (ASA) is a vital process in any aircraft production phase that integrates individual detail parts, sub-assemblies, major assemblies, components, and systems into a final deliverable, a completed aircraft structure fit for flight. ASA in an aircraft’s entire product life cycle represents more than half the cost and time that is a significant portion of the total aircraft production cost. ASA depends on highly skilled manual labor work across the global aerospace supply chain for various assembly processes and subprocesses required for assembling detail parts into sub-assemblies and components to achieve the design intent of the load-carrying aerostructure that is airworthy for the complete operational cycle till disposal of an aircraft. The assembly processes can significantly impact quality, safety, and reliability and can affect an aircraft structure’s performance and design intent. To mitigate the increase in defects due to non-standardization and to fulfill the need for robust process designs of the assembly processes, this technical paper proposes the enhancement of the 6M methodology as a Design for Assembly (DfA) tool for developing both detailed process designs and robust Compliance Assessment Guidelines (CAG) for evaluating the performance of these assembly processes. The 6M methodology is proposed as an Aerospace Design for Assembly (ADfA) tool using the Design For Six Sigma (DFSS) approach to Define, Measure, Analyze, Design, and Validate (DMADV) the requirements of the ASA process designs. The 6M enhanced framework is used to create as a process design tool, and the outputs of the research are converted in assessment guidelines, which were validated by a global aerospace accreditation body for its adoption in the aerostructures supply chain. This paper can also be used as a reference guide by ASA engineers to readily identify the factors that can impact any process, ensuring the highest quality and reliable aerostructures products to customers ensuring cost-effective On-Time Delivery (OTD).
Rajamani, Mani Rathinam
Design for Six Sigma (DFSS) is an essential tool and methodology for innovation projects to improve the product design/process and performance. This paper aims to present an application of the DFSS Taguchi Method for an automotive/vehicle component. High-Pressure Vacuum Assist Die Casting (HPVADC) technology is used to make Cast Aluminum Front Shock Tower. During the vehicle life, Shock Tower transfers the road high impact loads from the shock absorber to the body structure. Proving Ground (PG) and washout loads are often used to assess part strength, durability life and robustness. The initial design was not meeting the strength requirement for abusive washout loads. The project identified eight parameters (control factors) to study and to optimize the initial design. Simulation results confirmed that all eight selected control factors affect the part design and could be used to improve the Shock Tower's strength and performance. Non-dynamic analysis Smaller-the-Better (STB) was used for this project with the primary objective of reducing stress in part, which contributes to the higher durability life. The number of Simulation decks was generated using the L18 Orthogonal Array. Optimized front shock tower design met the strength requirement for 10% higher magnitude washout loads. The Optimum Design improved part robustness by 9.6 dB (actual) compared to the initial design. Key control factors that will enhance part strength are; shock tower material type, rib thickness, material addition at the rib/collar junction, spacer plate gauge/diameter and collar height. One of the project's objectives was to study the effect of several Shock Tower materials for this application, including HPDC alloys such as Aural-2, Silafont-36, Magsimal-59 and magnesium AM60B, which showed improvement in part strength and durability. Besides, the strength and ductility of AM60 material can be further improved by adopting the High-Pressure Supper Vacuum Die Casting process.
Hanamshet, MadhavMahadule, Roshan NMichalowski, Krzysztof
Vehicle suspension parts are subjected to variable road loads, manufacturing process variation and high installation loads in assembly process. Seam welding can be considered as such process to connect more components and parts. Typical in a Mc Pherson suspension system stabilizer bar link is connected to the strut assembly through ball stud and clamped to a bracket welded to the outer strut tube. Cracks have been observed in the stabilizer bar link bracket welds of vehicles in the field, effecting the functionality of the suspension system. During preliminary phase of product development CAE assessment of the seam weld is carried out against road load data, if the design does not meet the targets enabler studies are carried out in an iterative approach. Various design variables (control factors) can be considered to carry out the iterations. Design for Six Sigma (DFSS) and Taguchi approach are used to carry out a parametric design study of the weld attachment to quantify the effect of various control factors over fatigue life. This can quantify the relation and weight factor of each control factor or variables effecting the fatigue life. A study performed using Taguchi approach can provide an optimized design solution which can provide better fatigue life performance against higher road loads.
Pilla, SashankaAppana, Kameshwara RaoDatta, Sandip
Roof is one of the major subsystems of the Body-In-White Structure, which significantly affects the vehicle strength and durability performance criteria. The roof structure should meet the functional targets under the standard operating conditions. Roof design considering various parameters in the initial phase is beneficial in reducing the product timeline for the OEM. The first-time right approach provides an opportunity for Optimization and Cost benefits in the longer term. This paper provides the use of Design for Six Sigma techniques to arrive at a robust and optimum design for the standard roof structure. The roof structure is designed to meet the operating conditions for durability. Roof finite element models are developed with control factors that affect the structure design. Virtual Analysis is performed on the Standard roof structure models. Roof Performance is the contribution of multiple factors such as roof material, thickness, number of roof bows, positioning of the bows, number of beads in the roof, section and height of the roof bows. The paper looks at the contribution of each factor and shows how the combination of one or more factors can be effectively used to design an optimum and robust design that is light weight under the vehicle operating conditions. Standard roof is designed for Snow Load conditions. The final robust and optimized finite element design is validated for other durability loading conditions.
Srinivasan, SabarinathanMahadule, Roshan NPankaj, AnantaFahir, Ahamed
For new aircraft production, initial production typically reveals difficulty in achieving some assembly level tolerances which in turn lead to non-conformances at integration. With initial design, tooling, build plans, automation, and contracts with suppliers and partners being complete, the need arises to resolve these integration issues quickly and with minimum impact to production and cost targets. While root cause corrective action (RCCA) is a very well know process, this paper will examine some of the unique requirements and innovative solutions when addressing variation on large assemblies manufactured at various suppliers. Specifically, this paper will first review a completed airplane project (Project A) to improve fuselage circumferential and seat track joins and continue to the discussion on another application (Project B) on another aircraft type but having similar challenges. The use of Project A and B is used here to ensure proprietary protection of internal and supplier propriety information. One particularly innovative idea on both these projects is implementation of statistical process control for product acceptance as this provided and continues to provide additional incentive to invest more aggressively in quality improvements. For Project A, costs across the build cycle were overlaid with process capability to not only focus corrective action but also enlighten the program as to where increasing tolerances allowed focus on where it was really needed and avoid “false alarm”. This paper will detail how process capability requirements were adjusted to balance manufacturing capability with engineering requirements. For the Project B, this paper will review how these same principles are currently being applied to a fixed leading edge in concert with six sigma to address out of control variation.
Hall, Thomas D.
The aerospace industry had recently initiated the journey towards the transition to the Advanced Product Quality Planning (APQP) process, for the manufacturing and assembly process of their products in their supply chain, aiming to continually meet the rising delivery demand of the global aerospace industry and improve the quality and costs of current products and services. Of the various APQP process elements and requirements, one specific requirement is the application of Design For Manufacturing and Assembly (DFMA®) guidelines, early in the product design and development phase, aiming to design, develop, and analyze the designs for effective and efficient product realization. These guidelines, though widely used, are fairly new for the aerospace industry, and there is no standard framework readily available to aerospace organizations for the successful deployment of these guidelines in the Aerospace APQP process. The study in this technical paper is a continuation of the research work carried out on the enhanced Design For Manufacture (DFM) guidelines in the aerospace industry and focuses on the development of such a framework derived from the existing APQP and DfMA models that can be specifically enhanced to suit aerospace processes for the implementation and sustenance of the DFMA® guidelines in the Aerospace APQP product design and development phase. The study focuses on the importance of the framework for the application of DfMA principles in aerospace designs, highlighting the design intents, actions, and sources that support the design goals. The study analyzes the current challenges and opportunities that the design and supplier organizations can mitigate and adapt for a successful APQP transition from the current traditional manufacturing and assembly processes appropriate for all aerospace product designs and services. The framework methodology is developed using the Design For Six Sigma (DFSS) concept by defining, measuring, analyzing, designing, and validating the DfMA guidelines for successful implementation and sustenance in an aerospace environment. The framework proposed can be tested in an aerospace design manufacturing environment and used as a reference guide for organizations intending to effectively apply and sustain the DfMA element in the Aerospace APQP Phase 2 of Product Design and Development.
Rajamani, Mani RathinamPunna, Eshwaraiah
The main components present in the clutch disc assembly are friction facing, metallic disc, damper spring, drive plate, retainer plate, washers and hub. Among the parts, metallic disc is the weakest component present in the clutch system and moreover it is subjected to higher fatigue load during the vehicle operating condition. Hence it is necessary to make the design as more robust to withstand the worst loading conditions. The metallic disc is subjected to axial load, torque, speed and axial misalignment during vehicle operating condition. Through bench test, it was observed that higher severity in metallic disc was due to axial misalignment. Initially, metallic disc was tested for axial misalignment condition up to failure through bench test and the number of cycles were determined. Structural simulation was simulated as the same as bench test using ANSYS workbench 19.2. From this better correlation arrived between FEA and bench test. To make FEA result more robust, tolerance study was done using six sigma methodology. Therefore, this Numerical method was useful to obtain a sturdy design of metallic disc without investing much time through bench test. Optimization study was performed on metallic disc by considering all the possible design parameters without affecting the functionality of the component. A Novel Y shaped design profile was introduced in the metallic disc to increase the life cycle of the component, which is the main novelty of the current research work. This design pointed 15% and 20% reduction in stress and 10% and 62% least stiffness when equated with the initial design for gearbox side (GBS) and flywheel side (FWS) respectively. Hence the Novel Y shaped design was considered as robust design for the current disc assembly of the automotive application.
M, AnnamalaiM S, BrightantoV, NaveenkumarS, AvinashN, Sriram
The ongoing global demand for greater energy efficiency plays an essential role in vehicle development, especially in the case of electric vehicles (EVs). The thermal management of the full vehicle is becoming increasingly important, since the Heating, Ventilation, and Air Conditioning (HVAC) system has a significant impact on the EV range. Therefore the EV design requires new guidelines for thermal management optimization. In this paper, an advanced method is proposed to identify the most influential cabin design factors which affect the cabin thermal behavior during a cool down drive cycle in hot environmental conditions. These parameters could be optimized to reduce the energy consumption and to increase the robustness of the vehicle thermal response. The structured Taguchi’s Design for Six Sigma (DFSS) approach was coupled with CFD-Thermal FE simulations, thanks to increased availability of HPC. The first control factors selected were related to the thermal capacity of the panel duct, dashboard, interior door panels and seats. Surface IR emissivity and solar radiation absorptivity of these components were then added to the study. Car glass with absorptive and reflective glazing were finally included in the study. The design space of 18 vehicle configurations was simulated in spring and hot summer conditions, with steady state thermal simulations. A 2-step optimization was then conducted, trying first to increase the robustness of the cabin response and, secondly, to reduce the equivalent temperature actually felt by passengers. The Verify phase was then conducted on the Best Engineering design emerged by the 2-step optimization, through quasi-transient CFD-Thermal FE analyses. The thermal results were then sent to a CFD 1D energy prediction model, confirming the HV battery energy saving and the extended range reached during the cool down drive cycle.
Piovano, Andrea AlessandroScantamburlo, GiuseppeQuaglino, MassimoGautero, Matteo
It is a challenging task to find an optimal design concept for a truck frame structure given the complexity of loading conditions, vehicle configurations, packaging and other requirements. In addition, there is a great emphasis on light weight frame design to meet stringent emission standards. This paper provides a framework for fast and efficient development of a frame structure through various design phases, keeping durability in perspective while utilizing various weight reduction techniques. In this approach frame weight and stiffness are optimized to meet strength and durability performance requirements. Fast evaluation of different frame configurations during the concept phase (I) was made possible by using DFSS (Design for Six Sigma) based system synthesis techniques. This resulted in a very efficient frame ladder concept selection process. Frame gauge optimization during the subsequent development phase (II) utilizing a newly developed damage based approach greatly reduced the number of design iterations relative to a typical stress based approach. In the light weighting phase (III) that followed, a method was established to effectively locate and optimize lightening holes using fatigue damage contours. In the final optimization phase (IV) custom Python® scripts were developed to optimize weld lengths at joints. This whole framework provides a fast and efficient way to optimize a frame structure for durability.
Thandhayuthapani, ChandraLin, BarryMao, JianghuiByali, RaghavendraNaik, Venkatesh
In this paper we present an integrated approach which combines analysis of the effect of simultaneous variations in model input parameters on component or system temperatures. The sensitivity analysis can be conducted by varying model input parameters using specific values that may be of interest to the user. The alternative approach is to use a structured set of parameters generated in the form of a DFSS DOE matrix. The matrix represents a combination of simulation conditions which combine the control factors (CF) and noise factors. CF’s are the design parameters that the engineer can modify to achieve a robust design. Noise factors include parameters that are outside the control of the design engineer. In automotive thermal management, noise factors include changes in ambient temperature, exhaust gas temperatures or aging of exhaust system or heat shields for example. The integrated approach, presented in this paper, provides powerful tools that can significantly reduce the total simulation time and helps to provide robust thermal protection scenarios. The relative importance of the CF’s can be estimated, and the least costly but effective design can therefore be considered. An example is illustrated for optimization of catalytic converter design in order to reduce its impact on surrounding component temperatures.
El-Sharkawy, AlaaSami, AmrArora, DipanHekal, Abd El-Rahman
Robust engineering is an integral part of the quality initiative, Design For Six Sigma (DFSS), in most companies to enable good designs and products for reliability and durability. Taguchi’s signal-to-noise ratio has been considered as a good performance index for robustness for many years. An alternate approach that is direct and simple for measuring robustness is proposed. In this approach, robustness is measured in terms of an augmented output response and it is a composite index of variation and efficiency of a system. This formulation represents an engineering design intent of a product in a statistical sense, so engineers can understand, communicate, and resonate at ease. Robust formulations are illustrated and discussed with case studies for smaller-the-better, nominal-the-best, and dynamic responses. Confirmation runs of optimization show good agreement of the augmented response with the additive predictive models.
Chinta, Balakrishna
Active grille shutter (AGS) in a vehicle provides aerodynamic benefit at high vehicle speed by closing the front-end grille opening. At the same time this causes lesser air flow through the cooling module which includes the condenser. This results in higher refrigerant pressure at the compressor outlet. Higher head pressure causes the compressor to work more, thereby possibly negating the aerodynamic benefits towards vehicle power consumption. This paper uses a numerical method to quantify the compressor power consumed in different scenarios and assesses the impact of AGS closure on total vehicle energy consumption. The goal is to analyze the trade-off between the aerodynamic performance and the compressor power consumption at high vehicle speeds and mid-ambient conditions. These so called real world conditions represent highway driving at mid-ambient temperatures where the air-conditioning (AC) load is not heavy. AC system is modeled using 1D methodology and its performance simulated at system level. Net power consumed by the vehicle is computed for different scenarios using a robust comparison methodology. System model is validated against vehicle drive cell test data. Tests are conducted on a mid-size sport utility vehicle (SUV) equipped with a full face AGS. Simulations are then performed with the validated model using a Design for Six Sigma (DFSS) methodology to compute net power consumed by the vehicle by varying the blower setting, vehicle speed and ambient temperature. This paper provides guidelines regarding when to have the AGS closed or open for different noise factors considered.
Natarajan, ShankarMirzabeygi, PooyaWestra, MichaelSrinivasan, Kumar
Since the electronic shift lever detent system is used in vehicles on a large scale, it is urgent to solve the problem of robustness parameter design of the shift quality of SLDS under the uncertain dynamic parameters and manufacturing tolerances. We Build the MBD model of shift lever detent system, selecte the evaluation indicator for shifting quality and propose a two-stage method which associates the deterministic optimization of grey relational grade with the robustness parameter optimization of six sigma, in the early stage of product quality design. We use the grey relational grade to take the place of SNR in deterministic optimization, and compute the the optimal combination of controllable factors and their levels. The controllable parameters of shift lever detent system include three parameters that determine the detent profile structure parameters, spring parameters and contact pair parameters. The deterministic optimization of grey relational grade provides initial values for the six sigma optimization, and the six sigma optimization solves the problem of tolerance design of controllable factors under the uncertainty of noise factors in further. The test results of the experiment validate the rationality and correctness of the MBD model of shift lever detent system, the selected controllable parameters, and the two-stage optimization method. The results also prove these models, parameters and methods, which can solve the problem of robust design of the shift quality. What's more, The two-stage method proposed in this paper is more applicable to the problem of dynamic robust design with discrete-continuous parameters.
Xie, JipengYang, GuolaiSun, QuanzhaoGe, JianliHuang, Xinghao
Vehicle suspension parts are subjected to variable road loads, manufacturing process variation and high installation loads in assembly process. These parts must be robust to usage conditions to function properly in the field. Design for Six Sigma (DFSS) tools and Taguchi Method were used to optimize initial rear suspension trailing arm design. Project identified key control factor/design parameters, to improve part robustness at the lowest cost. Optimized design performs well under higher road loads and meets stringent durability requirements. This paper evokes use of Taguchi Method to design robust rear suspension trailing arm and study effect of selected design parameters on robustness, stress level/durability and part cost.
Kathoke, SunilMichalowski, KrzysztofSubramani, VinothkumarKorba, AhmedArchak, VijayThakare, Sameer
SUV Aerodynamics has received increased attention as the stake this segments holds in the automotive market keeps growing year after year, as well as its direct impact on fuel economy. Understanding the key physics in order to accomplish both fuel efficient and aesthetic products is paramount, which indeed gave origin to a major initiative to foster collaborative aerodynamic research across academia and industry, the so-called DrivAer model. In addition to this sedan-based model, a new dedicated SUV generic model, called AeroSUV [1], has been introduced in 2019, also intended to provide a common framework for aerodynamic research for both experimental work and numerical simulation validation. The present paper provides an area of common ground for SUV bodywork design focused on aerodynamic drag reduction by investigating both Estate and Fast back configurations of the generic AeroSUV model. Modified bodywork geometries focused at the rear end as well as spoiler angles, are evaluated using OpenFOAM Delayed Detached Eddy Simulations (DDES) utilising a Design for Six Sigma (DFSS) approach, such that not only a sensitivity study of drag response is yielded, but a ranking in terms of the potential for drag savings in certain areas of the car, is produced.
Barrera, DavidGuzman, Arturo
Nowadays development of automotive HVAC is a challenging task wherein thermal comfort and safety are very critical factors to be met. HVAC system is responsible for the demisting and defrosting of the vehicle’s windshield and for creating/maintaining a pleasing environment inside the cabin by controlling airflow, velocity, temperature and purity of air. Fog or ice which forms on the windshield is the main reason for invisibility and leads to major safety issues to the customers while driving. It has been shown that proper clear visibility for the windshield could be obtained with a better flow pattern and uniform flow distribution in the defrost mode of the HVAC system and defrost duct. Defroster performance has received significant attention from OEMs to meet the specific global performance standards of FMVSS103 and SAE J902. Therefore, defroster performance is seriously taken into consideration during the design of HVAC system and defroster duct. The HVAC unit provides hot air to the defroster duct which is blowing high velocity air to the windscreen to clear the frosting. Currently as a traditional defrost duct design process, multiple flow simulation needs to be carried out for various design configurations of defrost duct through CFD analysis until the performance targets are achieved during the design cycle and it is very time consuming. In this paper, the focus is to develop defrost duct modelling using parameterization technique and optimize the defrost duct system to meet the performance requirements through robust optimization Design for Six Sigma (DFSS) methodology to reduce the design time, cost, size and weight of the system. Parametric modelling technique is used for designing the defrost duct through design software to reduce the design time for simulation. A 3-dimensional model (3D) of a car cabin with full a HVAC system was developed using Star-CCM+® to predict the performance of the system in the windshield. DFSS methodology helps in finding out the optimized design factors of defrost duct to meet the performance targets such as pressure drop, airflow and velocity at windshield aim points simultaneously. The optimized defrost duct design results were compared with the baseline defrost duct design results and the improvement in performance results is achieved by more than 60%.
Khan, MohsinValencia, ManuelGarikipati, NagababuMarginean, Calin
An Aircraft’s assembly process plays a vital part in its design, development and production phases and contributes to about half of the Total cost spent in its entire product lifecycle. Design For Assembly (DFA®) principles have been one of the proven effective methodologies in Automotive and Process industries. Use of DFA® principles have resulted in proactively simplifying and optimizing engineering designs with reduced product costs, and improved efficiencies in product design and performance. Standardization of Assembly guidelines is vital for “Design and Build” and “Build-To-Print” manufacturing supplier organizations. However, Standardizing design methodologies, through use of proven tools like Advanced Product Quality Planning, (APQP) are still in the initial stages in Aerospace part and process design processes. Thus, there is a tremendous opportunity for research on the application of the existing DFA® guidelines to optimize Engineering Aerospace Assembly processes aiming to simplify, standardize design methodologies by building on existing industry practices which have a common platform for design communication and are easy to adopt within the existing process/systems. This technical paper is to discuss the framework for application of DFA® principles and design guidelines specifically aimed for engineering optimization of Aerospace Assembly Process Designs. The Aerospace DFA® implementation framework proposed in this paper is based on the study on the application of the existing DFA® guidelines proven and used in other Process industries to Aerospace Part and Process Design and development. This paper collates the findings, experiences and learnings gained during the study collated from a research point of view using Six Sigma methodology DMAIC and DMADV. This paper also focuses on the use and publication of this research outputs on Aerospace industry applicable DFA® guidelines, which can be used as a reference for emerging Aerospace designers in their future and current designs.
Rajamani, Mani RathinamPunna, Eshwaraiah
Multi-layered, high-density polyethylene (HDPE) fuel tanks are increasingly being used in automobiles due to advantages such as shape flexibility, low weight and corrosion resistance. Though, HDPE fuel tanks are perceived to be safer as compared to metallic tanks, the material properties are influenced by service temperature. At higher temperatures (more than 80oC), plastic fuel tanks can soften, sag and eventually spill out the fuel, while the extreme cold (less than -20°C) can lead to potential cracking problems. Damage may also occur due to accidental drop while handling or due to an impact from a flying shrapnel. This can be catastrophic due to flammability of the fuel. The objective of this work is to characterize and develop a failure model for the plastic fuel tank material to simulate damage and enhance predictive capability of CAE for chassis and safety load cases. Different factors influencing the material properties such as service temperature, rate of deformation, state of stress etc. were considered to develop a characterization and modelling strategy for the HDPE fuel tank material. Samples cut-out from different regions of the fuel tank were subjected to various tests such as tensile test at different strain rates viz. 0.01/s, 0.1/s, 1/s, 10/s and 100/s, compression, shear, flexure and instrumented dart impact tests at different temperatures, -40°C, 23°C and 85°C. Simulation of damage was accomplished via progressive damage and failure modeling capability available in ABAQUS. Ductile damage initiation criteria and equivalent plastic displacement for damage evolution were considered. The parameters of the failure model were optimized using Design for Six Sigma (DFSS) principles. The material model was validated by comparing simulation results with test at coupon and component levels.
R L, Vijaya KumarTripathy, BiswajitRadhakrishnan, Jayaraj
The Catalytic Converter along with the inlet pipe and heat shields are part of the exhaust system that emits powerful heat to the surrounding components. With increasing need for tight under-hood spaces it is very critical to manage the heat emitted by the exhausts that may significantly increase temperature of surrounding components. In this paper a design methodology for catalytic converter has been applied which optimizes the design of the catalytic converter to reduce the surface temperature. The exhaust surface temperature is simulated as a function of time to account for transient effects. The simulation also considers various duty cycles such as road load, city traffic and grade driving conditions. To control the heat output of the exhaust system to the surrounding components different materials and properties of catalytic converter have been considered to reduce radiative heat transfer. The most influential design factors for the catalytic converter which affect the surface temperature of the exhaust system have been identified with this process. The paper summarizes the optimization steps necessary to meet the optimal functional goals for the vehicle as mentioned above. Taguchi's Design for Six Sigma (DFSS) methods have been employed to conduct this analysis in a robust way.
El-Sharkawy, AlaaArora, DipanHuxford, Michael W.
PHEV Real World Driving Cycle Energy and Fuel and Consumption Reduction Potential for Connected and Automated Vehicles2019-01-03074/2/2019
This paper presents real-world driving energy and fuel consumption results for the second-generation Chevrolet Volt plug-in hybrid electric vehicle (PHEV). A drive cycle, local to Michigan Technological University, was designed to mimic urban and highway driving test cycles in terms of distance, transients and average velocity, but with significant elevation changes to establish an energy intensive real-world driving cycle for assessing potential energy savings for connected and automated vehicle (CAV) control. The investigation began by establishing baseline and repeatability of energy consumption at various battery states of charge. It was determined that drive cycle energy consumption under a randomized set of boundary conditions varied within 3.6% of mean energy consumption regardless of initial battery state of charge. After completing 30 baseline drive cycles, a design for six sigma (DFSS) L18 array was designed to look at sensitivity of a range of parameters to energy consumption as related to connected and automated vehicles to target highest return on engineering development effort. The parameters explored in the DFSS array that showed the most sensitivity, in order of importance, were battery state of charge, vehicle mass, propulsion system thermal conditioning, HVAC setting and driver behavior. Each of these areas are explored for energy savings and discussed briefly in the context of CAV control opportunity for energy savings potential.
Robinette, DarrellKostreva, EricKrisztian, AlexandraLackey, AnthonyMorgan, ChristopherOrlando, JoshuaRama, Neeraj
Automotive HVAC Dual Unit System Cool-Down Optimization Using a DFSS Approach2019-01-08924/2/2019
Automotive AC systems are typically either single unit or dual unit systems, while the dual unit systems have an additional rear evaporator. The refrigerant evaporates inside these heat exchangers by taking heat and condensing the moisture from the recirculated or fresh air that is being pushed into the car cabin by air blowers. This incoming cold air in turn brings the cabin temperature and humidity to a level that is comfortable for the passengers. These HVAC units have their own thermal expansion valve to set the refrigerant flow, but both are connected to the main AC refrigerant loop. The airflows, however, are controlled independently for front and rear unit that can affect the temperature and amount of air coming into the cabin from each location and consequently the overall cabin cool-down performance. The goal of this paper is to find the optimal configuration of an AC system to achieve maximum cool down by investigating the effect of parameters such as distribution of air between the front and rear unit, front and rear evaporator, TXV settings, etc. This study uses a Design for Six Sigma (DFSS) approach to identify the best combination of system components and air distributions that achieve the goal of optimized AC performance. This strategy can guide the engineers to design more efficient HVAC systems that are optimized to meet the requirements of the AC system and passenger comfort. A 1D numerical model, using Siemens’ LMS Imagine. Lab AMESim 15, is developed to predict the AC system performance for these different system configurations. Both the refrigerant side and the air side components including the cabin are modeled and validated against the vehicle test data.
Mirzabeygi, PooyaKhawaja, AamirGovindarajalu, MuraliJoshi, Sumant
Robustness and Variability Prediction of Seat Vibration Caused by All-Wheel Drive System Imbalance in Vehicle Development2018-01-14846/13/2018
During the vehicle development process in the premium and luxury automotive segments an important task is the refinement of noise, vibration and harshness. Along with other attributes such as styling, drivability and vehicle dynamics it strongly influences the overall perception of the vehicle. At the same time the automotive manufacturers need to release more products faster to the market using shorter vehicle development time with reduced cost. Altogether this has increased the use of virtual models and decreased the number of test vehicles in the programs. When assembling vehicles in production there will be a natural variation, which will result in a spread in the attribute performances. When shifting towards virtual models and reduced numbers of physical test vehicles there is a higher risk that the variations in production will be neglected, leading to more customer complaints. The question is if the production variability could be predicted before start of production by taking the component variability and assembly process into account early on in the vehicle development phase. This paper demonstrates a methodology how this could be performed for an all-wheel drive system. The all-wheel drive system imbalance can give vibrations in the steering wheel and seats and also induce a low frequency noise. This is a typical case where a robust solution needs to be considered. The imbalance could be reduced by balancing components and/or the assembly in the production. However, this will increase the cost and therefore the benefit of these solutions must be quantified before they are introduced. The paper will demonstrate that using a Design For Six Sigma, DFSS, approach the vehicle robustness can be predicted. Before their introduction, the effects of two proposals for reducing imbalance of the all-wheel drive system have been quantified. The results have also been verified by testing 30 cars in running production.
Olsson, MagnusSchwartz, JesperFransson, Mikael
Drive cycles have been an integral part of emission tests and virtual simulations for decades. A drive cycle is a representation of running behavior of a typical vehicle, involving the drive pattern, road characteristics and traffic characteristics. Drive cycles are typically used to assess vehicle performance parameters, perform system sizing and perform accelerated testing on a test bed or a virtual test environment, hence reducing the expenses on road tests. This study is an attempt to design a relatively robust process to generate a real world drive cycle. It is based on a Six Sigma design approach which utilizes data acquired from real world road trials. It explicitly describes the process of generating a drive cycle which closely represents the real world road drive scenario. The study also focuses on validation of the process by simulation and statistical analysis.
Kondaru, Murali KrishnaTelikepalli, Kumar PrasadThimmalapura, Satish VPandey, Nabal Kishore
The automotive Air Induction System (AIS) is an important part of the engine systems which delivers the air to the engine. A well-designed AIS should have low flow restriction and radiates a good quality sound at the snorkel. The GT-Power simulation tool has been widely utilized to evaluate the snorkel noise in industry. In Fiat Chrysler Automobiles, the simulation method enhanced with Design For Six Sigma (DFSS) approach has been developed and implemented in AIS development to meet the functional requirements. The development work included different types of DFSS projects such as identifying new concept, robust optimization and robust assessment etc. In this paper, the work of a robust optimization project is presented on developing an AIS parametric model to achieve optimized snorkel noise performance for a V8 engine. First, the theory of AIS acoustic modeling using GT-power and DFSS robust optimization using Taguchi’s parameter design method are described. Secondly, the effects of several AIS design control factors on the AIS sound attenuation and snorkel performance are studied. Finally, the eight steps of Taguchi’s parameter design method are presented on developing a parametric AIS model for a V8 engine. Based on the results from the verification step, an optimized AIS parametric model to this specified V8 engine is suggested. The optimized model is more robust against temperature variation and has better snorkel noise performance. The lessons learned from this project and future work are discussed in the conclusion section.
Zhang, WeiguoLikich, MarkButler, Brian
Process Parameters play a vital role in product quality of Injection Molded components. Variation in process parameters will lead to Injection Molded manufacturing defects like Sink Mark, Flow Mark, Silver Streak, Flash, Warping, Weld lines, Jetting, voids, Short Shot & Bubbles. This manuscript is innovative because suppliers (Tier 1 and Tier 2) do not use DoE for standardization of their process parameters in Injection Molding and High Pressure Die Casting. They do trial and error method to arrive at the process parameters which is error prone and time consuming. The variation of process parameters can be optimized using Six Sigma approach, a structured methodology which is Process focused & data driven approach. The purpose of this paper is to present through a case study how the concepts of Design of Experiments, which is a part of Six Sigma Methodology can be used for improving the Injection Molding Process at supplier end reducing defects & hence improving Quality at supplier which stops 100% BOP inspection and segregation when the parts reach the OEM. Here one of the products in Motorcycle Industry has been taken which has 100% Sink Mark defect & resulting in 100% rework. By following the six sigma DMAIC approach and using tools like SIPOC, PMAP, Fish Bone Diagram, Cause and Effect Matrix & Design of experiments to optimize the process parameters at supplier Injection Molding Machine through cross functional team approach. The result has proved that the quality of the product in automotive Industry can be improved by using Six Sigma Approach. This approach can be used for all suppliers and all OEMs or can be horizontally deployed in the Injection Molding Process and High Pressure Die Casting Process to reduce defects and improve product quality by reducing process variation.
Shankaranarayana, Raviprakash
Indian Automobile Industry has started using Six Sigma for Vehicle Design and process improvement to compete with Global competition. This Paper describes how the Tools of Six Sigma shall be used as an Effective Tool for both redefining the Design and the Process Improvement. This Paper talks on the evolution of DMADV approach in Indian Automobile Industry compared to the related Trends in Other Manufacturing Sectors. The Author describes how the warranty failures in Commercial Segment Vehicle Category which was the selling talk for the Competition was addressed in Leading Indian Automobile OEM. As this Failure was adversely impacting customer satisfaction and no solution seemed forthcoming, top Management indicated to use a radically different approach to solve the problem within a years’ time. Among the different processes evaluated, DMADV six sigma approach brought in a creative approach to problem solving and improved systematic team work between the supplier, manufacturing function and R&D function, which were based in different demographic locations, with different work culture. This approach resulted in the goal of 10x warranty failures reduction being achieved within 10 months, besides monetary saving to the Organisation.
Jaswal, Anil KumarChandrasekaran, PradeepRamadoss, Surendran
Motivation - Ambiguous product targets, a global market, innovation pressure, changing process requirements and limited resources describe the situation for engineering management in the most R&D organizations. Achieving complex objective with limited resources is a question of performance. Performance in engineering departments is highly correlated to the existing capability of the engineering staff. When the reduction of engineering effort in development projects becomes additional goal for the management, an increase of engineering productivity is required. International engineering sites are established globally to push the capacity limits and to increase the productivity by the accessing big employment markets of engineering talents. By solving the conflict of limited resources and complex engineering goals, a need organizational challenge occurs - global co-engineering. Co-engineering is the extension of simultaneous engineering by the distribution of tasks and responsibilities in a global organization. Different to other global enterprise functions, like sales, the individual engineering staff takes over global responsibilities independent of their own localization. Systems are designed, constructed, implemented or tested in one region for the product release in a different region. Contribution - This technical report analyzes the challenges of engineering management in a global co-engineering environment. The relevance and value of a transparent organization overview is described and derived. The Organization Architecture (OA) is explained as tool to achieve the required transparency of globally distributed roles and responsibilities. The relevance of the organization structure is distinguished from the process structure required for product quality (acc. Six Sigma) or process maturity (acc. SPICE). The method to introduce, maintain and use of the Organization Architecture is described, including the nomenclature for the organizational elements. The benefits of the OA along those phases are evaluated in an industry use-case. The typical organizational optimizations - identified by the OA - are introduced and explained. The limitations of the OA for optimization of engineering organizations are explained. The possible combination of the OA with other management methods for R&D are discussed.
Koark, Fabian Jorg UweKorandla, Arvind
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