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Technical Paper

Development of GM 10-Speed Allison Heavy Duty (HD) Transmission

2020-04-14
2020-01-0438
This paper describes the development of GM 10-Speed Allison Heavy Duty (HD) Transmission. The trend of engine power and towing capacity in the automotive heavy-duty truck segment has been steadily climbing for a past 10 years. The development of GM 10-Speed Allison Heavy Duty Transmission is designed to be best in class for towing performance with no compromise in fuel economy. GM 10-Speed Allison Heavy Duty Transmission also gives the customers the option to order an integrated power transfer unit to improve the installation of power transfer or generation accessories. GM Allison HD truly brings the best of towing performance and fuel economy to the customers.
Technical Paper

Axle Efficiency Comparison Method and Spin Loss Benefit of Front Axle Disconnect Systems

2020-04-14
2020-01-1412
There are a variety of test protocols associated with vehicle fuel economy and emissions testing. As a result, a number of test protocols currently exist to measure axle efficiency and spin loss. The intent of this technical paper is to describe a methodology that uses a singular axle efficiency and spin loss procedure. The data can then be used to predict the effects on vehicle FE and GHG for a specific class of vehicles via simulation. An accelerated pre-conditioning method using a comparable energy approach has been developed, and can be used to meet the pre-conditioning requirements of different vehicle emission test protocols. A “float to equilibrium” sump temperature approach has been used to produce instantaneous efficiency data, which can be used to more accurately predict vehicle FE and GHG, inclusive of Cold CO2. The “float to equilibrium” approach and “fixed sump temperature” approach has been compared and discussed.
Technical Paper

Applications of Hardware-in-the-Loop Simulation in Automotive Embedded Systems

2020-04-14
2020-01-1289
Hardware-in-the-loop (HIL) simulation is an advanced technique for development and testing of complex real-time embedded systems. This technique has greatly developed in the last decades and has been more and more used in automotive industries for algorithm and software development, hardware validation, safety validation, and fault investigation activities. Plant simulation model executes in HIL simulator to provide a virtual vehicle that interacts in an open-loop or closed-loop way with the embedded system that is under test. Comparing to in-vehicle testing, HIL simulation provides benefits of low cost, high availability, high flexibility, repeatability, and test automation capability. HIL simulation reduces the risk caused by control failure, which is especially important for self-driving control system development and testing. The HIL simulation system is more application specific.
Technical Paper

Characterization of Seat Lateral Support as a Mechanical Behavior

2020-04-14
2020-01-0870
Seat lateral support is often talked about as a design parameter, but usually in terms of psychological perception. There are many difficulties in quantifying lateral support mechanically to the engineering teams: Anthropometric variation causes different people to interact with the seat in different places and at different angles, BPD studies are usually planar and don’t distinguish between horizontal support and vertical resistance to sinking in, most mechanical test systems are typically single-DOF and can’t apply vertical and horizontal loads concurrently, and there is scant literature describing the actual lateral loads occupants. In this study, we characterize the actual lateral loading on example seating (both driver and passenger, as passenger experience will become more important as autonomous vehicles evolve) from various sized/ shaped occupants according to dynamic pressure distribution.
Technical Paper

Dynamics of Water Crossover in Fuel Cell and Application to Freeze Driveaway Reliability

2020-04-14
2020-01-0853
Reliable drive away from frozen condition is one of the challenging design and control problem for fuel cell vehicles. Different approaches for warm-up from frozen conditions have been developed by OEMs, e.g. low voltage inefficient operation, or use of coolant heaters. However, most methods result in water generation in the fuel cell which risk icing and blocking the valves and rendering them nonfunctional till they thaw. One such valve is the anode drain valve which is needed to remove water that crosses over across the membrane to anode side. This work discusses characterization of dynamics of water buildup in anode subsystem via experiments on full scale systems, and development of an online estimator to detect onset of anode water crossover via open loop model and closed loop feedback. Building on this understanding, a control approach is prototyped for warm up and drive-away even with a frozen valve.
Technical Paper

Springback Prediction and Correlations for Third Generation High Strength Steel

2020-04-14
2020-01-0752
Third generation advanced high strength steels (3GAHSS) have superior properties combining high strength and good formability. They are increasingly used in automotive components for light weight and safety body structures. However, high strength usually introduces high springback that affects the dimensional accuracy. The ability to accurately predict springback in simulations is very important to reduce the cost in stamping trials and to promote 3GAHSS applications. In this work, systematic parametric studies and material models evaluations have been conducted on 980 MPa 3GAHSS steels. Case studies from full-scale industrial part stamping are provided and the predicted springback results are compared to the measured springback data. Key variables affecting the springback prediction accuracy are identified. Simulation practices are recommended to improve springback prediction accuracy and robustness.
Technical Paper

Downsized-Boosted Gasoline Engine with Exhaust Compound and Lean Advanced Combustion

2020-04-14
2020-01-0795
This article presents the experimental results obtained with a disruptive engine platform, designed to maximize the engine efficiency through a synergetic implementation of downsizing, high compression-ratio, and importantly exhaust-heat energy recovery in conjunction with advanced lean/dilute low-temperature type combustion. The engine architecture is a supercharged high-power output, 1.1-liter engine with two-firing cylinders and a high compression ratio of 13.5:1. The integrated exhaust heat recovery system is an additional, larger displacement, non-fueled cylinder into which the exhaust gas from the two firing cylinders is alternately transferred to be further expended. The main goal of this work is to implement advanced lean/dilute combustion while minimizing NOx emissions and addressing the transition between the operating modes. The combustion modes include well-mixed charge compression-ignition at low-load, and a mixed-mode combustion strategy at higher loads.
Technical Paper

Large Scale Multi-Disciplinary Optimization and Long-Term Drive Cycle Simulation

2020-04-14
2020-01-1049
Market demands for increased fuel economy and reduced emissions are placing higher aerodynamic and thermal analysis demands on vehicle designers and engineers. These analyses are usually carried out by different engineering groups in different parts of the design cycle. Design changes required to improve vehicle aerodynamics often come at the price of part thermal performance and vice versa. These design changes are frequently a fix for performance issues at a single performance point such as peak power, peak torque, or highway cruise. In this paper, the motivation for a holistic approach in the form of multi-disciplinary optimization (MDO) early in the design process is presented. Using a Response-surface Informed Transient Thermal Model (RITThM) a vehicles thermal performance through a drive cycle is predicted and correlated to physical testing for validation.
Technical Paper

Dynamic Impact Transient Bump Method Development and Application for Structural Feel Performance

2020-04-14
2020-01-1081
Road induced structural feel “vehicle feels solidly built” is strongly related to the vehicle ride. Excellent structural feel requires both structural and suspension dynamics considerations simultaneously. Road induced structural feel is defined as customer facing structural and component responses due to tire force inputs stemming from the unevenness of the road surface. The customer interface acceleration and noise responses can be parsed into performance criteria to provide design and tuning vehicle integration program recommendations. A dynamic impact bump method is developed for vehicle level structural feel performance assessment, diagnostics, and development tuning. Current state of on-road testing has the complexity of multiple impacts, averaging multiple road induced tire patch impacts over a length of a road segment, and test repeatability challenges.
Technical Paper

Investigation of Fracture Behavior of Deep Drawn Automotive Part affected by Thinning with Shell Finite Elements

2020-04-14
2020-01-0208
In the recent decades tremendous effort has been made in automotive industry to reduce vehicle mass and costs in order to improve fuel economy and develop safer vehicles than any other decades. An accurate modeling approach of sheet metal fracture behavior under plastic deformation is one of the key parameters affecting optimal vehicle development process. FLD (Forming Limit Diagram) approach which plays an important role in judging forming severity has been widely used in forming industry and localized necking is the dominant mechanism leading to fracture in sheet metal forming and crash events. FLD is known as limited only to deal with the onset of localized necking and could not predict shear fracture. Therefore it is essential to develop accurate fracture criteria beyond FLD for vehicle development.
Technical Paper

Minimizing Disturbance Detection Time in Hydraulic Systems

2020-04-14
2020-01-0263
In a hydraulic system, parameter variation, contamination, and/or operating conditions can lead to instabilities in the pressure response. The resultant erratic pressure profile produces reduced performance that can lead to hardware damage. Specifically, in a transmission control system, the inability to track pressure commands can result in various types of slip and disturbances to the driveline. Therefore, it is advantageous to identify such pressure events and take remedial actions. The challenge is to detect the condition in the least amount of time while minimizing false alarms. In this study, cross and auto-correlation techniques are evaluated for the detection of pressure disturbances. The performance of the detectors is measured in terms of speed of detection and robustness to: 1) measurement noise, and 2) disturbance parameter uncertainty (frequency and amplitude).
Technical Paper

Simple Robust Formulations for Engineers: An Alternate to Taguchi S/N

2020-04-14
2020-01-0604
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 since many decades. 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 the engineering design intent of a product in a statistical sense, so engineers can understand, communicate, and resonate at ease. Illustrative formulations with case studies are discussed with respect to smaller-the-better, nominal-the-best, and dynamic responses. Confirmation runs of optimization show good agreement of the augmented response with the predictive models that are based on the additivity principle.
Technical Paper

Corroborative Evaluation of the Real-world Energy Saving Potentials of InfoRich Eco-Autonomous Driving System

2020-04-14
2020-01-0588
There has been an increasing interest in exploring the potentials of reducing energy consumption of future connected and automated vehicles (CAVs). People have extensively studied various eco-driving implementation that leverages preview information provided by on-board sensors and connectivity, as well as the control authority enabled by automation. To quantitatively evaluate the benefits of eco-driving in a real-world setting is a challenging task. The regulatory standard driving cycles that are being used for exhaust emissions and fuel economy measurements are not truly representative of real-world driving. To adequately take into account the real-world or “off-cycle” driving behavior, this paper presents four collaborative evaluation methods: large-scale simulation, in-depth simulation, vehicle-in-the-loop test, and vehicle road test. These four approaches, each focuses on certain aspects, evaluate the real-world fuel economy benefits with different ranges and resolutions.
Technical Paper

Enhancing Engine Starting Performance using High-Power Density Brushless Starter

2020-04-14
2020-01-0459
Modern hybrid technologies, especially mild hybrid and Auto-Start-Stop, demand a starter with higher power, better performance, and much higher life cycles. Therefore a new design of the starter using brushless motor is proposed in this paper which improves the functions of the brush-type starter due to lower inertia, higher torque and wider power band capability of the brushless motor, especially at higher speeds. The overall integrated system includes the motor, inverter, controller packaged in the same form factor of the original assembly housing and can be dropped in the existing engine designs. The design as the example in this paper applies 48V and 4kW can also be applied to various voltages such as the widely standard 12V. This paper will describe in detail the functionalities of the over systems, the simulation and experimental results of the prototype on engine test fixture with a 4-cylinder engine, and application in a crossover vehicle.
Technical Paper

Conjugate Heat Transfer CFD Analysis of an Oil Cooled Automotive Electrical Motor

2020-04-14
2020-01-0168
This study brings to forefront the analysis capability of CFD for the oil-cooling of an Electric-Motor (E-Motor) powering an automobile. With the rapid increase in electrically powered vehicle, there is an increasing need in the CFD modeling community to perform virtual simulations of the E-Motors to determine the viability of the designs and their performance capabilities. The thermal predictions are extremely vital as they have tremendous impact on the design, spacing and sizes of these motors. In this paper, with the Simerics, Inc. software, Simerics-MP+®, a complete three dimensional CFD with conjugate heat transfer CHT model of an Electric Motor, including all the important parts like the windings, rotor and stator laminate, endrings etc. is created. The multiphase Volume of Fluid (VOF) approach is used to model the oil flow inside this motor.
Technical Paper

Random Vibration Fatigue Life Assessment of Transmission Control Module (TCM) Bracket Considering the Mean Stress Effect

2020-04-14
2020-01-0194
Random loads are experienced by many engineering systems/components such as the housing and the brackets mounted on the chassis of an automobile, wind blowing on the wind turbine blades, Printed Circuit Board (PCB) used in battery electric vehicles, fuel cell stacks mounted on housing of a fuel cell etc. In automotive systems, random load is caused due to unevenness of the road surface. As these loads are varying in nature, it could lead to the fatigue failure of systems experiencing such loads. To ensure structural integrity, they are designed considering random loads and commercially used FE software packages have the capabilities available to evaluate random vibration fatigue. While above mentioned systems undergo random loads during operation, there are other loads/stresses also acting on them such as assembly loads (bolt preload), residual stresses due to casting, static loads i.e. load due to belt or chain drive etc.
Technical Paper

N&V Component Structural Integration and Mounted Component Durability Implications

2020-04-14
2020-01-1396
Exterior component integration has presented competing integration challenges for suitable exterior styling, safety, N&V structural feel and component durability balanced performances. Industry standard practice of N&V vehicle mode mapping uses vehicle source, path and receiver considerations for component mode frequency placement. Mounted component mode frequency performance can have an influence on structural feel and durability performances. Component integration headwinds have increased with additional nonstructural component styling content, component size, component mass and added sensor modules. Based on first principles, the effective mass of exterior mounted components are increased due to the geometric overhang from structure. Component input vibration levels are compounded due to the cantilevered nature as well as relative positioning to the suspension and propulsion vehicle source inputs locations.
Technical Paper

Development and Correlation of Co-Simulated Plant Models for Propulsion Systems

2020-04-14
2020-01-1416
Model-based system simulations play a critical role in the development process of the automotive industry. They are highly instrumental in developing embedded control systems during conception, design, validation, and deployment stages. Whether for model-in-the-loop (MiL), software-in-the-loop (SiL) or hardware-in-the-loop (HiL) scenarios, high-fidelity plant models are particularly valuable for generating realistic simulation results that can parallel or substitute for costly and time-consuming vehicle field tests. Correlated plant models enable control algorithm variation studies and virtual calibration. In this paper, the development of a powertrain plant model and its correlation performance are presented. The focus is on the following modules of the propulsion systems: transmission, driveline, and vehicle. The physics and modeling approach of the modules is discussed, and the implementation is illustrated in Amesim software.
Technical Paper

Design for crashworthiness optimization using the meta-modeling technique with extended-HCA framework

2020-04-14
2020-01-0627
In most engineering design problems, it is either difficult or impossible to directly couple the analyzing tool (e.g., finite element analysis) with the optimization algorithms. For instance, in the design optimization for crashworthiness, the implicit relationship between the design parameters and the crash indicators are not generally available. Moreover, the computational cost associated with repeated explicit finite element analysis of a crash simulation is substantial. Therefore, surrogate modeling or meta-model-based analysis have been widely used to solve such optimization problems. Among the different techniques, Kriging meta-model has shown good accuracy for highly non-linear problems. In this study, the extended Hybrid Cellular Automaton (xHCA) framework is employed to design for targeting desired crash indicators (maximum intrusion and maximum deceleration).
Technical Paper

Simulation Methodology to Analyze Overall Induction Heat Treatment Process of a Crank Shaft to Determine Effects on Structural Performance

2020-04-14
2020-01-0506
Steel crankshaft are subjected to an induction heat treatment process for improving the operational life. Hence, to predict the structural performance of a crankshaft using Computer Aided Engineering early in the design phase, it’s very important to simulate the overall induction heat treatment process. Metallurgical phase transformations during the heat treatment process have direct influence on the hardness and residual stress. The objective of this study is to establish the overall analysis procedure, starting from capturing the eddy current generation in the crank shaft due to rotating inductor coils to the prediction of resultant hardness and the induced residual stress. In the proposed methodology, an electromagnetic analysis is performed first to capture the Joule heating due to the surrounding inductor coil carrying high frequency alternating current.
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