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Technical Paper

DC-Link Capacitor Sizing in HEV/EV e-Drive Power Electronic System from Stability Viewpoint

2020-04-14
2020-01-0468
Selection of the DC-link capacitance value in an HEV/EV e-Drive power electronic system depends on numerous factors including required voltage/current ratings of the capacitor, power dissipation, thermal limitation, energy storage capacity and impact on system stability. A challenge arises from the capacitance value selection based on DC-link stability due to the influence of multiple hardware parameters, control parameters, operating conditions and cross-coupling effects among them. This paper discusses an impedance-based methodology to determine the minimum required DC-link capacitance value that can enable stable operation of the system in this multi-dimensional variable space. A broad landscape of the minimum capacitance values is also presented to provide insights on the sensitivity of system stability to operating conditions.
Technical Paper

Road Noise Prediction Assessment Using CAE Instead of Costly and Time Consuming Physical Tests

2020-04-14
2020-01-0492
Virtual Product Development (VPD) with a vision to eliminate prototype testing is the recent trend in the automotive industry. Reducing the total vehicle development period with optimized output has been the major advantage of this new trend, fueled by increasing competition and shorter product life cycle. In this regard, Computer Aided Engineering (CAE) has taken a more significant role than ever in the vehicle development programs. Prediction of road noise in passenger cars is one of the important attributes to NVH (Noise Vibration Harness) Simulations. In the present work, CAE - NVH simulation of road noise is carried out on the finite element model of the vehicle, eliminating the costly and laborious test procedures & the process of awaiting information from various departments. One of the major challenges in these simulations are generating the load inputs for the structure-borne road noise in a cost and time saving method with accuracy.
Technical Paper

Study on the Characteristics of Different Intake Port Structures in Scavenging and Combustion Processes on a Two-Stroke Poppet Valve Diesel Engine

2020-04-14
2020-01-0486
Two-stroke engines have to face the problems of insufficient charge for short intake time and the loss of intake air caused by long valve overlap. In order to promote the power of a two-stroke poppet valve diesel engine, measures are taken to help optimize intake port structure. In this work, the scavenging and combustion processes of three common types of intake ports including horizontal intake port (HIP), combined swirl intake port (CSIP) and reversed tumble intake port (RTIP) were studied and their characteristics are summarized based on three-dimensional simulation. Results show that the RTIP has better performance in scavenging process for larger intake air trapped in the cylinder. Its scavenging efficiency reaches 84.7%, which is 1.7% higher than the HIP and the trapping ratio of the RTIP reaches 72.3% due to less short-circuiting loss, 11.2% higher than the HIP.
Technical Paper

Computational Analysis of Spray Pre-treatment in Automotive Applications

2020-04-14
2020-01-0479
The automotive coating industry consists of several processes targeting the reliability and longevity of the manufactured Body-In-White (BIW) with process optimization playing a key role. Pre-treatment of BIW is one of the important aspects and this involves processes in the paint shop and body-in-white shop. The relevance of cleaning every part of the BIW is well known in the industry, and we will focus on the spray wash processes. While the industry currently relies on experiences from previous designs and experimental observations from model studies, this drastically slows down process optimization for new car models. Recent developments in Computer Aided Engineering (CAE) industry has shown capability to perform reliable studies using computer models that speed up processes. The current study focuses on the Computational Fluid Dynamic (CFD) evaluation of spray washing of a BIW using a meshless method known as Smoothed Particle Hydrodynamics (SPH).
Technical Paper

The Modal and Stiffness Analysis of the White Body of the Truck Cab by Using the Finite Element Method

2020-04-14
2020-01-0484
The safety and comfort of the truck cab, as driver’s location, are significant to the driver, and the white body of the truck cab is an important part of the truck, whose modal and stiffness are directly impact its safety and comfort. Moreover, its modal and stiffness are the key factors that affect the performance of the car, which are also the important indicators that evaluate the ability of preventing fatigue failure and resisting deformation. In order to study whether the modal and stiffness of a truck cab can meet the working requirements, the white body of a truck cab was taken as the research object, and the finite element method (FEM) was chosen to study the modal and stiffness in this paper. The finite element model of the white body of this truck cab was established. The natural frequency and vibration model of white body were obtained by modal analysis. And the lowest frequency of the white body was 22.8Hz, obtained by modal analysis.
Technical Paper

Improved PSD Fatigue Approach for Large FE Models with Wide Frequency Range

2020-04-14
2020-01-0499
Fatigue damage calculations are traditionally based on the time domain approach. Acceleration time history inputs are used to excite the system and the outputs are in a form of stress time history. This transient dynamic approach, as time history is intuitive to understand, provides straightforward and reasonable result. Nevertheless, a typical automotive proving ground test consists of 20 to 30 road events, it is not only computationally intensive but could be also a grueling process for an engineer to carry out as it requires several iterations for each event in the schedule before fatigue calculation. Alternatively, a frequency domain fatigue calculation is widely used. In this approach, both the dynamic loading and response are expressed in terms of Power Spectral Density (PSD) functions and the dynamic structure is treated as a linear transfer function. The transfer function is then multiplied with the event PSD to get the PSD of the stress.
Technical Paper

Volume of Fluid vs. Cavitation CFD-Models to Calculate Drag Torque in Multi-Plate Clutches

2020-04-14
2020-01-0495
Wet-running multi-plate clutches and brakes are important components of modern powershift gearboxes and industrial powertrains. In the open stage, drag losses occur due to fluid shear. The identification of drag losses is possible by experiment or CFD-simulation. For the calculation of the complex fluid flow of an open clutch, CFD-approaches such as the volume of fluid (vof) method or the Singhal cavitation model are applicable. Every method has its own specific characteristics. This contribution sets up CFD-calculation models for different clutches with diverse groove designs. We present results of calculations in various operating conditions obtained from the Singhal cavitation model and the vof method. The usage of modern commercial CFD-Tools (Simerics MP+) results in short calculation times.
Technical Paper

A Method Using FEA for the Evaluation of Tooling and Process Requirements to Meet Dimensional Objectives

2020-04-14
2020-01-0497
Dimensional Engineering concentrates effort in the early design phases to meet the dimensional build objectives in automotive production. Design optimization tools include tolerance stack up, datum optimization, datum coordination, dimensional control plans, and measurement plans. These tools are typically based on the assumption that parts are rigid and tooling dimensions are perfect. These assumptions are not necessarily true in automotive assemblies of compliant sheet metal parts on high volume assembly lines. To address this issue, Finite Element Analysis (FEA) has been increasingly used to predict the behavior of imperfect and deformable parts in non-nominal tooling. This paper demonstrates an application of this approach. The complete analysis is divided into three phases. The first phase is a nominal design gravity analysis to validate the nominal design and tooling.
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 crankshafts are subjected to an induction heat treatment process for improving the operational life. Metallurgical phase transformations during the heat treatment process have direct influence on the hardness and residual stress. To predict the structural performance of a crankshaft using Computer Aided Engineering (CAE) early in the design phase, it is very important to simulate the complete induction heat treatment process. 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, a sequentially coupled electromagnetic and thermal model is developed to capture the resultant temperature distribution due to the rotation of the inductor coil.
Technical Paper

Method to Evaluate the Acoustic Performance of the Pillar Filler Foam in a Truck Cab

2020-04-14
2020-01-0505
The truck cab is made of many structural members like hinge, A/B/C - pillar, rocker, roof rails, headliner, quarter panels, cross-members at the floor and other body panels. For an acoustic example, the source energy travels easily from one end to another end through pillars. To reduce these acoustic effects, the filler foams were added inside the pillars. The proper usage of filler design and filler material type produces the optimal sound response at the driver head space location. In this paper, an analytical method is used to evaluate the acoustic performance of the fillers as described above and the method also avoids the expensive full vehicle tests. The statistical energy analysis (SEA) model simulations and post-processing techniques were used to evaluate the results quickly with an acceptable level of accuracy.
Technical Paper

Experimentation for Design Improvements for Coil Spring in the Independent Suspension

2020-04-14
2020-01-0503
The objective of this project is to analyze potential design changes that can improve the performance of helical spring in an independent suspension. The performance of the helical spring was based upon the result measure of maximum value of stress acting on it and the amount displacement caused when the spring undergoes loading. The design changes in the spring were limited to coil cross section, spring diameter (constant & variable), pitch and length of the spring. The project was divided into Stage I & Stage II. For Stage I, using all the possible combinations of these design parameters, linear stress analysis was performed on different spring designs and their Stress and displacement results were evaluated. Based on the results, the spring designs were classified as over designed or under designed springs.
Technical Paper

A Simulation Study of Rotating Impact within a Damper of Torque Converter

2020-04-14
2020-01-0500
It is common that angular velocities can be different from time to time between an engine output and transmission input, because both are connected by a damper in torque converter with flexible elements in it. When this difference occurs abruptly for some reasons, an internal impact could start between the engine-attached members (also known as driving members) and the transmission-attached members (or driven members). The resulting impact load could be several times the torque an engine’s combustion force can generate, depending on the impact energy. An impact load can be very devastating to a torque converter and other power-train members, just as to all other mechanical systems. This work presents a comprehensive and interesting study to help understand the rotational impact behavior for a system where none of bodies is stationary at the onset of impact.
Technical Paper

Occupant Dynamics during Moderate-to-High Speed Rear-End Collisions

2020-04-14
2020-01-0516
Numerous studies have evaluated occupant kinematics and dynamics in “low-speed” rear-end impacts (delta-V ≤ 8 mph). Occupant biomechanics during “moderate-to-high” speed rear impacts (9 ≤ delta-V ≤ 20 mph) has not been thoroughly examined. This study characterized the motions and forces experienced by the head, neck, torso, hip, and left/right femur during these collisions. The publicly available NHTSA rear-end crash test data were examined. More specifically, the FMVSS 301 Fuel System Integrity tests were used. The test procedure involved a 30 mph moving barrier impacting the rear of the vehicles. Instrumented 50th-percentile male (N = 47) or 5th-percentile female (N = 4) Hybrid III ATDs were positioned in the driver seat.
Technical Paper

Virtual Validation of BHL Dipper Using CAE and Correlation with Test Data

2020-04-14
2020-01-0515
Use of Computer Aided Engineering (CAE) tools for virtual validation has become an essential part of every product development process. Using CAE tools, accurate prediction of potential failure locations is possible even before building the proto. This paper presents a detailed case study of virtual validation of Backhoe Loader (BHL) dipper arm using CAE tools (MBD: Multi Body Dynamics and FEA: Finite Element Analysis) and comparison of simulation results with test data. In this paper, we have illustrated the modelling of Backhoe Loader in MSc ADAMS software. The detail ADAMS model was created and validated. The component mass, Center of Gravity (C.G) and Mass Moment of Inertia (MOI) was taken from CAD data. Trenching is simulated by operating the different hydraulic cylinders of the BHL. Loader arm cylinders and stabilizer cylinders are operated to lift the machine tires above the ground level.
Technical Paper

Rolling Element Bearings - Advanced Modeling for Multibody Simulations

2020-04-14
2020-01-0508
This paper focuses on the modeling of rolling element bearings, a key component that is responsible of transmitting the vibrations from the gear pairs to the surrounding structure while introducing additional excitation frequencies. The modeling techniques use the relative displacement of the rings to compute the corresponding reaction forces by calculating the equilibrium of each rolling element. To do so, the interaction between the rolling elements and the raceways can be modeled employing two different contact models depending on the level of accuracy required. The contact models are, respectively, a Hertz-based approach that allows for fast computations, and an EHL (Elasto-Hydrodynamic Lubricated) contact model which accounts for the effects of lubrication. The procedure to calculate the equilibrium of the rolling elements allows for grasping the main effects, including centrifugal loads and misalignments.
Technical Paper

Evaluation of Methods for Identification of Driving Styles and Simulation-Based Analysis of their Influence on Energy Consumption on the Example of a Hybrid Drive Train

2020-04-14
2020-01-0443
Due to current progresses in the field of driver assistance systems and the continuously growing electrification of vehicle drive trains, the evaluation of driver behavior has become an important part in the development process of modern cars. Findings from driver analyses are used for the creation of individual profiles, which can be permanently adapted due to ongoing data processing. A benefit of data-based dynamic control systems lies in the possibility to individually configure the vehicle behavior for a specific driver, which can contribute to increasing customer acceptance and satisfaction. In this way, an optimization of the control behavior between driver and vehicle and the resulting mutual system learning and -adjustment hold great potential for improvements in driving behavior, safety and energy consumption.
Technical Paper

Design and Optimization of a Muffler Integrated with an Adaptive Quarter Wave Tube for Noise Reduction in Commercial Vehicles

2020-04-14
2020-01-0507
With rising concerns on internal combustion engine noise levels in commercial vehicles, it is necessary to attenuate noises present in specific frequency bands. This can be achieved with the implementation of a quarter wave tube on the present exhaust system. Historically such passive attenuators have been efficient only at specific engine speeds and exhaust gas temperatures. A new folded adaptive quarter wave tube design is proposed here which can give significant noise attenuation at various engine operating conditions. The proposed design eliminates the requirement of complex electronic actuating mechanisms for the adaptive quarter wave tubes and replaces the same by perforated diaphragms and adjustable end plates, which are more robust and effective. The module can replace the turbo S-flow single chambered muffler which is installed on most of the commercial vehicles. A design is conceptualized and developed using CAD tools.
Technical Paper

Design of a Flexible Hybrid Powertrain Using a 48 V-Battery and a Supercapacitor for Ultra-Light Urban Vehicles

2020-04-14
2020-01-0445
Global warming has put the transport sector, a major contributor of CO2 emissions, under high pressure to improve efficiency. In this context, ultra-light vehicles weighting less than 500 kg, as well as hybrid powertrains, are nowadays seen as promising development trends. The design process of the powertrain of a vehicle combining the advantages of the two concepts is presented in this paper. Through a performance study based on a simple MATLAB model, and mathematical simulation, a proposal is made. A powertrain using a battery and supercapacitor 48V dual power source network, two electric motors and clutches to switch between conventional, parallel, series and full electric modes proves to be an interesting system in terms of performance and costs. A simulation study conducted on a scenario with different outcome possibilities showed that high modularity of the system allows to achieve fuel efficiencies equivalent to approximately 3 l/100 km on the Artemis cycle.
Technical Paper

Effects of Using an Electrically Heated Catalyst on the State of Charge of the Battery Pack for Series Hybrid Electric Vehicles at Cold Start

2020-04-14
2020-01-0444
Battery models are being developed as a component of the powertrain systems of hybrid electric vehicles (HEVs) to predict the state of charge (SOC) accurately. Electrically heated catalysts (EHCs) can be employed in the powertrains of HEVs to reach the catalyst light off temperature in advance. However, EHCs draw power from the battery pack and hence sufficient energy needs to be stored to power auxiliary components. In series HEVs, the engine is primarily used to charge the battery pack. Therefore, it is important to develop a control strategy that triggers engine start/stop conditions and reduces the frequency of engine operation to minimize the equivalent fuel consumption. In this study, a battery pack model was constructed in MATLAB-Simulink to investigate the SOC variation of a high-power lithium ion battery during extreme engine cold start conditions (-7°C) with/without application of an EHC.
Technical Paper

Eco-Vehicle Battery System Big-Data Analysis and Fault Mode and Fault Tree Analysis (FTA) Related Robust System Development

2020-04-14
2020-01-0447
High-voltage battery system plays a critical role in eco-friendly vehicles due to its effect on the cost and the electric driving range of eco-friendly vehicles. In order to secure the customer pool and the competitiveness of eco-vehicle technology, vehicle electrification requires lowering the battery cost and satisfying the customer needs when driving the vehicles in the real roads, for example, maximizing powers for fun drive, increasing battery capacities for achieving appropriate trip distances, etc. Because these vehicle specifications have a critical effect on the high-voltage battery specification, the key technology of the vehicle electrification is the appropriate decision on the specification of the high-voltage battery system, such as battery capacity and power. These factors affect the size of battery system and vehicle under floor design and also the profitability of the eco-friendly vehicles.
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