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Viewing 31 to 60 of 15302
2017-03-28
Technical Paper
2017-01-0164
Venkatesan Muthusamy, S. Sathish Kumar, Saravanan Sambandan
Abstract In an automotive air-conditioning (AC) system, upfront prediction of the cabin cool down rate in the initial design stage will help in reducing the overall product development (PD) time. Vehicle having higher seating capacity will have higher thermal load and providing thermal comfort to all passengers uniformly is a challenging task for the automotive HVAC (Heating Ventilation and Air conditioning) industry. Dual HVAC unit is generally used to provide uniform cooling to a large cabin volume. One dimensional (1D) simulation is being extensively used to predict the HVAC performance during the initial stage of PD. The refrigerant loop with components such as compressor, condenser, TXV and evaporator was modeled. The complicated vehicle cabin including the glazing surfaces and enclosures were modeled as a three row duct system using 1D tool AMESim®. The material type, density, specific heat capacity and thermal conductivity of the material were specified.
2017-03-28
Technical Paper
2017-01-0275
N. Obuli Karthikeyan, N. Prajitha, P. Sethu Madhavan
Abstract As technology gets upgraded every day, automotive manufacturers are paying more attention towards delivering a highly reliable product which performs its intended function throughout its useful life (without any failure). To develop a reliable product, accelerated combined stress testing should be conducted in addition to the conventional design validation protocol for the product. It brings out most of the potential failure modes of the product, so that necessary actions can be taken for the reliability improvement. This paper discusses about the field failure simulation and reliability estimation of automotive headlamp relays using accelerated combined stress testing. To analyze various field failure modes, performance and tear down analysis were carried out on the field failure samples. Field data (i.e. electrical, thermal and vibration signals) were acquired to evaluate normal use conditions.
2017-03-28
Technical Paper
2017-01-0260
Yuanying Wang, Heath Hofmann, Denise Rizzo, Scott Shurin
Abstract This paper presents a computationally-efficient model of heat convection due to air circulation produced by rotor motion in the air gap of an electric machine. The model calculates heat flux at the boundaries of the rotor and stator as a function of the rotor and stator temperatures and rotor speed. It is shown that, under certain assumptions, this mapping has the homogeneity property. This property, among others, is used to pose a structure for the proposed model. The coefficients of the model are then determined by fitting the model to the results of a commercial Computational Fluid Dynamics (CFD) simulation program. The accuracy of the new model is compared to the CFD results, shown an error of less than 0.3% over the studied operating range.
2017-03-28
Technical Paper
2017-01-0320
Xiao Qing Zhang, Yuxian Han, Emma Huang, An Bo Pan, Ashley Walsh, Xinhua Zhang, Xiyang Yu, Lisong Wang
Abstract Customer expectations for improved performance, comfort levels, and aesthetics have led automobile manufacturers to use leather for seats, steering wheels, instrument panels, door panels, and other components. To increase the drivers’ comfort level, there is always a soft pad layer applied under the leather in the steering wheel. This paper will describe a potential failure mode that occurs when materials migrate from one material to another material in multilayer material constructions. In this case dioctyl phthalate migrated from the soft pad layer into the leather surface, affecting the durability performance of the leather coating. This paper describes the failure and demonstrates an effective test methodology to test for this failure during the materials and components validation process.
2017-03-28
Technical Paper
2017-01-0321
Silvio César Bastos
Abstract This case study describes improvements to the pin grinding and superfinishing processes for a 900-mm long, 60-kg forged crankshaft used in a six-cylinder diesel engine. Machining vibrations caused by the eccentricity of the mass of the pins in relation to the journals increase the difficulty of achieving a stable and capable process. Through analysis of the crankshaft and connecting rod assembly, an opportunity is identified to improve the pin profile along its 30-mm length. Based on measurements, it is found that, owing to variations of the order of 5 μm, the pin profile (nominally flat) may vary between a concave and a convex shape. Process improvements are focused on the grinding profile. The amplitude of the grinding profile is established between 0 and 5 μm, tending toward a convex shape. The practical implementation of the proposed improvements involves the imposition of a greater restriction on the extent of the grinding profile to 3.5 μm.
2017-03-28
Technical Paper
2017-01-0324
Anbo Pan, Ashley Walsh, Mark Dearth, Xiao Qing Zhang
Abstract Ford China had carried out a research project to validate the target compounds that lead to Chinese customers’ complaint about interior cabin odor. The aim of the study was to understand the sensitivity of the customers, using experimental design and determine which substances that are key contributors to customer odor concerns. In this research, acetaldehyde, toluene, xylene, ethylbenzene, acetone and butyraldehyde are used to conduct odor re-manufacture study through reconstituting their concentration in vehicles, it is concluded that compound classes aromatics, aldehydes, and ketones have direct relationship to the odor concerns in China.
2017-03-28
Technical Paper
2017-01-0352
Zhigang Wei, Limin Luo, Richard Voltenburg, Mark Seitz, Jason Hamilton, Robert Rebandt
Durability and reliability assessment of stress raisers is difficult in testing because the true deformation at a stress raiser often cannot be directly measured. Many approximate engineering approaches have been developed over the last decades, but further fundamental understanding of the problems and the development of more effective engineering methods are still strongly demanded. In this paper, several new concepts and engineering testing approaches are developed and introduced with the emphasis on thermal-fatigue assessment of welded structures.
2017-03-28
Technical Paper
2017-01-0371
Raju Gandikota, Amit Nair, Kurt Miller
Abstract Testing elastomeric materials that undergo large strains pose challenges especially when establishing failure criteria. The failure criterion for composites and polymers based on finite elasticity published by Feng (1) requires testing under uniaxial and biaxial stretching modes. The classic inflation of a circular disk for biaxial stretch mode poses stability and safety challenges. The test can also be sensitive to end constraints resulting in failure of materials at the constraints. Biaxial stretching with a hemispherical punch is explored in this work. The biaxial stretching allows controlled and repeatable testing. It establishes a clear and reliable failure mechanism of the material at the poles. Through a combination of testing and numerical methods, the stretch ratios and its relation to failure have been established. The method greatly simplifies testing and provides reliable data for a failure criterion for elastomers in numerical modeling.
2017-03-28
Technical Paper
2017-01-0341
Seyyedvahid Mortazavian, Javid Moraveji, Reda Adimi, Xingfu Chen
Abstract In this study, a finite element analysis method is developed for simulating a camshaft cap punching bench test. Stiffness results of simulated camshaft cap component are correlated with test data and used to validate the model accuracy in terms of material and boundary conditions. Next, the method is used for verification of cap design and durability performance improvement. In order to improve the computational efficiency of the finite element analysis, the punch is replaced by equivalent trigonometric distributed loads. The sensitivity of the finite element predicted strains for different trigonometric pressure distribution functions is also investigated and compared to strain gage measured values. A number of equivalent stress criteria are also used for fatigue safety factor calculations.
2017-03-28
Technical Paper
2017-01-0393
Keunsoo Kim
Abstract Fuel tank in vehicle must hold the fuel in a stable way under any driving condition. However, the fuel tank might not conserve the fuel firmly in case a crack emerged while the fuel tank is exposed to different driving condition. Basically, when the engine is in purging at a normal ambient temperature before fuel boiling, the pressure inside the fuel tank decreases. However, the pressure inside a fuel tank increases while a vehicle is driven at extreme hot ambient temperature as fuel is boiling. This repetitive pressure change in the fuel tank comes with fuel tank’s physical expansion and shrink, which would cause a damage to the fuel tank. The main purpose of this research is to investigate the root cause of why fuel tank cracks at a fatigue point. We also aim to set up the method of how to test durability of the fuel tank in association with the pressure inside the tank.
2017-03-28
Technical Paper
2017-01-0405
Tianqi Lv, Xingxing Feng, Peijun Xu, Yunqing Zhang
Abstract Three constitutive models which capture the amplitude and frequency dependency of filled elastomers are implemented for the conventional engine mounts of automotive powertrain mounting system (PMS). Firstly, a multibody dynamic model of a light duty truck is proposed, which includes 6 degrees of freedom (DOFs) for the PMS. Secondly, Three constitutive models for filled elastomers are implemented for the engine mounts of the PMS, including: (1) Model 1: Kelvin-Voigt model; (2) Model 2: Fractional derivative Kelvin-Voigt model combined with Berg’s friction; (3) Model 3: Generalized elastic viscoelastic elastoplastic model. The nonlinear behaviors of dynamic stiffness and damping of the mounts are investigated. Thirdly, simulations of engine vibration dynamics are presented and compared with these models and the differences between common Kelvin-Voigt model and other constitutive models are observed and analyzed.
2017-03-28
Technical Paper
2017-01-0402
Zhigang Zhang, Shi Xiaohui, Ye Bin
Abstract Based on the formation mechanism of engaging force of clutch, the engagement was divided into four stages: idle stage, cushion spring stage, diaphragm spring stage and locked stage. The mechanism of transmitted torque in each stage was analyzed and the transmitted torque model of clutch was deduced. Multi-load step analysis method based on finite element was used to analyze the coupling load-deformation characteristics of diaphragm spring and cushion spring in engagement, and the change laws of engaging force, diaphragm spring force and release bearing force were achieved and their coupling interaction were studied. And then change of friction coefficient of clutch with oscillating temperature was measured on friction test rig, and effect of temperature on transmitted torque was further discussed. Finally, simulation results of transmitted torque were validated by the experiment. Results indicate that the transmitted torque in clutch engagement has a nonlinear characteristic.
2017-03-28
Technical Paper
2017-01-0381
L. Karthik, R. Dinesh Kumar, E. Prasanna Kumar, V. Srinivasa Chandra
Abstract This abstract work describes a method of data acquisition and validation procedure followed for a metal bumper used in commercial vehicle application. Covariance is considered as major phenomenon for repeatable measurements in proving ground data acquisition and it is to be maintained less than 0.05. In this project covariance of data acquisition is analyzed before physical simulation of acquired data. In addition to that, multiple testing conditions like uni-axial and bi-axial testing were carried out to attain the failure. PG data is used for bi-axial vibration test and conventional constant spectrum signal (CSD signal) is used for uni-axial vibration test. Target duration for uni-axial test (Z direction) was arrived using pseudo damage calculation. Strain gauges were installed in failure locations to compare PG data and rig data as well as to calculate strain life. Failures were simulated in bi-axial vibration test.
2017-03-28
Technical Paper
2017-01-0004
Norbert Wiechowski, Thomas Rambow, Rainer Busch, Alexander Kugler, Norman Hansen, Stefan Kowalewski
Abstract Modern vehicles become increasingly software intensive. Software development therefore is critical to the success of the manufacturer to develop state of the art technology. Standards like ISO 26262 recommend requirement-based verification and test cases that are derived from requirements analysis. Agile development uses continuous integration tests which rely on test automation and evaluation. All these drove the development of a new model-based software verification environment. Various aspects had to be taken into account: the test case specification needs to be easily comprehensible and flexible in order to allow testing of different functional variants. The test environment should support different use cases like open-loop or closed-loop testing and has to provide corresponding evaluation methods for continuously changing as well as for discrete signals.
2017-03-28
Technical Paper
2017-01-0544
Philipp Mayr, Gerhard Pirker, Andreas Wimmer, Markus Krenn
Abstract It is critical for gas and dual fuel engines to have improved transient characteristics in order that they can successfully compete with diesel engines. Testing of transient behavior as well as of different control strategies for the multi-cylinder engine (MCE) should already be done on the single cylinder engine (SCE) test bed during the development process. This paper presents tools and algorithms that simulate transient MCE behavior on a SCE test bed. A methodology that includes both simulation and measurements is developed for a large two-stage turbocharged gas engine. Simple and fast models and algorithms are created that are able to provide the boundary conditions (e.g., boost pressure and exhaust back pressure) of a multi-cylinder engine in transient operation in real-time for use on the SCE test bed. The main models of the methodology are discussed in detail.
2017-03-28
Technical Paper
2017-01-0536
William Goodwin, Claudio Mancuso, Nicolas Brown
This paper describes how distributive computing along with statistical subsystem simulation can be applied to produce near production ready embedded vehicle software and calibrations. Coupling distributive computing and statistical simulation was first employed over a decade ago at General Motors to design and analyze propulsion subsystem hardware. Recently this method of simulation has been enhanced extending its capabilities to both test embedded vehicle code as well as develop calibrations. A primary advantage of this simulation technique is its ability to generate data from a statistically significant population of subsystems. The result is the acquisition of an optimal data set enabling the development of a robust design now including both embedded code and calibrations. Additionally it has been shown that there are significant economic advantages in terms of time and cost associated with this type of development when compared to traditional method.
2017-03-28
Technical Paper
2017-01-0534
Bojan S. Jander, Roland Baar
Abstract The knowledge of thermal behavior of combustion engines is extremely important e.g. to predict engine warm up or to calculate engine friction and finally to optimize fuel consumption. Typically, thermal engine behavior is modeled using look-up tables or semi-physical models to calculate the temperatures of structure, coolant and oil. Using look-up tables can result in inaccurate results due to interpolation and extrapolation; semi-physical modeling leads to high computation time. This work introduces a new kind of model to calculate thermal behavior of combustion engines using an artificial neural network (ANN) which is highly accurate and extremely fast. The neural network is a multi-layered feed-forward network; it is trained by data generated with a validated semi-physical model. Output data of the ANN-based model are calculated with nonlinear transformation of input data and weighting of these transformations.
2017-03-28
Technical Paper
2017-01-0738
Akhilendra Pratap Singh, Avinash Kumar Agarwal
Abstract Premixed charge compression ignition (PCCI) combustion is an advanced combustion technique, which has the potential to be operated by alternative fuels such as alcohols. PCCI combustion emits lower oxides of nitrogen (NOx) and particulate matter (PM) and results thermal efficiency similar to conventional compression ignition (CI) engines. Due to extremely high heat release rate (HRR), PCCI combustion cannot be used at higher engine loads, which make it difficult to be employed in production grade engines. This study focused on development of an advanced combustion engine, which can operate in both combustion modes such as CI combustion as well as PCCI combustion mode. This Hybrid combustion system was controlled by an open engine control unit (ECU), which varied the fuel injection parameters for mode switching between CI and PCCI combustion modes.
2017-03-28
Technical Paper
2017-01-0745
R. Vallinayagam, S. Vedharaj, Yanzhao An, Alaaeldin Dawood, Mohammad Izadi Najafabadi, Bart Somers, Bengt Johansson
Abstract This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON = 46). The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar to account for the difference in fuel properties between naphtha and diesel. Single injection strategy is employed and the fuel is injected at a pressure of 800 bar. Photron FASTCAM SA4 that captures in-cylinder combustion at the rate of 10000 frames per second is employed. The captured high speed video is processed to study the combustion homogeneity based on an algorithm reported in previous studies. Starting from late fuel injection timings, combustion stratification is investigated by advancing the fuel injection timings. For late start of injection (SOI), a direct link between SOI and combustion phasing is noticed.
2017-03-28
Technical Paper
2017-01-0764
Gabriele Di Blasio, Giacomo Belgiorno, Carlo Beatrice
Abstract The paper reports the results of an experimental campaign aimed to assess the impact of the compression ratio (CR) variation on the performance and pollutant emissions, including the particle size spectrum, of a single cylinder research engine (SCE), representatives of the engine architectures for automotive application, operated in dual-fuel methane-diesel mode. Three pistons with different bowl volumes corresponding to CR values of 16.5, 15.5 and 14.5 were adopted for the whole test campaign. The injection strategy was based on two injection pulses per cycle, as conventionally employed for diesel engines. The test methodology per each CR included the optimization of both 1st injection pulse quantity and intake air mass flow rate in order to lower as much as possible the unburned methane emissions (MHC).
2017-03-28
Technical Paper
2017-01-1417
Enrique Bonugli, Richard Watson, Mark Freund, Jeffrey Wirth
Abstract This paper reports on seventy additional tests conducted using a mechanical device described by Bonugli et al. [4]. The method utilized quasi-static loading of bumper systems and other vehicle components to measure their force-deflection properties. Corridors on the force-deflection plots, for various vehicle combinations, were determined in order to define the system stiffness of the combined vehicle components. Loading path and peak force measurements can then be used to evaluate the impact severity for low speed collisions in terms of delta-v and acceleration. The additional tests refine the stiffness corridors, previously published, which cover a wide range of vehicle types and impact configurations. The compression phase of a low speed collision can be modeled as a spring that is defined by the force-deflection corridors. This is followed by a linear rebound phase based on published restitution values [1,5].
2017-03-28
Technical Paper
2017-01-1239
Naoya Take, Takuya Kadoguchi, Masao Noguchi, Kimihiro Yamanaka
Abstract Power modules are used to operate three-phase alternating current motors in hybrid vehicles and electric vehicles. Good fuel efficiency and high power density are required in the field of hybrid vehicles. To achieve this goal, the miniaturization of the power module will be necessary. This trend may make a current density, which is created by insulated gate bipolar transistors (IGBTs) and free wheel diodes (FWDs), higher in power modules. Solder is often used as the joint material of power modules. It is known that a current density larger than 10 kA/cm2 causes solder electromigration. This phenomenon may cause delamination of the joint area. In addition, the ambient temperature has an influence on electromigration. The temperature of an engine compartment is high, so it is likely to cause electromigration. However, the current density of the double-sided cooling power modules in 2007 with solder joint is lower than 0.4 kA/cm2, and this value is lower than 10 kA/cm2.
2017-03-28
Technical Paper
2017-01-0003
Tetsuya Tohdo
Abstract We propose a verification method in the field of automotive control systems integrating the concepts of Formal Methods with testing, aiming at efficient and reliable software development. Although Formal Methods are believed to provide the benefits of their rigorous nature and their inherent capability of automation, only limited cases are known where Formal Methods were applied in system and software development, in practice, due to two major difficulties: appropriate abstraction in modeling and scalability in automated reasoning. Focusing on testing on the other hand, there is the difficulty of selecting reasonable set of tests for given verification objectives. In order to overcome these difficulties, our approach is to present verification criteria for testing to appropriately cover the property with the help of the Formal Method concepts.
2017-03-28
Technical Paper
2017-01-0174
Ravi Rungta, Noori Pandit
Abstract A simple and rapid immersion type corrosion test has been successfully developed that discriminates corrosion performance in condensers from various suppliers and with differing manufacturing processes. The goal is to develop a test specification that will be included in the Ford corrosion specification for condensers so that condensers received from various suppliers may be evaluated rapidly for their relative corrosion performance to each other. Sections from condensers from Supplier A (tube is silfluxed), Supplier B (tube is zinc arc sprayed), and Supplier C (bare folded tube with no zinc for corrosion protection) were tested in 2% v/v hydrochloric acid for 16, 24 and 48 hours. The results showed that in terms of corrosion performance, zinc arc sprayed Supplier B condenser performed the worst while Supplier C condenser performed the best with Supplier A in between.
2017-03-28
Technical Paper
2017-01-0166
Noori Pandit
Abstract The effects of substituting a 12 mm thick subcool on top condenser in place of a 16 mm subcool on bottom condenser are evaluated in a vehicle level AC pull down test. The A to B testing shows that a thinner condenser with subcool on top exhibits no degradation in AC performance while resulting in a lower total system refrigerant charge. The results are from vehicle level tests run in a climatically controlled vehicle level wind tunnel to simulate an AC pull down at 43°C ambient. In addition to cabin temperature and AC vent temperatures, comparison of compressor head pressures was also done. The conclusion of the study was that a standard 16 mm thick subcool on bottom IRD condenser can be replaced by a 12 mm thick subcool on top IRD condenser with no negative effects on performance.
2017-03-28
Technical Paper
2017-01-0626
LeeAnn Wang, George Garfinkel, Ahteram Khan, Mayur Harsha, Prashanth Rao
Abstract When a driver completes an aggressive drive cycle on a hybrid vehicle, the High Voltage (HV) battery system may be at risk of exceeding the power limit temperature, due to continuous absorption of radiative and convective heat from the environment, such as from exhaust and pavement, even after key-off. In such a case, in the absence of active cooling, the vehicle may not be keyed-on until battery temperatures are reduced below critical values. A transient thermal analysis is conducted on a HV battery system to simulate the key-off operation using an effective Computational Fluid Dynamics (CFD) methodology. Two stages are considered in this methodology to capture the complexity of the geometry and the multiple phenomena that need to be simulated in the model. The introduced modeling technique can be used for Full Hybrid Electric Vehicle (FHEV) and Plug-in Hybrid Electric Vehicle (PHEV) transient key-off situations.
2017-03-28
Technical Paper
2017-01-1671
Johannes Bach, Marc Holzäpfel, Stefan Otten, Eric Sax
Abstract Enhanced technological capabilities render the application of various, increasingly complex, functional concepts for automated driving possible. In the process, the significance of automotive software for a satisfactory driving experience is growing. To benefit from these new opportunities, thorough assessment in early development stages is highly important. It enables manufacturers to focus resources on the most promising concepts. For early assessment, a common approach is to set up vehicles with additional prototyping hardware and perform real world testing. While this approach is essential to assess the look-and-feel of newly developed concepts, its drawbacks are reduced reproducibility and high expenses to achieve a sufficient and balanced sample. To overcome these drawbacks, new flexible, realistic and preferably automated virtual test methods to complement real world verification and validation are especially required during early development phases.
2017-03-28
Technical Paper
2017-01-1672
Siddartha Khastgir, Gunwant Dhadyalla, Stewart Birrell, Sean Redmond, Ross Addinall, Paul Jennings
Abstract The advent of Advanced Driver Assistance Systems (ADAS) and automated driving has offered a new challenge for functional verification and validation. The explosion of the test sample space for possible combinations of inputs needs to be handled in an intelligent manner to meet cost and time targets for the development of such systems. This paper addresses this research gap by using constrained randomization techniques for the creation of the required test scenarios and test cases. Furthermore, this paper proposes an automated constrained randomized test scenario generation framework for testing of ADAS and automated systems in a driving simulator setup. The constrained randomization approach is deployed at two levels: 1) test scenario randomization 2) test case randomization.
2017-03-28
Technical Paper
2017-01-1676
Hartmut Lackner
Abstract Software systems, and automotive software in particular, are becoming increasingly configurable to fulfill customer needs. New methods such as product line engineering facilitate the development and enhance the efficiency of such systems. In modern, versatile systems, the number of theoretically possible variants easily exceeds the number of actually built products. This produces two challenges for quality assurance and especially testing. First, the costs of conventional test methods increase substantially with every tested variant. And secondly, it is no longer feasible to build every possible variant for the purpose of testing. Hence, efficient criteria for selecting variants for testing are necessary. In this contribution, we propose a new test design method that enables systematic sampling of variants from test cases. We present six optimization criteria to enable control of test effort and test quality by sampling variants with different characteristics.
2017-03-28
Technical Paper
2017-01-1679
Felix Martin, Michael Deubzer
Abstract In the automotive industry a steady increase in the number of functions driven by innovative features leads to more complex embedded systems. In the future even more functions will be implemented in the software, especially in the areas of automatic driving assistance functions, connected cars, autonomous driving, and mobility services. To satisfy the increasing performance requirements, multi- and many-core controllers are used, even in the classic automotive domains. This case study has been conducted in the steering system domain, but the results can be applied to other areas as well. Safety critical functions of classic automotive domains must fulfill strict real-time requirements to avoid malfunctions, which can potentially endanger people and the environment. For this reason, ISO 26262 requires verification of the performance and timing behavior of system critical functions.
Viewing 31 to 60 of 15302