Criteria

Text:
Display:

Results

Viewing 1 to 30 of 15290
2017-03-28
Technical Paper
2017-01-0276
Lev Klyatis
This paper considers the situation in the laboratory testing: different stress types and accelerated testing, including accelerated reliability/durability testing, accelerated life testing, reliability testing, proving grounds, vibration, temperature, voltage, humidity, and others. In comparison with field situation, most of these testing simulate only one or part of the field input influences. One uses often not accurately the theory of physics-of-degradation process or failures for comparison of the field results with laboratory results. Thos situation will be considered with practical examples. It will be demonstrated that often used laboratory testing does not offer the possibility for successful prediction of product performance during service life As a result, there are many complaints, recalls, less profit than was predicted during design and manufacturing. It will be shown how one can improve this situation..
2017-03-28
Technical Paper
2017-01-0321
Silvio César Bastos
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 was identified to improve the pin profile along its 30 mm length. Based on measurements, it was found that, due to variations on the order of five microns, the pin profile (nominally linear) may vary between concave or convex shape. Process improvements were focused on the form grinding profile. The amplitude of the grinding profile was established between zero and five microns tending to convex shape.
2017-03-28
Technical Paper
2017-01-0134
Jan Eller, Heinrich Reister, Thomas Binner, Nils Widdecke, Jochen Wiedemann
There is a growing need for life-cycle data – so-called collectives – when developing components like elastomer engine mounts. Current standardized extreme load cases are not sufficient for establishing such collectives. Instead of using endurance testing data – which necessitates full vehicle on-road tests – a prediction methodology for component temperature collectives utilizing existing 3D CFD simulation models is presented. The method uses support points to approximate the full collective. Each support point is defined by a component temperature and a position on the time axis of the collective. Since it is the only currently available source for component temperature data, endurance testing data is used to develop the new method. The component temperature range in this data set is divided in temperature bands. Groups of driving states are determined which are each representative of an individual band.
2017-03-28
Technical Paper
2017-01-1555
Mirosław Jan Gidlewski, Krystof JANKOWSKI, Andrzej MUSZYŃSKI, Dariusz ŻARDECKI
Lane change automation appears to be a fundamental problem of vehicle automated control, especially when the vehicle is driven at high speed. Selected relevant parts of the recent research project are reported in this paper, including literature review, the developed models and control systems, as well as crucial simulation results. In the project, two original models describing the dynamics of the controlled motion of the vehicle were used, verified during the road tests and in the laboratory environment. The first model – fully developed (multi-mass, 3D, nonlinear) – was used in simulations as a virtual plant to be controlled. The second model – a simplified reference model of the lateral dynamics of the vehicle (single-mass, 2D, linearized) – formed the basis for theoretical analysis, including the synthesis of the algorithm for automatic control. That algorithm was based on the optimal control theory.
2017-03-28
Technical Paper
2017-01-0392
Dae-Un Sung, James Busfield, Yong Hyun Ryu
The vehicle elastomeric components such as engine mounts are aged and degraded by environmental loads during long term usage. These make the degradation of vehicle driving performance comparing with a new condition. In this study, the degradation of NVH (Noise, Vibration and Harshness) of used vehicles was analyzed. The main cause could be identified by the analysis of elastomers’ vibration insulation property changes. The properties changes of aged engine mounts were analyzed and compared with initial properties. The accelerated laboratory aging test mode was developed for simulating the degradation of engine mounts. Moreover, parametric study was carried out. The engineering design parameters of elastomers such as volume, thickness and loading types were identified to improve the thermal aging phenomenon.
2017-03-28
Technical Paper
2017-01-0623
Zun Wang, Yi Zhang, Christophe lenormand, Mohammed Ansari, Manuel Henner
Radiator thermal cycle test is a test method to check out the robustness of a radiator. During the test, the radiator is going through transient cycles that includes high and low temperature spikes. These spikes could lead to component failure and transient temperature map is the key to predict high thermal strain and failure locations. In this investigation, an accurate and efficient way of building a numerical model to simulate the transient thermal performance of the radiator is introduced. A good correlation with physical test result is observed on temperature values at various locations.
2017-03-28
Technical Paper
2017-01-0764
Gabriele Di Blasio, Giacomo Belgiorno, Carlo Beatrice
The paper reports the results of a wide experimental campaign aimed to assess the effects of the geometric compression ratio variation on the performance of light-duty diesel engines operated in dual-fuel NG-diesel mode in terms of fuel consumption, NVH and pollutant emissions. The single-cylinder research engine employed in the experimental campaign had a combustion system is representatives of a 2L automotive diesel engine for passenger cars. The test methodology was defined in order to analyse carefully the effects of the compression ratio, injection parameters and air throttling on the global performances and emissions, also in terms of emitted carbonaceous particles. Three pistons with different bowl volumes corresponding to compression ratio (CR) values of 16.5, 15.5 and 14.5 were selected for the whole test campaign.
2017-03-28
Technical Paper
2017-01-0626
LeeAnn Wang, George Garfinkel, Ahteram Khan, Mayur Harsha, Prashanth Rao
When a driver completes an aggressive drive cycle on a hybrid vehicle, the High Voltage (HV) battery system may risk exceeding the power limit temperature, due to continuous absorption of radiative and convective heat from the exhaust and pavement, even after key-off. In such case, the vehicle may not be keyed-on after a certain time. A transient thermal analysis is conducted on a HV battery system to simulate the key-off operation using Computational Fluid Dynamics (CFD). The analysis is partitioned into two stages, due to complex geometry and multiple phenomena captured in the model. The first stage involves two steady-state simulations. The first simulation is to model the HV battery system, during an aggressive drive cycle. The second simulation is to model the vehicle at an idle condition immediately after the aggressive drive cycle.
2017-03-28
Technical Paper
2017-01-1239
Naoya Take, Takuya Kadoguchi, Masao Noguchi, Kimihiro Yamanaka
Power modules are used to operate three-phase alternative motors in hybrid vehicles and electric vehicles. The good fuel efficiency and high power density are requested in the field of hybrid vehicles. To achieve this goal, the miniaturization of power module will be necessary. This trend may make current density, which is operated 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 which exchanges momentum from electrons to metallic atoms .This phenomenon may cause delamination of the joint area and void formation. 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.
2017-03-28
Technical Paper
2017-01-0341
Seyyedvahid Mortazavian, Javid Moraveji, Reda Adimi, Xingfu Chen
Engine camshaft cap components experience high number of fluctuating loads during engine operation. The problem is complicated in engines with variable cam timing, because the loading for these components are sensitive to engine valve timing (combustion phasing) which can lead to catastrophic overload or fatigue failures. Improving the design of these components using computer-aided tools can drastically reduce the cost and time to the market of the final acceptable design, by eliminating the number of physical prototypes. Hence, a decent and robust finite element analysis with representative load and boundary conditions can significantly reduce the premature failures in engine development. In this study, first a finite element analysis method is developed for simulating a cap punching bench test. Effect of punch radius and shape on the component stiffness is investigated and correlated with test data.
2017-03-28
Technical Paper
2017-01-0781
Philip Zoldak, Jeffrey Naber
In recent years, natural gas has been considered a replacement for diesel fuel in large bore engines, due to its low cost, high heating value and widespread availability. Stoichiometric premixed spark-ignition (SI), defined as port-fuel injection (PFI) of natural gas (NG) followed by SI close to top dead center (TDC), has traditionally been used as the main fuel delivery and combustion method for light and medium duty engines. However, premixed SI of NG results in inefficiencies in the intake process and combustion that is knock limited as boost and load are increased. Traditionally, high knock is addressed by spark timing retard. Spark timing retard can lead to misfires and low brake mean effective pressures. Thus premixed SI has limited low load use in heavy duty where compression ignition of diesel fuel remains dominant.
2017-03-28
Technical Paper
2017-01-1540
Yuri M. Lopes, Maxwell R. Taylor, Todd H. Lounsberry, Gregory J. Fadler
Typical production vehicle testing includes testing of a vehicle towing a trailer to evaluate powertrain thermal performance. In order to correlate tests with simulations, the aerodynamic effects of pulling a trailer behind a vehicle must be estimated. Since during real world conditions a vehicle encounters crosswinds most of the time, the effects of cross winds on the drag of a vehicle–trailer combination should be taken into account. Improving the accuracy of aerodynamic forces for a vehicle-trailer combination should in turn lead to improved simulations and a better prediction of thermal performance. In order to best simulate real world conditions, a study was performed using reduced scale models of an SUV and a pickup truck towing a medium size cargo trailer. The vehicle and trailer combinations were tested in a full scale wind tunnel.
2017-03-28
Technical Paper
2017-01-0865
Mark Walls, Michael Joo, Michael Ross
Liquefied petroleum gas (LPG) is commonly known as autogas when used as a fuel for internal combustion engines. Autogas is primarily made up of propane, but can contain small amounts of butane, methane and propylene. Autogas is not a new fuel for internal combustion engines, but as engine technology evolves, the properties of autogas can be utilized to improve engine and vehicle efficiency. With support from the Propane Education & Research Council (PERC), Southwest Research Institute (SwRI) performed testing to quantify efficiency differences with liquid autogas direct injection in a modern downsized and boosted direct-injected engine using the production gasoline fuel injection hardware. Engine dynamometer testing demonstrated that autogas produced similar performance characteristics to gasoline at part load, but could be used to improve brake thermal efficiency at loads above 12 bar BMEP.
2017-03-28
Technical Paper
2017-01-1220
Ahmad Arshan Khan
In an electrified vehicle, magnet temperature plays a critical role in determining optimal current control trajectory of an interior permanent magnet machine. Monitoring magnet temperature is a challenging task. In lab and various specialized applications, infrared sensors or thermocouples are used to measure the temperature. But it adds cost, maintenance issues and their integration to electric machine drives could be complicated. To tackle the issues due to sensor based methods, various sensor-less model based approaches are proposed in the literature recently such as flux observer, high-frequency signal injection, and thermal models, etc. Although magnet temperature monitoring received a lot of attention of researchers, very few papers give a detailed overview of the effects of magnet temperature on motor control from a controls perspective. In this paper, we will show the effect of the change in magnet temperature on Maximum Torque per Ampere control and Flux Weakening Control.
2017-03-28
Technical Paper
2017-01-1681
Kyaw Soe
This paper describes a test system for improving the completeness, representativeness (hence usage and effectiveness) of automotive E/E test benches (enables more testing). A proportion of testing for automotive electrical and electronics systems and components is conducted using E/E testing boards (“testboards”). These are table like rigs consisting of most or all electrical and electronic parts connected together as per a car/truck/van. A major problem is that the testing is conducted on the equivalent of a static vehicle: testboards lack basic dynamic elements such as a running engine, vehicle motion, environmental, component and fluid temperatures, etc. This limits the testing that can be carried out on such a testboard. One solution is to provide one (or more) facilities to simulate and stimulate the electrical/electronic signals needed to effectively replace these missing dynamic elements (such as engine speed, vehicle speed and power supply voltage fluctuations).
2017-03-28
Technical Paper
2017-01-1676
Hartmut Lackner
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 investigate the cost drivers of testing multivariable systems and define novel criteria to systematically sample variants for the purpose of testing. The presented criteria reduce the test effort by means of tested variants as well as executed test steps.
2017-03-28
Technical Paper
2017-01-0123
Saiful Bari
In general, diesel engines have an efficiency of about 35% and hence, a considerable amount of energy is expelled to the ambient air. In water-cooled engines, about 25%, 33% and 7% of the input energy are wasted in the coolant, exhaust gas, and friction, respectively. The heat from the exhaust gas of diesel engines can be an important heat source to provide additional power and improve overall engine efficiency. Studies related to the application of recoverable heat to produce additional power in medium capacity diesel engines (< 100 kW) using separate Rankine cycle are scare. To recover heat from the exhaust of the engine, an efficient heat exchanger is necessary. For this type of application, the heat exchangers are needed to be designed in such a way that it can handle the heat load with reasonable size, weight and pressure drop. This paper describes the study of a diesel generator-set attached with an exhaust heat recovery system.
2017-03-28
Technical Paper
2017-01-0371
Raju Gandikota, Amit Nair, Kurt Miller
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 byFeng (1) requires testing under uni-axial and bi-axial stretching modes. The classic inflation of a circular disk for bi-axial stretch mode poses stability and safety challenges. The test can also be sensitive to end constraints resulting in failure of materials at the constraints. Bi-axial stretching with a hemispherical punch is explored in this work. The bi-axial stretching allows controlled and repeatabletesting. It establishes 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 has been established.
2017-03-28
Technical Paper
2017-01-1259
Eduardo D. Marquez, John Stevenson, Ethan Dietrich, Douglas Nelson, Christopher Flake, Alexander Neblett, Samuel Reinsel
The Hybrid Electric Vehicle Team of Virginia Tech (HEVT) is modeling and testing powertrain components for a parallel plug-in hybrid electric vehicle (PHEV). The custom powertrain is being implemented in a 2016 Chevrolet Camaro for EcoCAR 3. The engine, a General Motors (GM) L83 5.3L V8 with Active Fuel Management (AFM) from a 2014 Silverado, is of particular importance for vehicle integration and functionality. The engine is one of two torque producing components in the powertrain. AFM allows the engine to deactivate four of the eight cylinders which is essential to meet competition goals to reduce petroleum energy use and greenhouse gas emissions. In-vehicle testing is performed with a 2014 Silverado on a closed course to understand the criteria to activate AFM. Parameters required for AFM activation are monitored by recording vehicle CAN bus traffic. Simulink models of the engine plant and SoftECU are developed to represent the operation of the engine system.
2017-03-28
Technical Paper
2017-01-0352
Zhigang Wei, Limin Luo, Richard Voltenburg, Mark Seitz, Jason Hamilton, Robert Rebandt
Thermal-fatigue performance assessment of components and systems is challenging due to the inherent complexities in mechanical and thermal loadings, material inhomogeneity, manufacturing inconsistency etc. Among all of possible failure modes, the fatigue and thermal-fatigue failures at stress raisers are of particular importance because they consist of the majority of failure modes in vehicle components and systems. Stress raisers in components include the welds, notches, and other material and geometry discontinuities. 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.
2017-03-28
Technical Paper
2017-01-1354
Timothy Morse, Michael Cundy, Harri Kytomaa
One potential fire ignition source in a motor vehicle is the hot surfaces of the engine exhaust system. These hot surfaces can come into contact with combustible liquids (such as engine oil, transmission fluid, brake fluid, gasoline, or diesel fuel) due to a fluid leak, or during a vehicle collision. If the surface temperature is higher than the hot surface ignition temperature of the combustible liquid in a given geometry, a fire can ignite and potentially propagate. In addition to automotive fluids, another potential fuel in post-collision vehicle fires is grass, leaves, or other vegetation. Studies of hot surface ignition of dried vegetation have found that ignition depends on the type of vegetation, surface temperature, and on the duration of contact. Ignition can occur at surface temperatures as low as 300 °C, if the vegetation is in contact with the surface for 10 minutes or longer.
2017-03-28
Technical Paper
2017-01-1042
Eric J. Passow, Paras Sethi, Max Maschewske, Jason Bieneman, Kimm Karrip, Paul Truckel
Current market demands in conjunction with increased emission legislation's, have OEM’s striving to improve fuel economy and reduce CO2 emissions. One way to meet these demands, is through engine downsizing. Engine downsizing allows for reduced pumping and frictional losses. However, to maintain drivability, specifically in trucks and SUV's, power density increase through the addition of either a turbocharger or supercharger is necessary. Furthermore, engine efficiencies have been improved through reduced engine speed, paired with high gear count transmissions, providing an opportunity for manufactures to achieve desired drivability (strong acceleration coupled with fuel efficient high gears for cruising). With these advancements taken to improve engine/vehicle efficiency, gasoline turbo charge direct injected (GTDI) engines operate at low engine speeds with high torque output.
2017-03-28
Technical Paper
2017-01-1682
Matthew von der Lippe, Mark Waterbury, Walter J. Ortmann, Bernard Nefcy, Scott Thompson
The FMEA and DV&PV process of developing automotive products requires identifying and repeatedly testing critical vehicle attributes and their response to noise factors that may impair vehicle function. Ford Electrified Powertrain Engineering has developed a new process and an automated scripting tool to streamline in-vehicle robustness testing and produce more accurate and repeatable results. Similar noise factors identified during the FMEA process are grouped together, condensed, and scripts are developed to simulate these noise factors using calibration parameters and vehicle controls. The automated testing tool uses the ATI Vision API and a graphical scripting interface to consistently simulate driver inputs with greater precision than a human calibrator and enable more sophisticated controls, which would have previously required experimental software builds.
2017-03-28
Technical Paper
2017-01-1226
Nurani Chandrasekhar, Chun Tang, Natee Limsuwan, Joel Hetrick, Jacob Krizan, Zhichun Ma, Wei Wu
Noise and Vibration signature of an electric machine is an outcome of complex interaction between various source level disturbances like torque ripple and radial magnetic force and the surrounding structure to which the motor is attached. These can be radiated directly from the motor housing and also can be transmitted through the structural attachments (stator bolts, mounts etc.). The stator excitation current is not perfectly sinusoidal but contains different levels of harmonics. Harmonics impact Torque ripple, which in turn could translate into undesirable Motor noise. This paper addresses the impact of torque ripple on Motor whine noise. In this work, the electric machine torque ripple was computed based on the stator current that was measured during Motor dyno testing at prescribed torque and speed levels. The Motor NVH under specific torque levels was measured through testing in an anechoic transmission dynamometer cell.
2017-03-28
Technical Paper
2017-01-1383
Satheesh Kumar Chandran, James Forbes, Carrie Bittick, Kathleen Allanson, Fnu Brinda
There is a strong business case for automotive interfaces to undergo usability testing throughout their product development life cycle. System Usability Scale (SUS) is a simple and standard measure of usability. To meet the timing needs for product development, usability testing needs to be performed in a quick, cost effective manner. Hence the required sample size of participants for a usability study is one of the critical factors. To determine an acceptable sample size, a Monte Carlo simulation using SUS scores from eleven different in-vehicle automotive interface usability studies was used to create 500,000 sub-samples of different sample sizes. The percentage of sub-samples with mean scores within the confidence interval of the population mean was calculated. At a sub-sample size of thirty five, 95% of the sub-samples have a mean SUS score within the 95% confidence interval of the population mean.
2017-03-28
Technical Paper
2017-01-0260
Yuanying Wang, Heath Hofmann, Denise Rizzo, Scott Shurin
The increasing electrification of military vehicles is also increasing the need for accurate models of electric motors and generators for use in powertrain design. In particular, there is a strong need to accurately model the internal temperatures of these machines. Thus, an accurate yet computationally-efficient thermal model is required. In previous work, a technique capable of dramatically reducing the order of a 3-dimensional finite-element (FE) thermal conduction model was developed. The developed model has acceptable accuracy but is orders of magnitude faster than the FE model. This new model was validated by a locked-rotor test with close agreement, but the results are unsatisfactory when the rotor is spinning, since the resulting heat convection behavior is not precisely modeled. This paper will present a computationally-efficient model of heat convection due to air circulation produced by rotor motion.
2017-03-28
Technical Paper
2017-01-0160
Longjie Xiao, Tianming He, Gangfeng Tan, Bo Huang, Xianyao Ping
In the background of the increasing amount of car ownership in the world, the amount of heat that is not utilized in automobile exhaust should not be ignored, and the importance of using automobile exhaust gas for power generation is gradually being realized and valued by people. However, the urban traffic environment is changeable. The frequent start and stop as well as the acceleration and deceleration of the car will lead to the fluctuation of gas temperature and flow and then the temperature fluctuation of the thermoelectric module’s hot end, which reduces the power generation efficiency of thermoelectric module. By arranging the heat conduction oil circulation at the hot end, the temperature fluctuation of the hot end of thermoelectric module can be effectively reduced, but the system volume is large, and the working fluid circulation needs additional energy supply.
2017-03-28
Technical Paper
2017-01-1671
Johannes Bach, Marc Holzäpfel, Stefan Otten, Eric Sax
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
The advent of Advanced Driver Assistance Systems (ADAS) and autonomous 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. Various test methods like VEHiL (Vehicle Hardware-in-the-Loop), Vehicle-in-the-Loop and Co-ordinated automated driving have been developed for validation of ADAS and autonomous systems. Increasingly, driving simulators are being used for testing ADAS and autonomous systems as they offer a safer and a more reproducible environment for verifying such systems. While each of these test methods serves a specific purpose, they have a common challenge between them. All of these methods require the generation of test scenarios for which the systems are to be tested.
2017-03-28
Technical Paper
2017-01-0536
William Goodwin, Claudio Mancuso, Nicolas Brown
The development of automotive embedded software and calibrations presently involves an expensive development cycle in terms of both time and cost. A primary reason is the associated expense and time require to apply the various technologies needed for software testing and calibration development. Early in the design cycle software-in-the-loop (SIL) and Hardware-in-the-Loop (HIL) systems are typically employed. Later stages use costly engine and vehicle hardware as part of the software test and calibration development process. During this phase propulsions systems may initially utilize dynamometers and eventually migrate to vehicle level testing. All these technologies contribute to large budgets and design times required for embedded software and calibration development.
Viewing 1 to 30 of 15290