Criteria

Display:

Results

Viewing 181 to 210 of 33174
2017-03-28
Technical Paper
2017-01-0079
Hao Liu, Gangfeng Tan, Mengying Yang, Xiaoxiao Zhou, Yu Tang
Abstract Road traffic congestion sometimes happens at tunnel exit even without high traffic flow. One reason is that the deceleration process is imperceptible when the vehicle is driving to the tunnel exit with gradual upgrade slopes. Nowadays regulations are more concentrated in transport sectors, and control measures are applied to vehicles through the tunnel. This process is careless of vehicles’ specific characteristics and easily distract the driver attention. In this paper, a tunnel climbing acceleration reminder system is introduced. When the speed drop is detected and the analysis show this is due to the driver's unconscious behavior, the system will remind the driver to speed up. Based on the dynamic model and the tunnel properties, the relationship between the throttle opening degrees and the duration with the speed change is studied. Then, the engine braking is considered for the variation of speeds and slopes.
2017-03-28
Technical Paper
2017-01-0085
Wanyang Xia, Yahui Wu, Gangfeng Tan, Xianyao Ping, Benlong Liu
Abstract Typical vehicle speed deceleration occurs at the freeway exit due to the driving direction change. Well conducting the driver to control the velocity could enhance the vehicle maneuverability and give drivers more response time when running into potential dangerous conditions. The freeway exit speed limit sign (ESLS) is an effect way to remind the driver to slow down the vehicle. The ESLS visibility is significant to guarantee the driving safety. This research focuses on the color variable ESLS system, which is placed at the same location with the traditional speed limit sign. With this system, the driver could receive the updated speed limit recommendation in advance and without distraction produced by eyes contract change over the dashboard and the front sight. First, the mathematical model of the drivetrain and the engine brake is built for typical motor vehicles. The vehicle braking characteristics with various initial speeds in the deceleration area are studied.
2017-03-28
Technical Paper
2017-01-0084
Jiantao Wang, Bo Yang, Jialiang Liu, Kangping Ji, Qilu Wang
Abstract Studies show that driving in foggy environment is a security risk, and when driving in foggy environment, the drivers are easy to accelerate unconsciously. The safety information prompted to the driver is mainly from fog lights, road warning signs and the traffic radio. In order to increase the quality of the safety tips to prevent drivers from unintended acceleration and ensure the security of driving in foggy environment, the study proposes a safety speed assessment method for driving in foggy environment, combining the information of driving environment, vehicle’s speed and the multimedia system. The method uses camera which is installed on the front windshield pillar to collect the image about the environment, and uses the dark channel prior theory to calculate the visibility. And by using the environment visibility, the safety speed can be calculated based on the kinematics theory. And it is appropriate for vehicles which have different braking performance.
2017-03-28
Technical Paper
2017-01-0081
Majid Majidi, Majid Arab, Vahid Tavoosi
Abstract In this research, an optimal real-time trajectory planning method is proposed for autonomous ground vehicles in case of overtaking a moving obstacle. When an autonomous vehicle detects a moving vehicle ahead of it in a proper speed and distance and the braking is not efficient due to the lost of its kinematic energy, the autonomous vehicle decides to overtake the obstacle by performing a double lane-change maneuver. A two-phase nonlinear optimal problem is developed for generating the path for the overtaking maneuver. The cost function of the first phase is defined in such a way that the vehicle approaches the moving obstacle as close as possible. Besides, the cost function of the second phase is defined as the minimization of the sum of the vehicle lateral deviation from the reference path and the rate of steering angle during the overtaking maneuver while the lateral acceleration of the vehicle does not exceed a safe limit.
2017-03-28
Technical Paper
2017-01-0080
Qilu Wang, Bo Yang, Gangfeng Tan, Shengguang Xiong, XiaoXiao Zhou
Abstract Mountain road winding and bumpy, traffic accidents caused by speeding frequently happened, mainly concentrated on curves. The present curve warning system research are based on Charge-coupled Device, but the existing obstacles, weather , driving at night and road conditions directly affect the accuracy and applicability. The research is of predictability to identify the curves based on the geographic information and can told the driver road information and safety speed ahead of the road according to the commercial vehicle characteristic of load, and the characteristics of the mass center to reduce the incidence of accidents. In this paper, the main research contents include: to estimate forward bend curvature through the node classification method based on the digital map.
2017-03-28
Technical Paper
2017-01-0093
Balachander Dhanavanthan
Abstract Radio Frequency (RF) propagation in vehicular environments exhibits major transformations from indoor, outdoor and farmland multipath environments. The innovative advancement in Wireless Sensor Networks (WSNs) has made it necessary to recognise and predict the RF propagation losses for WSNs in vehicular environments. Very few models exist for network planning and deployment in vehicular environments. All of these models need an extensive statistical estimations and an in-depth knowledge of the vehicular environment. In this paper a different approach has been pursued and as a first step is to evaluate the factors which affect RF propagation in vehicular environments and how these factors affect each other while predicting propagation losses in vehicular environments.
2017-03-28
Technical Paper
2017-01-0090
Ondrej Santin, Jaroslav Beran, Jaroslav Pekar, John Michelini, Junbo Jing, Steve Szwabowski, Dimitar Filev
Abstract Conventional cruise control systems in automotive applications are usually designed to maintain the constant speed of the vehicle based on the desired set-point. It has been shown that fuel economy while in cruise control can be improved using advanced control methods namely adopting the Model Predictive Control (MPC) technology utilizing the road grade preview information and allowance of the vehicle speed variation. This paper is focused on the extension of the Adaptive Nonlinear Model Predictive Controller (ANLMPC) reported earlier by application to the trailer tow use-case. As the connected trailer changes the aerodynamic drag and the overall vehicle mass, it may lead to the undesired downshifts for the conventional cruise controller introducing the fuel economy losses. In this work, the ANLMPC concept is extended to avoid downshifts by translating the downshift conditions to the constraints of the underlying optimization problem to be solved.
2017-03-28
Technical Paper
2017-01-0135
Jose Grande, Julio Abraham Carrera, Manuel Dieguez Sr
Abstract Exhaust Gas Recirculation (EGR) is an effective technique for reducing NOx emissions in order to achieve the ever more stringent emissions standards. This system is widely used in commercial vehicle engines in which thermal loads and durability are a critical issue. In addition, the development deadlines of the new engine generations are being considerably reduced, especially for validation test phase in which customers usually require robust parts for engine validation in the first stages of the project. Some of the most critical issues in this initial phases of program development are heavy boiling and thermal fatigue. Consequently it has been necessary to develop a procedure for designing EGR coolers that are sufficiently robust against heavy boiling and thermal fatigue in a short period of time, even when the engine calibration is not finished and the working conditions of the EGR system are not completely defined.
2017-03-28
Technical Paper
2017-01-0138
Chris Lim, Peter Ireland, Nicholas Collett
Abstract The analysis of thermal fields in the underhood region is complicated by the complex geometry and the influence of a multitude of different heat sources. This complexity means that running full CFD analyses to predict the thermal field in this region is both computationally expensive and time consuming. A method of predicting the thermal field using linear superposition has been developed in order to analyse the underhood region of a simplified Formula One race car, though the technique is applicable to all vehicles. The use of linear superposition allows accurate predictions of the thermal field within a complex geometry for varying boundary conditions with negligible computational costs once the initial characterisation CFD has been run. A quarter scale, rear end model of a Formula One race car with a simplified internal assembly is considered for analysis, though the technique can also be applied to commercial and industrial vehicles.
2017-03-28
Technical Paper
2017-01-0143
Neelakandan Kandasamy, Steve Whelan
Abstract During cabin warm-up, effective air distribution by vehicle climate control systems plays a vital role. For adequate visibility to the driver, major portion of the air is required to be delivered through the defrost center ducts to clear the windshield. HVAC unit deliver hot air with help of cabin heater and PTC heater. When hot air interacts with cold windshield it causes thermal losses, and windshield act as sink. This process may causes in delay of cabin warming during consecutive cabin warming process. Thus it becomes essential to predict the effect of different windscreen defrost characteristics. In this paper, sensitivity analysis is carried for different windscreen defrosts characteristics like ambient conditions, modes of operation; change in material properties along with occupant thermal comfort is predicted. An integrated 1D/3D CFD approach is proposed to evaluate these conditions.
2017-03-28
Technical Paper
2017-01-0139
Fei Dong, Liuwendi Hou, Zhenlong Xu, TaoTao Cao
Abstract The objective of this present research is to investigate the influence of bubble waiting time coefficient on subcooled flow boiling heat transfer in internal combustion engines and propose an approach to predict its value. The three-dimension simulated cooling jacket structure of valve bridges for forced water-cooling system was developed respectively. The numerical model for subcooled flow boiling based on two-fluid approach was established and calculated. Numerical results suggest that the bubble departure diameter increases with the increasing wall superheat or decreasing inlet subcooling. And the proportion of the quenching heat flux gradually rises and its peak value is delayed along the direction of the higher wall superheat when the subcooling degree increases. The bubble waiting time coefficient has been found to have a significant impact upon the boiling heat transfer.
2017-03-28
Technical Paper
2017-01-0148
Majid Arab, Majid Majidi
Abstract The approaching the ideal efficiency assumption is possible in Stirling engine. Regenerator is the main component in improving the efficiency of the engine. Besides the Geometry and materials of the regenerator, amount and quality of porosity have significant impacts on the regenerator performance which is focused on this research. The main idea of this study is to evaluate the effect of porosity, or unsymmetrical porosity gradient in pressure drop and the thermodynamic performance of regenerator, so three models of regenerator are developed and analyzed: First, a model in which the porosity is constant and do not change (Common mode). In the Second model, the length of regenerator porosity is changed from high to low and in the third model, the length of regenerator porosity is changed from low to high. All versions of models have the same global porosity.
2017-03-28
Technical Paper
2017-01-0144
Zhijia Yang, Song Lan, Richard Stobart, Edward Winward, Rui Chen, Iain Harber
Abstract The application of state-of-art thermoelectric generator (TEG) in automotive engine has potential to reduce more than 2% fuel consumption and hence the CO2 emissions. This figure is expected to be increased to 5%~10% in the near future when new thermoelectric material with higher properties is fabricated. However, in order to maximize the TEG output power, there are a few issues need to be considered in the design stage such as the number of modules, the connection of modules, the geometry of the thermoelectric module, the DC-DC converter circuit, the geometry of the heat exchanger especially the hot side heat exchanger etc. These issues can only be investigated via a proper TEG model. The authors introduced four ways of TEG modelling which in the increasing complexity order are MATLB function based model, MATLAB Simscape based Simulink model, GT-power TEG model and CFD STAR-CCM+ model. Both Simscape model and GT-Power model have intrinsic dynamic model performance.
2017-03-28
Technical Paper
2017-01-0168
B. Vasanth, Muthukumar Arunachalam, Sathya Narayana, S. Sathish Kumar, Murali govindarajalu
In current scenario, there is an increasing need to have faster product development and achieve the optimum design quickly. In an automobile air conditioning system, the main function of HVAC third row floor duct is to get the sufficient airflow from the rear heating ventilating and air-conditioning (HVAC) system and to provide the sufficient airflow within the leg locations of passenger. Apart from airflow and temperature, fatigue strength of the duct is one of the important factors that need to be considered while designing and optimizing the duct. The challenging task is to package the duct below the carpet within the constrained space and the duct should withstand the load applied by the passenger leg and the luggage. Finite element analysis (FEA) has been used extensively to validate the stress and deformation of the duct under different loading conditions applied over the duct system.
2017-03-28
Technical Paper
2017-01-0159
Peng Liu, Ge-Qun Shu, Hua Tian, Xuan Wang, Dongzhan Jing
Abstract The environmental issues combined with the rising of crude oil price have attracted more interest in waste heat recovery of marine engine. Currently, the thermal efficiency of marine diesels only reaches 48~51%, and the rest energy is rejected to the environment. Meanwhile, energy is required when generating electricity and cooling that are necessary for vessels. Hence, the cogeneration system is treated as the promising technology to conform the strict environment regulation while offering a high energy utilization ratio. In this paper, an electricity and cooling cogeneration system combined of Organic Rankine Cycle (ORC) and Absorption Refrigeration Cycle (ARC) is proposed to recover waste heat from marine engine. ORC is applied to recover exhaust waste heat to provide electricity while ARC is used to utilize condensation heat of ORC to produce additional cooling.
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
2017-01-0179
Saravanan Sambandan, Manuel Valencia, Sathish Kumar S
Abstract In an automotive air-conditioning (AC) system, the heater system plays a major role during winter condition to provide passenger comforts as well as to clear windshield defogging and defrost. In order to meet the customer satisfaction the heater system shall be tested physically in severe cold conditions to meet the objective performance in wind tunnel and also subjective performance in cold weather regions by conducting on road trials. This performance test is conducted in later stage of the program development, since the prototype or tooled up parts will not be available at initial program stage. The significance of conducting the virtual simulation is to predict the performance of the HVAC (Heating ventilating air-conditioning) system at early design stage. In this paper the development of 1D (One dimensional) model with floor duct systems and vehicle cabin model is studied to predict the performance. Analysis is carried out using commercial 1D simulation tool KULI®.
2017-03-28
Technical Paper
2017-01-0274
Xueyu Zhang, Zoran Filipi
Abstract This paper presents the development of an electrochemical aging model of LiFePO4-Graphite battery based on single particle (SP) model. Solid electrolyte interphase (SEI) growth is considered as the aging mechanism. It is intended to provide both sufficient fidelity and computational efficiency required for integration within the HEV power management optimization framework. The model enables assessment of the battery aging rate by considering instantaneous lithium ion surface concentration rather than average concentration, thus enhancing the fidelity of predictions. In addition, an approximate analytical method is applied to speed up the calculation while preserving required accuracy. Next, this aging model are illustrated two applications. First is hybrid electric powertrain system model integration and simulation.
2017-03-28
Technical Paper
2017-01-0285
Navid Nazemi, Mohammad K. Alam, Ruth Jill Urbanic, Syed Saqib, Afsaneh Edrisy
Abstract Laser cladding is used to coat a surface of a metal to enhance the metallurgical properties at the surface level of a substrate. For surface cladding operations, overlapping bead geometry is required. Single bead analyses do not provide a complete representation of essential properties; hence, this research focuses on overlapping conditions. The research scope targets the coaxial laser cladding process specifically for P420 stainless steel clad powder using a fiber optic laser with a 4.3 mm spot size on a low/medium carbon structural steel plate (AISI 1018). Many process parameters influence the bead geometrical shape, and it is assumed that the complex temperature distributions within the process could cause subsequent large variations in hardness values. The bead overlap configurations experiments are performed with 40%, 50% and 60% bead overlaps for a three-pass bead formation.
2017-03-28
Technical Paper
2017-01-0257
Liang Wu, Fangwu Ma, Yongfeng Pu, HongBin Yin
Abstract This research focuses on an integration of two optimal tracking controllers, the active suspension controller and the rear-wheel steering controller, with the objective of improving vehicle performances in terms of maneuverability and safety by enhancing road holding capability and lateral stability. The active suspension controller adjusts the vehicle roll angle and utilizes the vertical force at each active suspension to boost road holding capability. On the other hand, the rear-wheel steering controller adjusts rear steering angles to use lateral force at each ground-tire contact point and amplify the vehicle’s ability to follow the desired yaw rate and sideslip angle during cornering maneuvers. Though the active attitude motion and mass shifting of car body may seem to hold relationship with lateral stability, its ability to evenly distribute vertical tire forces benefits the rear-wheel steering controller by enhancing the road holding capability.
2017-03-28
Technical Paper
2017-01-0255
Malli Kartheek Yalamanchili, Nitin Sharma, Kevin Thomson
Abstract The crashworthiness of body-in-white (BIW) plays a vital role in full vehicle crash performance. The structural integrity of BIW is controlled via strength of the spot welds and adhesives that are the primary entities to join sheet metal. The number of welds and amount of adhesives in the entire BIW directly affects the cost and the cycle time of the BIW; which makes them a good candidate for optimization. However optimization of the welds and/or adhesives not only reduces the number of connections but also provides the opportunity to improve the structural performance and mass saving by placing them optimally for the structural responses. This paper discusses the optimization of full vehicle structural performance for the small overlap crash event using the length of adhesives in the BIW as parameters. Included in the study were length of the adhesives and gage variables, defined in the front-end structure of the vehicle.
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
2017-01-0261
Randolph Jones, Robert Marinier III, Frank Koss, Robert Bechtel, John A. Sauter
Abstract When evaluating new vehicle designs, modeling and simulation offer techniques to predict parameters such as maximum speed, fuel efficiency, turning radius, and the like. However, the measure of greatest interest is the likelihood of mission success. One approach to assessing the likelihood of mission success in simulation is to build behavior models, operating at the human decision-making level, that can execute realistic missions in simulation. This approach makes it possible to not only measure changes in mission success rates, but also to analyze the causes of mission failures. Layering behavior modeling and simulation on underlying models of equipment and components enables measurement of more conventional parameters such as time, fuel efficiency under realistic conditions, distance traveled, equipment used, and survivability.
2017-03-28
Technical Paper
2017-01-0259
Xinran Tao, John R. Wagner
Abstract Heat rejection in ground vehicle propulsion systems remains a challenge given variations in powertrain configurations, driving cycles, and ambient conditions as well as space constraints and available power budgets. An optimization strategy is proposed for engine radiator geometry size scaling to minimize the cooling system power consumption while satisfying both the heat removal rate requirement and the radiator dimension size limitation. A finite difference method (FDM) based on a heat exchanger model is introduced and utilized in the optimization design. The optimization technique searches for the best radiator core dimension solution over the design space, subject to different constraints. To validate the proposed heat exchanger model and optimization algorithm, a heavy duty military truck engine cooling system is investigated.
2017-03-28
Technical Paper
2017-01-0264
Venkatesh Babu, Ravi Thyagarajan, Jaisankar Ramalingam
Abstract In this paper, the capability of three methods of modelling detonation of high explosives (HE) buried in soil viz., (1) coupled discrete element & particle gas methods (DEM-PGM) (2) Structured - Arbitrary Lagrangian-Eulerian (S-ALE), and (3) Arbitrary Lagrangian-Eulerian (ALE), are investigated. The ALE method of modeling the effects of buried charges in soil is well known and widely used in blast simulations today [1]. Due to high computational costs, inconsistent robustness and long run times, alternate modeling methods such as Smoothed Particle Hydrodynamics (SPH) [2, 9] and DEM are gaining more traction. In all these methods, accuracy of the analysis relies not only on the fidelity of the soil and high explosive models but also on the robustness of fluid-structure interaction. These high-fidelity models are also useful in generating fast running models (FRM) useful for rapid generation of blast simulation results of acceptable accuracy.
2017-03-28
Technical Paper
2017-01-0270
Richard Gerth, Ryan Howell
Abstract The recently published Lightweight Combat Vehicle Science and Technology Campaign [1] recommended the Army develop a quantitative understanding of the operational impact that weight reduction has to the Army and create appropriate metrics that would better reflect the performance trade with regards to weight. That paper raised the question of what a ton of weight is worth in operational effectiveness and cost. This paper is an attempt to clarify this complex topic. The impact of select programmatic considerations, operational considerations, and financial considerations are discussed. Throughout, the paper provides example analyses based on vehicle weight, performance, and cost data. The paper closes with a discussion of the issues presented, research recommendations, and closing comments.
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
2017-01-0326
Samuel J. Tomlinson, Martin J D Fisher, Thomas Smith, Kevin Pascal
Abstract When sealing an application with a radial O-ring system design there is a balance that must be struck between O-ring function and the ease of assembly. If design parameters are not properly controlled or considered it is possible to design an O-ring seal that would require assembly insertion forces that exceed acceptable ergonomic practices from a manufacturing standpoint. If designs are released into production with these high insertion forces manufacturing operators will struggle to assemble parts, creating opportunity for potential operator injury due to repetitive strain or CTD. In this study several variables impacting O-ring system insertion forces were tested to quantify the effects. Results were analyzed to identify design controls that could be implemented from an early design phase to optimize both functionality and ease of assembly.
Viewing 181 to 210 of 33174