Browse Topic: Traction

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STANDARD FOR TIRE TRACEABILITY CONTENT AND FORMAT FOR THE RADIO-FREQUENCY IDENTIFICATION (RFID) TAG AND ASSOCIATED TIRE DATA SETUSCAR39-1 (Current)11/19/2020
This standard describes a requirement for automotive tire traceability. It includes a definition of the RFID tag and the associated tire data set that can be accessed using the RFID tag as an identifier. The standard describes a unique identification and the associated data set for each tire produced by the tire fabricator. This data will either be provided or transmitted at the time of shipment to retailers, wholesalers or original equipment vehicle manufacturers. Tire identification code and data may be used for error proofing, determining the tire specifications or supporting any inquiries that occur for the duration of its automotive life.
USCAR
Experimental Study of Tread Rubber Compound Effects on Tire Performance on Ice02-13-02-00066/16/2020
Mechanical and thermal properties of the rubber compounds of a tire play an important role in the overall performance of the tire when it is in contact with the terrain. Although there are many studies conducted on the properties of the rubber compounds of the tire to improve some of the tire characteristics, such as the wear of the tread, there are a limited number of studies that focused on the performance of the tire when it is in contact with ice. This study is a part of a more comprehensive project looking into the tire-ice performance and modeling. In this study, to understand the effect of different rubber compounds on the tire performance, three identical tires from the same company have been chosen. The tires’ only difference is the material properties of the rubber. Two approaches have been implemented in this study. For the first approach, several tests were conducted for the chosen tires at Terramechanics, Multibody, and Vehicle Systems (TMVS) laboratory at Virginia Tech to compare their performance experimentally. For the second approach, a tire-ice model has been used to compute the height of the water film created at the contact patch. As will be shown in this study, an increase in the height of water film results in a decrease in the friction coefficient, which is one of the most critical parameters for the tire performance. By having this knowledge, the performance of the three tires considered in the study was compared using the developed tire-ice model, based on the values obtained for the height of the water film. It is shown that the results obtained by simulation coincide with the results obtained experimentally. The results from this study show the sensitivity of the magnitude of the tractive force with respect to parameters such as tire temperature, normal load, etc. The results also indicate that the tire with the lowest value of Young’s modulus has the highest traction among all three tires used in this study.
Mousavi, Hoda, Sandu, Corina
System Interactions Affecting NVH Performance of an Electric Vehicle Drivetrain2019-01-15456/5/2019
The paper will present an integrated approach to system NVH analysis, which gives an insight into the system response in an EV driveline due to electrical and mechanical excitations; namely rotor mechanical imbalance, electrical machine torque ripple, and stator radial force shapes. The paper will address the fact that, as part of a practical design exercise, different subsystems and components may achieve design maturity at different times. It is therefore important to understand to what extent various drivetrain components may be considered in isolation, and at what point it becomes necessary to consider the interactions present in the full system. The paper will compare predicted NVH performance of a representative EV traction motor when different boundary conditions are considered; for example, when considering the motor being bested in isolation as part of a typical test setup, and when included in a representative drivetrain. For each configuration, the response to mechanical and electro-mechanical noise mechanisms will be assessed, and the fidelity of simulation required to achieve an appropriate engineering insight will be considered. From these studies, the best practice for the assessment of NVH as part of a holistic design process will be discussed. Consideration will be made of the factors which may influence the choice of simulation approach; for example, the level of design maturity, the availability and reliability of system data, and the design targets which are to be addressed.
Michon, Melanie, Holehouse, Robert, Shahaj, Annabel, Jafarali, Hisham, Janakiraman, Venkatakrishna
Design Optimization of a Hybrid Spur GearF-0075-2019-146745/13/2019
This study develops an optimization technique for a sinusoidal interlock design of a hybrid spur gear consisting of a metallic outer ring to support high contact stress bonded to a composite inner web for weight reduction. Two objectives (mass and shear traction on the metal-composite interface under static loading conditions) were minimized for four design variables subject to two constraints. Borg MOEA, a multi-objective evolutionary algorithm developed at The Pennsylvania State University, and an in-house finite element solver were used to generate Pareto-optimal solutions to this design problem. Two of the designs were then analyzed in greater detail to determine stress distributions throughout the gear. In the future, this technique will be refined and applied to optimization of more representative rotorcraft gears, with the aim of reducing drive train weight and meeting performance requirements.
Gauntt, Sean, Campbell, Robert, McIntyre, Sean
An Analysis of Sport Bike Motorcycle Dynamics during Front Wheel Over-Braking2019-01-04264/2/2019
There is extensive literature on motorcycle skid/brake to stop testing on a host of motorcycle types, rider experience, brake system configurations and the associated deceleration rates. Very little information exists on deceleration rates involved with over-braking the front wheel. The subject of this paper addresses the deceleration rates of sport bike type motorcycles during over-braking of the front wheel. Based on the physics of a two-wheeled vehicle like the motorcycle, once the front wheel is over-braked and becomes locked, the rider has very little time to recover from the skid and often times falls. Another over-braking scenario, especially on sport bike type motorcycles, is the possibility of the rear wheel lifting and pitching over the front wheel. During the initial phase of braking, weight transfer to the front wheel occurs creating a greater level of traction. As the motorcycle begins to fall or pitch over, the weight on the front wheel decreases significantly and therefore the frictional force decreases significantly as well. The goal of this publication was to perform maximum front wheel brake testing that involves front wheel skid-to-fall as well as front wheel brake-to-pitch over scenarios on various sport bike motorcycles and determine an applicable deceleration rate. Three motorcycles; a 2002 Kawasaki ZRX1200R, a 2006 Yamaha YZF-R6, and a 2013 Ninja EX300 were subject to various maximum front wheel brake tests. The speed of the motorcycle at brake application ranged from 50 to 60 mph. The results of the testing concluded that the average deceleration rates during front wheel skid-to-fall tests were in the range of 0.32-0.8g depending on the lean angle of the motorcycle at brake application. The average deceleration rates for the front wheel brake-to-pitch over tests were in the range of 0.8-0.86g.
Fatzinger, Edward, Landerville, Jon, Bonsall, Jeffrey, Simacek, Daniel
Investigation of Cabin Noise while Accelerating on Low Mu Track through Simulation Approach Using Full Vehicle ADAMS/Car Model2019-26-01791/9/2019
Cabin noise is a significant product quality criteria which enables the customers for product differentiation. There are various sources of cabin noise such as wind, structures(panels), engine, suspension, tire and roads. During product development phase, extensive tests has been conducted to improve vehicle dynamics behavior on various climatic conditions. One such test is accelerating vehicle on low mu or icy surface. While performing acceleration manoeuvre (tractions) on a low mu tracks, Cabin noise with source identified from front underbody & low tractive torque build up is reported. This undesirable behavior may occur due to following reason (1) Excitation of coupled modes between suspension and powertrain which induces torque fluctuation. (2) Transmissibility of various subsystem can be the reason for above problem statement. (3) Poorly chosen tire compounds and design leads to fluctuation in torque. A detailed simulation based study using ADAMS/CAR has been performed to assess the contribution of various full vehicle sub-systems, primarily suspension & powertrain sub-system towards the said problem statement. The dynamic interaction between road, suspension, powertrain and BIW has been is the focus of study both in time and frequency domain. This simulation helped understand the factor effects and contribution levels and correlates well with the subjective feel observed on the physical vehicle on low-mu track. This model has been further used to provide design recommendation on the compliance parameters to overcome the issue at hand. Test has been conducted with recommended tire grip properties and suspension bushing parameters which lead to reduction in cabin noise
Singh, Vivek, Prasad, Tej, Srivastava, Harshit
Structural Integrity of In-Wheel Motors2018-01-18299/10/2018
In-wheel motors offer an optimized solution for novel drivetrain architectures of future electric vehicles that could penetrate into the mainstream automotive industry, moving the wheel actuation where it’s required, directly inside the wheels. Obtainable literature mainly deals with optimization of electromagnetically active parts, however, mechanical design of electromagnetically passive parts that indirectly influence motor performance also requires detailed analysis and extensive validation. To meet the optimal performance requirements (also durable) of an in-wheel traction motor, their mechanical design requires topology optimization of housing elements, thermal mapping, geometrical and dimensional tolerance checks and selection of proper hub bearings, in order to assure consistent electromagnetic behavior stability The following paper uniquely describes the review of loads acting on an in-wheel motor, the workflow of a typical mechanical design process, testing, and validation processes for achieving the required durability of an in-wheel assembly.
Frajnkovic, Matic, Omerovic, Senad, Rozic, Uros, Kern, Jurij, Connes, Raphael, Rener, Kristof, Biček, Matej
Development of a Vision-Based Situational Awareness Capability for Unmanned Surface VesselsTBMG-289095/1/2018
Using unmanned surface vessels (USVs) for “dull, dirty and dangerous missions” is gaining traction in recent years as it removes the human element from a potentially life-threatening environment in missions such as mine hunting or maritime interdiction. Current USVs rely on human operators sitting in remote control stations to monitor the vessels’ surroundings and perform collision detection and avoidance. This reliance on the human operator constrains the operating envelope of the USV as it requires a high bandwidth and low latency communication link for safe operations, especially in waters with heavy traffic.
Investigation of a Six-Phase Interior Permanent Magnet Synchronous Machine for Integrated Charging and Propulsion in EVs08-07-02-00064/17/2018
Merits such as reduced weight, overall and operational costs of the electric vehicle (EV) while providing level 3 charging capability, are propelling research on integrated charging (IC) technology for EVs. Since the same interior permanent magnet synchronous machine (IPMSM) is used during IC and traction conditions, it is important to understand the behavior of the machine during these conditions and optimally design the machine. Hence, firstly, this paper presents a case study on performance of a laboratory 3-phase IPMSM under IC and traction conditions. Thereafter, understanding the challenges such as low magnet operating point, losses and torque oscillation in 3-phase IPMSM during IC, a 6-phase IPMSM with an unconventional configuration is investigated to yield traction characteristics like that of the 3-phase IPMSM and mitigate challenges during IC. In the process, mathematical model of the 6-phase IPMSM is developed employing the dq-axis theory. The developed model is then employed to exclusively derive the relation between various per-unitized machine parameters to obtain optimal performance under IC and traction conditions. Thereafter, a novel bottom-up machine design methodology based on maximum-torque per ampere control technique is proposed to design a 6-phase IPMSM that will yield desired performance under traction and IC conditions. Finally, a 6-phase IPMSM has been designed using the proposed design methodology and its performance has been investigated under traction and IC conditions through a developed prototype and electromagnetic model of the machine in conjunction with finite element analysis.
Lai, Chunyan, Dhulipati, Himavarsha, Mukundan, Shruthi
Investigation of Pre-conditioning Strategies that Enable State-of-Health Improvement for A Remanufactured Li-Ion Battery in Automotive Circular Economy Applications2018-01-04444/3/2018
Implementing and optimizing the sustainability of vehicles that contain embedded electrochemical energy storage have recently been afforded more attention in research due to legislative requirements and cited benefits from circular economy activities. The State-of-Health (SoH) for a traction battery system that prematurely failed can be restored through circular economy activities such as remanufacturing. To enable these circular economy activities, the ability to introduce a new or graded cell or module into a series string to replace the weakest cell or module in a battery module or pack is vital. However, very little is understood about the optimal strategy that will lead to maximizing the lifetime of the most aged cell or module in the new string and predict the expected lifetime of the repaired or remanufactured battery system. The aim of this research is to assess whether aged lithium-ion cells in series, with some of the aged cells replaced with new cells, have an optimized pre-conditioning strategy to ensure the weakest cell’s life is prolonged. Three modules with six 18650 cells in series have been evaluated to determine the optimal replacement strategy for an energy storage unit albeit cell or module in series for in-use life extension activities. Results highlight that it is possible to significantly reduce the degradation of the weakest cell in a repaired string of series cells. Reduction of circa 4% in aging of the weakest cells is reached with bottom pre-conditioning, while an increase in degradation of the new cell is only 2.5% relative to the worst case scenario. Additionally, the authors show that the energy capacity of the string pre-conditioned at the top reduces the most during cycling of the three strings. Based on these experimental results, an optimal pre-conditioning strategy for circular economy activities for electric vehicle traction battery systems is proposed.
Groenewald, Jakobus, Marco, James, Grandjean, Thomas
System-Level Investigation of Traction Inverter High-Temperature Operation2018-01-04644/3/2018
In this paper, the high-temperature capability of the traction inverter was investigated by applying coolant with temperature much higher than the typical allowed value until the system fails. The purpose of this study is to identify the weakest link of the traction inverter system in terms of temperature. This study was divided into two stages. In the first stage, a series of nondestructive tests were carried out to investigate temperature rise (ΔT) of the key component above coolant temperature as a function of the outside controllable parameters-i.e., dc link voltage, phase current, and switching frequency. The key components include power modules, gate driver board, gate driver power supply, current sensors and dc link capacitor. Their temperatures were monitored by thermocouples or on-die temperature sensors. The result showed that temperature rises of most key components were strongly affected by phase current, moderately affected by switching frequency, and slightly affected by dc link voltage. Therefore, the operating conditions used in the second stage (destructive test) were chosen to stress the phase current only rather than the dc link voltage and switching frequency for better effectiveness. In the second stage (the destructive test), the coolant temperature was controlled to increase every a few hours after the temperature stabilized while maintaining the controllable electrical parameters to be the same. Testing results showed that the traction inverter employed in this study can sustain coolant temperature > 105 °C for more than 10 hours, while the IGBT on-die temperatures were measured to be >200 °C. Under this specific condition, the IGBT module is the first component to fail after the coolant temperature was raised to a certain level (>120 °C). On the contrary, many other components are found to be functioning after the long-time operation at high temperatures. The measurement results were confirmed by the theoretical analysis.
Lu, Xi, Xiao, Kewei, Lei, Guangyin, Chen, Chingchi
A Packaging Layout to Mitigate Crosstalk for SiC Devices2018-01-04624/3/2018
SiC devices have inherent fast switching capabilities due to their superior material properties, and are considered potential candidates to replace Si devices for traction inverters in electrified vehicles in future. However, due to the comparatively low gate threshold voltage, SiC devices may encounter oscillatory false triggering especially during fast switching. This paper analyzed the causes of false triggering, and also studied the impact of a critical parasitic parameter - common source inductance. It is shown that crosstalk is the main cause for the false triggering in the case and some positive common source inductance help to mitigate the crosstalk issue. A packaging layout method is proposed to create the positive common source inductance through layout of control terminals / busbars, and/or the use of control terminal bonded wires at different height.
Xu, Zhuxian, Chen, Chingchi, Lei, Thomas
Development of Traction Motor for New Fuel Cell Vehicle and New Electric Vehicle2018-01-04504/3/2018
Honda’s purpose is to realize the joy and freedom of mobility and a sustainable society in which people can enjoy life. As such, three series of environmental vehicles-FCVs, BEVs, and PHEVs-have been developed so that users in communities around the world can select the ones best suited to their local energy circumstances and individual lifestyles. This paper discusses a structure that enhances both the motive power performance and quietness of a newly developed FCV/BEV traction motor. To enhance motive power performance, the research focused on the stator lamination technique. As for methods of affixing the stator’s layers, the practice with previous models has been adhesion lamination, using electric steel sheets that come pre-made with adhesive layers. Having adhesive layers, however, lowers the ratio (space factor) of steel sheet layers. The new motor uses electric steel sheets without an adhesive layer in order to enhance motive power performance. To enhance the quietness of the auto interior, it is important to lower the magnetism excitation force. To do this, a new magnetic circuit was developed and magnet positioning was optimized. For the rotor structure, level skewing was used to shift the rotor yoke in the direction of the perimeter. A new motor to go on new FCVs/BEVs was developed and a traction motor that offers quietness, power, and a smooth driving feeling was achieved. Compared to the previous motor, the new motor raises maximum output from 100 kW to 130 kW, and maximum torque from 256 Nm to 300 Nm, all while maintaining the same volume. It also lowers motor noise heard in the interior of the vehicle by 5-10 dB(A), when compared to the previous motor.
Honjo, Satoshi, Iwai, Akinobu, Suzumori, Hirofumi, Okamura, Mitsuhiro
Numerical Three-Dimensional Study of an Open Wheel Race Car Undertray2018-01-07234/3/2018
An Undertray is an aerodynamic downforce generator used in racing cars to enhance traction. It has the highest downforce to drag ratio among other aerodynamic devices. The objective of this study is to optimize the performance of a FSAE undertray through full vehicle three-dimensional numerical experiments. Based on Preliminary experiments, the basic undertray features are chosen. A simple sequential analysis approach is taken to study the downforce trends versus the variation of three undertray geometrical parameters. It is found that downforce generated is proportional to the diffuser angle until breakdown caused by separation of flow in the lower diffuser duct. A secondary diffuser guide vane is found to retard said separation, allowing uniform expansion at higher diffuser angles. Lower ground clearances cause boundary layer chocking and advanced separation. Finally the effect of the undertray on the aerodynamic wings is studied, and found to be negligible.
Abdel Hady, Nouran
A Smart Gate Driver with Active Switching Speed Control for Traction Inverters2017-01-12433/28/2017
The IGBTs are dominantly used in traction inverters for automotive applications. Because the Si-based device technology is being pushed to its theoretical performance limit in such applications during recent years, the gate driver design is playing a more prominent role to further improve the traction inverter loss performance. The conventional gate driver design in traction inverter application needs to consider worst case scenarios which adversely limit the semiconductor devices' switching speed in its most frequent operation regions. Specifically, when selecting the gate resistors, the IGBT peak surge voltage induced by fast di/dt and stray inductance must be limited below the device rated voltage rating under any conditions. The worst cases considered include both highest dc bus voltage and maximum load current. However, the traction inverter operates mainly in low current regions and at bus voltage much lower than the worst case voltage. This paper proposes a low-cost and simple gate driver circuit that can actively adjust the turn-off switching speed based on IGBT current levels. The proposed circuit utilizes the current sensing pin which is widely available for IGBTs used in current generation traction inverters. When the current is low, the switching is speeded up to minimize loss. Under worst cases, it can keep the maximum surge voltage same as the value of conventional gate driver. For applications that the system operates mostly in low current regions, the proposed method can significantly improve the system efficiency.
Zhou, Yan, Chen, Lihua, Yang, Shuitao, Xu, Fan, Alam, Mohammed Khorshed
Power Module Design Verification for xEV Application Under Extreme Conditions2017-01-12463/28/2017
Power modules play a key role in traction inverters for vehicle electrification applications. The harsh automotive operating environment is a big challenge for power modules. The paper highlights the challenges for power modules usage in electrified vehicles (xEVs), and proposes a design verification procedure for such application in order to ensure the reliable operation under all conditions. First, power modules operate in all climate zones and are exposed to a wide ambient temperature range underhood from -40°C to 105°C. A typical automotive power module should therefore withstand a junction temperature from -40°C to up to 175°C without exceeding its safe operating area (SOA), e.g. avalanche breakdown voltage, maximum current, and thermal limit. Second, an inductive induced high voltage spike could be generated during the power semiconductor fast switching at high voltage and high current conditions. The voltage clamping capability is usually required to prevent power semiconductor breakdown under such high voltage spike. Moreover, IGBT short circuit capability is desired to allow adequate time to trigger protection once a short circuit occurs in the motor windings or the inverter. The power module in xEV application is used as an example to show the proposed design verification process including 1) wide temperature range of operation, 2) voltage clamping capability, and 3) short circuit capability.
Xu, Fan, Chen, Lihua, Yang, Shuitao, Zhou, Yan, Alam, Mohammed Khorshed
Traction Inverter Design with a Direct Bypass to Boost Converter2017-01-12473/28/2017
Direct bypass to DC-DC boost converter in traction inverter increases converter's capability and efficiency significantly by providing a lower loss path for power flow between the battery and DC-link terminal. A bypass using diode is an excellent solution to achieve this capability at low cost and system complexity. Bypass diode operates in the linear operating region (DC Q-point) when the battery discharges through the bypass diode to drive the electric motors. Therefore, thermal stress on the DC-link capacitor is shared between the input and DC-link capacitors through the bypass diode. On the other hand, inverters introduce voltage oscillation in the DC-link terminal which results in unwanted energy oscillation through the bypass diode during battery charging. Both of these phenomena have been explained in details. It is possible to eliminate this power oscillation during battery charging using minimum voltage level boosting at a reduced frequency or using a bi-directional switch (i.e., IGBT/diode or MOSFET/diode pair). The control strategy to achieve minimum voltage level boosting has been described in details. Moreover, it is possible to further reduce power loss of the boost converter by completely bypassing the inductor using a bi-directional switch during high voltage battery charging.
Alam, Mohammed Khorshed, Chen, Lihua, Zhou, Yan, Xu, Fan, Yang, Shuitao
Effect of the Variable Switching Frequency and DPWM Switching Schemes on the Losses of Traction Drives2017-01-12273/28/2017
This paper studies different switching schemes for loss reduction in a traction motor drive. The system under examination is composed of a battery, a 2 level Voltage Source Inverter, and an Interior Permanent Magnet motor. Discontinuous PWM (DPWM) control strategy is widely used in this type of motor drive for the reduction of losses. In some publications, the effect of the DPWM modulation scheme is compared to the reduction of the switching frequency which can also cause a reduction in switching losses of the inverter. Extensive studies have examined the effect of variation of the switching frequency on the motor and inverter losses. However, the effect of applying both switching schemes simultaneously has not been explored. This paper will use a system that is operated at a fixed switching frequency as the baseline. Afterwards, three different switching schemes will be studied and compared to the baseline. The first scheme (S1) will decrease the losses by optimizing the switching frequency in different regions of the torque-speed envelope. The second strategy (S2) will achieve the same goal by keeping the base switching frequency the same and introducing DPWM operation to the map. Finally, the third scheme (S3) will use S1’s switching frequency map and apply DPWM to that. Through experimental validation, this paper will paper will demonstrate that the loss reduction of S1 and S2 will be very similar to one another and S3 will not provide a considerable advantage compared to S1 or S2.
Najmabadi, Ali, Kress, Michael, Dryer, Brett, Khan, Ahmad Arshan
Spray-Formed Hybrid-Field Traction Motor2017-01-12253/28/2017
An advanced electric motor with hybrid-field topology has been developed for automotive traction applications. Departing from the conventional radial- and axial-field designs, the hybrid-field motor features three-dimensional magnetic flux paths, which are enabled by a novel isotropic soft magnetic material produced by a unique additive-manufacturing process based on spray forming. The motor is expected to offer an unprecedented combination of high power output, compact size, low weight and energy efficiency, achieving more than two times higher power density than state-of-the-art high-performance traction motors.
Krishnasamy, Jayaraman, Hosek, Martin
Tire Tread Performance Modification Utilizing Polymeric Additives2017-01-15023/28/2017
Tire manufacturers have long grappled with the challenge of balancing the conflicting tire attributes of traction, rolling resistance, and treadwear. Improvements to one of these “magic triangle” attributes often comes at the expense of the other attributes. Recent regulations have further increased the pressure on manufacturers to produce optimized tires with minimal performance compromises. In order to meet this challenge, the tire industry is looking to new material systems beyond the traditional tire tread components. Polymeric materials beyond the base elastomers and processing oils used in tread provide opportunities to modify the physical and viscoelastic properties of tread. In this study, various polymeric materials were evaluated as additives in a model tire tread formulation. Hydrocarbon resin, high styrene resin, and thermoplastic styrene elastomers were added to the model formulation at various loading levels and through various addition strategies. The thermal behavior of the raw polymeric additives was characterized utilizing differential scanning calorimetry (DSC). The impact of the polymeric additives on the tread compound was assessed by evaluating the cure kinetics, physical properties, and viscoelastic properties of the experimental compounds. The viscoelastic properties, as measured by dynamic mechanical analysis (DMA), were utilized to predict the relative tire tread performance attributes. Each polymeric additive evaluated in this study was predicted to modify the tire tread performance in a unique way. The potential advantages and challenges of utilizing the polymeric additives to optimize tire tread performance will be discussed.
Harper, Madeline, Tardiff, Janice, Haakenson, Daniel, Joandrea, Maria, Knych, Matthew
A Hybrid Approach to Model the Temperature Effect in Tire Forces and Moments2017-01-96763/14/2017
Tire is an integral part of any vehicle which provides contact between the vehicle and the surface on which it moves. Forces and moments generated at the tire-road interaction imparts stability and control of motion to the vehicle. These forces and moments are functions of many variables such as slip, slip angle, contact pressure, inflation pressure, coefficient of friction, temperature, etc. This paper deals with the effect of temperature on the lateral force, the longitudinal force and the self-aligning moment. The analysis is done at different tire surface temperatures such as 20°C, 40°C, and 60°C. Since the experimental set up with the mounted tire is complex and expensive, we use a hybrid approach in which we take the results from the experiments done by the researchers on a sample piece of tire rubber at various temperatures. Then, we do the steady state analysis in ABAQUS considering the variation of coefficient of friction, slip speed and the elastic modulus of rubber with temperature. The steady state numerical results from ABAQUS at different surface temperatures are compared with the modified PAC2002 tire model to capture the temperature effect. After validating the variations of steady state forces and moments from ABAQUS with the modified PAC2002, we use these steady state tire models to do the transient analysis in order to capture the effect of temperature on the transient response of tire forces and moments for different driving conditions of acceleration, braking and double lane change using MSC ADAMS/CAR.
S, Bibin, Pandey, Ashok Kumar
Off-Road Tire Replacement GuidelinesJ2611_201702 (Current)2/13/2017
This SAE information report covers the basic guidelines concerning off-road tire conditions that warrant replacement, removal, or repair. This material can assist the tire user in establishing specific written procedures for each job site.
MTC8, Tire and Rim
Off-Road Tire-Terrain Interaction: An Analytical Solution2016-01-80299/27/2016
A novel semi-analytical solution has been developed for the calculation of the static and dynamic response of an off road tire interacting with a deformable terrain, which utilizes soil parameters independent of the size of the contact patch (size-independent). The models involved in the solution presented, can be categorized in rigid and/or pneumatic tires, with or without tread pattern. After a concise literature review of related methods, a detailed presentation of the semi-analytical solution is presented, along with assumptions and limitations. A flowchart is provided, showing the main steps of the numerical implementation, and various test cases have been examined, characterized in terms of vertical load, tire dimensions, soil properties, deformability of the tire, and tread pattern. It has been found that the proposed model can qualitatively capture the response of a rolling wheel on deformable terrain.
Papazafeiropoulos, George, Prins, Jan, Bekakos, Chrysostomos-Alexandros, O'Boy, Dan J., Mavros, George
Design Analysis of High Power Density Additively Manufactured Induction Motor2016-01-20639/20/2016
Induction machines (IM) are considered work horse for industrial applications due to their rugged, reliable and inexpensive nature; however, their low power density restricts their use in volume and weight limited environments such as an aerospace, traction and propulsion applications. Given recent advancements in additive manufacturing technologies, this paper presents opportunity to improve power density of induction machines by taking advantage of higher slot fill factor (SFF) (defined as ratio of bare copper area to slot area) is explored. Increase in SFF is achieved by deposition of copper in much more compact way than conventional manufacturing methods of winding in electrical machines. Thus a design tradeoff study for an induction motor with improved SFF is essential to identify and highlight the potentials of IM for high power density applications and is elaborated in this paper. A traction/propulsion motor application is considered due to its demanding requirements on power density, constant power to speed ratio and efficiency. The motor design space explores different number of poles, slots-per-pole-per-phase and slot fill factors while satisfying the stringent requirements. Then the total weight reduction of active materials in the proposed design is compared with traditional manufacturing methods. The analysis and proposed design validates the power density and efficiency improvement given the increased SFF availed due to additive manufacturing method.
Wawrzyniak, Beata I., Tangudu, Jagadeesh
E-KERS Energy Management Crucial to Improved Fuel Economy2016-01-19479/18/2016
The operation of a conventional passenger car is characterised by increasing or maintaining the kinetic energy, when accelerating or cruising the vehicle, and reducing the kinetic energy by using the brakes. While the energy taken by the friction brakes to slow the vehicle is dissipated into heat, the introduction of Kinetic Energy Recovery Systems (KERS) has permitted the recovery of part of the braking energy. This reduces the amount of energy needed from the internal combustion engine (ICE). The contribution reviews the latest developments in electric KERS (E-KERS), with emphasis to round trip efficiency wheels to wheels and electrification of the powertrain. The contribution considers the opportunity to connect the E-KERS traction battery to other electric machines, such as an electrically assisted turbocharger (E-TC) connected to a motor/generator unit, or an electric water pump (EWP), to further optimise the vehicle operation. The electrically assisted TC permits a reduced turbo-lag and the recovery of the extra energy at the TC turbine. The EWP permits to reduce the inertia of the cooling system precisely operated for a faster warm-up and better steady state conditions. The vehicle energy management permitted by the E-KERS and the electrification is concluded to represent a fundamental step to improve the fuel economy of today’s passenger cars.
Boretti, Albert, Al-Zubaidy, Sarim
Development of the Synchronizer-Less System for HV-AMT2016-01-11724/5/2016
Recently, for the aspects of ecology and economy, fuel efficiency improvement demand has been increased globally. And, various types of hybrid systems have been suggested. In response to this market demand, AISIN SEIKI has been developing Synchronizer-less hybrid automated manual transmission (HV-AMT) system aiming excellent transmission efficiency, excellent agility, and shift change quality like a step automatic transmission (AT). This hybrid system is constructed based upon a parallel 2-axis manual transmission (MT) which originally has high transmission efficiency. The synchronizer system of a MT is replaced by a Dog clutch system which does not spoil the transmission efficiency and never makes failure in synchronization. This Dog clutch system includes a modified detent function, a shift actuator of linear motor, advanced function controls for a clutch and a shift actuator. The system does have a motor, the traction motor, perhaps say that it does not need an additional motor for synchronization. This hybrid system also realizes smooth acceleration feel of the vehicle like a step AT and excellent drive feel of a MT for agility and drivability, eliminating torque interruption at power-on-down shift or power-on-up shift by coordinate control of a hybrid motor generator (MG), a clutch and an engine. In this paper, AISIN SEIKI describes the “Synchronizer-less system” for the HV-AMT system.
Iwata, Takashi, Mori, Kyosuke, Maruyama, Taketoki, Nakamura, Shinobu, Yoshida, Yusuke, Yamanaka, Toshihiko
The GM RWD PHEV Propulsion System for the Cadillac CT6 Luxury Sedan2016-01-11594/5/2016
This paper describes the capabilities of a new two-motor plug-in hybrid-electric propulsion system developed for rear wheel drive. The PHEV system comprises a 2.0L turbocharged 4-cylinder direct-injected gasoline engine with the new hybrid transmission [1], a new traction power inverter module, a liquid-cooled lithium-ion battery pack, and on-board battery charger and 12V power converter module. The capability and features of the system components are described, and component performance and vehicle data are reported. The resulting propulsion system provides an excellent combination of electric-only driving, acceleration, and fuel economy.
Grewe, Timothy, Liu, Jinming, Anwar, Mohammad, Holmes, Alan, Balsley, Richard
Analysis Lead Drivability Assessment2015-01-28049/29/2015
Drivability and powertrain refinement continue to gain importance in the assessment of overall vehicle quality. This notion has transcended its light duty origins and is beginning to gain considerable traction in the medium and heavy duty markets. However, with drivability assessment and refinement also comes the high costs associated with vehicle testing, including items such as test facilities, prototype component evaluation, fuel and human resources. Taking all of this into account, any and all measures must be used to reduce the cost of drivability evaluation and powertrain refinement. This paper describes an analysis based co-simulation methodology, where sophisticated powertrain simulation and objective drivability evaluation tools can be used to predict vehicle drivability. A fast running GT power engine model combined with simplified controls representation in Matlab/Simulink was used to predict engine transients and responses. This high fidelity engine model was coupled with a detailed vehicle model in an AVL CRUISE™ environment that included dynamic models of the various driveline elements. With such a detailed vehicle model, specific driving scenarios and conditions were simulated and the responses were passed to AVL DRIVE™ for drivability evaluation. AVL DRIVE is a drivability evaluation tool comprising of a data collection system and data analysis software that can recognize and score individual drivability events. Within Drive the collected objective data was compared to a database of best in class vehicles and a subjective driveability score based on a 1-10 scale was returned. The results of this initial drivability simulation were then used to determine needed improvements to the powertrain calibration and control strategy. While this study is a preliminary step towards using analytical models for driveability assessment, greater refinement of the models is necessary in order to achieve better correlation with the experimental data. Such a methodology can tremendously reduce the amount of time and effort required to understand and tune drivability, before on-road testing commences.
Walters, Travis Lee, Shaw, Phillip, Madurai Kumar, Mahesh, Hoop, Joshua
Active Control of Structure-Borne Road Noise Based on the Separation of Front and Rear Structural Road Noise Related Dynamics2015-01-22226/15/2015
Axle forces from tire-road interaction can excite different structural resonances of the vehicle hence a high number of sensors is required for observing and separating all the vibrations dynamics that are coherent with the cabin noise. Feed-forward road noise control strategies adopted so far rely mainly on capturing these dynamics and thus the number of sensors constitutes one major limitation of this approach. Therefore there is a necessity for reducing the number of sensors without degrading the performance of an ANC system. In the past coherence function analysis has been found to be a useful tool for optimizing the sensor location. In this case coherence function mapping was performed between an array of vibration sensors and the headrest microphones in order to identify the locations on the structure that are highly correlated with road noise bands in the compartment. A vehicle with an advanced suspension system was used for applying the method and defining some locations as reference signals for feed-forward active road noise control. Three different real-time control experiments were performed with structure-borne road noise simulated by applying broad band random forces to tires through shaker transducers. A single reference feed-forward adaptive controller evaluated the signals from each sensor location with simulated road noise excitation applied to: front wheels only, rear wheels only and whole vehicle. This way it is demonstrated that the control can be focused at specific road noise bands with a low number of sensors.
Zafeiropoulos, Nikos, Ballatore, Marco, Moorhouse, Andy, Mackay, Andy
Tyre Load Analysis of Hydro-Pneumatic Interconnected Suspension with Zero Warp Suspension Stiffness2015-01-06304/14/2015
The purpose of this paper is to present a concept of Hydro-Pneumatic Interconnected Suspension (HPIS) and investigate the unique property of the zero warp suspension stiffness. Due to the decoupling of warp mode from other modes, the road holding ability of the vehicle is maximized meanwhile the roll stability and ride comfort can be tuned independently and optimally without compromise. Ride comfort can be improved with reduced bounce stiffness and the progressive air spring rate can reduce the requirement of suspension deflection space. The roll stability can also be improved by increased roll stiffness. Vehicle suspension system modelling and modal analysis are carried out and compared with conventional suspension. The frequency response of tyres' dynamic load reveals that the proposed zero-warp-stiffness suspension enables the free articulation of front and rear axles at low frequency. The wheel load transfer is significantly reduced when travelling on uneven off-road surface at low speed, hence the handling/traction performance are greatly improved and twisting load on vehicle body/frame can be reduced.
Xu, Guangzhong, Zhang, Nong, Roser, Holger, Ruan, Jiageng
Comparing Robust Design Optimization and Reliability Based Optimization Formulations for Practical Aspects of Industry Problems2015-01-04714/14/2015
Need for accounting Robustness and Reliability in engineering design is well understood and being researched. However, the actual practice of applying robustness and reliability methods to high fidelity CAE based simulations, especially during optimization is just starting to gain traction in last few years. Availability of computing power is helping the use of such methods, but, at the same time the demand for modeling stochastic behavior with high fidelity CAE simulations and considering large number of stochastic variables still makes it prohibitive. Typically, Robust Design Optimization (RDO) formulations calculate mean and standard deviation of responses based on sampling. On the other hand Reliability Based Design Optimization (RBDO) formulations have been using methods like First Order Reliability Method (FORM) or Second Order Reliability Method (SORM) which require nested optimization to evaluate joint probability distribution and reliability factor. It is difficult for an industry practitioner with limited expertise in optimization to decide which approach to use when they want to find a robust yet optimal design. This paper will try to evaluate these approaches based on following criteria; 1. Ease of articulating the problem formulation; 2. Effectiveness and flexibility of solution strategy; and 3. Ease of analyzing the data from optimization and picking a final solution. This Paper will also try to highlight the use of multi-objective formulations for both approaches. The paper will focus on industry examples where one has to use commercial tools for optimization and simulation. This paper covers the application and comparison of the above mentioned methods based on practical solution aspects for automotive problems and crash safety. One of the Automotive problem will be from safety application that will use models from MADYMO. All the optimization, uncertainty quantification and automation of CAE analysis tools is performed using commercial optimization software modeFRONTIER. Based on results from various cases, the paper will summarize advantages and disadvantages of both approaches and try to recommend a formulation better suitable for certain problem type.
Gokhale, Apurva, Parashar, Sumeet, Kansara, Saket
Power Dense and Robust Traction Power Inverter for the Second-Generation Chevrolet Volt Extended-Range EV2015-01-12014/14/2015
The Chevrolet Volt is an electric vehicle with extended-range that is capable of operation on battery power alone, and on engine power after depletion of the battery charge. First generation Chevrolet Volts were driven over half a billion miles in North America from October 2013 through September 2014, 74% of which were all-electric [1, 12]. For 2016, GM has developed the second-generation of the Volt vehicle and “Voltec” propulsion system. By significantly re-engineering the traction power inverter module (TPIM) for the second-generation Chevrolet Volt extended-range electric vehicle (EREV), we were able to meet all performance targets while maintaining extremely high reliability and environmental robustness. The power switch was re-designed to achieve efficiency targets and meet thermal challenges. A novel cooling approach enables high power density while maintaining a very high overall conversion efficiency.
Anwar, Mohammad, Hayes, Monty, Tata, Anthony, Teimorzadeh, Mehrdad, Achatz, Thomas
The True Definition and Measurement of Oversteer and Understeer2015-01-15924/14/2015
The concept of vehicle understeer and oversteer has been well studied and equations, test methods, and test results have been published for many decades. This concept has a specific definition in the steady-state driving range as opposed to quantification in highly transient limit handling events. There have been specific test procedures developed and employed by automotive engineers for decades on how to quantify understeer. These include the constant radius method, the constant steering wheel angle/variable speed method, the constant speed/ variable radius method, and the constant speed/variable steer method. These methods are very good for calculating the understeer gradient but care must be taken in interpreting the result at the limits of tire traction since lateral tire forces can be reduced on a drive axle when significant throttle is applied. This paper focusses on the mainstream definition of understeer and oversteer and how that objective metric should be measured on a motor vehicle and where care should be taken in interpreting results. A proposed “Transient Oversteer metric” was also evaluated and was found to not have mainstream acceptance and was very dependent on driver inputs and not vehicle handling characteristics. In fact, the results could not be repeated.
Tandy, Donald F., Colborn, Jason, Bae, Jung C., Coleman, Clay, Pascarella, Robert
Advanced Rolling Mechanics Analysis (AROMA) 1.0TBMG-218654/1/2015
AROMA uses a boundary-element formulation to calculate normal and shear pressure distributions and sub-surface stresses for elastic bodies in contact. In addition to handling static normal and sheer loading, it also solves the contact problem for rolling elements such as bearings, traction drives, and wheel-to-rail interfaces. AROMA is a powerful and flexible tool for studying the tractive forces that arise during rolling in combination with kinematic effects, such as creepage and spin that are related to rolling element alignment. This GUI-based tool was developed in MATLAB, and can run within the MATLAB environment or as a standalone application.
Torque Vectoring of a Formula SAE through Semi Active Differential Control2014-32-008811/11/2014
In a Formula SAE car, as for almost all racecars, suppressing or limiting the action of the differential mechanism is the technique mostly adopted to improve the traction exiting the high lateral acceleration corners. The common Limited Slip Differentials (LSDs) unbalance the traction torque distribution, generating as a secondary effect a yaw torque on the vehicle. If this feature is electronically controlled, these devices can be used to manage the attitude of the car. The yaw torque introduced by an electronically controlled LSD (which can also be called SAD, “Semi-Active Differential”) could suddenly change from oversteering (i.e. pro-yaw) to understeering (i.e. anti-yaw), depending on the driving conditions. Therefore, controlling the vehicle attitude with a SAD could be challenging, and its effectiveness could be low if compared with the common torque vectoring systems, which act on the brake system of the car. In addition, unlike common ESC (“Electronic Stability Control”) systems do, a SAD can modify the vehicle attitude without limiting its traction performance, which is a crucial factor for racecars. This paper shows the SAD designed at the University of Florence, highlighting its technical features and discussing its torque vectoring capabilities through the results of the simulation performed with a numerical vehicle model. These results show that this system is capable of improving the performance of the vehicle, in terms of both vehicle stability and traction.
Annicchiarico, Claudio, Capitani, Renzo
Frictional Characteristics of Crystalline Calcium Sulfonate Detergent in Engine Oil by Mini-Traction Machine2014-01-278910/13/2014
Harsh emission control regulation restricted the sulfated ash, sulfur and phosphorus (SAPS) level in passenger car motor oil (PCMO), thus lubricant industry need to find new additive to partially or wholly replace Zinc dialkyldithiophosphate (ZDDP), which has been used as an antioxidant and anti-wear agent for several decades. Overbased crystalline calcium sulfonate (CCS) detergent comprises calcite calcium carbonate and this structure might be useful to improve the anti-wear property of engine oil in severe lubrication condition, especially for PCMO with lower SAPS level. Frictional characteristics were studied between overbased amorphous calcium sulfonate (ACS) detergent and CCS and their interactions with dispersant and ZDDP by Mini-Traction Machine, which is often used to measure the Stribeck Curve of lubricant. In poly alpha-olefin base oil, both the two detergents showed lower traction coefficient in boundary lubrication (BL) regime, and higher traction coefficient in mixed lubrication (ML) regime than that of the base oil itself, and the traction coefficient of CCS was higher than that of the ACS. With 0.5% high molecular weight dispersant (HMWD) existing in the oil, the traction coefficient of ACS increased significantly in BL regime, while that of CCS decreased dramatically in ML and elasto-hydrodynamic lubrication (EHL) regimes. The traction coefficient of CCS in BL regime raised gradually by increasing the treat level of dispersant, and the same phenomenon was also shown for ACS, which indicated that HMWD has some antagonistic effect on the anti-wear property in engine oil. In addition, introducing 1% ZDDP in the 5% dispersant and 1% detergent system, the traction coefficient of CCS reduced remarkably in BL regime and increased evidently in ML and EHL regimes, but the coefficient of ACS changed little comparatively. In fully formulated engine oil, the traction coefficient of the two detergents was similar to the results when they blended with HMWD and ZDDP. In summary, the traction coefficient of oil with CCS can be reduced in BL regime, but it also induced the increase of traction coefficient in ML and EHL regimes. It should be carefully balanced in fully formulated engine oil.
Cao, Congrui, Liu, Gongde, Zhang, Runxiang, She, Haibo, Tao, Qiangqiang
The Study of Operating Efficiency Enhancement of Traction Motor with the Application of a Two-Speed Transmission in an Electric Bus2014-01-289110/13/2014
This paper discusses whether it is possible to improve the motor efficiency by a two-speed transmission in an electric bus, and if so, to what extent. Based on the China Bus Urban Cycle, an 8-meter electric bus was studied via simulation in Matlab/Simulink. The comparison of motor efficiency between two different configurations was made: direct drive and drive through a two-speed transmission. In the first part of the simulation, the speed ratios of the two-speed transmission were chosen as 1.5 and 3.5. The motor efficiency was improved by 1.22% for driving and 1.66% for generation. To find out the maximum improvement and corresponding optimal speed ratio combination, scanning experiment of the lower ratio and upper ratio was conducted in the second part. As much as 1.66% improvement of driving efficiency and 2.20% of regenerating efficiency was achieved. Moreover, two 3-D maps (drive and regenerate) were derived, in which X-axle and Y-axle represented upper gear ratio and lower gear ratio respectively and Z-axle for the improvement of efficiency. Moreover, two 3-D maps were generated to show the relationship between efficiency and lower/upper gear ratios. These two maps revealed optimal speed ratio combination and provided reference for choosing ratios. This study shows that two-speed transmission has potential to improve overall operating efficiency of traction motor, and also provided a method to determine the optimal speed ratio combination.
Yang, Fuyuan, Du, Lei, Yao, Changsheng, Du, Jiaen, Yu, Ping
Safe and Eco Friendly Train Traction System with No Rails2014-01-22899/30/2014
In this research paper, a novel train traction system is described. In this system, the vehicle is lifted like a hovercraft by air cushion and the traction is achieved by using horizontally mounted all-wheel drive. Chance of derailment is completely eliminated and wherein even in the event of failure of few traction wheel stations during run, the train remains mobile with absolute safety even at high speeds. All-wheel drive traction is powered by overhead electrification to maintain high power to weight ratio and faster acceleration. In the present invention, no rail is used. This eliminates the enormous cost of laying the complex and expensive railway tracks. Other advantages include the lack of exhaust fumes and carbon emissions at point of use especially in countries where electricity comes primarily from non-fossil sources, less noise, lower maintenance requirements of the traction units. In case, where the availability or laying the overhead electrification is an issue, the present invention has the potential to adopt alternate power sources such as petrol or diesel or gas turbine or jet engines or hybrid power sources for traction. But ecological issues may have to be compromised in such cases. The present invention has a potentially wide scope to revolutionize urban and suburban railway traction (both passengers and goods) and long distance traction. For proving the technical feasibility, a working model was developed. In this paper, the results from the working model are discussed in detail. (Indian patent and PCT application are pending).
Giridharan, K
Comparison of Fuel Efficiency and Traction Performances of 6 × 4 and 6 × 2 Class 8 Tractors2014-01-23589/30/2014
The objective of this project was to compare the fuel consumption and traction performances of 6 × 2 and 6 × 4 Class 8 tractors. Two approaches have been considered: evaluation of 6 × 2 tractors, modified from 6 × 4 tractors, and evaluation of OEM 6 × 2 tractors. Compared to the 6 × 4 tractors, which are equipped with a rear tandem with both drive axles, the 6 × 2 tractors have a rear tandem axle with one drive axle, and one non-drive axle, also called dead axle. The 6 × 2 tractor configurations are available from the majority of Class 8 tractor manufacturers. The SAE Fuel Consumption Test Procedures Type II (J1321) and Type III (J1526) were used for fuel consumption track test evaluations. Traction performances were assessed using pull sled tests to compare pulling distance, maximum speed, and acceleration when pulling the same set sled on similar surface. Fuel consumption tests showed that 6 × 2 tractors consume up to 3.5% less than the similar 6 × 4 tractors, whilst pull sled tests showed shorter distance, lower maximum speed, and lower acceleration for the 6 × 2 tractors, when compared to similar 6 × 4 tractors. These differences are not critical or even not observable in normal operating conditions of on-highway transport but in specific conditions characteristic of particular northern operations, these differences could impact the performance of the tractor. However, systems are available for transferring the load from the dead axle to the drive axle in special conditions, for increasing the traction. With 6 × 2 axles, traction tires can be installed only on the drive axle, while the dead axle can be equipped with more fuel-efficient tires, which can bring more fuel savings and tire cost savings. Another advantage is the weight reduction: it was shown that the 6 × 2 tractors were lighter than the 6 × 4 tractors, and reducing a vehicle's tare weight can translate into an increase in payload, which would enhance freight transportation efficiency. At no additional cost, the 6 × 2 tractors replacing 6 × 4 Class 8 tractors could reduce annually the GHG emissions up to 1.93 tonnes per vehicle.
Surcel, Marius-Dorin, Provencher, Yves
Study of Two-Motor Hybrid Bulldozer2014-01-23769/30/2014
Hybrid bulldozers use less fuel by providing better efficiency and fewer emissions, which was confirmed by one Caterpillar application of D7E in the market in 2010. To take advantages of the series hybrid bulldozer system, Chinese government launched similar hybrid bulldozer with independent double motor design. The Hybrid Bulldozer Power-Train system includes 14 components including motor, motor control system, engine, super capacitor to BMS and etc. This specific hybrid architecture, compared with D7E, removes the complicated hydraulic steering system. Instead, the steering function was developed by running both traction motors, further simplifying the power-train system. A Diesel engine is used to propel the attached generator to produce AC power which is then converted to DC power and connected with the main power link (super capacitor). DC power is finally converted back to AC to propel those two independent traction motors. CAN network is applied for communication. Information could be displayed by the CAN connected instruments while components' status can be detected and diagnosed. By using remote wireless system (GPRS), the bulldozer could realize remote monitoring and remote driving functions. The energy-saving principles with the corresponding power flow control algorithm of hybrid bulldozer are discussed. The power-train controller, based on driver's demand and vehicle situation, send torque or speed commands to the traction motors. A super capacitor was used as energy storage device. The vehicle control algorithms control the engine in the highly efficient load conditions, while the super capacitor works as a buffer to prevent the voltage from fluctuating. The results of vehicle tests show that the power follow control strategy can achieve the performances of 24% fuel efficiency.
Wang, Hongyu, Liu, Lin, Zheng, Guanyu, Liu, Xiaohui, Zhao, Xiumin
Identification of Traction and Power Characteristics of Air-Screw Propulsors in Mathematical Description of Airship2014-01-21349/16/2014
The paper formulated and solved the problem of investigating the traction and power characteristics of air-screw propulsor for airships. The study is performed by constructing a mathematical model relating the steady-state values of the shaft power and traction on the axis of the screw with the velocity of rotation and the actual velocity of the aircraft. Proved design scheme selection of computer simulation of aero-and thermodynamic processes occurring during rotation of the airscrew. Describes plan developed under the experimental task, providing variation in the basic parameters of the airscrew, motion parameters and flight environment The results of computer modeling of the interaction of the airflow with the airscrew at various combinations of these parameters. Results are shown in tabular and graphical form and as a mathematical model of the studied airscrew. Importantly, by developed and tested the method can construct mathematical models of airscrew propulsors any specific structures and geometrical parameters. This result is extremely important and useful for solving problems related to the selection, design and optimization of airscrew propulsors of airships and other aircraft with airscrew propulsors. These results are important for the development of motion control systems aircraft.
Neydorf, Rudolf, Sigida, Youriy
A Novel Method for Side Slip Angle Estimation of Omni-Directional Vehicles2014-01-03034/1/2014
The omni-directional vehicle is an innovative vehicle, in which the in-wheel steering motor and in-wheel driving motor are integrated into each wheel of the vehicle so that each wheel can be independently controlled to have traction, braking, and turning motions to improve the vehicle's mobility, handling and stability. To realize good performance, various control strategies have been proposed, like the active steering control and the direct yaw moment control, where the accurate slip angle information is critical to these control strategies. However, in practice, the side slip angle is hard or expensive to be measured for a passenger vehicle, therefore, different estimation methods have been proposed in the literature. In this paper, a novel side slip angle estimation method is proposed for the omni-directional vehicle that has four independent steering motors. This method includes the estimation of total alignment torque and side slip angle, and only needs the measurements of steering angles and steering motor currents, which are available by using angle sensors and current sensors embedded with the in-wheel steering motors. Numerical simulations are used to validate the effectiveness of the proposed side slip angle estimation approach.
Li, Boyuan, Du, Haiping, Li, Weihua
A Study on North American Customer Preference to Interior Noise using Sound Balance Analysis2014-01-00234/1/2014
A new approach to achieve better customer perception of overall vehicle quietness is the sound balance improvement of vehicle interior sound during driving. Interior sound is classified into 3 primary sound source shares such as engine sound relative to revolution speed, tire road noise and wind noise relative to vehicle speed. Each interior sound shares are classified using the synchronous time-domain averaging method. The sound related to revolution order of engine and auxiliaries is considered as engine sound share, tire road noise and wind noise shares are extracted by multiple coherent output power analysis. Sound balance analysis focuses on improving the relative difference in interior sound share level between the 3 primary sound sources. Virtual sound simulator which is able to represent various driving conditions and able to adjust imaginary sound share is built for several vehicles in same compact segment. Objective sound evaluation targeting the North American customer is carried out using the virtual sound simulator tool in audio lab and it is verified that overall customer perception is improved by modification of sound balance between 3 primary sound shares. Through objective evaluation for the North American customer, the effectiveness of each sound source to each driving condition and customer perception of overall quietness and preference was found. In this paper the development guideline for interior for the North American market is suggested as well as effective countermeasures for improving sound balance.
Lim, Cha-Sub, Han, Eunjun, Apelian, Chahe, Bogema, David
Terrain Model as an Interface for Real-Time Vehicle Dynamics SimulationsTBMG-194264/1/2014
In order to enable off-road vehicle dynamics analysis simulations when traveling on soft soil, a deformable Vehicle Terrain Interface (VTI) model that interfaces with existing vehicle and tire dynamics models was developed. It is modularized to be interfaced to a multibody dynamics vehicle that supports the Standard Tire Interface (STI). Any tire model can be used that supports the STI as well; currently, both rigid and flexible tire models are supported.
A Simplified Method to Make the Flux Table Considering Temperature Dependence of IPMSM2013-01-249710/14/2013
This paper proposes a simplified method to make the flux table considering the magnetic flux variation of the IPMSM (Interior Permanent Magnet Synchronous Machine) caused by temperature change in vehicle traction applications. Nowadays, normally an IPMSM with a rare-earth magnet is used for HEV traction applications. But because the flux density of the magnet varies with temperature, the optimal operating points, such as MTPA (Maximum Torque Per Ampere) and MTPV (Maximum Torque Per Voltage) of the motor drift according to temperature change. Those operating points can be expressed in a lookup table, that is, a flux table obtained by off-line experiment, which produces the DQ-axis current command with respect to the torque and flux reference. To reflect this temperature dependence in control, usually flux tables are generated at high, medium and low temperatures. Conventionally, all the three tables are constructed by experiment, which takes a great deal of time. In this paper, suggested is a simplified way that the two tables at low and high temperatures are constructed using a flux table at a medium temperature and the back EMF values at three temperatures. The simulation and experimental results of the proposed method are shown to verify its feasibility.
Kim, Sang Min, Kwon, Taesuk, Kim, Hyeong Su
Study on the Vehicle Cabin Noise Employing the Interfacial Friction in Double Layered Frames Used in Electric Vehicle Traction Motors2013-01-259010/14/2013
Electric vehicles are considered not only eco-friendly but also quieter than vehicles with conventional internal combustion engines. However, less noisy environments in cabins make passengers feel uncomfortable to moderate noise. This paper discusses noise reduction for electric vehicles radiated from traction motors. In the analysis of the noise generation mechanisms it is demonstrated that frequency ranges of the highest level in the noise spectrum of electromagnetic harmonic orders of the induction motor coincide with structural resonances of the motor housing. Interfacial friction between the inner and outer housings of the motor is employed in reducing structural vibration of the motor. Measured noise in the cabin and vibration at the motor housing indicates that slip damping presented from interfacial friction between the inner and outer housing is effective in reducing noise from the traction motor and in the cabin.
Park, Jongchan, Lee, Hyeoun Dong
Electric Drive of an Industrial Tractor2013-01-24699/24/2013
A traction electric drive is offered for an industrial tractor. The drive contains the generator, the controlled rectifier, the independent inverters, and two onboard motors. The important feature of the offered electric drive is application of synchronous reactive machines of independent excitation as the generator and traction motors. These electric machines have the following technical features: the generator and motor design is brushless; and simple, the rotor has high mechanical rigidity that raises reliability at high speeds and overloads. There are no windings on the rotor; the motor is designed for ease of manufacture (by expert estimations its price is lower than the squirrel cage induction motor on the order of 15-20 %). The machines have increased efficiency a result of a “cold” rotor design; the motors have high torque overloads capacity (up to 4-6 times the values of nominal torque). The windings of the motor and the generator are single-layered with full step capability of current and voltage. The motor control is transistors based. The range of the torque regulation is 1:10 resulting in constant power for the drive. The stator circuits are supplied from individual current sources via transistor single-phase autonomous inverters. The intermediate direct current link design of the three-wire circuit allows the use of half the number of transistors in the autonomous inverters. In the generator, working and excitation are divided to simplify the power circuits of the converter. The control system of the drive is similar to electric drives of a direct current machine and can have several operating modes. This electric drive is not only a good traction drive, but also has possible application for other mechanisms where high load duty cycles are required for operation, because the simplicity of a design. It is brushless and has a high operational and overload torques capability.
Usinin, Uriy, Gladyshev, Sergey, Grigoryev, Maxim, Shishkov, Alexander, Bychkov, Anton, Belousov, Evgeny
Development of a Combat Vehicle FEA Tire Model for Off-Road Applications2013-01-06324/8/2013
Off-road vehicle performance of a multi-wheeled 8×8 combat vehicle is strongly affected by the tire-terrain interaction characteristics. Soft soil reduces traction and modifies vehicle handling; therefore tire dynamics play a strong role in off-road mobility evaluation. In this paper three-dimensional, non-linear Finite Element Analysis (FEA) off-road tire models are developed using PAM-CRASH and the general trends of vertical load-deflection, cornering characteristics and aligning moment on rigid terrains are predicted and compared with published, measured data of a similar tire for validation purposes. The FEA off-road tire models are used to investigate the multi-pass behavior of the wheels running and steering on soft terrain. The steering characteristics of the multi-wheels are also predicted for the purpose of the development of tire-soft soil empirical equations for future research work.
Ragheb, Hossam, El-Gindy, Moustafa, Kishawy, Hossam
Development of Down-sized Motor Stator2013-01-17634/8/2013
Down-sizing and dielectric insulation were required for the traction motors of hybrid vehicles. By utilizing the newly developed coil with thick resin insulation atop the conventional enamel film, the use of conventional inter-phase insulation paper was abolished. Furthermore, by adopting the stair-shaped coil structure and spiral winding configuration, the stator size was minimized. With the above technologies, the motor installation to smaller hybrid vehicles was realized, thus contributing to weight reduction of hybrid vehicles.
Utaka, Ryosuke, Kaneiwa, Hiroshi, Umeda, Atsushi, Mizutani, Tatsuhiko, Takasaki, Akira, Kato, Mitsuru
Development of an Integrated Electrified Powertrain for a Newly Developed Electric Vehicle2013-01-17594/8/2013
This paper describes a newly developed electrified powertrain that incorporates various energy-saving improvements and is intended for use on a 2013 model year EV. Based on a 2011 model year EV that was specifically designed and engineered as a mass-produced EV, this powertrain integrates the traction motor, inverter and charging unit to achieve a smaller, lighter package for expanding application to more vehicles. Integration of the motor and inverter in particular reduced the part count for enhanced assembly ease, in addition to reducing heat transfer, noise and vibration. The specific features described in the paper are the three points below. Improving the layout of the inverter parts in order to downsize and integrate the inverter with the motor. Reducing the transfer of heat from the motor to the inverter. Reducing the excitation forces of the motor and optimizing the inverter for noise and vibration.
Shimizu, Hirofumi, Okubo, Takahito, Hirano, Izuho, Ishikawa, Shigeaki, Abe, Makoto
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