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Viewing 271 to 300 of 11068
2017-03-28
Technical Paper
2017-01-1491
Manish Kumar Seth, Jens Glorer, Ralf Schellhaas
Abstract For long automakers around the globe are trying to reduce weight and cost of the components in order to make vehicles more cost and fuel efficient. This paper deals with same problem for rear twist beam for an upcoming vehicle, the task was to reduce the weight and cost of the twist beam structure without compromising on attributes as compared to the surrogate part. This problem was solved by inventing a new torsion profile and gusset combination which uses shape instead of thickness to use material more efficiently thereby reducing weight and cost. This invention has been successfully patented as well.
2017-03-28
Journal Article
2017-01-0411
Yuming Yin, Subhash Rakheja, Jue Yang, P-E. Boileau
Abstract This study is aimed at characterizing the nonlinear stiffness and damping properties of a simple and low cost design of a hydro-pneumatic suspension (HPS) that permits entrapment of gas into the hydraulic fluid. The mixing of gas into the oil yields highly complex variations in the bulk modulus, density and viscosity of the hydraulic fluid, and the effective gas pressure, which are generally neglected. The pseudo-static and dynamic properties of the HPS strut were investigated experimentally and analytically. Laboratory tests were conducted to measure responses in terms of total force and fluid pressures within each chamber under harmonic excitations and nearly steady temperature. The measured data revealed gradual entrapment of gas in the hydraulic fluid until the mean pressure saturated at about 84% of the initial pressure, suggesting considerably reduced effective bulk modulus and density of the hydraulic fluid.
2017-03-28
Journal Article
2017-01-0404
Anatoliy Dubrovskiy, Sergei Aliukov, Sergei Dubrovskiy, Alexander Alyukov
Abstract Currently, a group of scientists consisting of six doctors of technical sciences, professors of South Ural State University (Chelyabinsk, Russia) has completed a cycle of scientific research for creation of adaptive suspensions of vehicles. We have developed design solutions of the suspensions. These solutions allow us to adjust the performance of the suspensions directly during movement of a vehicle, depending on road conditions - either in automatic mode or in manual mode. We have developed, researched, designed, manufactured, and tested experimentally the following main components of the adaptive suspensions of vehicles: 1) blocked adaptive dampers and 2) elastic elements with nonlinear characteristic and with improved performance.
2017-03-28
Journal Article
2017-01-0419
Yuliang Yang, Yu Yang, Ying Sun, Jian Zeng, Yunquan Zhang
Abstract In addition to ride comfort, handling stability and other conventional vehicle performances, we should also focus on other aspects of performance to a center axle trailer combination, such as the maximum stable side-inclination, the anti-rolling stability, the lateral stability and so on. Based on the finite element method, a rigid-flexible coupling model for the truck combination was built and analyzed in the multi-body environment (ADAMS), in which the key components of the chassis and cab suspension were treated as flexible bodies. A series of simulations were carried out to evaluate the lateral stability of the center axle trailer in accordance with the relevant regulations of the vehicle. The influence of design variables on the lateral stability was studied by an experiment. Furthermore, in order to improve the lateral stability of the trailer combination, the optimal design was obtained by the co-simulation of the ADAMS/Car, iSIGHT and Matlab.
2017-03-28
Journal Article
2017-01-0418
Gregory McCann, Prashant Khapane
Abstract An increase in data measurement and recording within vehicles has allowed Anti-lock Braking Systems (ABS) to monitor a vehicle’s dynamic behavior in far more detail. This increased monitoring helps to improve vehicle response in scenarios such as braking whilst cornering and braking on uneven surfaces. The Durability and Robustness (D&R) CAE department within Jaguar Land Rover discovered that the lack of a complex ABS system in virtual vehicle models was contributing to poor lateral and longitudinal loads correlation throughout the suspension and mounting systems. D&R CAE started a project to incorporate Continental’s ABS system, provided by ‘©Continental AG’ for physical JLR vehicles, into SIMPACK virtual vehicles by means of a co-simulation (2017 n.d.). The work involved collaboration between 3 departments in Jaguar Land Rover and ultimately led to implementation of the ABS into the JLR standard automotive virtual database.
2017-03-28
Journal Article
2017-01-0412
Mina M.S. Kaldas, Kemal Çalışkan, Roman Henze, Ferit Küçükay
Abstract Semi-active suspension offers variety of damping force range which demands greater need to optimize the top mount to ensure multiple objectives of ride comfort, harshness and safety can be achieved. For this purpose, this paper proposes a numerical optimization procedure for improving the harshness performance of the vehicle through the adjustment of the damper top mount characteristics of the semi-active suspension system. The proposed optimization process employs a frequency dependent combined objective function based on ride comfort and harshness evaluation. A detailed and accurate damper top mount mathematical model is implemented inside a validated full vehicle model to provide a realistic simulation environment for the optimization study. The semi-active suspension system employs a Rule-Optimized Fuzzy-Logic controller. The ride comfort and harshness of the full vehicle are evaluated by analyzing the body acceleration in different frequency ranges.
2017-03-28
Journal Article
2017-01-0437
Bin Li, Subhash Rakheja
Abstract In this paper, a gain-scheduling optimal control approach is proposed to enhance yaw stability of articulated commercial vehicles through active braking of the proper wheel(s). For this purpose, an optimal feedback control is used to design a family of yaw moment controllers considering a broad range of vehicle velocities. The yaw moment controller is designed such that the instantaneous tractor yaw rate and articulation angle responses are forced to track the target values at each specific vehicle velocity. A gain scheduling mechanism is subsequently constructed via interpolations among the controllers. Furthermore, yaw moments derived from the proposed controller are realized by braking torque distribution among the appropriate wheels. The effectiveness of the proposed yaw stability control scheme is evaluated through software-in-the-loop (SIL) co-simulations involving Matlab/Simulink and TruckSim under lane change maneuvers.
2017-03-28
Journal Article
2017-01-0421
Xiang Liu, Wei Chen, Ying Chen, Jing Zhao
Abstract The leaf spring has significant hysteresis characteristics due to the interleaf friction. The traditional three-link model could not simulate the hysteresis characteristics at all. According to the dynamic load test results one can find that the dynamic stiffness of leaf spring has a nonlinear relationship with the travel distance and the load frequency has a tiny influence on it. Based on the traditional three-link model, this paper proposed a simulation modeling method by introducing torsional friction on the revolute joints. The key parameters including torsional spring stiffness, friction torque preload, stiction transition velocity and max stiction deformation are optimized by combining the ADAMS and OPTIMUS. The comparison analysis between the simulation and test results of front and rear leaf springs have revealed that the maximum average errors are 4.84% and 6.41%, respectively.
2017-03-28
Journal Article
2017-01-1554
Ajith Jogi, Sujatha Chandramohan
Abstract Over the years, commercial vehicles, especially tractor-semitrailer combinations have become larger and longer. With the increasing demand for their accessibility in remote locations, these vehicles face the problem of off-tracking, which is the ensuing difference in path radii between the front and rear axles of a vehicle as it maneuvers a turn. Apart from steering the rear axle of the semitrailer, one of the feasible ways of mitigating off-tracking is to shift the fifth wheel coupling rearwards. However, this is limited by the distribution of the semitrailer’s load between the two axles of the tractor; any rearward shift of the fifth wheel coupling results in the reduction of the total static load on the tractor’s front axle and hence available traction. This may in turn lead to directional instability of the vehicle. In the present work, a new model of the fifth wheel coupling is proposed which the authors call Split fifth wheel coupling (SFWC).
2017-03-28
Journal Article
2017-01-1519
Arturo Guzman, Young-Chang Cho, John Tripp, Kumar Srinivasan
Abstract Pickup trucks are designed with a taller ride height and a larger tire envelope compared to other vehicle types given the duty cycle and environment they operate in. These differences play an important role in the flow field around spinning wheels and tires and their interactions with the vehicle body. From an aerodynamics perspective, understanding and managing this flow field are critical for drag reduction, wheel design, and brake cooling. Furthermore, the validation of numerical simulation methodology is essential for a systematic approach to aerodynamically efficient wheel design as a standard practice of vehicle design. This paper presents a correlation the near-wheel flow field for both front and rear spinning wheels with two different wheel designs for a Ram Quad Cab pick-up truck with moving ground. Twelve-hole probe experimental data obtained in a wind tunnel with a full width belt system are compared to the predictions of numerical simulations.
2017-03-28
Journal Article
2017-01-1111
Marcello Canova, Cristian Rostiti, Luca D'Avico, Stephanie Stockar, Gang Chen, Michael Prucka, Hussein Dourra
Abstract To improve torque management algorithms for drivability, the powertrain controller must be able to compensate for the nonlinear dynamics of the driveline. In particular, the presence of backlash in the transmission and drive shafts excites sharp torque fluctuations during tip-in or tip-out transients, leading to a deterioration of the vehicle drivability and NVH. This paper proposes a model-based estimator that predicts the wheel torque in an automotive drivetrain, accounting for the effects of backlash and drive shaft flexibility. The starting point of this work is a control-oriented model of the transmission and vehicle drivetrain dynamics that predicts the wheel torque during tip-in and tip-out transients at fixed gear. The estimator is based upon a switching structure that combines a Kalman Filter and an open-loop prediction based on the developed model.
2017-03-28
Technical Paper
2017-01-0439
Joydeep Chatterjee, Yuva Kishore Vaddi, Chetan Prakash Jain
Abstract In urban driving conditions, the steering vibration plays a major role for a customer, spending a significant amount of time behind the steering wheel. Considering the urban drive at Indian roads, 1000~1600rpm band becomes primary area of concern. In this paper, study has been conducted to define the target areas as well as its achievement in reference to given driving pattern on a front wheel powered passenger car for steering vibration. During the concept stage of vehicle development, a target characteristic of steering wheel vibration was defined based on the competitor model benchmarking and prior development experience. A correlated CAE model was prepared to evaluate the modification prior to prototype building and verification. Vibration level in all 3 degrees of freedom at the steering wheel location was measured in the initial vehicle prototypes and target areas of improvement are identified.
2017-03-28
Technical Paper
2017-01-1058
L.V. Pavan Kumar Maddula, Ibrahim Awara
Abstract Increased focus on fuel efficiency and vehicle emissions has led the automotive industry to look into low weight alternative designs for powertrain system components. These new design changes pose challenges to vehicle attributes like NVH, durability, etc. Further, the requirement of high power applications produces even more complexities. The present work explains how a potential design change of half shafts driven by a desire to reduce weight and cost can lead to NVH problems caused by half shaft resonances and explains how using multiple dynamic vibration absorbers can solve the issue to meet customer expectation while improving efficiency. With the aid of Finite Element Analysis (FEA) & optimization software, interactions between multiple DVA’s on a system was understood and optimal damper parameters for effective damping was identified. The final DVA design was tested and verified on the vehicle for optimal attribute performance.
2017-03-28
Technical Paper
2017-01-1551
Charlie Lew, Nath Gopalaswamy, Richard Shock, Bradley Duncan, James Hoch
Abstract The aerodynamics of a rotating tire can contribute up to a third of the overall aerodynamic force on the vehicle. The flow around a rotating tire is very complex and is often affected by smallest tire features. Accurate prediction of vehicle aerodynamics therefore requires modeling of tire rotation including all geometry details. Increased simulation accuracy is motivated by the needs emanating from stricter new regulations. For example, the upcoming Worldwide harmonized Light vehicles Test Procedures (WLTP) will place more emphasis on vehicle performance at higher speeds. The reason for this is to bring the certified vehicle characteristics closer to the real-world performance. In addition, WLTP will require reporting of CO2 emissions for all vehicle derivatives, including all possible wheel and tire variants. Since the number of possible derivatives can run into the hundreds for most models, their evaluation in wind tunnels might not be practically possible.
2017-03-28
Technical Paper
2017-01-1562
Junyu Zhou, Chao Liu, Jan Kubenz, Günther Prokop
Abstract This paper describes a new hybrid algorithm for multibody dynamics in vehicle system dynamics which combines the advantages of both embedding technique algorithm and augmented formulation algorithm. An approach to vehicle dynamics modeling based on the hybrid algorithm is presented. Embedding technique algorithm has relatively small number of equations of motion. With help of this technique, an enhanced parametric vehicle dynamics model can be built, representing characteristic curves of suspension comprised in kinematic and compliance. Small number of equations enables the vehicle dynamics model to be simulated very efficiently. In comparison to embedding technique algorithm, the main benefit of augmented formulation algorithm is relatively simple for computer programming. With help of augmented formulation algorithm, the structure of the vehicle dynamic model can be easily extended.
2017-03-28
Technical Paper
2017-01-1565
Xiangkun He, Kaiming Yang, Xuewu Ji, Yahui Liu, Weiwen Deng
Abstract A vehicle dynamics stability control system based on integrated-electro-hydraulic brake (I-EHB) system with hierarchical control architecture and nonlinear control method is designed to improve the vehicle dynamics stability under extreme conditions in this paper. The I-EHB system is a novel brake-by-wire system, and is suitable to the development demands of intelligent vehicle technology and new energy vehicle technology. Four inlet valves and four outlet valves are added to the layout of a conventional four-channel hydraulic control unit. A permanent-magnet synchronous motor (PMSM) provides a stabilized high-pressure source in the master cylinder, and the four-channel hydraulic control unit ensures that the pressures in each wheel cylinder can be modulated separately at a high precision. Besides, the functions of Anti-lock Braking System, Traction Control System and Regenerative Braking System, Autonomous Emergency Braking can be integrated in this brake-by-wire system.
2017-03-22
Article
Replacing the decade-old Jeep Compass is the new-for-2017 Jeep Compass, FCA’s (and Jeep’s) first truly global vehicle program. Styled to resemble a slightly scaled-down Grand Cherokee, the new C-segment SUV is being produced in four plants (Mexico, China, India and Brazil) and offered in 17 powertrain combinations including diesels and 6-speed manual gearboxes.
HISTORICAL
2017-03-21
Standard
AS5714
This SAE Aerospace Standard (AS) prescribes the Minimum Performance Standards (MPS) for wheel, brake, and wheel and brake assemblies to be used on aircraft certificated under 14 CFR Parts 23, 27, and 29. Compliance with this specification is not considered approval for installation on any aircraft.
2017-03-13
Article
Startup-company Twin Spring Coupling features its new power transfer coupling that is warrantied to 300 lb·ft (407 N·m) of torque.
CURRENT
2017-03-13
Standard
J2995_201703
This recommended practice will specify a standard duty cycle and set of conditions for component-level durability testing. The "duty cycle" refers to a set of loading conditions (e.g. torque or pressure and cycling count), and the 'test conditions" refers to environmental conditions such as temperature, humidity, and part conditioning from prior exposure (e.g. heat aging).
CURRENT
2017-02-13
Standard
J2611_201702
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.
2017-02-13
WIP Standard
J2789
This Recommended Practice is useful to determine the inertia value (wheel load and tire radius) using three basic methods (fixed brake work split, dynamic weight transfer, and axle rating) to determine the wheel load and two methods to determine the tire radius (SLR and rolling radius). The inertia values are required to determine the amount of energy and brake work imposed on the brake during testing. The inertia level (mechanical or simulated) is required also to calculate deceleration levels from a given torque value or the torque level for a given deceleration value or set-point. This procedure is applicable to all passenger cars and light trucks up to 4,540kg of GVWR.
2017-02-09
Article
UQM Technologies signed a development agreement with Meritor to jointly develop E-axles for the medium- and heavy-duty EV commercial market, according to a February 2 announcement. Prototypes are expected by early fall of 2017.
2017-02-09
WIP Standard
J2247
This SAE Recommended Practice identifies the minimum truck tractor electrical power output of the stop lamp and ABS (antilock brake system) circuits measured at the primary SAE J560 tractor trailer interface connector(s).
CURRENT
2017-02-09
Standard
J1469_201702
This SAE Recommended Practice provides procedures and methods for testing service, spring applied parking, and combination brake actuators with respect to durability, function, and environmental performance. A minimum of six test units designated A, B, C, D, E, and F are to be used to perform all tests per 1.1 and 1.2.
CURRENT
2017-02-02
Standard
J380_201702
Specific gravity is a nondestructive test used as a quality control check of the consistency of formulation and processing of brake lining. The specific gravity and the range of specific gravity are peculiar to each formulation and, therefore, the acceptable values or range must be established for each formulation by the manufacturer. Specific gravity alone shows nothing about a materials in use performance. The specific gravity of sintered metal powder friction materials, particularly those which have steel backing members, is usually determined somewhat differently. Reference ASTM B 376.
CURRENT
2017-02-02
Standard
J379_201702
Hardness measurements are used as a quality control check of the consistency of formulation and processing of brake linings. Gogan hardness is nondestructive (the penetrator causes shallow surface deformation.). Gogan hardness method alone does not show anything about a lining’s ability to develop friction or to resist fade when used as a friction element in brakes. The hardness and the range of hardness are peculiar to each formulation, thickness, and contour; therefore, the acceptable values and ranges must be established for each formulation and part configuration by the manufacturer.
CURRENT
2017-02-02
Standard
J2581_201702
This SAE Information report defines the thermal transport properties important in the assessment of heat management capability of brake lining, shoe, disc and drum materials. The report discusses thermal diffusivity, specific heat capacity, thermal conductivity and thermal expansion. Measurement techniques for the appropriate ASTM standards are identified. The thermal transport properties discussed are material sample properties, not the properties of entire components such as pad assemblies.
2017-01-31
WIP Standard
AIR6417
This Aerospace Information Report (AIR) provides information related to experience with carbon brake quality-assurance rejected takeoff tests, and considerations regarding test setup, test conditions, test frequency and cost considerations.
2017-01-25
Article
Dr. Christian Wiehen, Chief Technology Officer for WABCO, discusses ADAS, platooning and automated future for trucks.
Viewing 271 to 300 of 11068

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