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Viewing 61 to 90 of 10218
2015-04-14
Technical Paper
2015-01-1127
Wenbin Liu, Gangfeng Tan, Xiaoqing Tian, Zhiqiang Hu, Yuanqi Gao, Zhi Li, Junyi Yuan, Wei Liu
Abstract The hydraulic retarder is an important auxiliary braking device for the heavy vehicle, which has some characteristics, such as the big brake torque and long duration braking, when the vehicle is traveling in braking state. However, the transmission power loss will be produced when the vehicle is traveling in non-braking state. This transmission power loss is called Air-friction. Firstly, the air flow distribution characteristics of retarder cavity are studied by computational fluid mechanics, and the Air-friction characteristic in different conditions is analyzed. Then, according to the Air-friction characteristics for the condition of different filling density, a set of vacuum air loss reduction system is designed. Meanwhile, the test bench for retarder Air-friction is set up, the test data of the revolution speed, pressure in cavity and air loss resistance is obtained according to the test bench for hydraulic retarder.
2015-04-14
Technical Paper
2015-01-1504
WeiNing Bao
A ball screw regenerative shock absorber was designed for the relief of the vehicle vibration and the energy recovery of the vehicle vibration. The effect of its main parameters on the suspension system was numerically analyzed. According to the principle of the ball screw regenerative suspension system, a mathematical model of the ball screw regenerative shock absorber was established regarding the ball screw rotational inertia, the motor rotational inertia, the screw lead and the radius of the screw nut. A suspension dynamic model based on the ball screw regenerative shock absorber was developed combining the road model and the two-degrees-of-freedom suspension dynamic model.
2015-04-14
Journal Article
2015-01-1505
Ibrahim A. Badiru
Vehicle pull is a condition experienced by customers where a constant torque at the steering wheel is required to maintain the vehicle on a straight path. Vehicle lead is a condition where a non-zero steering wheel angle is required to maintain a straight path. There are many potential causes for vehicle pull or lead—road condition, suspension asymmetry, and tire characteristics to name a few. Both vehicle pull and lead can cause customer dissatisfaction with the vehicle as well as drive OEM warranty service costs. Electronic Power Steering (EPS) systems have overtaken Hydraulic Power Steering (HPS) as the predominate steering architecture for new passenger vehicles. One of the key benefits of EPS is the ability to program value added features (VAF) into the EPS controller. These features can significantly enhance the pleasure and safety of the driving experience for the customer. EPS pull compensation is a feature that reduces the driver workload to compensate a vehicle pull.
2015-04-14
Technical Paper
2015-01-1502
Liangyao Yu, Wenwei Xuan, Liangxu Ma, Jian Song, Xianmin Zhu, Shuai Cheng
Energy saving is one of the most popular and significant motifs of contemporary and future vehicles. A relatively large amount of concern is concentrated on the power steering system as over 70% of the fuel consumed by conventional HPS system is unnecessary and avoidable, so the application of advance power steering systems like EPS and EHPS can help a lot on saving energy. Although the EHPS system has been widely used among passenger cars, SUV, Pickup trucks and Vans, it is now still infeasible on the conventional heavy duty vehicles because of the contradiction between the limitation of the 24V electric power system and the power demand of the electric motor of the general EHPS system. As a solution for this problem, a new type of EHPS system was investigated, which can decrease the demand of the motor power significantly, so that it can be applied to heavy duty vehicles.
2015-04-14
Technical Paper
2015-01-1508
Lijiao Yu, Hongyu Zheng
As the electric technique develops fast, steering systems change from conventional mechanic steering systems to electrically controlled steering (ECS) systems, including electric power (EPS) system, active front steering (AFS) system and steer-by-wire (SBW) system. ECS could improve vehicles’ steering portability at a low speed and handing stability at a high speed. The study of ECS involves mechanic design, detection of electric components, software design and so on, which need a lot of trials and errors. By now, the development of ECS mostly depends on experiments on hard-ware-in-the-loop (HIL) and real vehicles. Because tests on real vehicles have many short cuts, such as a higher cost, a longer period, etc. HIL is gradually taking the place of real vehicles to carry out kinds of experiments in order to reduce test times, cycles and cost, which has been a main means to research and develop ECS.
2015-04-14
Technical Paper
2015-01-1513
Anudeep K. Bhoopalam, Kevin Kefauver
Indoor laboratory tire testing on flat belt machines and tire testing on the actual road yield different results. Testing on the machine offers the advantage of repeatability of test conditions, control of the environmental condition, and performance evaluation at extreme conditions. However, certain aspects of the road cannot be reproduced in the laboratory. It is thus essential to understand the connection between the machine and the road, as tires spend all their life on the road. This research, investigates the reasons for differences in tire performance on the test machine and the road. The first part of the paper presents a review on the differences between tire testing in the lab and on the road, and existing methods to account for differences in test surfaces.
2015-04-14
Journal Article
2015-01-1507
Kentaro Komori, Takahito Nagataki
Research on passenger vehicles responds to mechanical loss-reduction demands for improving fuel economy. Handling, steering feel, and ride-comfort can be attributed to the steering and suspension. We researched friction behavior in terms of low- or high- friction coefficients, and in terms of static-kinetic transient motion. We improved the vehicle handling and ride comfort by giving the appropriate friction to the tie-rod end ball joint. Controlling friction behavior, we used diamond-like carbon (DLC) coating submitted to boundary lubrication. Different DLC coatings varied widely in hydrogen content, mechanical properties and micro-surface roughness were applied to the ball joint studs. The larger the micro-surface roughness in asperity of DLC coatings, the higher the kinetic friction torque. The friction behaviors corresponded to the DLC properties.
2015-04-14
Technical Paper
2015-01-1498
Yuyao Jiang, Weiwen Deng, Sumin Zhang, Shanshan Wang, Qingrong Zhao, Bakhtiar Litkouhi
Driver steering torque feedback is one of the critically important factors in the consideration and measurement both on vehicle design and performance, and on model accuracy of vehicle dynamics. On the one hand, driver steering torque feedback is one of the key measures on human-machine interface for drivers’ comfort and intuitive road feel, such as return-to-center capability, on-center feel and ease of steering effort, etc. This mainly involves the design of vehicle dynamics as a whole, but in particular, vehicle steering system. On the other hand, it is also the most determining factor to the quality of drivers’ interaction with or driver-in-loop simulation of vehicle dynamics models, such as driver simulator, etc.
2015-04-14
Technical Paper
2015-01-1501
Ryusuke Hirao, Kentaro Kasuya, Nobuyuki Ichimaru
Many electronic control components have been introduced into vehicles with the aims of improving their safety and comfort, and saving energy. Various suspension systems have been developed, to reconcile ride feeling with control stability at a high level. Development efforts have been particularly active in the field of semi-active suspension, prompted by its superior energy-saving and cost performance. Algorithm which is based on skyhook control has been applied mostly to the ride comfort control of semi-active suspension system of vehicle. Also, at the time of steering, control for enhancing damping force are commonly used as handling control to restrain transitional roll angle. Therefore, in this development we developed new ride comfort control and new handling control, and constructed a system which uses only vehicle height sensor as dedicated sensor and uses damping force variable damper of pressure control type.
2015-04-14
Journal Article
2015-01-1506
Bastian Scheurich, Tilo Koch, Michael Frey, Frank Gauterin
Today, body vibration energy of passenger cars gets dissipated by linear working shock absorbers. A new approach substitutes the damper of a passenger car by a cardanic gimbaled flywheel mass. The constructive design leads to a rotary damper in which the vertical movement of the wheel carrier leads to revolution of the rotational axis of the flywheel. In this arrangement, the occurring precession moments are used to control damping moments and to store vibration energy. A gyroscope is set to high speed revolutions by an electric motor and a gimbal is used for bearing. The gimbal consists of an outer ring which is connected to the vertical movement of the wheel carrier. Right-angled to the outer ring, there is an inner ring pivoting the gyroscope right-angled. In order to avoid undesirable body movements, the directional vector of the angular velocity of the gyroscope is parallel to the car’s yaw axis.
2015-04-14
Technical Paper
2015-01-1211
Zhuoping Yu, Caitao Jian, Songyun Xu, Lu Xiong
Abstract To research the dynamic response of active power source of electronic hydraulic brake system, the paper proposes a restricted distribution control strategy. Building control strategy model and active power source model to simulation with Matlab/Simulink and AMEsim, and bench test is conducted on different driving cycles, which proves that the dynamic response of active power source is fit and controllable by adjusting PID parameters.
2015-04-14
Technical Paper
2015-01-1203
Subhashree Rajagopal, Sebastien Desharnais, Balamurugan Rathinam, Upendra Naithani
Abstract Electromagnetic brakes are found in a variety of applications. They offer tremendous advantages including: absence of fading, high braking torque and controllability. However they suffer from decreasing torque at low and high speeds. In this study, a novel concept of permanent magnet eddy-current brake is proposed that maintains a flat braking torque profile over a broad speed range. The principle is analytically investigated and numerically validated through finite element simulations using MAXWELL. It is demonstrated that a usably flat braking torque profile can be achieved by altering the path of eddy-currents by magnetic field orientation, thereby affecting the apparent rotor resistance.
2015-04-14
Journal Article
2015-01-0651
Mustafa Ali Arat, Saied Taheri, Edward Holweg
The road profile has been shown to have significant effects on various vehicle conditions including ride, handling, fatigue or even energy efficiency, as a result it has become a variable of interest in the design and control of numerous vehicle parts. In this study, an integrated state estimation algorithm is proposed that can provide continuous information on road elevation and profile variations, primarily to be used in active suspension controls. A novel tire instrumentation technology (smart tire) is adopted together with a sensor couple of wheel attached accelerometer and suspension deflection sensor as observer inputs. The algorithm utilizes an adaptive Kalman filter (AKF) structure that provides the sprung and unsprung mass displacements to a sliding-mode differentiator, which then yields to the estimation of road elevations and the corresponding road profile along with the quarter car states.
2015-04-14
Technical Paper
2015-01-0658
Min Zhou, Lifu Wang, Jie Zhang, Nong Zhang
Hydraulic suspensions with different interconnecting configurations can decouple suspension mode and improve performance of a particular mode. In this paper, two types of interconnected suspensions are compared for off-road vehicle trafficability. Traditionally, anti-roll bar, a mechanically interconnected suspension system, connecting left and right suspension, decouples roll mode from the bounce mode and results in a stiff roll mode and a soft bounce mode, which is desired. However, anti-roll bars fail to connect the front wheel motions with the rear’s, thus the wheels’ motions in the warp mode are affected by anti-roll bars and it results an undesired stiffened warp mode. A stiffened warp mode limits the wheel-ground contact and may cause one wheel lift up especially during off-road drive. In contrast to anti-roll bars, two types of hydraulic suspensions which interconnect four wheels (for two-axis vehicles) can further decouple warp mode from other modes.
2015-04-14
Technical Paper
2015-01-0657
Binglu Tu, Kai Shen
This innovation is a Developed Anti-Lock Brake System (DABS for short) to automatically and precisely identify, correct and verify the peak-value slip ratio S0'' (i.e. braking force = adhesion force) when ε (namely the utilization ratio of adhesion coefficient, which is defined as the quotient of maximum braking strength divided by adhesion coefficient when ABS works) =1, and control S0'' to output continuously. It is a revision on the theory, method and algorithm of current ABS control that intermittently produces S0''. The objects are to eliminate the hidden unsafety of sideslip or ε<1 due to excessive or insufficient braking force, have more simplified structure and reduced costs than ABS, and improve the eligibility from ε≥0.75 to ε≥0.95.
2015-04-14
Technical Paper
2015-01-0527
Pierre-Olivier Santacreu, Guillaume Badinier, Jean-Benoit Moreau, Jean-Marc Herbelin
Abstract A new Ni-free martensitic stainless steel (MSS) was developed for hot stamped automotive parts, especially in order to design lightweight chassis part. After hot stamping simulation, the material exhibited a 1.2 GPa ultimate tensile strength with a minimum of 10% total elongation, in the as-quenched condition (Q) without any tempering treatment (Q+T). Moreover the material's chemical composition was optimized to improve the ductility at low temperature and during high strain rate mechanical testing. As a result, no brittle fracture in impact testing at −40°C was observed, and a good behavior in crash was recorded. To further assess the material's performances, high cycle fatigue properties of the grade have been characterized including the effects of machining and surface treatments. Results show that the fatigue limits at 2 million cycles for a stress ratio of −1, for both bare and shot peened surface are quite high and in the range of 580 MPa to 640 MPa.
2015-04-14
Technical Paper
2015-01-1210
Bharat Singh, Naveen Kumar, Amaya Kak, Satya Kaul
Abstract At present, vast numbers of problems are triggered due to growing global energy crisis and rising energy costs. Since, on-road vehicles constitute the majority share of transportation; any energy losses in them will have a direct effect on the overall global energy scenario. Most of the energy lost is dissipated from the exhaust, cooling, and lubrication systems, and, most importantly, in the braking system. About 6% of the total energy produced is lost with the airstream in form of heat energy when brakes are applied. Thus, various technological systems need to be developed to conserve energy by minimize energy losses while application of brakes. Regenerative Braking is one such system or an energy recovery mechanism causing the vehicle to decelerate by converting its kinetic energy into another form (usually electricity), which further can be used either immediately or stored until needed.
2015-04-14
Technical Paper
2015-01-1598
Milad Jalaliyazdi, Amir Khajepour, Shih-Ken Chen, Bakhtiar Litkouhi
In this paper, the problem of stability control of an electric vehicle is addressed. To this aim, it is required that the vehicle follows a desired yaw rate at all driving/road conditions. The desired yaw rate is calculated based on steering angle, vehicle speed, vehicle geometric properties as well as road condition. The vehicle response is modified by torque vectoring on front and/or rear axles. This control problem is subject to several constraints. The electric motors can only deliver a certain amount of torque at a given rotational speed. In addition, the tire capacity also plays an important role in the stability control. It limits the amount of torque they can transfer without causing wheel over spinning. These constraints make Model Predictive Control (MPC) approach a suitable choice, because it can explicitly consider the constraints of the control problem, in particular the tire capacity, and help to prevent tire saturation, which is often the onset of vehicle instability.
2015-04-14
Journal Article
2015-01-1517
David Stalnaker, Ke-Jun Xie, Terence Wei
Tire manufacturers need to perform various types of testing to determine tire performance under representative vehicle load conditions. However, test results are influenced by a number of external variables other than tire construction. Vehicle load distribution and suspension properties are some of those external variables which can have a significant effect on tire wear rate and durability. Therefore, in order to measure tire performance in a controlled and repeatable manner, a representative vehicle and associated tire load conditions are needed. Laboratory or indoor tire testing offers many advantages over vehicle fleet testing. It provides a well-defined test environment and repeatable results without influence from external factors. Indoor testing has been largely developed around the process of simulating tire wear performance on a specific reference vehicle, including its specific weight distribution, suspension characteristics, and alignment.
2015-04-14
Technical Paper
2015-01-1516
Mohammed K Billal, Rizwan Basha, Anilkumar Nesarikar, Abdul Haiyum, Thomas Oery
Damages (fracture) in metals are caused by material degradation due to crack initiation and growth due to fatigue or dynamic loadings. The accurate and realistic modeling of an inelastic behavior of metals is essential for the solution of various problems occurring in engineering fields. Currently, various theories and failure models are available to predict the damage initiation and the growth in metals. In this paper, the failure of aluminum alloy is studied using progressive damage and failure material model using Abaqus explicit solver. This material model has the capability to predict the damage initiation due to the ductile and shear failure. After damage initiation, the material stiffness is degraded progressively according to the specified damage evolution response. The progressive damage models allow a smooth degradation of the material stiffness, in both quasi-static and dynamic situations.
2015-04-14
Technical Paper
2015-01-1515
Kwangwon Kim, Hyeonu Heo, Md Salah Uddin, Jaehyung Ju, Doo-Man Kim
Due to the relatively high freedom of selection of materials associated with a simple manufacturing method, a nonpneumatic tire (NPT) can be manufactured with a low viscoelastic energy loss material. A highly increasing demand to reduce greenhouse gases drives engineers to explore NPTs. NPTs consisting of flexible spokes and the shear band are still at an early stage of research and development. An optimization study of geometry of NPTs needs to be conducted, which is the objective of this paper. Parametric studies, design of experiments (DOE), and sensitivity analyses are conducted with a hyper-viscoelastic finite element (FE) model to determine the effects of three design variables on rolling resistance; the thickness of cellular spokes, the cell angle, and the shear band thickness.
2015-04-14
Technical Paper
2015-01-1512
Sairom Yoo, Md Salah Uddin, Hyeonu Heo, Jaehyung Ju, Doo Man Kim, Seok-Ju Choi
In an effort to develop tires with low rolling resistance, nonpneumatic tires (NPTs) with low viscoelastic energy loss materials are receiving more attention. For better design of NPTs for better fuel efficiency, one may need to analyze rolling energy loss of NPTs at a component level. The objective of this study is to develop a tool to quantify rolling energy loss and thermal dissipation of NPTs at a component level. For varying vehicle loads and rolling speeds, we suggest a thermo-mechanical model of an NPT with hexagonal cellular spokes to investigate temperature distribution of the NPT caused by hysteresis and convection loss into air. Using a hyper-viscoelastic model developed from a uniaxial (tensile and compression) testing and dynamic mechanical analysis (DMA), a thermo-mechanical model is developed by combining longitudinal shear deformation induced hysteresis and cooling to air.
2015-04-14
Journal Article
2015-01-1755
Atsushi Hirano
This paper studies various wheel stiffness configurations, with the aim of enhancing driving stability while minimizing the increase in weight associated with an increase in stiffness. Reinforcement was added to the wheel disk and the wheel rim of standard aluminum wheels for passenger vehicles in order to produce four wheels with different stiffness configurations. The effects of disk stiffness and rim stiffness on tire contact patch profiles and driving stability were quantitatively evaluated. From the results of tests with the four wheels, it was observed that disk stiffness and rim stiffness have differing effects on tire contact patch profiles, and on driving stability. Disk stiffness influences especially tire contact patch length, and tire contact patch length influences especially maneuverability in driving stability. Rim stiffness influences especially tire contact patch area, and tire contact patch area influences especially stability in driving stability.
2015-04-14
Journal Article
2015-01-0645
Jian Zhao, Jin Zhang, Bing Zhu
The longitudinal dynamics control is one of the essential tasks of vehicle dynamics control. In present, longitudinal dynamics control usually adjust the slip ratio of driving wheels by means of controlling the engine, transmission or braking pressure to achieve satisfied performances in stability and acceleration. In order to improve performance of longitudinal dynamics control, the coordination of the control of different parts in powertrain have to be considered. In addition, the proposed algorithms usually adopt the logic methods for simple and quick response based on less road condition information, which cannot achieve optimal performance on various road conditions. Focusing on these two issues, an integrated longitudinal vehicle dynamics control algorithm with tire/road friction estimation is proposed.
2015-04-14
Technical Paper
2015-01-0646
Jian Ou, Qing-lin Zhang, Yong Zhang, E-chuan Yang, Mei-zhi Liu
[Abstract] Vehicle transient response characteristics under steering angle input are very important to vehicle handling stability. It is of important significance to study the vehicle transient response by multi-body dynamics simulation. Be aimed at the delay of transient response under steering angle input, which gets from the tests for a new vehicle development under high speed during conditions, the following research works are carried out in this paper. (1) The lag time of transient response under steering angle input is too long for a new vehicle in its tests. And the subjective reaction of operators shows that the lag time increase obviously under high speed during conditions. Aiming at this problem, the feasibility of simulation and optimization using multi-body dynamics method is studied theoretically in this paper. (2) Based on the theory of multi-body dynamics, combining the finite element methods, a rigid -flexible coupling vehicle model is established in ADAMS/Car.
2015-04-14
Journal Article
2015-01-0643
Dzmitry Savitski, Kristian Hoepping, Valentin Ivanov, Klaus Augsburg
Anti-lock braking system (ABS) independently from the vehicle type is aimed to realize the maximally possible deceleration level and reduce the stopping distance during the braking maneuver where wheels are tending to lock. However, for better braking performance and system adaptability ABS must consider vehicle specifications and conditions in which this vehicle is going to be used. As it is experimentally approved in the represented research tire pressure variation produces noticeable influence on tire stiffness and peak friction coefficient. As consequence such changes in tire characteristics can cause distortion of the ABS functions and the stopping distance will significantly vary. In proposed research phenomenon of tire pressure variation in relation to the ABS control functions is experimentally investigated. For this purpose developed continuous ABS control algorithm was implemented to the full-electric vehicle with four individual on-board electric motors.
2015-04-14
Technical Paper
2015-01-0652
Hui Hua, Lifu Wang, Hengmin Qi, Jie Zhang, Nong Zhang
Air spring due to its superior ride comfort performance has been widely used in distance passenger transporting vehicles. Since the requirements for ride comfort and handling performance are contradict to each other, handling performance and even roll stability are sacrificed to some extent to obtain good ride comfort. Due to the complex terrain and limited manufacturing level, in the past several years, bus rollover accidents with serious casualties have been reported frequently and bus safety has attracted more and more attention from bus manufacturers in China. On one hand the bus standards have to be raised, and on the other hand, novel solutions which can effectively improve the roll stability of air spring bus are needed to replace the inadequate of anti-roll bars.
2015-04-14
Journal Article
2015-01-0649
Liangyao Yu, Shuhao Huo, WenWei Xuan, Lei Zuo
Conventional viscous shock absorbers, in parallel with suspension springs, passively dissipate the excitation energy from road irregularity into heat waste, to reduce the transferred vibration which causes the discomfort of passengers. In order to achieve better ride comfort and maneuverability, active suspensions have been proposed for decades. However, large energy consumption, which significantly increases the fuel consumption for conventional vehicles or battery consumption for electric vehicles, limits its widely utilization despite of better suspension performance. Considering the trade-off between the energy consumption and suspension performance, energy-harvesting shock absorbers, which have the potential of conversion of kinetic energy into electric power, have been proposed as semi-active suspension. Because of the high energy density of the rotary shock absorber, a rotational energy-harvesting shock absorber with mechanical motion rectifier (MMR) is used in this paper.
2015-04-14
Technical Paper
2015-01-0634
Adebola Ogunoiki, Oluremi Olatunbosun
This paper presents a statistical characterisation of the effects of variations in vehicle parameters using a quarter vehicle model as a case study. A quarter vehicle model of a commercial sport utility vehicle (SUV) is created in a multi-body dynamics simulation environment to reproduce the real-life behaviour of the SUV. The model is validated by correlating the data collected from both the model and laboratory test rig to the same road input. In order to ensure that only the effects of the variation of the vehicle parameters are captured, a time domain drive signal for a kerb strike on the on the physical vehicle is generated from the proving ground data collected during durability testing of the vehicle.
2015-04-14
Technical Paper
2015-01-0614
Ye Zhao, Liangmo Wang, Xiangli Yang, Liukai Yuan, Zunzhi Zhang
Abstract: In most cases, researches on the ride performance of air suspension system are based on simplified mathematical models which could be too theoretical or not be able to consider the coupling relationship between the various components so that they behave far away from the actual vehicle system. This paper represents the study on the ride performance of an air suspension vehicle based on the complex whole vehicle model which was established though ADAMS and Matlab. The applying of flexible components helped to improve the model accuracy and the tensile and compression tests of the air spring were used to establish the interconnected four-gasbag air suspension system. The vehicle ride performance was studied through the co-simulation between ADAMS and Matlab. The accuracy of the results were verified by the vehicle test results, which demonstrated the reliability of the whole model.
Viewing 61 to 90 of 10218

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