Display:

Results

Viewing 1 to 30 of 10186
2015-04-14
Technical Paper
2015-01-1371
Samuel T. Bartlett
With the many model variations produced on the same production line because of increasing power train options, fuel efficiency targets, performance and customer demands we saw limitations with our existing suspension mount equipment. Layout options were limited due to guided shifts and transfers. Large supporting frame work took up valuable floor space. Model wheelbase sizes and suspension pallets were limited to the model requirements of the original equipment. We needed an adaptable system to install the engine/front suspension assemblies and the rear suspension assemblies. We found a solution by utilizing the capabilities of 6-axis industrial robots to make the core components of the equipment simpler; many of the functions of a traditional machine can now be accomplished by the robot. We were able to vary install position to optimize handling characteristics and accommodate the model-to-model varieties on the same production line.
2015-04-14
Technical Paper
2015-01-1373
Yulong Lei, Hui Tang, Xingjun Hu, Ge Lin, Bin Song
With the continuous improvement of the road condition, commercial vehicles get to be faster and more overloaded than before, which puts higher pressure on the vehicle braking system. Conventional friction braking has been difficult to meet the needs of high-power commercial vehicle. The auxiliary brake equipment will become the future trend for commercial vehicle. Hydraulic retarder is superior secondary braking equipment. Previously hydraulic retarder research mainly focus on flow field analysis, the braking torque calculation, cascade system optimization and control methods for hydraulic retarder. The gas-liquid two-phase flow in working chamber is less researched. Based on this, this article discusses on the hydraulic retarder from two aspects, including CFD numerical modeling method, transient characteristics of oil-filling , which provides support for hydraulic retarder design and matching in the vehicle. The main contents and conclusions are as follows: 1.
2015-04-14
Technical Paper
2015-01-0608
Gang Tang, Hengjia Zhu, Yunqing Zhang, Ying Sun
The vehicle ride comfort behavior is closely associated with the vibration isolation system such as the primary suspension system, the engine mounting system, the cab suspension system and the seat suspension system. Air spring is widely used in the cab suspension system for its low vibration transmissibility, variable spring rate and inexpensive automatic leveling. The mathematical model of the pneumatic system including the air spring, the leveling valve and the pipe is presented. The frequency dependency of the air spring’s stiffness characteristic is highlighted. The air spring dynamic model is validated by comparing the results of the experiments and the simulation. The co-simulation method using ADAMS and AMESim is applied to integrate the pneumatic system into the cab multi-body dynamic model. The simulation and ride comfort test results under random excitation are compared.
2015-04-14
Technical Paper
2015-01-0216
Ping-Min Hsu, Ming Hung Li, Kuo-Ching Chang
This paper studies noise filtering in an autonomous emergency braking (AEB) system with a sensor fusion between a millimeter wave (MMW) radar and a camera. The AEB system may automatically brake cars by mistake due to the sudden appearance of noise signal if it does not involve any noise filtering mechanism for the object sensor. This may cause some accidents. To avoid such accidents, we propose the filters for three kinds of noise—named as twice harmonic noise, ground noise, and specular refection noise—which are commonly suffered while applying MMW radars. The former is caused by the reflection of a radar wave between a target object and the MMW radar. Based on the concern that the MMW radar evaluates the sensing distance based on the time interval between the transmitting and receiving of the radar wave, one of the sensing distances would be twice as longer as one of others due to the wave reflection. The object featuring this characteristic is further filtered.
2015-04-14
Technical Paper
2015-01-0624
Mustafa Arat, Emmanuel O. Bolarinwa
The increasing demand of energy use in transportation systems combined with the limited supply of fossil hydrocarbons to support conventional engines has led to a strong resurgence in interest for electric vehicles (EVs). Although EVs offer the possibility of decoupling the issue of energy source from the primary torque generator in an automobile, the current technology is yet to match the well-developed internal combustion (IC) systems, especially in terms of energy capacity and travel range. In this study, the influence of rolling-resistance on the energy efficiency and road holding of electric vehicles is described. Rolling resistance is taken in the context of energy loss (e.g. the mechanical energy converted into other sources of energy) for a unit distance traveled by the tire.
2015-04-14
Technical Paper
2015-01-0724
Liangxu Ma, Liangyao Yu, Jian Song, WenWei Xuan, Xuhui Liu
Magneto-rheological (MR) fluid is a novel composite material and can be used in different components of vehicle. Magneto-rheological fluids (MRF) are suspensions of micron sized whose yield stress varies rapidly as the change of magnetic field applied. The use of magneto-rheological (MR) fluids in vehicles has been gaining popular recently due to its strong rheological effect, fast response, good stability and low energy consumption, which give automotive designers more dimensions of freedom in functional designs. Nowadays, most of the related research of MRF is about the construction of the prototype and the realization of the brake force. However, due to a lack of optimal design and the understanding of MRF and magnetic field, the main research progress is only about the simulation which makes the braking effect of the prototype can hardly meet the requirement of vehicle.
2015-04-14
Technical Paper
2015-01-1600
Tong Zou, Lu Xiong, Pengfei Yang, Chi Jin
Distributed drive electric vehicles are driven by four independent hub motors mounted directly in wheels while retaining the traditional hydraulic brake system. So it can quickly produce drive/brake motor torque and large stable hydraulic brake force. In this paper a control allocation strategy for distributed drive electric vehicles (EV) is proposed to improve vehicles’ lateral stability performance. It exploits the quick response of motor torque and controllable hydraulic pressure of the hydraulic brake system. The allocation strategy is consisted of two sections. The first section uses an optimal allocation controller to calculate the total longitudinal force at each wheel. In the controller, a dynamic efficiency matrix is introduced via local linearization to improve lateral stability control performance, as it considers the influence of tire coupling characteristics over yaw moment control in extreme situations.
2015-04-14
Technical Paper
2015-01-1118
Fengyu Liu, Li Chen, Jian Yao, Jianlong Zhang, Chengliang Yin, Dongxu Li, Chunhao Lee, Ying Huang
A New Clutch Actuation System for a Dry DCT Fengyu Liu, Li Chen, Jian Yao, Jianlong Zhang, Cheng-Liang Yin Shanghai Jiao Tong University Dongxu Li, Chunhao Lee, Ying Huang General Motors LLC Abstract Dry DCT has played an important role in the high performance applications as well as low-cost market sectors in Asia, with a potential as the future mainstream transmission technology due to its high mechanical efficiency and driving comfort. Control system simplification and cost reduction has been critical in making dry DCT more competitive against other transmission technologies. Specifically, DCT clutch actuation system is a key component with a great potential for cost-saving as well as performance improvement. This paper is to propose a new actuation system that has a unique force-aid spring and consume less power. The main components of this mechanism include a lever and a pre-loaded spring. The spring can store and release energy when needed.
2015-04-14
Technical Paper
2015-01-0627
Xiaoguang Yang, Oluremi Olatunbosun, Daniel Garcia-Pozuelo, Emmanuel Bolarinwa
The development of intelligent tyre technology from concept to application covers multi-disciplinary fields. During its development course, computational method has a significant effect on understanding tyre behaviour, assisting design of intelligent tyre prototype system and developing tyre parameters estimation algorithm, etc. In this paper, finite element tyre model was adopted for developing strain-based intelligent tyre system. The finite element tyre model was created considering tyre composite structure and nonlinear material properties, which was also validated by fundamental test. It is used to study tyre strain characteristics by steady state simulation for straight line rolling, traction and braking, and cornering rolling. Tyre loading conditions were estimated by feature extraction and data fitting. This process forms the fundamentals for identifying tyre loadings from strain information on potential sensor locations.
2015-04-14
Technical Paper
2015-01-0626
Adam C. Reid, Moustafa El-Gindy, Fredrik Oijer, David Philipps
The purpose of this research paper is to outline the methodology and procedure used for the development of a wide base rigid ring tire model. A rigid ring model is a mechanical representation of a tire model in which its in-plane and out-of-plane characteristics and behaviour can be captured. The FEA construction of the tire model is first completed to match all known information regarding the physical dimensions and material properties of the tire. For information that is unknown, an optimization-based parameter tuning algorithm is then run in order to solve for said parameters while matching any experimental data that is supplied. A series of virtual experiments are then conducted which replicate laboratory tests as well as some high speed maneuvers in order to isolate for specific tire dynamic parameters.
2015-04-14
Technical Paper
2015-01-1117
Yang Liu, Zechang Sun
Regenerative braking control for a four-wheel drive (4WD) electric vehicle equipped with a decoupled electro-hydraulic brake system was studied. The 4WD electric vehicle powertrain with four in-wheel motors was introduced, and the four motors could be controlled independently during the driving or braking operation modes, which have advantages on powertrain configurations and fuel economy improvement over the vehicles driven by a single motor. An electro-hydraulic brake system using a master cylinder integrated with brake pedal feel simulator, hydraulic brake booster and failure backup was adopted to guarantee the coordinate control between the regenerative force and the hydraulic force, whose brake pedal force and wheel cylinder pressure was decoupled. The energy flow of the 4WD electric vehicle was analyzed during braking, and the brake force distribution strategy between the front-rear axles, in-wheel motor regenerative braking and hydraulic braking was studied.
2015-04-14
Technical Paper
2015-01-1127
Wenbin Liu, Gangfeng Tan, Xiaoqing Tian, Zhiqiang Hu, Yuanqi Gao, Zhi Li, Junyi Yuan, Wei Liu
As a kind of an important auxiliary brake of heavy vehicle, hydraulic retarder has good performance for stability and braking sustainability. However, the hydraulic retarder is filled with air when the vehicle is traveling in non-braking state, and the Air-friction may reduce the vehicle transmission efficiency obviously.   The air density in retarder cavity can be decreased by pumping the gas, which can reduce the transmission power loss. The gas pumping in retarder cavity has an important influence on the retarder working stability. Firstly, the dynamic characteristics relationships between the vacuum degree and the change of flow resistance in retarder cavity are analyzed by the 3D fluid simulation in different driving conditions, and the stability boundary conditions of the Air-friction change is determined.
2015-04-14
Technical Paper
2015-01-1120
Siddhartha Singh, Sudha Ramaswamy
Driving comfort is very important selling factor in today’s automobile market. Manual Transmission Clutch systems has to balance between driving control given to the driver and driver comfort.If ergonomics of ABC pedals are not taken care, driving stress will increase. The increase in engine torque because of change in technologies like turbocharging and pressure injection has also increased the release load for actuating clutch which in turn increases pedal load. There are many assistance mechanisms integrated with pedal to reduce the load like over-center spring, double torsion spring, each with its own limitations.
2015-04-14
Technical Paper
2015-01-0527
Pierre-Olivier Santacreu, Guillaume Badinier, Jean-Benoit Moreau, Jean-Marc Herbelin
A new Ni-free martensitic stainless steel was developed for hot stamped automotive parts, especially in order to design lightweight chassis. After hot stamping simulation, the material exhibits 1.2 GPa ultimate tensile strength with 8% total elongation, in the as-quenched condition (without any tempering treatment). Moreover the material’s chemical composition was optimised 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 behaviour in crash was recorded. To further assess the material’s performance, high cycle and low-cycle fatigue properties of the grade were characterized and the effects of machining and surface were studied. Results show that the fatigue limits at 2 million cycles for a stress ratio of -1 for rough bare surface and shot peened surface are quite high at 0.45 and 0.55 times the ultimate tensile strength (in the range of 540 MPa to 640 MPa).
2015-04-14
Technical Paper
2015-01-1601
Long Chen, Mingyuan Bian, Yugong Luo, Keqiang Li
Nowadays, vehicle active safety systems have attracted more attention than ever before due to the dramatically increasing demand for driving safety.Since the forces between the tires and road interface primarily determine the states of vehicle motion, accurate information about road-tire friction coefficient is crucial to get a better performance in such system. As a new type of vehicle structure, the distributed electric vehicle, which has some advantages in estimating states of vehicle and tire, may bring new breakthroughs in estimating road-tire friction coefficient. This paper proposes a method of estimating road-tire friction coefficient for the distributed electric vehicle during the pure longitudinal wheel slip, lateral sideslip and combined slip situations.
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
Technical Paper
2015-01-0628
Bin Li, Xiaobo Yang, Yunqing Zhang, James Yang
As one of the most important components of a vehicle, a tire is essential for vehicle handling, ride comfort as well as durability. Although several decade efforts have been dedicated to tire modeling, there is still room to improve its performance. Currently tire models cannot accurately predict the longitudinal spindle force under severe road conditions. In order to improve the prediction results, a detailed in-plane flexible ring tire model is proposed based on multi body dynamic (MBD) approach in this paper. In this model, we discretize the belt into different belt segments, and each belt segment is considered as a rigid body and attached to a number of parallel tread blocks. This model is able to describe the tire behavior for the transformation among static condition, quasi-static rolling, as well as dynamic rolling conditions.
2015-04-14
Technical Paper
2015-01-0607
Xincheng Liang, Jingshan Zhao
This paper proposes a theoretical model to interpret the heat generation mechanism and thermal failure of shock absorber. For a common structure of double-tube shock absorber, all frictions between two contacting components of shock absorber are calculated particularly. The heat generation mechanism and heat distribution can be explained with the theoretical model. Thermal failure is a recurrent malfunction for traditional shock absorber, which leads to shorten the service lives of vehicle components. Heat generation experiments are accomplished to validate the thermal degeneration of shock absorber. So this study is meaningful to develop a new system of vibration attenuation that is essential to improve the riding comfort and handling stability of vehicles.
2015-04-14
Journal Article
2015-01-1088
Tomohiko Usui, Tomoya Okaji, Tatsuya Muramatsu, Yoshiyuki Yamashita
A low-cost lock-up damper displaying a high level of damping performance has been developed for use in torque converters in automatic transmissions. The new damper was actualized by sharing parts (the turbine and damper components) and optimizing parameters for damping characteristics. The new torque converter displays equivalent conversion performance to a conventional model while reducing the width of the torus by approximately 30%. The combination of the lock-up damper and the small torus has made it possible to reduce torque fluctuation transmitted to the transmission to less than 50% with no increase in the overall width of the torque converter against a conventional model. This has reduced engine speed when the vehicle is cruising by 400rpm, resulting in an increase in fuel efficiency of approximately 2%.
2015-04-14
Journal Article
2015-01-1481
Myles Wilson, David Aylor, David Zuby, Joseph Nolan
The Insurance Institute for Highway Safety (IIHS) evaluates autonomous emergency braking systems as part of its front crash prevention (FCP) ratings. The evaluation is based on the vehicle’s ability to avoid or mitigate crashes at 20 and 40 km/h. To ensure that the tested vehicle’s brakes are in service condition, IIHS protocol requires each test vehicle accumulate between 200 and 5,000 miles before testing and also complete a brake warm-up with 10 stops from 56 km/h at 5 to 6 m/s2 and three stops from 72 km/h that activate ABS. Other organizations, including automakers, conducting AEB testing follow the brake burnishing procedure described in Federal Motor Vehicle Safety Standard (FMVSS) 135; Light Vehicle Brake Systems. Before testing compliance with the standard, FMVSS 135 requires test vehicles make 200 stops from 80 km/h at a deceleration of 3.0 m/s2.
2015-04-14
Technical Paper
2015-01-1436
Divyanshu Joshi, Anindya Deb, Manoj Mahala, Clifford Chou
In the past few decades, increasing concern for vehicle occupant safety and comfort has motivated the development of advanced tools for vehicle dynamics analysis. To date, most of the published work on vehicle stability predominantly employs basic handling models such as 2-DOF (degrees of freedom) bicycle model, as well as 3, 4 and 5-DOF models that capture lateral and yaw dynamics alone or coupled with longitudinal, roll and pitch dynamics. 2-DOF quarter car, 4-DOF half car and 7-DOF full car models are found to be the most popular configurations for ride comfort analysis. It is noted that ride comfort and stability have mostly been dealt with independently by researchers, however, a coupling may exist in reality when a vehicle encounters road irregularities, bumps, potholes, etc. while undergoing a maneuver.
2015-04-14
Technical Paper
2015-01-0591
Karan R. Khanse, Eric Pierce, Michael Ng, Saied Taheri
Outdoor objective evaluations form an important part of both tire and vehicle design process since they validate the design parameters through actual tests and can provide insight into the functional performances associated with the vehicle. Even with the industry focused towards developing simulation models, their need cannot be completely eliminated as they form the basis for approving the performance predictions of any new vehicle model. An objective test was conducted to measure the ABS performance as part of validation of a tire design tool. A sample vehicle and a set of tires were to perform the tests- on a road with known profile. These specific vehicle and tire sets were selected due to the availability of the vehicle parameters, tire parameters and the ABS control logic. A test matrix was generated based on the validation requirements.
2015-04-14
Technical Paper
2015-01-0576
Jiaquan Chen, Yongfeng Jiang, Min Qin, Wenquan Hao, Yin-Ping Chang, Lingge Jin
This research proposes an automatic computer aided design, analysis, and optimization process of a twist beam rear suspension system. The process combines both CAD (Computer-Aided Design) and CAE (Computer-Aided Engineering) technologies which includes: structural analysis, dynamic analysis, vibration analysis, durability analysis, and multidisciplinary optimization. The results show the durability and K&C (kinematics & compliance) characteristics of the twist beam suspension are improved.
2015-04-14
Technical Paper
2015-01-0625
Manfred Baecker, Axel Gallrein, Michael Roller
The tire plays a fundamental role in the generation of acoustically perceptible driving noise and also in the generation of vibrations inside the vehicle. Drivers and passengers will perceive vibrations inside the vehicle as interference of their physical comfort. An essential part of these vibrations will be induced by the road excitation and be transferred via the tire into the vehicle. There are 2 basic ways to study the NVH behavior of a tire or a full vehicle including a tire: • Transient simulation scenario • Frequency based or modal simulation scenario In the first case the tire or full vehicle will be simulated using a transient dynamic simulation method. The vehicle or tire is driving over an arbitrary digitized road profile. There is no need for a stationary driving state or for the necessity of a constant driving velocity.
2015-04-14
Journal Article
2015-01-0623
Jiaquan Chen, Min Qin, Yongfeng Jiang, Lingge Jin, Yin-Ping Chang
The theory of rigid-elastic coupling (REC) model is introduced. The REC model of a twist beam is verified by comparing with results of FEM model. In order to increase computation speed of simulation, an artificial neural network is constructed to substitute complex model. Finally the Pareto theory and NSGAⅡ genetic algorithm are applied to carry out multi-objective optimization design of bushing stiffness and setting angle.
2015-04-14
Journal Article
2015-01-0622
H. Metered, A. Elsawaf, T. Vampola, Z. Sika
Proportional integral derivative (PID) control technique is the most common control algorithm applied in various engineering applications. Also, particle swarm optimization (PSO) is extensively applied in various optimization problems. This paper introduces an investigation into the use of a PSO algorithm to tune the PID controller for a semi-active vehicle suspension system incorporating magnetorheological (MR) damper to improve the ride comfort and vehicle stability. The proposed suspension system consists of a system controller that determine the desired damping force using a PID controller tuned using PSO, and a continuous state damper controller that estimate the command voltage that is required to track the desired damping force. The PSO technique is applied to solve the nonlinear optimization problem to find the PID controller gains by identifying the optimal problem solution through cooperation and competition among the individuals of a swarm.
2015-04-14
Journal Article
2015-01-0621
Mina M.S. Kaldas, Kemal Çalışkan, Roman Henze, Ferit Küçükay
Nowadays with the advances in the vehicle control systems, the customers want new and exciting features in their vehicles, which make the vehicle driving characteristics adjustable as they prefers. One of the vehicle controlled systems which can be used to change the vehicle driving characteristics from time to time is the semi-active suspension system. Therefore, the paper presents a rule-optimized fuzzy controller for semi-active suspension system which is continuously adjusts itself according to the road conditions and the drivers’ requirements. The proposed rule-optimized fuzzy controller has three different control modes (Sport, Normal and Comfort), which can be switched using the button and thus adjusted to customer requirements. The Normal Mode is adjusted to provide an overall balance between the vehicle ride comfort and road holding. On the other hand, the Comfort Mode is adapted to leads to a comfort-oriented, softer basic configuration of the damping.
2015-04-14
Technical Paper
2015-01-0620
Manoj Mahala, Anindya Deb, Clifford Chou
Idealized mathematical models, also known as lumped parameter models (LPMs), are widely used in analyzing vehicles for ride comfort and driving attributes. However, the limitations of some of these LPMs are sometimes not apparent and a rigorous comparative study of common LPMs is necessary in ascertaining their suitability for various dynamic situations. In the present study, the mathematical descriptions of three common LPMs, viz. quarter, half and full car models, are systematically presented and solved for the appropriate response parameters such as body acceleration, body displacement, and, pitch and roll angles using representative passive suspension system properties. By carrying out a comparison of the three stated LPMs for hump-type road profiles, important quantitative insights, not previously reported in the literature, are generated into their behaviors so that their applications can be judicious and efficient.
2015-04-14
Technical Paper
2015-01-0616
Aref M.A. Soliman
In this paper, passive and various types of intelligent vehicle suspension systems are compared in terms of their relative ride performance capabilities and power requirements. These systems are, two and three setting switchable dampers and active suspension systems. The control gains of the intelligent systems are obtained using optimal control theory and gain scheduling strategy (GS) is used for the system behaviour. In the first strategy used, gains are selected based on suspension working space. While, the other strategy, gains are selected based on body acceleration. These strategies are used to maintain suspension working space and dynamic tyre deflection levels within design limits and to minimise body acceleration level. The mean power consumed in rolling resistance and the mean power dissipation within the suspensions are evaluated. The results showed that the gain scheduling strategy improves ride performance for all the types of suspension compared.
2015-04-14
Journal Article
2015-01-0432
Xingxing Feng, Jinglai Wu, Yunqing Zhang, Ming Jiang
The optimization of vehicle suspension kinematic/compliance characteristics is of significant importance in the chassis development. Practical suspension system contains many uncertainties which may result from poorly known or variable parameters or from uncertain inputs. However, in most suspension optimization processes these uncertainties are not accounted for. This study explores the use of Chebyshev polynomials to model complex nonlinear suspension systems with interval uncertainties. In the suspension model, several kinematic/compliance characteristics are considered as objectives to be optimized. Suspension bushing characteristics are considered as design variables as well as uncertain parameters. A high-order response surface model using the zeros of Chebyshev polynomials as sampling points is established to approximate the suspension kinematic/compliance model.
Viewing 1 to 30 of 10186

Filter