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Viewing 31 to 60 of 10218
2015-04-14
Technical Paper
2015-01-1524
Ping Chen, Nan Xu, Konghui Guo, Rongsheng Liu
Tire lateral force is essential to vehicle handling and stability under cornering. However, it is difficult for engineers to get tire lateral force under high loading condition due to the loading ability limitation of most tire test machine in the world. Widely used semi-empirical tire lateral force models are obtained by curve-fitting experiments data and don’t possess load prediction ability. The objective of this paper is to predict the tire lateral force model under high-load condition based on low-load tire data. The nonlinear characteristic of tire cornering stiffness vary with load is greatly affected by tire carcass compliance. In this paper, a theoretical tire lateral model was built by considering carcass complex deformation. Combined with the relationship between half-length of tire contact patch and load, the non-linear characteristic of tire cornering stiffness vary with load was obtained.
2015-04-14
Technical Paper
2015-01-1500
Marcus Ljungberg, Mikael Nybacka, Gaspar Gil Gómez, Diomidis Katzourakis
This paper present and discusses the process to parameterize an electric power assist steering (EPAS) system, employing solely computer-aided engineering (CAE). It addresses the model and the simulation environment setup as-well-as methods for setting the optimal metric targets, based on correlation studies from expert test drivers. The rationale for the study derives from today’s vehicle manufacturer’s needs, to develop high quality cars in a short period of time that satisfy the consumer needs and to stand out in the competition. Further exploitation of the potentials of simulation and CAE tools is needed to enable quick evaluation of different vehicle concepts and setups without the need of building physical prototypes. The main goal of the current study is to facilitate the aforementioned need by developing and evaluating an optimisation process for the control parameters of an EPAS system by solely using CAE tools.
2015-04-14
Technical Paper
2015-01-0591
Karan R. Khanse, Eric Pierce, Michael Ng, Saied Taheri
Abstract 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 newly developed model. An objective test was conducted to measure the ABS performance as part of validation of a tire simulation design tool. A sample vehicle and a set of tires were used 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
2015-01-0625
Manfred Baecker, Axel Gallrein, Michael Roller
Abstract The tire plays a fundamental role in the generation of acoustically perceptible driving noise and vibrations inside the vehicle. An essential part of these vibrations is induced by the road excitation and transferred via the tire into the vehicle. There are two basic ways to study NVH behavior: Simulations in time and frequency domains. The system can be simulated using a transient simulation method with the disadvantage of high simulation and process turnaround times. Alternatively, a linearization around a stationary state is performed and solved in frequency domain with fast numerical schemes. Modelling the tire transfer behavior in frequency domain requires special attention to the rotation of the tire. This paper shows the approach taken by the authors to include the transfer behavior in the frequency range up to 250 Hz from geometric road excitations to resulting spindle forces in frequency domain. Special care has been used in the modelling of local road excitations.
2015-04-14
Technical Paper
2015-01-0616
Aref M.A. Soliman
Abstract 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 active, two and three setting switchable dampers 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 (GS) used, gains are selected based on suspension working space. While, the other strategy (GS), 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 is evaluated.
2015-04-14
Technical Paper
2015-01-0620
Manoj Mahala, Anindya Deb, Clifford Chou
Abstract 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
2015-01-0641
R. Pradeepak, Mihir Bhambri, Shafeeq Rahman
Abstract This paper describes about handling validation of a motorcycle on a steady state condition. Nowadays, it is very usual and common to get a feedback by motorcycle test riders that the steering feel is heavy due to which more effort is required to complete a full track circuit. So it has become a necessity to focus the study on handling dynamics of motorcycle at the initial stage itself using a numerical tool. To decide the handling characteristics it is very important to focus on the steering effort required at the handle bar by the rider, as it is the main control to study the ‘out of plane’ dynamics. To test the vehicle for steering performance, track radius and velocity were chosen as the variables to avoid the transient behavior and identify the key parameters at a faster rate. To study & investigate the steering effort influencing factors, an MBD numerical tool helped to solve the problem.
2015-04-14
Technical Paper
2015-01-0724
Liangxu Ma, Liangyao Yu, Jian Song, WenWei Xuan, Xuhui Liu
Abstract This paper presents a new magnetorheological braking which can be used in vehicles. Magneto-rheological (MR) fluid is a novel material which can be used in different components of vehicle. Magneto-rheological fluids (MRF) are suspensions of micron size whose yield stress varies rapidly as the change of magnetic field. The use of MRF in vehicles has been gaining popular recently due to its strong rheological effect, fast response and low energy consumption. Besides, these performances give designers more choice in automotive designs. However, most of the related research of MRF brake is about the construction of small prototype to verify its rheological performance. As a result, research progress is limited to calculation and simulation which make the braking force of prototype can hardly meet the requirement of vehicle due to a lack of optimal design and the understanding of MRF in the situation of high sheer stress and magnetic field.
2015-04-14
Technical Paper
2015-01-0630
Guangzhong Xu, Nong Zhang, Holger Roser, Jiageng Ruan
Abstract 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.
2015-04-14
Technical Paper
2015-01-1347
Fiona Ruel, Pierre-Olivier Santacreu, Saghi Saedlou, Guillaume Badinier, Jean Herbelin
In order to meet new environmental regulations (i.e. mass of CO2 rejected in the atmosphere per km), car manufacturers are looking for new solutions to lighten chassis and structural parts in cars. High strength steels formed by hot stamping have proved to be good candidates for achieving better in-use performances together with a lighter structure. In particular, our martensitic stainless steel MaX fulfils the industrial targets for chassis parts in terms of mechanical and fatigue properties which could potentially lead to a 15% to 20% weight saving. However, those parts are often made of a complex assembly of different materials (high strength steels, aluminium and cast iron among others) which are subjected to aggressive environments in service. Therefore galvanic corrosion of those complex assemblies has to be evaluated.
2015-04-14
Technical Paper
2015-01-0635
Changxin Wang, Wenku Shi, Zhijun Guo, Meilan Liu
Abstract For the roll vibration problem of a Truck, a 4-DOF roll vibration model of its front suspension system was built. According to dynamics theory, the complex modal vibration modes of the model were all obtained. At the same time, the frequency response functions of frame roll angle acceleration, the relative dynamic load of wheel and the suspension dynamic deflection were respectively presented. Then their characteristics were respectively researched. In the process of characteristic analysis, a new system parameter was proposed, which is the space ratio of the space between suspensions of left and right sides and the wheel track of the front axle (space ratio in short). At last, the influence of system parameters on the vibration transmission property was also reserached, which included the natural frequency of the frame, the damping ratio, the stiffness ratio, the mass ratio, the rotational inertia ratio and the space ratio.
2015-04-14
Technical Paper
2015-01-0617
Jie Zhang, Xiao Chen, Bangji Zhang, Lifu Wang, Shengzhao Chen, Nong Zhang
Abstract This paper demonstrates time response analysis of the mining vehicle with bounce and pitch plane hydraulically interconnected suspension (HIS) system. Since the mining vehicles working in harsh conditions inducing obvious pitch motion and the hard stiffness of suspensions leading to the acute vibration, the passive hydraulically interconnected system is proposed to provide better ride comfort. Furthermore, the hydraulic system also increases the suspension stiffness in the pitch mode to prevent vehicle from large pitch motions. According to the hydraulic and mechanical coupled characteristic of the mining vehicles, a 7degrees of freedom (7-DOFS) mathematical model is employed and the state space method is used to establish the mechanical and hydraulic coupled dynamic equations. In this paper, the vehicles are subjected to straight line braking input, triangle block bump input applied to the wheels and random road tests.
2015-04-14
Technical Paper
2015-01-0613
Donghong Ning, James Coyte, Hai Huang, Haiping Du, Weihua Li
Abstract This paper presents a study on experimental vibration simulation using a multiple-DOF motion platform for heavy duty vehicle seat suspension test. The platform is designed to have 6-DOF with the advantages of high force-to-weight ratio, high dexterity and high position accuracy. It can simulate vehicle vibrations in the x, y and z translational axis and in the roll pitch and yaw axis rotation. To use this platform to emulate the real vibration measured from vehicle seat base under real operation for vehicle seat suspension test in lab, an Inertial Measurement Unit (IMU) is applied to collect the acceleration data from a real vehicle. An estimation algorithm is developed to estimate the displacement from the measured acceleration. The estimated displacement is then used to calculate the length of each leg of the platform so that the platform can generate the motion similar to the measured one.
2015-04-14
Technical Paper
2015-01-0216
Ping-Min Hsu, Ming Hung Li, Kuo-Ching Chang
Abstract This paper discusses noise filtering in an autonomous emergency braking (AEB) system with a sensor fusion between a millimeter wave (MMW) radar and a camera. Three kinds of noise, namely twice harmonic noise, ground noise, and specular reflection noise, are then filtered. The former is caused by the reflection of a radar wave between a target object and the MMW radar; therefore, one of the sensing distances would be twice as longer as one of others. An object featuring this characteristic is treated as the noise and filtered. Next, detecting a ground metal as the target object generates the second noise with a focus of car-like objects. That is, an object-with the sensing distance from the MMW radar being smaller than that from the camera by a threshold value-is taken as the ground metal noise and ignored. Moreover, the third noise happens when there is a radar wave reflection between an object and its surroundings.
2015-04-14
Technical Paper
2015-01-1612
Wei Liu, Gangfeng Tan, Jiafan Li, Xin Li, Fuzhao Mou, Yongqiang Ge
Abstract The hydraulic retarder is a significant auxiliary braking device [1] for the heavy duty vehicle. Traditionally, cooling circulatory system of the hydraulic retarder was coupled with the engine cooling system [2], and the thermal energy of the transmission medium would be cooled by the engine radiator ultimately. For this scheme, radiator's spare heat removal capacity could be fully utilized whereas the cooling system is very complicated and is hard to maintain. Furthermore, the corresponding of thermal management system lags behind the power change of the retarder. In this research, integrated cooling evaporation system is developed for the hydraulic retarder, which makes the cooling water contact with the transmission medium through the stator wall, so that it can rapidly response to the thermal variation of the retarder, keep the stability of the oil temperature and meanwhile reduce the risk of cooling medium leakage.
2015-04-14
Technical Paper
2015-01-1601
Long Chen, Mingyuan Bian, Yugong Luo, Keqiang Li
Abstract This paper proposes an estimation method of road-tire friction coefficient for the 4WID EV(4-wheel-independent-drive electric vehicle) in the pure longitudinal wheel slip, lateral sideslip and combined slip situations, which fuses both estimated longitudinal and lateral friction coefficients together, compared with existing methods based on a tire model in one single direction. Unscented Kalman filter (UKF) is introduced to estimate one-directional friction coefficient based on a modified Dugoff tire model. Considering the output results for each direction as a signal for the same target with different noise, MSE-weighted fusion method is proposed to fuse these two results together in order to reach a higher accuracy. The tire forces are estimated with the benefits of the 4WID EV that the driving torque and rolling speed of each wheel can be accurately known. The sideslip angles and slip ratios of each tire are calculated with a vehicle kinematic model.
2015-04-14
Technical Paper
2015-01-0159
Zhihui Tan, Zhenfu Chen, Xiaofei Pei, Jie Zhang, Xuexun Guo
Abstract Analogous to a vacuum boosted system, Electro-Hydraulic Braking System (EHB) is free from engine vacuum and supplies a braking force proportional to driver input. The independence of engine vacuum makes it especially suitable to be used in electric vehicles (EVs) and hybrid electric vehicles (HEVs). As a key component of EHB, master cylinder is driven by the pump rather than the vacuum booster. Even if the pump fails, the cylinder can also build proper pressure. Meanwhile, in order to maintain the pedal feeling, a pedal stroke simulator is applied in the system. In this paper, aiming at decreasing the size and cost of master cylinder and providing an ideal pedal feeling without compromise of performance, a new integrated master cylinder of EHB system is designed including two parts: master cylinder and pedal stroke simulator. The key components of the integrated master cylinder are motor pump, solenoid valves and composite springs.
2015-04-14
Technical Paper
2015-01-0637
Mohammed K Billal, Guilherme Carneiro, Renan Ozelo, Makarand Kulkarni
Abstract During the service life, the impacts of vehicle against potholes result in damage for the wheel and suspension components. Knowing the internal forces generated in the suspension components during this event would helpful to design the critical components. Measurement of these loads in physical test is more costly and not feasible for new designs. There are several virtual tools and methods available to predict the loads during this event. Using the ABAQUS FE solver, the non-linear dynamic behavior could be captured accurately during the impact. The tire model plays an important role during this event by absorbing energy during the impact. The CAE tire model is validated with some physical tests results and it is used in the vehicle pothole impact simulation. In vehicle pothole physical test, the force and acceleration measurement are taken and compared with the CAE results. The effect of the tire pressure variations and the vehicle speed at pothole impact is also studied.
2015-04-14
Technical Paper
2015-01-0628
Bin Li, Xiaobo Yang, Yunqing Zhang, James Yang
Vehicle tire performance is an important consideration for vehicle handling, stability, mobility, and ride comfort as well as durability. Significant efforts have been dedicated to tire modeling in the past, but there is still room to improve its accuracy. In this study, a detailed in-plane flexible ring tire model is proposed, where the tire belt is discretized, and each discrete belt segment is considered as a rigid body attached to a number of parallel tread blocks. The mass of each belt segment is accumulated at its geometric center. To test the proposed in-plane tire model, a full-vehicle model is integrated with the tire model for simulation under a special driving scenario: acceleration from rest for a few seconds, then deceleration for a few seconds on a flat-level road, and finally constant velocity on a rough road. The simulation results indicate that the tire model is able to generate tire/road contact patch forces that yield reasonable vehicle dynamic responses.
2015-04-14
Technical Paper
2015-01-0624
Mustafa Arat, Emmanuel O. Bolarinwa
Abstract 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 investigated. 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
2015-01-1117
Yang Liu, Zechang Sun
Abstract Regenerative braking control for a four-wheel-drive (4WD) electric vehicle (EV) equipped with a decoupled electro-hydraulic brake system was studied. The energy flow of the 4WD electric vehicle was analyzed during braking, and the brake force distribution strategy between the front-rear axles, regenerative braking and hydraulic braking was studied. Considering ECE R13 regulations, motors and battery pack characteristic constraints, the optimal regenerative braking control strategy using Genetic Algorithm (GA) was proposed. A Hardware-in-loop (HIL) test was built to verify the proposed regenerative braking control strategy. The results show that the optimal regenerative braking control strategy for the 4WD electric vehicle was advantageous over the comparison program, and regenerative energy efficiency reaches 78.87% under the Shanghai Urban Driving Cycle (SUDC).
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 CAD (Computer-Aided Design), CAE (Computer-Aided Engineering), and optimization technologies into an automation procedure, which includes: structural design, dynamic analysis, vibration analysis, durability analysis, and multidisciplinary optimization. The automation results shown the twist beam rear suspension weight reduced, the durability fatigue life increased, and the K&C (kinematics & compliance) characteristics are improved significantly.
2015-04-14
Technical Paper
2015-01-1405
Guanjun Zhang, Feng Yu, Zhigao OuYang, Huiqin Chen, Zhonghao Bai, Libo Cao
Abstract The combination of passive and active vehicle safety technologies can effectively improve vehicle safety. Most of them predict vehicle crashes using radar or video, but they can't be applied extensively currently due to the high cost. Another collision forecasting method is more economic which is based on the driver behavior and vehicle status, such as the acceleration, angular velocity of the brake pedal and so on. However, the acceleration and angular velocity of the brake pedal will change with the driver and the vehicle type. In order to study the effect of different drivers and vehicle types on the braking acceleration and angular velocity of the brake pedal, six volunteers were asked to drive five vehicles for simulating the working conditions of emergency braking, normal braking, inching braking and passing barricades under different velocities. All the tests were conducted on asphalt road, and comprehensive experimental design was used to arrange tests.
2015-04-14
Technical Paper
2015-01-1410
Shotaro Odate, Kazuhiro Daido, Yosuke Mizutani
According to the National Automotive Sampling System (NASS) Crashworthiness Data System (CDS), which is a North American automobile accident database, collision events referred to as multiple-collision accidents, in which multiple collisions occur during travel, account for 55% of all accidents. In addition, multiple-collision accidents in which collision events following the first collision event are more severe than the first event account for 20% of all accidents. In a first collision, the system had simultaneously operated to restrain and protect the vehicle occupant. If the multiple-collision accidents occurs, because the system for restraining and protecting vehicle occupants will have already deployed, the performance of the system can be limited from subsequent collisions.
2015-04-14
Technical Paper
2015-01-1414
Jitendra Shah, Mohamed Benmimoun
In the framework of large scale project interactIVe co-funded by the European Commission Ford has developed an active safety system for the supported and autonomous avoidance of rear end collisions by intervention of braking and steering systems. This paper focuses on the assessment of threat perceived by drivers in collision avoidance situation. The decision making related to the initiation of the interventions by driver is crucial to understand how much threat is the driver can hold. The study has helped to understand how driver feels a threat arising from environment. It is a step towards autonomous driving where the system interventions have to be initiated as early as possible in order to avoid the collision and avoid unstable vehicle dynamics situations. In parallel the reaction has to be delayed long enough until it is likely that the driver will no longer intervene or respectively he is no longer able to intervene. For this reason an experiment is conducted with 26 subjects.
2015-04-14
Technical Paper
2015-01-1096
Robert Lloyd
Abstract The frequent stops of the typical postal delivery vehicle make it an attractive application for regenerative braking. The hydro-mechanical automatic transmission described in SAE paper 2014-01-1717 contains all the functions necessary to implement hydraulic regenerative braking including the accumulator and reservoir. This paper describes the substitution of the hydro-mechanical transmission for the present transmission of the postal LLV vehicles and estimates the performance benefits. The result represents a low impact path for the US Postal Service to extend the useful life of the LLV vehicles and increase the mpg by approx. 100%. A cost comparison between a convention ICE mid-sized passenger sedan and a similar size gas/hydraulic hybrid vehicle illustrates the cost advantage of the hydraulic approach using the new transmission design. Besides lower cost, the vehicle will have greater initial acceleration and 25%+ better mpg.
2015-04-14
Technical Paper
2015-01-1120
Siddhartha Singh, Sudha Ramaswamy
Abstract 1 The modern engine is capable of producing high torque and horsepower. Now the customer wants state of the art comfort and ergonomics.Thus the manufacturers are focusing on reducing the clutch pedal effort and providing a pleasurable driving experience. In heavy traffic conditions where the clutch is used frequently, the pedal effort required to disengage the clutch should be in comfortable range. Often drivers who drive HCV complain about knee pain which is caused due to high pedal effort, this occurs when ergonomics of ABC (accelerator, brake and clutch) pedals is not designed properly. Thus there is a need to reduce the driving fatigue by optimizing the clutch system. Latest technologies like turbo charging and pressure injection have increased the engine power and torque but have also led to increase the clamp load of clutch. Thus the release load required to disengage the clutch has also increased.
2015-04-14
Technical Paper
2015-01-0492
Gaurav Paliwal, Naveen Sukumar, Umashanker Gupta, Ashutosh Dubey, Nitin Chopra
Abstract The need to develop products faster and to have designs which are first time right have put enormous pressure on the product development timelines, thus making computer aided optimization one of the most important tool in achieving these targets. In this paper, a design of experiments (DOE) study is used, to gain an insight as to, how changes to different parameters of front suspension and steering of a passenger bus affect its kinematic properties and thus to obtain an optimized design in terms of handling parameters such as bump steer, percent ackermann error and lock to lock rotation angle of steering wheel. The conventional hit and trial method is time consuming and monotonous and still is an approximate method, whereas in design of experiments (DOE), a model is repeatedly run through simulations in a single setup, for various combinations of parameter settings.
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.
Viewing 31 to 60 of 10218

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