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WIP Standard
2014-04-10
This SAE Recommended Practice describes the determination of passenger car and light truck tire force and moment properties on a belt-type flat surface test machine. It is suitable for accurately determining five tire forces and moments in steady-state under free-rolling conditions as a function of slip angle and normal force which are incrementally changed in a given sequence. Heavy-duty tires are not considered in this document, because the measuring system would have force and moment ranges too large to meet sensitivity requirements for passenger and light truck tire force and moment measurements. A standard for heavy-duty truck tires would have many of the same features as this document, but the measuring system, would have to be extensively altered. Inclination angle combined with slip angle, pull forces, and any combination with spindle torque are not considered in this document. Standards needed for these topics will be considered separately. The test method described in this document is suitable for comparative evaluations of tires for research and development purposes.
WIP Standard
2014-04-10
This SAE Recommended Practice provides a method for testing the speed performance of passenger car tires under controlled conditions in the laboratory on a test wheel. This procedure applies to "standard load," "extra load," and "T-type high-pressure temporary-use spare" passenger tires.
WIP Standard
2014-04-10
This SAE Recommended Practice provides performance and sampling requirements, test procedures, and marking requirements for aftermarket wheels intended for normal highway use on passenger cars, light trucks, and multipurpose passenger vehicles. For aftermarket wheels on trailers drawn by passenger cars, light trucks or multipurpose vehicles, see SAE J1204. These performance requirements apply only to wheels made of materials included in Table 1 and Table 2. New nomenclature and terms are added to clarify wheel constructions typically not used in OEM applications. The testing procedures and requirements are based on SAE standards listed in the references.
WIP Standard
2014-04-07
This SAE Standard covers performance requirements and methods of test for master cylinder reservoir diaphragm gaskets that will provide a functional seal and protection from outside dirt and water.
WIP Standard
2014-04-01
This SAE Standard applies to the usage of tires of the same nominal size and tread type, but with different outside diameter for articulated front-end loaders. Articulated four-wheel-drive front-end loader performance and component life can be affected by excessive differences in the tire outside circumference and/or diameter. The purpose is to provide specific guidelines for the usage of tires with different outside circumference and/or diameter on articulated front-end loaders.
Technical Paper
2014-04-01
Yao Fu, Yulong Lei, Ke Liu, Yuanxia Zhang, Huabing Zeng
Abstract In a traditional shift control strategy, the gear range is selected based on the throttle opening and the vehicle speed. The disadvantage of two-parameter based system is that the shift map is lack of adaptability in certain special conditions. The driving environment and the true intentions of the drivers are not fully taken into account by the shift control system. Therefore, improving the feasibility of the shift control strategy for the true intentions of the driver and driving environment is of great significance. Under braking conditions, Automatic transmission shift map with two parameters is unable to use engine braking effectively, which affects the drivability and safety of vehicles greatly. This paper presents a newly developed shift control strategy under braking conditions. First of all, the necessity of engine braking was analyzed. Then, this paper proposed a shift control strategy based on fuzzy inference of braking duration, load, braking deceleration and the vehicle speed.
Technical Paper
2014-04-01
Jiageng Ruan, Paul Walker
Abstract Regenerative braking energy recovery bears significance in extending the driving mileage of electric vehicles (EVs) while fulfilling real-time braking demands. Braking energy strategy plays a significant role in improving the regenerative braking performance and ensuring braking safety. This paper presents a regenerative braking energy recovery strategy for an example EV with a two-speed Dual Clutch Transmission (DCT). The two-speed DCT, with simple structure, can effectively extend the active vehicle speed-range for regenerative braking. Meanwhile, a shifting strategy is proposed for the DCT, working with the presented braking energy recovery strategy, to optimize the brake force distribution between front and rear wheels, motor and friction brake force. The EVs' model with the proposed regenerative braking strategy and the optimal shifting schedule was established and implemented in Matlab/Simulink. A testing rig based on an example EV was then set up in our laboratory to experimentally validate the proposed strategy.
Technical Paper
2014-04-01
Quan Zhou, Gangfeng Tan, Xuexun Guo, Zhigang Fang, Bian Gong
Abstract Focusing the vehicle riding safety and global environmental problems, plenty of solutions on vehicle braking systems appeals during the recent period. Criteria and standards set up for commercial vehicles which should have equipped assisted braking systems were established by amounts of governments. Since eddy current retarders plays an important role in the area of assisted braking system, this article presents an energy-recuperation retarder, which is parallel connected with the driveline through a planet gear system. This paper offers a particular Energy-Recuperation Eddy Current Retarder (ERECR) system with a pedal control system and its characteristics is presented, either. Initially, the constitution of the energy-recuperation eddy current retarder system is established whereas the working principle of the energy-recuperation eddy current retarder is presented by modeling the system and simulation. According to the characteristics presented by simulation, the newly designed mechanical control system is established, and the characteristics of it is analysis.
Technical Paper
2014-04-01
Yoshiharu Inaguma, Naohito Yoshida
Abstract This article describes the friction torque caused by pushing vanes on a cam contour and its influence on a variation of pump driving torque in a balanced vane pump. In the vane pump, the friction torque of the vane is significant to discuss a variation in the driving torque as well as an improvement in the mechanical efficiency. In this work, the influence of the thickness of a vane and the number of vanes on the friction torque of the vane and their additional effect on the variation in the pump driving torque are theoretically and experimentally investigated. The friction torque of the vane occupies a large part of the total friction torque in the vane pump and strongly depends on the number of vanes existing in a suction area as well as the thickness of the vane. The variation in the pump driving torque is composed of the variation of the ideal torque and that of the friction torque of the vane. The former is determined by vane arrangement in the suction area, and the latter is caused by a change in the number of vanes in the suction area.
Technical Paper
2014-04-01
Rong He, Hongyu Zheng, Changfu Zong
Abstract In order to improve the braking energy recovery and ensure the braking comfort, a new type of regenerative braking coordinated control algorithm is designed in this paper. The hierarchical control theory is used to the regenerative braking control algorithm. First, the front axle braking force and rear axle braking force are distributed. Then the rear axle motor braking force and mechanical braking force are distributed. Finally, the dynamic coordinated control strategy is designed to control pneumatic braking system and motor braking system. Aimed at keeping the fluctuation of the total braking force of friction and the regenerative braking force small during braking modes switch, a coordinated controller was designed to control the pneumatic braking system to compensate the error of the motor braking force. Based on Matlab/Simulink platform, a parallel hybrid electric bus simulation model with electric braking system (EBS) was established. Then the simulation in different operating conditions was used to analyze the braking energy utilization and the braking performance based on the simulation model.
Technical Paper
2014-04-01
Axel Gallrein, Manfred Baecker, Michael Burger, Andrey Gizatullin
Abstract In the last two years, Fraunhofer has developed an advanced tire model which is real-time capable. This tire model is designed for ride comfort and durability applications for passenger cars and trucks, as well as for agricultural and construction machines. The model has a flexible belt structure with typically about 150 degrees of freedom and a brush contact formulation. To obtain sufficient computational efficiency and performance for real time, a dedicated numerical implicit time-integration scheme has been developed. Additionally, specific coordinate frames were chosen to efficiently calculate and use the needed Jacobian matrices. Independently from this, Fraunhofer ITWM has developed and installed the new driving simulator RODOS (RObot based Driving and Operation Simulator), which is based on the industrial robot KUKA KR1000. The main application area of this driving simulator are interactive human-in-the-loop simulations with agricultural and construction machines, but also with trucks and passenger cars.
Technical Paper
2014-04-01
Adam C. Reid, David Philipps, Fredrik Oijer, Inge Johansson, Moustafa EL-Gindy
Abstract The rigid-ring tire model is a simplified tire model that describes a tire's behaviour under known conditions through various in-plane and out-of-plane parameters. The complex structure of the tire model is simplified into a spring-mass-damper system and can have its behaviour parameterized using principles of mechanical vibrations. By designing non-linear simulations of the tire model in specific situations, these parameters can be determined. They include, but are not limited to, the cornering stiffness, vertical damping constants, self-aligning torque stiffness and relaxation length. In addition, off-road parameters can be determined using similar methods to parameterize the tire model's behaviour in soft soils. By using Finite Element Analysis (FEA) modeling methods, validated soil models are introduced to the simulations to find additional soft soil parameters. By determining the full FEA tire model's characteristics, a simplified rigid-ring model can replace the complex model in full vehicle model simulations to reduce computation time and effort.
Technical Paper
2014-04-01
Wenku Shi, Changxin Wang
Abstract In order to reasonably match the variable stiffness suspension and optimize the ride comfort and stability of a light bus, a virtual prototype model of the light bus was established in Adams-Car. Before the optimization, the tyre mechanical characteristics were tested by using a plate-type tyre tester, then the magic formula model of the tyre (Pac2002) was obtained by means of the global parameter identification method. The vertical vibration of the virtual model was simulated with the simulated B-class road profile, and its handling stability performance was also studied by simulation of the pylon course slalom test and steady static circular test. After that, an optimal method of the variable stiffness suspension was put forward. In the proposed method, the two-level stiffness (k1, k2) and the damping of the rear suspension and the torsional stiffness of the pre and post stabilizer bars were taken as the optimal variables. The Z-direction acceleration RMS of the bus frame, the yaw rate and the roll angle of the bus body were selected as the optimal target.
Technical Paper
2014-04-01
Edoardo Sabbioni, Federico Cheli, Matteo Riva, Andrea Zorzutti
Abstract For passenger cars, individual tyre model parameters, used in vehicle models able to simulate vehicle handling behavior, are traditionally derived from expensive component indoor laboratory tests as a result of an identification procedure minimizing the error with respect to force and slip measurements. Indoor experiments on agricultural tyres are instead more challenging and thus generally not performed due to tyre size and applied forces. However, the knowledge of their handling characteristics is becoming more and more important since in the next few years, all agricultural vehicles are expected to run on ordinary asphalt roads at a speed of 80km/h. The present paper presents a methodology to identify agricultural tyres' handling characteristics based only on the measurements carried out on board vehicle (vehicle sideslip angle, yaw rate, lateral acceleration, speed and steer angle) during standard handling maneuvers (step-steers, J-turns, etc.), instead than during indoor tests.
Technical Paper
2014-04-01
Barys Shyrokau, Dzmitry Savitski, Danwei Wang
Abstract Nowadays there is a tendency to implement various active vehicle subsystems in a modern vehicle to improve its stability of motion, handling, comfort and other operation characteristics. Since each vehicle subsystem has own limits to generate supporting demand, their potential impact on vehicle dynamics should be analyzed for steady-state and transient vehicle behavior. Moreover, the additional research issue is the assessment of total energy consumption and energy losses, because a stand-alone operation of each vehicle subsystem will provide different impact on vehicle dynamics and they have own energy demands. The vehicle configuration includes (i) friction brake system, (ii) individual-wheel drive electric motors, (iii) wheel steer actuators, (iv) camber angle actuators, (v) dynamic tire pressure system and (vi) actuators generating additional normal forces through external spring, damping and stabilizer forces. A passenger car is investigated using commercial software. The actuator models are defined using experimental test results and technical literature information.
Technical Paper
2014-04-01
Mustafa Ali Arat, Saied Taheri
Abstract A vehicle's response is predominately defined by the tire characteristics as they constitute the only contact between the vehicle and the road; and the surface friction condition is the primary attribute that determines these characteristics. The friction coefficient is not directly measurable through any sensor attachments in production-line vehicles. Therefore, current chassis control systems make use of various estimation methods to approximate a value. However a significant challenge is that these schemes require a certain level of perturbation (i.e. excitation by means of braking or traction) from the initial conditions to converge to the expected values; which might not be the case all the time during a regular drive. This study proposes an observer scheme that utilizes an instrumented tire (i.e. smart tire) as an additional sensor input and develops a sliding-mode observer based on tire force feedback to provide the estimated friction coefficient irrespective of the available excitation.
Technical Paper
2014-04-01
Sanghun Cho, Taewan Gu, Eunyoung Yoo, Youngkyu Jeong, Baegsu Joo
Abstract In automotive software developments, since the types of software functionalities are depending on automotive engineering domains such as powertrain, body, and chassis, software logic and data processing, code complexity, and its reliability are also depending on them. Therefore, it has some challenges that monolithic code quality measures are applied to software code for all domains. In addition, imprecise criteria for the measures also can make software developers and testers confused whether their code verifications are enough or not. This paper proposes domain-specific code quality measures and precise criteria by combining a new functionality model, named Abstract Function Model (AFM), and shows results of automotive software functionality analysis using the model. Using 8 real automotive software projects, we derived statistics of software code on specific automotive engineering domain and identified code quality measures from the statistics. For the identified code quality measures, we tactically modified the legacy software code quality measures to be more reasonable and suitable for domain-specific code verification in terms of coding rule checking, potential semantic error checking, and code structural metrics.
Technical Paper
2014-04-01
Suhas Kangde, Vishal Shitole, Ashish Kumar Sahu
Abstract Automotive Suspension is one of the critical system in load transfer from road to Chassis or BIW. Using flex bodies in Multi body simulations helps to extract dynamic strain variation. This paper highlights how the MBD and FE integration helped for accurate strain prediction on suspension components. Overall method was validated through testing. Good strain correlation was observed in dynamic strains of constant amplitude in different loading conditions. Combination of different direction loading was also tested and correlated. Method developed can be used in the initial phase of the vehicle development program for suspension strength evaluation. Suspension is one of the important system in vehicle which is subjected to very high loading in all the directions. To predict the dynamic stresses coming on the suspension system due to transient loads, faster and accurate method is required. To accelerate the suspension design process it become necessary to get good accuracy in the results.
Technical Paper
2014-04-01
Dongmei Wu, Haitao Ding, Konghui Guo, Zhiqiang Wang
Abstract Pressure following control is the basic function of Electro-Hydraulic Braking system (EHB), which is also the key technology of stability control system and regenerative braking system for hybrid and electric vehicles. Experimental research is an important method for the control and application of EHB. This paper describes a method to test and control the EHB system through experiment on the Hardware-in-the-loop (HIL) test bench and wheel motor electric vehicle. First, the HIL test bench was established, in which the EHB was tested, including the characteristics of solenoid valves and motor. Then the wheel cylinder pressure was controlled to follow the specific signal input and the master cylinder pressure. Based on this, EHB and the pressure following control method were applied to the wheel motor electric vehicle. The results show that the braking pressure can follow the driver's braking intention to realize the conventional braking function of electric vehicles. This is the basis of stability control system and regenerative braking system for hybrid and electric vehicles.
Technical Paper
2014-04-01
Xinxin Shao
Abstract In this paper, a passive anti-pitch anti-roll hydraulically interconnected suspension is proposed for compromising the control between the pitch and roll mode of the sprung mass. It has the advantage in improving the directional stability and handling quality of vehicles during steering and braking manoeuvres. Frequency domain analysis of a 7-DOF full-car model with the proposed system is presented. The modeling of mechanical subsystem is established based on the Newton's second law. Then the mechanical-hydraulic system boundary conditions are developed by incorporating the hydraulic strut forces into the mechanical subsystem as externally applied forces. The hydraulic subsystem is modelled by using the impedance method, and each circuit are determined by the transfer matrix method. And then the modal analysis method is employed to perform the vibration analysis between the vehicle with the conventional suspension and the proposed HIS. Comparison analysis focuses on natural frequencies and modal shapes with identified eigenvalues and eigenvectors.
Technical Paper
2014-04-01
Andrew Hall, John McPhee
Abstract Physical rig testing of a vehicle is often undertaken to obtain experimental data that can be used to ensure a mathematical model is an accurate representation of the vehicle under study. Kinematics and Compliance (K&C) testing is often used for this purpose. The relationship between the hard point locations and compliance parameters, and K&C characteristics of a suspension system is complex, and so automating the process to correlate the model to the test data can make the exercise easier, faster and more accurate than hand tuning the model. In this work, such a process is developed. First, the model parameters are adjusted, next a simulation is run, before the results are read and post processed. This automation processed is used in conjunction with an optimization procedure to carry out the K&C correlation. MATLAB scripts are created to modify the model parameters, run simulations and read the results so that MATLAB optimization algorithms can be used to identify the most appropriate suspension parameter values.
Technical Paper
2014-04-01
Yoon Cheol Kim, Seong Jin Kim, Jaeyoung Lee, Jeongkyu Kim, SooHyuk Lee, Kyoungdon Yi, KiJeong Kim
Abstract Reducing unsprung mass of the car is a representative method to enhance the ride & handling performance and fuel efficiency. In this study, brake disc weight is reduced 15∼20% using a hybrid type material. The basis for this study is the separation of the friction surface and HAT(mounting part). Aluminum material is applied in the HAT for a light weight effect. Gray iron is applied in the friction surface section to maintain braking performance. Two types of joining between aluminum and cast iron are developed. One is the aluminum casting method utilizing a gray iron insert and the other is a bolted assembly method. Detailed structure, process and material are optimized using try-out & dynamometer experiments. The Reliability of this development is proved through durability (dynamometer and vehicle) testing.
Technical Paper
2014-04-01
Noboru Uchida, Akira Fukunaga, Hideaki Osada, Kazuaki Shimada
Abstract Heat loss reduction could be one of the most promising methods of thermal efficiency improvement for modern diesel engines. However, it is difficult to fully transform the available energy derived from a reduction of in-cylinder heat loss into shaft work, but it is rather more readily converted into higher exhaust heat loss. It may therefore be favorable to increase the effective expansion ratio of the engine, thereby maximizing the brake work, by transforming more of the enthalpy otherwise remaining at exhaust valve opening (EVO) into work. In general, the geometric compression ratio of a piston cylinder arrangement has to increase in order to achieve a higher expansion ratio, which is equal to a higher thermodynamic compression ratio. It is still necessary to overcome constraints on peak cylinder pressure, and other drawbacks, before applying higher expansion ratios to current high-boost, high brake mean effective pressure (BMEP), and high exhaust gas recirculation (EGR) diesel engines.
Technical Paper
2014-04-01
Flaura Winston, Catherine McDonald, Venk Kandadai, Zachary Winston, Thomas Seacrist
Abstract Driving simulators offer a safe alternative to on-road driving for the evaluation of performance. In addition, simulated drives allow for controlled manipulations of traffic situations producing a more consistent and objective assessment experience and outcome measure of crash risk. Yet, few simulator protocols have been validated for their ability to assess driving performance under conditions that result in actual collisions. This paper presents results from a new Simulated Driving Assessment (SDA), a 35- to-40-minute simulated assessment delivered on a Real-Time® simulator. The SDA was developed to represent typical scenarios in which teens crash, based on analyses from the National Motor Vehicle Crash Causation Survey (NMVCCS). A new metric, failure to brake, was calculated for the 7 potential rear-end scenarios included in the SDA and examined according two constructs: experience and skill. The study included an inexperienced group (n=21): 16-17 year olds with 90 days or fewer of provisional licensure, and an experienced group (n=17): 25-50 year olds with at least 5 years of PA licensure, at least 100 miles driven per week and no self-reported collisions in the previous 3 years.
Technical Paper
2014-04-01
Sajjad Beigmoradi, Kambiz Jahani, Babak Ravaji
Abstract Efficient function of brake system is considered a crucial stage in the vehicle development process. Heat exchange reduction can decrease the operational condition of braking system. Although the rims patterns have a significant role on vehicle aerodynamics, they can also have effect on air flow around the brake disk. So, selecting a rim is vital from both a safety and an aerodynamic point of view. In this paper the effect of air flow around a brake disk for two different types of rims was studied; a steel casting and an aluminum alloy rim. Numerical simulation was used for this analysis. First, the flow field around brake disk with iron casting rim was investigated at different velocities. Second, the flow field around the same brake disk system with an aluminum alloy rim was modeled at the same velocities. Finally, the effect of rim design on flow pattern over brake disk was compared. It was found that changing rim design has significant influence on velocity distribution around brake disc and pads.
Technical Paper
2014-04-01
Masayuki Naito, Yasuhiro Koike, Shintaro Osaki, Shinichiro Morishita, Nanhao Quan
Abstract HEV and EV markets are in a rapid expansion tendency. Development of low-cost regenerative cooperation brake system is needed in order to respond to the consumers needs for HEV and EV. Regenerative cooperation brake system which HEV and EV are generally equipped with has stroke simulator. We developed simple composition brake system based on the conventional ESC unit without the stroke simulator, and our system realized a low-cost regenerative cooperation brake. The key technologies are the quiet pressurization control which can be used in the service application, which is to make brake force depending on brake travel, by gear pump and the master cylinder with idle stroke to realize regenerative cooperation brake. Thanks to the key technologies, both the high regenerative efficiency and the good service brake feeling were achieved.
Technical Paper
2014-04-01
Yuan Qu, Wang Hongbin, Dechao Zhang, Linbo Zhang, Shen Wu
Abstract The understeer of vehicle is desired for the vehicle's handling performance, and the roll rate of rear suspension is one of the key characteristics to achieve the understeer performance. A proper roll rate of the rear suspension is required to assure a certain level of understeer. Generally, in the vehicle dynamic tuning process, several methods are available for improving understeer performance, e.g., changing the hard-points of suspensions, adjusting stiffness of bushings, etc. On the other hand, structure optimization of components can be used in some case to improve the performance. In this paper, the optimization method is applied to the twist beam of rear suspension. The change in local geometry by optimized design leads to appropriate adjustment of the roll rate. Finally the vehicle understeer performance reaches design target.
Technical Paper
2014-04-01
Yong-Sub Yi, Joonhong Park, Kyung-Jin Hong
Abstract In the early stage of vehicle development process, it is customary to establish a set of goals for each kinematic and compliance (K&C) characteristic and try to find out design variables such as the location of hard points and bushing stiffness which can achieve these goals. However, since it is very difficult to find out adequate set of design variables which satisfy all the goals, many engineers should rely on their own experiences and intuitions, or repeat trial and error to design a new suspension and improve old one. In this research, we develop a suspension design process by which suspension K&C characteristic targets can be achieved systemically and automatically. For this purpose, design optimization schemes such as design of experiments (DoE) and gradient-based local optimization algorithm are adopted. Firstly, sensitivity analysis is carried out using DoE and then, according to the analysis results, the whole problem is divided into two partial problems which are independent of each other.
Technical Paper
2014-04-01
Mohamed Sithik, Rama Vallurupalli, Barry (Baizhong) Lin, Subash Sudalaimuthu
Abstract In recent trend, there is a huge demand for lightweight chassis frame, which improves fuel efficiency and reduces cost of the vehicle. Stiffness based optimization process is simple and straightforward while durability (life) based optimizations are relatively complex, time consuming due to a two-step (Stress then life) virtual engineering process and complicated loading history. However, durability performances are critical in chassis design, so a process of optimization with simplified approach has been developed. This study talks about the process of chassis frame weight optimization without affecting current durability performance where complex durability load cases are converted to equivalent static loadcases and life targets are cascaded down to simple stress target. Sheet metal gauges and lightening holes are the parameters for optimization studies. The optimization design space is constrained to chassis unique parts. The optimized design is verified for detailed load case and life target.
Technical Paper
2014-04-01
Tae-Sang Park, Sungho Jin, Jeon IL Moon, Seung-Han Yang
Abstract As is well known, the brake systems of vehicles are used in order to decelerate or stop the vehicle while the driving. The operational principle of the brake is the conversion of kinetic energy into thermal energy. In this case, the thermal energy is released to the atmosphere. Recently, electromechanical brakes (EMB) were developed in order to replace hydraulic brake calipers. Such brake-by- wire systems are composed of an electronic pedal, electronic control unit (ECU), wire, and an electromechanical caliper. A typical electromechanical brake is similar to existing floating brakes. In other words, an inner pad pushes out one side of a disc driven by the energy of a motor; by means of a screw-thread gear. Then, the caliper slides in the opposite direction by reaction force and moves the outer pad toward the other side of the disc. Then pads clamp both sides of the rotating disc and stop the wheel. While effective, this design has the problem that there is a difference in the wear of the inner and outer pads.
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