Browse Topic: Electronic brake controls

Items (88)
Find
Vehicle E/E Architecture and Its Adaptation to New Technical Trends2019-01-08624/2/2019
With the ever-increasing requirements on vehicle performance, as well as the trend of vehicle becoming an integral part of a much bigger ecosystem involving automated driving, intelligent transportation and smart city, more and more electrical/electronic (E/E) systems are integrated in vehicles. Vehicle E/E architecture being the fundamental organization of E/E components, the relationship among the components and with the environment, as well as the principles guiding the design and evolution, has essential influences on vehicle E/E system functions and performance. This paper gives the definition of vehicle E/E architecture and provides different views. The guidelines, contents and process of E/E architecture design are discussed. The evolution of E/E architecture, influence of the latest technical trends including electrification, automated driving, and connectivity functions on E/E architecture, and how vehicle E/E architecture adapts to the technical trends are studied.
Jiang, Shugang
Study on a Method for Evaluating the Safety of the Braking Control Algorithm for Automated Driving System When Following2019-01-10154/2/2019
The purpose of this study is to develop a method for evaluating the safety of the braking control algorithm for automated driving under mixed traffic flow of automated driving system and vehicles driven by drivers. We consider that the automated driving system should be controlled such that it blends in with mixed traffic. Therefore, in evaluating the safety of braking control for the automated driving system when following, the influence of the automated driving system on the driver of the following vehicle is an important evaluation index. First, we analyzed past traffic accidents in Japan to determine a suitable traffic environment for evaluating the safety of the braking control algorithm for the automated driving system when following. Second, the driver’s braking operations were measured using actual vehicles in this situation. We developed a method of generating sample algorithms of braking control based on the driver’s braking operations. Finally, we developed a method of identifying the most suitable range of parameters of braking control algorithms by evaluating these sample algorithms based on the results of actual experiments. This evaluation method uses a driving simulator. The automated driving system in which the sample algorithm of braking control is installed runs ahead of the vehicle driven by a subject in the driving simulator. The subject evaluates the sense of danger for braking by the automated driving system.
Gokan, Masato, Tanaka, Nobuhisa, Furukawa, Yoshimi, Iwase, Tunetoshi, Hirowatari, Taichi
Development of General Motors’ eAssist Gen3 Propulsion System2018-01-04224/3/2018
General Motors’ 3rd generation eAssist propulsion systems build upon the experience gained from the 2nd generation 115v system and the 1st generation 36v system. Extensive architectural studies were conducted to optimize the new eAssist system to maintain the performance and fuel economy gains of the 2nd generation 115v system while preserving passenger and cargo space, and reducing cost. Three diverse vehicle applications have been brought to production. They include two similar pickup trucks with 5.3 liter V8 engines and 8 speed transmissions, a 4-door passenger car with 2.5 liter 4 cylinder normally aspirated gasoline engine and a 6-speed automatic transmission, and a crossover SUV with a 2.0-liter turbocharged engine and 9 speed transmission. The key electrification components are a new water cooled induction motor/generator (MG), new water cooled power electronics module, and two major variants of 86v lithium ion battery packs. All three applications share variations of the same components, showing the bandwidth of the 3rd generation system. The engines include special dual tensioner accessory drive systems to couple the MG to the crankshaft. The transmissions are all modified to support the eAssist system. The torque based control system of the 2nd generation eAssist system was carried into these applications and integrated with the latest GM corporate common electrical and controls architectures.
Cottrell, Daniel, Miller, Michael Andrew, Oury, Andrew, Staley, Eric, Mui, Danny, Osterkamp, Dale, Poulos, Stephen
Research on Regenerative Braking Control Strategy of Distributed EV based on Braking Intention2018-01-13424/3/2018
Focusing on distributed electric vehicles with in-wheel motors, a novel regenerative braking control strategy based on braking intention is proposed. Firstly, a design scheme for the regenerative braking system is described. Four in-wheel motors and an Electro-Hydraulic Braking (EHB) system are respectively designed for regenerative braking and hydraulic braking. Then, Braking intention recognition self-learning libraries are trained based on Hidden Markov Model method, which is validated by driver-in-loop tests. According to three speed states and four braking intentions, the regenerative braking control strategy for multiple brake modes is developed. The coefficient of regenerative braking is defined to describe the intervening time and proportion of motor maximum regenerative braking. Eventually, the co-simulation results show that the proposed strategy can not only significantly improve the energy recovery capability, but also provide the coordinated control of regenerative braking and hydraulic braking, in consistence with the driver braking intention highly.
Pan, Hao, Guo, Xuexun, Pei, Xiaofei, Pan, Jin, Zhang, Jie
Research on a Novel Electro-Hydraulic Brake System and Pressure Control Strategy2018-01-07644/3/2018
Based on the research and analysis of the current brake systems, this paper presents a novel electro-hydraulic brake system, which can better meet the functional requirements. The system mainly contains a master cylinder, two brake hydraulic cylinders and drive motors, two transmission mechanisms, thirteen solenoid valves, pedal force simulator, etc. Since the proposed brake system uses a dual motor along with two brake hydraulic cylinders, it has advantages in providing fast pressure response, flexible working modes, high precision and strong fault tolerance. In order to facilitate the study of pressure control algorithm for the proposed brake system, a mathematical model of the brake system is firstly established, then a multiplexed time-division pressure control algorithm is proposed to realize the simultaneous or partially simultaneous pressure control, which ensures the high precision and short response time. Finally, based on the model of the proposed brake system, some extensive simulation and experiment have been conducted, which demonstrate the validity and effectiveness of the proposed multiplexed time-division pressure control algorithm. From the result, the proposed system has good performance for pressure control, the response time is about 100-120 ms for pressure increasing from 0 to 100 bar or decreasing from 100 bar to 5 bar.
Liu, Haizhen, He, Rui, Deng, Weiwen, Yang, Shun, Wu, Jian, Chen, Pengcheng
Autonomous Emergency Braking Control Based on Hierarchical Strategy Using Integrated-Electro-Hydraulic Brake System2017-01-19649/23/2017
Highway traffic safety has been the most serious problem in current society, statistics show that about 70% to 90% of accidents are caused by driver operational errors. The autonomous emergency braking (AEB) is one of important vehicle intelligent safety technologies to avoid or mitigate collision. The AEB system applies the vehicle brakes when a collision is eminent in spite of any reaction by the driver. In some technologies, the system forewarns the driver with an acoustic signal when a collision is still avoidable, but subsequently applies the brakes automatically if the driver fails to respond. This paper presents the development and implementation of a rear-end collision avoidance system based on hierarchical control framework which consists of threat assessment layer, wheel slip ratio control layer and integrated-electro-hydraulic brake (IEHB) actuator control layer. The threat assessment layer continuously calculates threat metrics associated with collision avoidance by braking control. The tire slip ratio control layer with radial basis function (RBF) neural network control based on robust compensation term (RCT) is designed to obtain a desired braking torque, which enabled the controlled vehicle to generate the highest possible deceleration. As for the I-EHB actuator control layer, a resembling pulse width modulation (PWM) control method is adopted to convert the regulation information of the upper controller into the PMSM torque, the valve status (open / closed), and the hydraulic pump status (enabled / disabled). Finally, simulation test is conducted via co-simulation platform of MATLAB/Simulink and AMESim under scenarios of the active emergency braking process on high adhesion coefficient road and low adhesion coefficient road. The results show that the proposed AEB system control scheme is verified.
He, Xiangkun, Ji, Xuewu, Yang, Kaiming, Liu, Yulong, WU, Jian, Liu, Yahui
Regenerative Brake-by-Wire System Development and Hardware-In-Loop Test for Autonomous Electrified Vehicle2017-01-04013/28/2017
As the essential of future driver assistance system, brake-by-wire system is capable of performing autonomous intervention to enhance vehicle safety significantly. Regenerative braking is the most effective technology of improving energy consumption of electrified vehicle. A novel brake-by-wire system scheme with integrated functions of active braking and regenerative braking, is proposed in this paper. Four pressure-difference-limit valves are added to conventional four-channel brake structure to fulfill more precise pressure modulation. Four independent isolating valves are adopted to cut off connections between brake pedal and wheel cylinders. Two stroke simulators are equipped to imitate conventional brake pedal feel. The operation principles of newly developed system are analyzed minutely according to different working modes. High fidelity models of subsystems are built in commercial software MATLAB and AMESim respectively. The control strategies of brake force distribution and hydraulic pressure modulation are designed on basis of closed-loop controller simultaneously. Co-simulations under typical braking and active braking scenarios are conducted to validate the feasibility of proposed system architecture and reasonability of designed control algorithm. Simulation results show that the motor brake torque works cooperatively with hydraulic brake force. More than 36% of recoverable energy can be regenerated during typical braking procedure. Active braking can shorten the brake distance by nearly 18% compared with conventional driver emergency braking. Hardware-in-loop (HIL) bench tests are implemented under scenarios identical with simulations. The data acquired from HIL bench tests matches well with simulation results. Nearly 37% of recoverable energy is regenerated under typical braking condition, and brake distance is shortened by 4.33 m during active braking procedure.
Yuan, Ye, Zhang, Junzhi, Li, Yutong, Lv, Chen
Research on Vehicle Stability Control Strategy Based on Integrated-Electro-Hydraulic Brake System2017-01-15653/28/2017
A vehicle dynamics stability control system based on integrated-electro-hydraulic brake (I-EHB) system with hierarchical control architecture and nonlinear control method is designed to improve the vehicle dynamics stability under extreme conditions in this paper. The I-EHB system is a novel brake-by-wire system, and is suitable to the development demands of intelligent vehicle technology and new energy vehicle technology. Four inlet valves and four outlet valves are added to the layout of a conventional four-channel hydraulic control unit. A permanent-magnet synchronous motor (PMSM) provides a stabilized high-pressure source in the master cylinder, and the four-channel hydraulic control unit ensures that the pressures in each wheel cylinder can be modulated separately at a high precision. Besides, the functions of Anti-lock Braking System, Traction Control System and Regenerative Braking System, Autonomous Emergency Braking can be integrated in this brake-by-wire system. A sliding mode variable structure vehicle dynamics stability controller based on hierarchical control framework is built in MATLAB/Simulink. The I-EHB actuator model and vehicle dynamic model with 15 degrees of freedom are built in simulation package AMESim through a parameterized and modularized method. Simulations are conducted via co-simulation platform using MATLAB/Simulink and AMESim under scenarios of the typical braking and NHTSA FMVSS 126 standard-Sine With Dwell. Simulation results show that hydraulic braking forces are coordinated well during typical braking process, verifying the feasibility and effectiveness of the models built and the control strategy proposed. Under Sine With Dwell maneuver, compared with the base systems equipped without/with the conventional ESP, the proposed stability control system has a good improvement on the vehicle dynamics.
He, Xiangkun, Yang, Kaiming, Ji, Xuewu, Liu, Yahui, Deng, Weiwen
Analysis of Energy Consumption on Typical Main Cylinder Booster Based Brake-by-Wire System2016-01-19559/18/2016
The traditional vacuum booster is gradually replaced by Brake-by-Wire system (BBW) in modern passenger car, especially Electric Vehicle (EV). Some mechanical and hydraulic components are replaced by electronic components in Brake-by-Wire system. Using BBW system in modern passenger vehicles can not only improve the automotive safety performance, reliability and stability, but also promote vehicle maneuverability, comfort, fuel economy and environmental protection. Although vehicle's braking performance is greatly improved by using BBW, the system will inevitably consume some energy of the vehicle power supply, thus introducing unexpected drawback in comparison with the traditional vacuum assist braking system, since it doesn't need any electric power. Therefore, the analysis of energy consumption on typical main cylinder booster based BBW system under typical driving cycles will contribute to advanced design of current advanced braking system. In this paper, energy consumption of the typical main cylinder booster based BBW system is simulated by changing the brake response time and reduction ratio of the system under different driving cycles. The average power needed of conventional BBW system is also calculated. Energy consumption of the conventional and typical main cylinder booster based BBW systems is compared. The results show that the energy consumption of the typical main cylinder booster based BBW system is around 30W∼60W which is obvious better than the conventional BBW system with power need of 500W under typical driving cycles, such as USDC, EDC and JDC. The energy consumption of the Brake-by-Wire system can be reduced obviously through an optimal design on parameters of the system's actuator.
Yu, Liangyao, Liu, Xiaohui, Liu, Xiaoxue
Development of New Electronically Controlled Hydraulic Unit for Various Applications2016-01-16604/5/2016
The use of hybrid, fuel cell electric, and pure electric vehicles is on the increase as part of measures to help reduce exhaust gas emissions and to help resolve energy issues. These vehicles use regenerative-friction brake coordination technology, which requires a braking system that can accurately control the hydraulic brakes in response to small changes in regenerative braking. At the same time, the spread of collision avoidance support technology is progressing at a rapid pace along with a growing awareness of vehicle safety. This technology requires braking systems that can apply a large braking force in a short time. Although brake systems that have both accurate hydraulic control and large braking force have been developed in the past, simplification is required to promote further adoption. This paper describes the following three items: (1) an examination of the brake system functions that realize the regenerative-friction brake coordination and collision avoidance support functions, (2) considerations and a proposal for a brake system that achieves the functions described in item (1) with a simple structure, and (3) development of core technology for controlling the wheel cylinder pressure in a brake system equipped with a hydraulic regulator.
Okano, Takahiro, Sakai, Akira, Kamiya, Yusuke, Masuda, Yoshio, Yamaguchi, Tomoyuki
Development of an Electronically Controlled Brake System for Fuel-efficient Vehicles2016-01-16644/5/2016
To solve various environmental problems, fuel-efficient vehicles that reduce CO2 emissions as well as exhaust gas emissions have been developed. In such vehicles, a regenerative brake is used to further reduce fuel consumption. Because the market size for such vehicles is expanding, a brake system is required that can be used in a wide range of vehicles extending from internal combustion engine vehicles (ICEVs) to electric vehicles (EVs). In addition, issues such as deceleration fluctuation and brake pedal fluctuation arise because the regenerative brake force is dependent on the vehicle speed. This paper presents a brake system configuration and its element technologies that can replace existing brake systems in different vehicles ranging from ICEVs to EVs. The proposed system can realize a regenerative cooperative brake not only by replacing the brake booster unit but also without replacing the modulator. The advantages of this system are the maximization of regenerative efficiency, assurance of system reliability, and better brake feel.
Masuda, Yoshio, Yamasoe, Yosuke, Kuki, Yosuke, Okano, Takahiro, Uchida, Kiyoyuki
Design and Performance Analysis of a Novel Regenerative Braking System for Electrified Passenger Vehicles2016-01-04384/5/2016
A novel type of regenerative braking system for electric vehicles is proposed in this paper. Four pressure-difference-limit valves, two relief valves and two brake pedal simulators, are added to the layout of a conventional four-channel hydraulic modulator. The cooperation of relief valves and hydraulic pumps provides a stabilized high-pressure source. Pressure-difference-limit valves ensure that the pressure in each wheel cylinder can be modulated separately at a high precision. Besides, the functions of anti-lock braking system and electronic stability program are integrated in this regenerative braking system. The models of regenerative braking controller and vehicle dynamics are built in MATLAB/Simulink. Hydraulic brake model is built in AMESim through a parameterized and modularized method. Meanwhile, the control strategy of hydraulic brake modulation and brake force distribution are designed. Simulations are conducted via co-simulation interface between MATLAB and AMESim under scenarios of typical braking and ECE driving cycle. Simulation results show that regenerative and hydraulic braking forces are coordinated well during typical braking process, verifying the feasibility and effectiveness of the models built and strategies proposed. Under an ECE driving cycle, the proposed RBS can recover more than 75% of the total recoverable braking energy, which lengthen the vehicle’s driving range by more than 24%.
Yuan, Ye, Zhang, Junzhi, Lv, Chen, Li, Yutong
A Custom Integrated Circuit with On-chip Current-to-Digital Converters for Active Hydraulic Brake System2016-01-00914/5/2016
This paper presents a custom integrated circuit (IC) on which circuit functions necessary for “Active Hydraulic Brake (AHB) system” are integrated, and its key component, “Current-to-Digital Converter” for solenoid current measurement. The AHB system, which realizes a seamless brake feeling for Antilock Brake System (ABS) and Regenerative Brake Cooperative Control of Hybrid Vehicle, and the custom IC are installed in the 4th-generation Prius released in 2015. In the AHB system, as linear solenoid valves are used for hydraulic brake pressure control, high-resolution and high-speed sensing of solenoid current with ripple components due to pulse width modulation (PWM) is one of the key technologies. The proposed current-to-digital converter directly samples the drain-source voltage of the sensing DMOS (double-diffused MOSFET) with an analog-to-digital (A/D) converter (ADC) on the IC, and digitizes it. The conversion characteristic is compensated for the DMOS onresistance variation by an ADC reference compensation technique. A hybrid Active-Passive ΔΣ A/D converter is adopted and realizes small chip area and low power dissipation. A post-processing digital CIC (cascaded integrator-comb) decimation filter removes the ripple components which synchronize with the PWM switching efficiently. Through the design optimization of these, a 12-bit resolution and a response speed necessary for the solenoid current control have been achieved. The IC chip is fabricated in Toyota in-house SOI 0.35μm BiCDMOS process.
Watanabe, Hikaru, Segawa, Tsutomu, Okuhira, Takumi, Mima, Hiroki, Hoshikawa, Norishige
The New Era of Infotainment Systems2015-36-02379/22/2015
This paper focuses on present information and technical details about the connectivity and new technologies in automotive infotainment systems, based on an independent research of the authors using public references. The evolution of the consumer electronics and the electronic products in all areas allowed new features in the automotive market. The changes in the microelectronics industries accelerate the release of new technologies. Transistor by transistor, the electronics industry is literally changing the world. Consider this: in 2015, there will be more than seven billion mobile devices in the world consuming and generating massive amounts of data. In addition to that, there are more than one billion transistors for each person in world due to the popularization of computers, smartphones and tablets. In this sense, vehicle’s development is following the same tendency, the leverage of new technology even in the entry level vehicles is a must. Product life cycles are compressing, emphasizing the need to create innovative products and services faster than ever before. Innovation is new automaker’s watchword. In other words, innovation is the creative development of a specific product, service, tool, or process with the fundamental goal of pleasing the customers with the new creation and allowing the industry to be more profitable. For automotive industry, innovation can be translated as new features or services available in the vehicle. Nowadays, it is known that new technologies and features have a direct impact on the driving experience.
de Souza, Rafael Navarenho, de Souza Fino, Leonardo Navarenho
Research and Simulation of Electro-Hydraulic Braking System Based on Integrated Master Cylinder2015-01-01594/14/2015
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. A model of the EHB and other key components of the brake system are established in AMEsim-MATLAB/SIMULINK. AMEsim is responsible for hydraulic part while SIMULINK for control part. Some parameters of the components are discussed to research their effects on system performance. In addition, to verify the system availability, the PWM method is adopted to regulate the fluid pressure in the pressure following control. Finally, braking performance is tested under three modes through the match of EHB model and vehicle model in CarSim. The simulation result demonstrates that the EHB system not only can satisfy the demands of braking system, but also conform to ideal stroke-force curve.
Tan, Zhihui, Chen, Zhenfu, Pei, Xiaofei, Zhang, Jie, Guo, Xuexun
New Slip Control System Considering Actuator Dynamics2015-01-06564/14/2015
A new control strategy for wheel slip control, considering the complete dynamics of the electro-hydraulic brake (EHB) system, is developed and experimentally validated in Cranfield University's HiL system. The control system is based on closed loop shaping Youla-parameterization method. The plant model is linearized about the nominal operating point, a Youla parameter is defined for all stabilizing feedback controller and control performance is achieved by employing closed loop shaping technique. The stability and performance of the controller are investigated in frequency and time domain, and verified by experiments using real EHB smart actuator fitted into the HiL system with driver in the loop.
Soltani, Amir, Assadian, Francis
Vehicle Refinement and Testing of a Series-Parallel Plug-in Hybrid Electric Vehicle2014-01-290410/13/2014
The Hybrid Electric Vehicle Team (HEVT) of Virginia Tech is ready to compete in the Year 3 Final Competition for EcoCAR 2: Plugging into the Future. The team is confident in the reliability of their vehicle, and expects to finish among the top schools at Final Competition. During Year 3, the team refined the vehicle while following the EcoCAR 2 Vehicle Development Process (VDP). Many refinements came about in Year 3 such as the implementation of a new rear subframe, the safety analysis of the high voltage (HV) bus, and the integration of Charge Sustaining (CS) control code. HEVT's vehicle architecture is an E85 Series-Parallel Plug-In Hybrid Electric Vehicle (PHEV), which has many strengths and weaknesses. The primary strength is the pure EV mode and Series mode, which extend the range of the vehicle and reduce Petroleum Energy Usage (PEU) and Greenhouse Gas (GHG) emissions. A primary weakness is the architectures complexity, which made it difficult for the team to truly reap the benefits of the added components to the vehicle which are utilized in Parallel mode. The control system of the vehicle is extremely complicated and is explained in sufficient detail in the Controls System Overview section. The ultimate goal of the control strategy is to meet team Vehicle Technical Specifications (VTS) while performing safely and meeting driver demand. Finally, this paper details the predicted VTS, the modeling and tests done to predict the VTS, and other features of the vehicle which assist in meeting overall competition goals.
Manning, P. Christopher, Marquez, Eduardo D., Figueroa, Leonard, Nelson, Douglas J., White, Eli Hampton, Shoults, Lucas Wayne
Development & Integration of a Charge Sustaining Control Strategy for a Series-Parallel Plug-In Hybrid Electric Vehicle2014-01-290510/13/2014
The Hybrid Electric Vehicle Team of Virginia Tech (HEVT) is participating in the 2012-2014 EcoCAR 2: Plugging in to the Future Advanced Vehicle Technology Competition series organized by Argonne National Lab (ANL), and sponsored by General Motors Corporation (GM) and the U.S. Department of Energy (DOE). The goals of the competition are to reduce well-to-wheel (WTW) petroleum energy consumption (PEU), WTW greenhouse gas (GHG) and criteria emissions while maintaining vehicle performance, consumer acceptability and safety. Following the EcoCAR 2 Vehicle Development Process (VDP), HEVT is designing, building, and refining an advanced technology vehicle over the course of the three year competition using a 2013 Chevrolet Malibu donated by GM as a base vehicle. The team selected a series-parallel Plug-In Hybrid Electric Vehicle (PHEV) with P2 (between engine and transmission) and P4 (rear axle) motors, a lithium-ion battery pack, an internal combustion engine, and an automatic transmission as the final powertrain of choice. Development of a charge sustaining control strategy for this vehicle involves coordination of controls for each of the main powertrain components through a distributed control strategy. This distributed control strategy includes component controllers for each individual component and a single supervisory controller responsible for interpreting driver demand and determining component commands to meet the driver demand safely and efficiently. The charge sustaining strategy is based on a simplified estimate of best powertrain efficiency under current load conditions including constraints such as battery state of charge, time between mode transitions, and drivability. For example, the algorithm will account for a variety of system operating points and will penalize or reward certain operating points for other conditions. These conditions include but are not limited to rewards for discharging the battery when the state of charge (SOC) is above the target value or penalties for operating points with excessive emissions. Development of diagnostics and remedial actions is an important part of controlling the powertrain safely. In order to validate the control strategy prior to in vehicle operation, it is necessary to run simulations against a plant model of the vehicle systems. This plant model can be run in both controller Software- and controller Hardware-In-the-Loop (SIL and HIL) simulations. This paper details the development of the controls for diagnostics, major selection algorithms, and execution of commands and its integration into the series-parallel PHEV through the supervisory controller. It also covers the plant model development and testing of the control algorithms using controller SIL and HIL methods. It details reasons for any changes to the control system, and describe improvements or tradeoffs that had to be made to the control system architecture for the vehicle to run reliably and meet its target specifications. SIL test data is presented from development and compared to corresponding controller HIL data and some bench testing or in vehicle data. These test results illustrate how changes to the plant model and control code properly affect operation of the control system in the actual vehicle.
Manning, P. Christopher, White, Eli, Marquez, Eduardo, Figueroa, Leonard, Shoults, Lucas, Nelson, Douglas
Design, Modeling and Simulation of a New Compact Electro-Hydraulic Brake System2014-01-25359/28/2014
With the advantages of free from engine vacuum, wheel cylinder pressure decoupled from the brake pedal and can be regulated individually and precisely, the brake-by-wire system has a huge application potential in vehicles, especially in electric vehicles (EV) and hybrid electric vehicles (HEV). Electro-hydraulic Brake system is the first approach towards brake-by-wire technology. This paper proposed a new compact EHB, aiming at decreasing the size, volume and cost without compromise of performance. The main components of the proposed EHB are pedal simulator, motor pump, accumulator and eight solenoid valves. An authentic model of the EHB and other key components of the brake system were established based on the test data from the test bench. A control algorithm using Round-Robin scheduling was presented to regulate the fluid pressure. Some parameters of the components were discussed to research their effects on system performance. The effects of pressure regulation were examined in simulation, and the results showed that the response time and the control precision of the system are feasible for vehicle application.
Pan, Ning, Yu, Liangyao, Wang, Zhizhong, Ma, Liangxu, Song, Jian, Zhang, Yongsheng, Wei, Wenruo
Experimental Study of Interaction between Brake-Disc Surface Texture and Friction Material on Friction and Wear through Small-Scale Tests on Tribotester2014-01-25029/28/2014
There are various processes for finishing the friction surfaces of a brake disc, which affect the braking effectiveness of a vehicle in the early stages of use in some cases. To examine the interaction between the disc surface texture, rotational direction, and friction material, a series of experiments on a tribotester using small-scale specimens was conducted. In a previous paper (2013-01-2056), the results from the first series of experiments, which involved of thirty disc surface textures and a less aggressive non-asbestos organic (NAO) friction material in on-brake-drag conditions combining constant speed and normal-load, was reported. Disc surfaces were finished by the following finishing processes in two rotational directions: turning under four cutting conditions, roller burnishing after turning, turning with a wiper insert, and grinding with two stones. Contact-pressure dependency of friction and wear was confirmed. Roller-burnished and wiper-turned discs exhibited different friction and wear at a certain contact pressure between rotational directions in the turning process. In the present study, four discs finished by grinding in a different cross-hatch pattern from that in the previous study and two friction materials (aggressive NAO and low-steel friction materials) were additionally tested. The findings from the test results on friction, wear, and transfer-layer build-up are presented. The directional difference in friction and wear was confirmed to depend on the combinations of disc surface texture, friction material, contact pressure, and test period. Even a grinding-finished disc and low-steel friction material exhibited a directional effect in some cases.
Okamura, Toshikazu
Regenerative Braking Control Algorithm for an Electrified Vehicle Equipped with a By-Wire Brake System2014-01-17914/1/2014
Regenerative braking, which can effectively improve vehicle's fuel economy by recuperating the kinetic energy during deceleration processes, has been applied in various types of electrified vehicle as one of its key technologies. To achieve high regeneration efficiency and also guarantee vehicle's brake safety, the regenerative brake should be coordinated with the mechanical brake. Therefore, the regenerative braking control performance can be significantly affected by the structure of mechanical braking system and the brake blending control strategy. By-wire brake system, which mechanically decouples the brake pedal from the hydraulic brake circuits, can make the braking force modulation more flexible. Moreover, its inherent characteristic of ‘pedal-decouple’ makes it well suited for the implementation in the cooperative regenerative braking control of electrified vehicles. With the aims of regeneration efficiency and braking performance, a regenerative braking control algorithm for electrified vehicles equipped with a brake-by-wire system is researched in this paper. The layout of the adopted brake-by-wire system is introduced. The proposed regenerative braking control algorithm is illustrated. To validate the control performance of the algorithm, hardware-in-the-loop simulations are carried out. The simulation results show that, based on brake-by-wire system, the proposed control algorithm, coordinating regenerative brake and hydraulic brake well, can further improving the regeneration efficiency of electrified vehicle and guarantee the braking performance in the meantime.
Lv, Chen, Zhang, Junzhi, Li, Yutong, Yuan, Ye
Development of a Control Strategy and HIL Validation of Electronic Braking System for Commercial Vehicle2014-01-00764/1/2014
This article focuses on the research of control algorithm and control logic for the pneumatic EBS (Electronic Braking System) of commercial vehicle. An overall technical program was proposed which develops conventional braking and emergency braking for commercial vehicle EBS. According to the overall scheme, the methods of vehicle state estimation and driver's braking intention were determined, modeling and simulation for key components of commercial vehicle EBS were then carried out. This lead to the development of deceleration control, braking force distribution, brake assist and ABS control. Simulation models for key components of EBS and control strategy were validated through hardware-in-the-loop simulation tests. Simulation results show that the control strategy improves vehicle braking stability and vehicle active safety.
Han, Jongchol, Changfu, Zong, Weiqiang, Zhao
Vehicle Design and Implementation of a Series-Parallel Plug-in Hybrid Electric Vehicle2013-01-249210/14/2013
The Hybrid Electric Vehicle Team (HEVT) of Virginia Tech has achieved the Year 2 goal of producing a 65% functional mule vehicle suitable for testing and refinement, while maintaining the series-parallel plug-in hybrid architecture developed during Year 1. Even so, further design and expert consultations necessitated an extensive redesign of the rear powertrain and front auxiliary systems packaging. The revised rear powertrain consists of the planned Rear Traction Motor (RTM), coupled to a single-speed transmission. New information, such as the dimensions of the high voltage (HV) air conditioning compressor and the P2 motor inverter, required the repackaging of the hybrid components in the engine bay. The P2 motor/generator was incorporated into the vehicle after spreading the engine and transmission to allow for the required space. This spreading of the components meant a redesign of the front powertrain mounts and integration of a torque damper as an interface with the combustion engine and P2 motor. Furthermore, the Energy Storage System (ESS) was redesigned to include the 5-bar replacement structure within the battery support structure. HEVT has spent a large amount of time in algorithm development and testing such as modeling the soft- ECUs of vehicle components and physical plant model concurrently with the control code. The team then advanced to Software-In-the-Loop (SIL) testing with iterative code and model modifications. Once SIL testing was complete, Hardware-In-the-Loop (HIL) testing began. At this stage, the team ensures a robust control strategy by introducing faults to see how the controller handles different situations. Only after these tests are complete does the team conduct in-vehicle testing. Overall, HEVT has integrated all necessary hybrid components and developed a robust control code to complete their EcoCAR 2 Year 2 Chevrolet Malibu.
Manning, Peter C., White, Eli, Caroncino, Kyle, Ashworth, Taylor, Kelly, Brian, Shoults, Lucas, Nelson, Douglas
Prototype of Distributed Electro-Hydraulic Braking System and its Fail-Safe Control Strategy2013-01-20669/30/2013
Prototype of a brake-by-wire (BBW) system named Distributed Electro-hydraulic Braking System (DEHB) has been developed. As a BBW system, DEHB is suitable to be used in electric vehicles (EV) and hybrid electric vehicles (HEV). Comparing to the ‘dry’ type distributed BBW systems such as Electro-mechanical Braking System (EMB) or Electric Wedge Brake (EWB), the ‘wet’ feature of DEHB brings benefits to system cost, installation, performance and reliability. In this paper, prototype of the DEHB was described. Based on its ‘wet’ feature, a new fail-safe control for DEHB was proposed. Two types of DEHB architectures that can perform the proposed fail-safe control were described. Superiority of the proposed fail-safe control and architectures for DEHB were examined and verified through simulations and HIL experiments, which helps DEHB to reach a high level of safety and reliability with reduced cost on electro/electronic redundancy.
Wang, Zhizhong, Yu, Liangyao, Wang, Yufeng, You, Changxi, Ma, Liangxu, Song, Jian
Mass Estimation and Axle Load Distribution Algorithm for EBS of Large Bus2013-01-04174/8/2013
The paper describes an algorithm, which estimates the mass of large buses and axle load distribution using pedal position, wheel speed and the wheel cylinder pressure sensors. This algorithm is allowed to achieve the purpose without additional sensors by using the rotational speed sensors from ABS system and air pressure sensors in brake cylinders form ESP system. The axle load distribution algorithm mainly consists of three steps. Firstly, deceleration of the bus is estimated and then the mass of the bus is estimated. After that, the position of the mass centre is estimated. Taking account of the tire nonlinear characteristics under longitudinal forces and vertical forces, mass estimation, deceleration and the position of the mass centre of buses is corrected by the coefficient, which is determined by the wheel cylinder pressure, the wheel speed and mass estimation. When the deceleration, mass of the large bus and the mass center of the whole bus are completely estimated, load of each axle can be obtained through the formula, and also the optimal braking force of each axle for Electronically Controlled Brake System (EBS) can be determined. The comparison between the value of estimation and the value from the Trucksim indicates that: the estimation algorithm is able to achieve accurate value of the mass and axle load of the bus and lays a ground for the development of EBS.
Nie, Zhigen, Zong, Changfu, Wan, Ying
A Unified Framework of Adaptive Cruise Control for Speed Limit Follower and Curve Speed Control Function2013-01-06184/8/2013
Today many vehicles are being developed with advanced computing and sensing technologies. These new technologies have contributed in enhancing driving safety and convenience. As an example, the Adaptive Cruise Control (ACC) can automatically adjust the vehicle speed to driver's set speed and maintain the driver-requested headway distance to the lead vehicle. In this paper, we further consider the automatic control of speed according to the road attributes, e.g., the speed limit and curve of the road. Two new features, ‘speed limit follower’ and ‘curve speed control’ algorithms, are proposed in this paper. These new features communicate with the conventional ACC system and control the vehicle speed while traveling across different curved roads and speed limit zones. These new features were developed as an independent function, so they can be integrated with any other existing ACC systems. The key enabler for these features is sensing the speed limit and the curvature of upcoming roads using the OnStar GPS and a digital Map. The speed planning algorithm determines the desired vehicle speed profile to provide smooth speed transition along the road curve and the speed limit changes. The vehicle control system regulates the speed of the vehicle according to the desired speed profile. The speed limit follower and the curve speed control algorithms are implemented into a test vehicle with the production cruise control module. The vehicle test results are provided at the end of the paper.
Lee, Jin-Woo, Prabhuswamy, Shilpa
Application of Electric Servo Brake System to Plug-In Hybrid Vehicle2013-01-06974/8/2013
An electric servo brake system applied for use on electric vehicles was applied for use on plug-in hybrid vehicles in order to achieve fuel-savings together with good brake feel and enhanced operability for plug-in hybrid vehicles. The electric servo brake system is made up of highly accurate braking pressure control that functions cooperatively with regenerative brakes together with a structure in which pedal force is not influenced by braking pressure control. The configuration of these components enabled good braking feel even when the power train was being switched from one drive mode to another. Automated pressurization functions that are intended for plug-in hybrid vehicles and that operate with electric servo brake systems were also developed. These developed functions include stall cooperative control that functions cooperatively with the power train, regenerative coordinate adaptive cruise control, and hill-start assist. The application of these automated pressurization functions enabled the reduction of fuel consumption and enhancement of operability.
Ohkubo, Naoto, Matsushita, Satoshi, Ueno, Masayuki, Akamine, Kohei, Hatano, Kunimichi
Analysis of Input Power, Energy Availability, and Efficiency during Deceleration for X-EV Vehicles2013-01-14734/8/2013
The recovery of braking energy through regenerative braking is a key enabler for the improved efficiency of Hybrid Electric Vehicles, Plug-in Hybrid Electric, and Battery Electric Vehicles (HEV, PHEV, BEV). However, this energy is often treated in a simplified fashion, frequently using an overall regeneration efficiency term, ξrg [1], which is then applied to the total available braking energy of a given drive-cycle. In addition to the ability to recapture braking energy typically lost during vehicle deceleration, hybrid and plug-in hybrid vehicles also allow for reduced or zero engine fueling during vehicle decelerations. While regenerative braking is often discussed as an enabler for improved fuel economy, reduced fueling is also an important component of a hybrid vehicle's ability to improve overall fuel economy. Much like energy captured though regenerative braking, engine fueling during deceleration is also often treated using an estimated deceleration fueling rate which is then applied to the total time of deceleration for a particular drive cycle.
Rask, Eric, Santini, Danilo, Lohse-Busch, Henning
Integrated HIL Test and Development System for Pneumatic ABS/EBS ECU of Commercial Vehicles2012-01-20319/24/2012
The quality of the brake system is a significant safety factor in commercial vehicles on the roads. With the development of automobile technology, the single function ABS system didn't meet active safety requirements of the user. The Electronically Controlled Brake System (EBS) system will replace the ABS system to become the standard safety equipment of commercial vehicles in the near future. EBS can be said an enhanced ABS system, it contains load sensor, brake valve sensor and pressure sensor of chamber, etc, and it is more advantages than ABS. This paper describes a flexible integrated test bench for ABS/EBS Electronic Control Unit (ECU) based on Hardware-In-the-Loop (HIL) simulation technique. It consists of most commercial vehicle pneumatic braking system components (from brake pedal valve, brake caliper to brake chambers), and uses the dSPACE real-time simulation system to communicate to the hardware I/O interface. A precise fifteen degrees of freedom (DOF) commercial vehicle model has been developed in order to simulate the vehicle motion that is called by the user control interface developed by LabVIEW. The main purpose of this paper is exploiting the braking force control strategy of EBS system, and testing the EBS ECU error recognition function. A simplified EBS system test bench is developed in order to achieve these purposes by using HIL simulation technology.
Weiqiang, Zhao, Zong, Changfu, Zheng, Hongyu, Wang, Huaji, Yang, Shengnan
A New Approach to the Electronic Wedge Brake2012-01-18019/17/2012
The aim of this research is to develop a new electronic braking system based on an electric powered controlled friction brake with high self-reinforcement capability which has performance advantages over the conventional electromechanical brake systems. To avoid jamming, a special control technology was developed. Thus, by intelligently controlling a brake wedge, the kinetic energy of a vehicle is transformed into braking power. The physical effects involved, lead to a significant reduction of energy consumption of the brake actuator compared to “conventional” brake-by-wire systems. The performance of the “Electronic Wedge Brake” (EWB) in a vehicle was studied using a quarter vehicle model. A sliding mode controller was designed for an optimum wheel slip control, and the control simulation results show significant shorter braking distance in comparison to other conventional braking systems.
Ghajari, Amirhossein, Kazemi, Reza
An Innovative 4WD PHEV Utilizing a Series-Parallel Multiple-Regime Architecture2012-01-17649/10/2012
The focus of this paper is the design and implementation of a series-parallel multiple-regime plug-in hybrid electric vehicle (PHEV) using a 2013 Chevrolet Malibu as a platform. The University of Victoria EcoCAR team used a 3-year vehicle development process (VDP) modeled after those used by Tier 1 automotive manufacturers, and maintained by the rules of EcoCAR 2: Plugging into the Future. Intensive research was conducted to determine the ideal architecture selection based on overall greenhouse gas (GHG) emissions, criteria air contaminant (CAC) emissions, fuel economy, petroleum use, and vehicle performance. As a result, a series-parallel design was pursued, using a high power rear traction motor and large BAS electric machine tied to an E85 compatible 4-cylinder internal combustion engine (ICE). This architecture platform provides for multiple regimes of operation including electric only operation provided by the 14.8 kWh lithium ion battery. The architecture is very flexible in operability, allowing for use of the vehicle beyond direct competition goals to further UVic research activities on hybrid controls. Vehicle control strategy development has relied heavily on hardware-in-loop (HIL) simulation. This allows for rapid development of control strategy concepts. Mechanical integration of new components has been conducted with the primary objectives of minimizing structural impacts to the existing vehicle, and maintaining consumer appeal. Mechanical design will continue to move forward and be refined in the implementation phase of the competition with support from General Motors regarding structural changes.
Kaban, Stefan, Nelford, Jason Clancy, Dong, Zuomin, Dong, Jian, Killy, David, Prescott, Daniel, Crawford, Curran
Design and Development Process of a Parallel-Through-The-Road Plug-In Hybrid Electric Vehicle2012-01-17699/10/2012
The CSULA EcoCAR 2 Team is participating in the EcoCAR 2 Advanced Vehicle Technology Competition Series sponsored by General Motors Corporation, the U.S. Department of Energy, Natural Resources Canada, and Argonne National Lab. This report documents the design process of the CSULA Hybrid Electric Vehicle. The Vehicle Design Process, Powertrain Configuration, Control Development Process, Control System Architecture, Control Algorithm and Strategy, Packaging and Integration, and Energy Storage System are explained. Ultimately, anE85 Parallel Through-The-Road Plug-in Hybrid Electric Vehicle (PTTR) was chosen as the vehicle architecture that could accomplish competition requirements and team goals.
Reid, Christopher, Blekhman, David, Banales, Guadalupe, Fang, Ren, Liu, Phat
Development of General Motors' eAssist Powertrain2012-01-10394/16/2012
General Motors' (GM) eAssist powertrain builds upon the knowledge and experience gained from GM's first generation 36Volt Belt-Alternator-Starter (BAS) system introduced on the Saturn VUE Green Line in 2006. Extensive architectural trade studies were conducted to define the eAssist system. The resulting architecture delivers approximately three times the peak electric boost and regenerative braking capability of 36V BAS. Key elements include a water-cooled induction motor/generator (MG), an accessory drive with a coupled dual tensioner system, air cooled power electronics integrated with a 115V lithium-ion battery pack, a direct-injection 2.4 liter 4-cylinder gasoline engine, and a modified 6-speed automatic transmission. The torque-based control system of the eAssist powertrain was designed to be fully integrated with GM's corporate common electrical and controls architectures, enabling the potential for broad application across GM's global product portfolio.
Hawkins, Shawn, Billotto, Fred, Cottrell, Daniel, Houtman, Alan, Poulos, Stephen, Rademacher, Roger, Van Maanen, Keith, Wilson, Daryl
Brake Design and Safety, Third EditionR-39810/4/2011
The objectives of this third edition of an SAE classic title are to provide readers with the basic theoretical fundamentals and analytical tools necessary to design braking systems for passenger vehicles and trucks that comply with safety standards, minimize consumer complaints, and perform safely and efficiently before and while electronic brake controls become active. This book, written for students, engineers, forensic experts, and brake technicians, provides readers with theoretical knowledge of braking physics, and offers numerous illustrations and equations that make the information easy to understand and apply. New to this edition are expanded chapters on: • Thermal analysis of automotive brakes • Analysis of hydraulic brake systems • Single vehicle braking dynamics
Limpert, Rudolf
Integrated Control of Dynamometer Using LabVIEW Platform - Hardware2011-36-007110/4/2011
The paper addresses the development of an electromagnetic brake control and data capture of torque and rotation, using a graphical interface implemented in LabVIEW for evaluating the performance of internal combustion engines. To control the electromagnetic brake is used like a SMPS Buck, and programming interface developed in LabView is responsible for generating the pulses of voltage that feeds the brake and the data capture system. This project started with the need for improved equipment control and data acquisition dynamometers, eddy-current, installed at the Automotive Laboratory, Instituto Federal de Santa Catarina (IFSC). In the system of control and data acquisition parameters can be added as temperatures, pressures etc., further improving the precision of torque and power these devices.
Luca, Andrei Moro de, Victorette, Milena, Vandresen, Marcelo, Alves Neto, José de Pinho
Effect of Directional Surface Finish of Brake Discs on Friction Behavior During Running-in2011-01-23829/18/2011
This paper focuses on the interaction in friction behavior between the surface texture of brake discs, rotational directions in braking operations and metal-cutting process, and friction materials with different degrees of aggressiveness. A factorial experiment for front brake discs was conducted by combining eight discs with directional surface finishes, two rotational directions, and two NAO friction materials on a brake dynamometer. The author analyzed several test results, such as the friction coefficients, disc wear, roughness, and the correlation between them. An assumed mechanism describing the friction behavior is discussed using the experimental results and by introducing the contribution of the aggressiveness and adhesiveness to the friction and confirmed by the test results.
Okamura, Toshikazu
Development of an Electrically-Driven Intelligent Brake Unit2011-01-05724/12/2011
An electrically-driven, intelligent brake unit has been developed, to be combined with a regenerative braking system in electric vehicles (EVs) and hybrid electric vehicles (HEVs) which went into production in 2010 - 11. The brake pedal force is assisted by an electrically driven motor, without using vacuum pressure, unlike conventional braking systems. The actuator can be implemented to coordinate with a regenerative braking system, and to have adjustable pedal feel through use of a unique pressure-generating mechanism and a pedal-force compensator. In this paper, we describe features of the actuator mechanism and performance test results
Ohtani, Yukio, Innami, Toshiyuki, Obata, Takuya, Yamaguchi, Tohma, Kimura, Tetsuo, Oshima, Toshiaki
Estimation of Vehicle Roll Angle and Side Slip for Crash Sensing2010-01-05294/12/2010
Estimation of vehicle roll angle, lateral velocity and side slip angle for the purpose of crash sensing is considered. Only roll rate sensor and the sensors readily available in vehicles equipped with ESC (Electronic Stability Control) systems are used in the estimation process. The algorithms are based on kinematic relationships, thus avoiding dependence on vehicle and tire models, which minimizes tuning efforts and sensitivity to parameter variations. The estimate of roll angle is obtained by blending two preliminary estimates, each valid in different conditions, in such a manner that the final estimate continuously favors the more accurate one. The roll angle estimate is used to compensate the gravity component in measured lateral acceleration due to vehicle roll or road bank angle. This facilitates estimation of lateral velocity and side slip angle from fundamental kinematic relationships involving the gravity-compensated lateral acceleration, yaw rate and longitudinal velocity. The results of simulations and vehicle tests in a variety of maneuvers demonstrate accuracy of the proposed estimation methods and the use of side slip information in rollover discrimination.
Hac, Aleksander, Nichols, David, Sygnarowicz, Daniel
Brake Response Time Measurement for a HIL Vehicle Dynamics Simulator2010-01-00794/12/2010
Vehicle dynamics simulation with Hardware In the Loop (HIL) has been demonstrated to reduce development and validation time for dynamic control systems. For dynamic control systems such as Anti-lock Braking System (ABS) and Electronic Stability Control (ESC), an accurate vehicle dynamics performance simulation system requires the Electronic Brake Control Module (EBCM) coupled with the vehicles brake system hardware. This kind of HIL simulation-specific software tool can further increase efficiency by means of automation and optimization of the development and validation process. This paper presents a method for HIL vehicle dynamics simulator optimization through Brake Response Time (BRT) correlation. The paper discusses the differences between the physical vehicle and the HIL vehicle dynamics simulator. The differences between the physical and virtual systems are used as factors in the development of a Design Of Experiment (DOE) quantifying HIL simulator performance. Finally, the DOE results are used to drive the development of a tool to correlate the HIL system hardware to the physical vehicle BRT. This leads to the development of hardware with improved BRT, and to the design of new HIL simulators with improved brake response.
Wilkinson, John, Mousseau, Cedric W., Klingler, Thomas
Design, Modeling and Hardware Implementation of a Next Generation Extended Range Electric Vehicle2010-01-08304/12/2010
Advances in battery and hybrid powertrain technology have significantly expanded the automotive design space. In this work, the design process of a new extended range electric vehicle (E-REV) is presented, following the industry standard vehicle development process (VDP). To effectively achieve the design targets, the team developed the project following a model-based design (MBD) approach which is similar to what is used in industrial practice. The design process started from a vehicle technical specification, which defines the required vehicle performance characteristics. Then models were built to exam various design options against the design targets. Improved vehicle performance was demonstrated through model-in-loop (MIL), software-in-loop (SIL) and hardware-in-loop (HIL) simulations. The designed vehicle uses a 2009 Saturn VUE as a baseline platform and incorporates a new powertrain which includes a GM 2-Mode transmission, a GM E85 flex-fuel engine, a rear traction motor and a high-capacity battery system. It achieves zero fuel consumption in charge depleting mode under normal operating conditions, while maintaining the highly efficient 2-Mode hybrid functionality in charge-sustaining mode. By integrating an additional traction motor with the 2-Mode transmission, the new design overcomes the constraints imposed by the size of the original electric motors and gearing configuration in the 2-Mode transmission, to allow the vehicle to be operated at higher speeds and loads without turning on the IC engine. The work is part of the collective efforts of the UVic EcoCAR team in the EcoCAR - Next Challenge collegiate advanced vehicle technology engineering competition.
Zhou, Leon, Wise, Jeremy, Bowman, Shaun, Crawford, Curran, Dong, Zuomin
Development of an Auxiliary Pressurized Hybrid Brake System for a Parallel Hybrid Electric Commercial Van2009-01-287610/6/2009
Efficient use of oil resources has become the number one priority throughout the world. Vehicles, operating with alternative fuels like solar or hydrogen energy are still in the development phase. In this transition period, automotive companies are trying to produce more efficient road vehicles to reduce the negative impacts of the internal combustion engine. Advances in high-efficiency electrical machines (EM), high-specific energy/power units, lower-cost power electronics and embedded systems have promoted the use of EM solely and/or along with the internal combustion engine (ICE) to develop pollution-free vehicles. Due to the high cost of the energy storage units for a pure electric drive the current trend is towards the practice of hybrid electric vehicle (HEVs). This paper presents the design of a novel brake system, namely Auxiliary Pressurized Hybrid Brake System (APHBS), which enables energy recovery and a safe transition from regenerative brake (RB) to hydraulic brake (HB) with minimum intervene to the existing hydraulic brake line of the second generation Ford Transit hybrid electric van. To be able to develop a commercially feasible system, not only energy recovery but also safety is considered during the development phase. Since the vehicle's existing hydraulic brake module is not altered; system functions as a conventional brake system in case of a failure, panic stopping condition and violation of the limits of EM and/or battery. Under normal operating conditions and when the braking deceleration is less than the predetermined value, the proposed system runs the front and rear electrical machines in the generator mode to recover the kinetic energy of the vehicle resulting in fuel savings. If the desired braking force cannot be generated by regenerative braking, a safe transition is provided from RB to HB through the auxiliary pressurized brake line. This proposed system is simulated in MATLAB®/Simulink to demonstrate its successful operation. The simulation results have shown that a continuous braking without compromising the brake performance and energy recovery can be maintained by the implementation of the APHBS to the hybrid van.
Altidemir, Esen, Hartavi, Ahu Ece, Güvenç, Levent, Göktan, Ali, Yildirim, Murat
Braking System Definitions—Truck and BusJ2627_200908 (Historical)8/3/2009
This SAE Recommended Practice identifies and defines terms specifically related to truck and bus braking systems including Antilock Brake Systems (ABS) and Electronically Controlled Braking Systems (ECBS).
Truck and Bus Brake Systems Committee
Research on Control of Vehicle Stability Control Based on Electro-Hydraulic Brake System2007-01-36508/5/2007
Electro-Hydraulic Brake (EHB) system is a kind of active control brake systems of automobile, the pedal from the calipers actuation separated and no longer limited by conventional hardware. The system may come together with ABS, ESP, and ASR function, also the communication with other systems is done via the CAN network. EHB system may be classified a “stepping stone” technology to full brake-by-wire and brings huge transform for the performance of braking system. In this paper, vehicle dynamic models were established and accomplished the control strategy for vehicle stability control with EHB system which can adjust wheel and vehicle motion, improve the lateral and longitudinal vehicle stability. This result was verified by simulation which shows that the controller is effective on improving the vehicle stability.
Zheng, Hongyu, Zong, Changfu, Zhu, Tianjun, Tian, Chengwei
Development of Hydraulic Servo Brake System for Cooperative Control with Regenerative Brake2007-01-08684/16/2007
A new brake system, able to make efficient use of regenerative braking while maintaining excellent brake feel, has been developed to increase the fuel economy of hybrid vehicles. A hydraulic servo was used as a base to enable mechanical operation of the service brakes; solenoid valves and brake fluid pressure sensors were added to this base to make it possible to control brake line pressure as demanded. The use of a stroke simulator in the hydraulic servo prevents brake feel from being affected by the control of the brake pressure. In addition, high-accuracy brake pressure control that functions cooperatively with the regenerative brakes is enabled, resulting in stable braking effectiveness.
Aoki, Yasushi, Suzuki, Kenji, Nakano, Hiroshi, Akamine, Kohei, Shirase, Takaomi, Sakai, Kouji
Lexus hybridizes sports sedanAUTOOCT06_0810/1/2006
The GS450h is the world's first series production ICE-electric hybrid in a front-engine, rear-wheel-drive configuration, according to Toyota. What makes a GS a Lexus GS is the spirit of a sports sedan, possessing exceptional vehicle dynamics that stimulate the driver,” declares Chief Engineer Shigetoshi Miyoshi, who had tested the excitement of sports and GT car driving during his tenure in Europe. The Lexus GS450h is a premium high-performance sedan endowed with extraordinary driving performance due to its hybrid drive system. In conjunction with a conventional 3.5-L V6 internal combustion engine (ICE), it allows the car to accelerate from 0 to 100 km/h (62 mph) in 5.6 s and reaches a top speed of 210 km/h (130 mph)-the “allowable limit” by its powertrain for most markets. The Japanese-market model is governed not to exceed 180 km/h (112 mph) by an unwritten decree/agreement among the manufacturers there. For America, quoted numbers are 5.2 s from 0 to 60 mph (97 km/h) and a 131-mph (211-km/h) top speed. The European version's top speed is extended to 250 km/h (155 mph) by taller final gearing at a slight sacrifice in the acceleration department. The performance matches that of a high-performance sedan powered by a conventional V-configured engine in the 4.5-5.0 L displacement range, thus the 450 designation.
Yamaguchi, Jack
Development of Vehicle Dynamics Integrated Management2006-01-09224/3/2006
We have developed a new vehicle dynamics control system that is based on a new concept and uses a new hydraulic modulator. The new algorithm, which reflects the concept and hydraulic modulator, can control a vehicle not only in emergency but also in normal driving situation. This results in excellent vehicle controllability.
Hamada, Chiaki, Fukatani, Katsumi, Yamaguchi, Katsuyuki, Kato, Tomohiro
Vibration Reduction Applying Skew Phenomena of Needle Roller Bearings in Brake Actuators2006-01-08814/3/2006
Generally, automobiles have many performance requirements for comfort, of which noise, vibration and harshness are very important. Toyota Motor Corporation equipped several 2003 models with the second-generation Electronically Controlled Brake system (ECB2). These ECB2 actuator units adopted a new structure that reduced pumping noise by controlling the skew phenomena of needle roller bearings. Normally, needle roller bearings are advantageous over other bearings in cases where a large force is loaded on bearings, because the contact areas can be made larger. However, a thrust force arises from skew phenomena because of minute clearances among the component parts of needle roller bearings. As a result, axial vibration of the bearing shaft sometimes occurs due to the thrust force. This paper explains how the thrust force generated from the skew phenomena of needle roller bearings occasionally affects the pumping vibration level of equipped machinery such as the brake actuator unit. Based on this study result, we developed a needle roller bearing that suppresses skew phenomena (i.e., a low-vibration needle roller bearing). Analysis and measurements have revealed that by using the developed bearings and controlling the magnitude and direction of generated thrust force, it is possible to suppress the influence of thrust force on equipment (brake actuator) vibration thereby reducing noise in a vehicle. This paper reports on these studies and findings.
Suzuki, Masakuni, Ishida, Takeshi, Kono, Shingo
Advances in Indoor Tire Tread Wear Simulation2006-01-14774/3/2006
Indoor or laboratory testing of tire tread wear offers many advantages over vehicle fleet testing. Advances in test equipment capabilities and the technologies for defining and simulating meaningful tire loading histories has made indoor tread wear testing a reality. Tire loading histories are influenced by vehicle characteristics, wear course and driving style, and tire stiffnesses. Methods for independently characterizing each of these are reviewed. A simulation technique, TS-Sim, is also described that combines specific vehicle, course and tire characterizations to create a tire load history. The vehicle characterization is critical to the process since both wear rate and various forms of uneven and irregular wear are strongly dependent on vehicle suspension/steering characteristics and on dynamic load transfer behavior. The characterization process involves mapping the vehicle over a practical range of acceleration, deceleration and cornering maneuvers. This mapping can be carried out by use of a computational vehicle model or by experimental testing of an actual vehicle. The proposed vehicle characterization method distinctly captures each wheel position response, showing differences in driven and non-driven positions, steered and non-steered positions, as well as effects of suspension type, alignment, stiffness and kinematic properties. Improvements and recent advances in the modeling method are reviewed. Vehicle modeling with commercially available software has progressed to the point that it can be used in place of an actual vehicle to provide the necessary characterization. Examples of how this is used and comparisons to actual vehicle measurements are included. Altering of vehicle characteristics can be done with the model and used to determine the effect on tire wear through this process. Tire wear results are shown.
Knuth, Erik F., Stalnaker, David O., Turner, John L.
Regenerative Braking Strategies for A Parallel Hybrid Powertrain with Torque Controlled IVT2005-01-382610/24/2005
Hybrid electric vehicles (HEV) are considered as the most cost effective solution, in the short term perspective, for the achievement of improved fuel economy (FE) and reduced emissions. This paper focuses on regenerative braking in a mild hybrid powertrain with infinitely variable transmission (IVT) and specifically on how its control strategy can be formulated and optimized. The study is conducted using a previously validated fully dynamic powertrain model. An initial investigation of the dynamic vehicle behaviour under braking conditions serves as the basis for the development of a control strategy for best braking performance and maximum energy recovery, the implementation of which requires a fully active and integrated brake control system. Limitations and constraints due to driveline configuration and driveability issues are considered and their effect evaluated. Simulation results show that fuel consumption reductions of 12% are achievable along a standard drive cycle.
Cacciatori, Enrico, Bonnet, Baptiste, Vaughan, Nicholas D., Burke, Matthew, Price, David, Wejrzanowski, Krzysztof
Investigating Possible Fuel Economy Bias Due To Regenerative Braking in Testing HEVs on 2WD and 4WD Chassis Dynamometers2005-01-06854/11/2005
Procedures are in place for testing emissions and fuel economy for virtually every type of light-duty vehicle with a single-axle chassis dynamometer, which is why nearly all emissions test facilities use single-axle dynamometers. However, hybrid electric vehicles (HEVs) employ regenerative braking. Thus, the braking split between the driven and non-driven axles may interact with the calculation of overall efficiency of the vehicle. This paper investigates the regenerative braking systems of a few production HEVs and provides an analysis of their differences in single-axle (2WD) and double-axle (4WD) dynamometer drive modes. The fuel economy results from 2WD and 4WD operation are shown for varied cycles for the 2000 Honda Insight, 2001 Toyota Prius, and the 2004 Toyota Prius. The paper shows that there is no evidence that a bias in testing an HEV exists because of the difference in operating the same hybrid vehicle in the 2WD and 4WD modes.
Duoba, Michael, Bohn, Theodore, Lohse-Busch, Henning
Items per page:
1 – 50 of 88