Advanced hybrid energy storage system for mild hybrid electric vehicles

Hybrid electric vehicles (HEV) utilize electric power and a mechanical engine for propulsion; therefore, the performance of HEVs is directly influenced by the characteristics of the energy storage system (ESS). The ESS for an HEV generally requires high power performance, long cycle life, reliability and cost effectiveness; thus, a hybrid energy storage system (HESS) that combines different types of storage devices has been considered to fulfill both performance and cost requirements. To improve the operating efficiency and cycle life of a HESS, an advanced dynamic control regime in which pertinent storage devices in the HESS can be selectively operated based on their status is presented. Verification tests were performed to confirm the degree of improvement in energy efficiency. In this paper, an advanced HESS with a battery management system (BMS) that includes an optimal switching control function based on the estimated state of charge (SOC) is presented and verified.     

On-road assessment of in-vehicle driving workload for older drivers: Design guidelines for intelligent vehicles

There has been recent interest in intelligent vehicle technologies, such as advanced driver assistance systems (ADASs) or in-vehicle information systems (IVISs), that offer a significant enhancement of safety and convenience to drivers and passengers. However, the use of ADAS- and IVIS-based information devices may increase driver distraction and workload, which in turn can increase the chance of traffic accidents. The number of traffic accidents involving older drivers that are due to distraction, misjudgment, and delayed detection of danger, all of which are related to the drivers’ declining physical and cognitive capabilities, has increased. Because the death rate in traffic accidents is higher when older drivers are involved, finding ways to reduce the distraction and workload of older drivers is important. This paper generalizes driver information device operations and assesses the workload while driving by means of experiments involving 40 drivers in real cars under actual road conditions. Five driving tasks (manual only, manual primarily, visual only, visual primarily, and visual-manual) and three age groups (younger (20–29 years of age), middle-aged (40–49 years of age), and older (60–69 years of age)) were considered in investigating the effect of age-related workload difference. Data were collected from 40 drivers who drove in a real car under actual road conditions. The experimental results showed that age influences driver workload while performing in-vehicle tasks.     

Development of a semi-empirical program for predicting the braking performance of a passenger vehicle

Since the invention of automobiles, the need to know the braking performance of vehicles has been acknowledged. However, because there are numerous design variables as well as nonlinearities in the braking system, it is difficult to predict the performance accurately. In this paper, a computational program is developed to estimate the braking performance numerically. This synthetic braking performance program accounts for pedal force, pedal travel and deceleration of braking parts, such as master cylinder, booster, valve, brake pad, rotor, and hoses. To improve the accuracy of program, a semi-empirical model of a braking system is introduced by using the empirical test data of pad compression, hose expansion and the friction coefficient between the pad and rotor. The accuracy of the estimation is evaluated by comparing it to the actual vehicle test results. The developed program is easy for the brake system engineers to manipulate and it can be used in the development of new vehicles by incorporating the graphical presentations.     

Effect of punch angle on energy absorbing characteristics of tube-type crash elements

As a crash energy absorber, a tube-type crash element (expansion tube) dissipates kinetic energy through the internal deformation energy of the tube and through frictional energy. In this paper, the effects of the variation of punch angles on the energy-absorbing characteristics of expansion tubes were studied by quasi-static tests using three punch angles (15°, 30°, and 45°). A finite element analysis of the tube expanding process (m = τ _max /K) was performed using a shear friction model to confirm the variation of the shear friction factor with respect to punch angles using the inverse method. Additional analyses were performed using angles of 20°, 25°, 35°, and 40° to study the effect of the punch angles on the internal deformation energy, frictional energy, and expansion ratio of the tubes. The results of the experiment and finite element analysis showed that the shear friction factor was inversely proportional to the punch angles, and a specific punch angle existed at which the absorbed energy and expansion ratio remained constant.     

Sideslip angle estimation considering short-duration longitudinal velocity variation

The accurate estimation of sideslip angle is necessary for many vehicle control systems. The detection of sliding and skidding is especially critical in emergency situations. In this paper, a sideslip angle estimation method is proposed that considers severe longitudinal velocity variation over the short period of time during which a vehicle may lose stability due to sliding or spinning. An extended Kalman filter (EKF) based on a kinematic model of a vehicle is used without initialization of the inertial measurement unit to estimate vehicle longitudinal velocity. A dynamic compensation method that compensates for the difference in the locations of the vehicle velocity sensor and the IMU in on-road vehicle tests is proposed. Evaluations with a CarSim™ 27-degree-of-freedom (DOF) model for various vehicle test scenarios and with on-road tests using a real vehicle show that the proposed sideslip angle estimation method can accurately predict sideslip angle, even when vehicle longitudinal velocity changes significantly.     

Structural design of an outer tie rod for a passenger car

This study proposes a structural design method for an outer tie rod installed in a passenger car. The weight of the outer tie rod is optimized by using the aluminum alloy Al6082M, which is developed as a steel-substitute material, and applying structural optimization techniques. The high strength aluminum with improved mechanical properties was developed to reduce the weight of the outer tie rod. The newly developed aluminum alloy Al6082M is applied as the material of the outer tie rod. The static strength due to inertia force, durability and buckling performances are considered in the structural design of the outer tie rod. At the proto design stage of a new outer tie rod, it is cost-effective to utilize FE (finite element) analysis to predict each of these performances. In addition, the current trend in the structural design of automobile parts is to use optimization techniques to reduce the weights of the parts. First, for an arbitrary base design, the static strength, the life cycle and the buckling load are calculated to check whether the design satisfies its criteria. Then, the critical performance is selected so as to include its loading condition only in the optimization process. In this study, the metamodel based optimization process using kriging is adopted to obtain the minimum weight satisfying the critical design requirement. Then, the feasibility of the determined optimum shape is investigated against the other performances. Finally, the optimum design of outer tie rod is modified by considering forging efficiency. The performances of the final design are investigated through simulation and experiment.     

Experimental studies on the heating performance of the PTC heater and heat pump combined system in fuel cells and electric vehicles

In this study, a combined system consisting of a heat pump and a PTC heater was developed as a heating unit in electric vehicles. The system consists of a compressor, a condenser, an evaporator, an expansion device and a PTC heater. Experiments were conducted to examine the steady-state performance and dynamic characteristics of this system. The compressor speed, outdoor air inlet temperature, and indoor air inlet temperature were varied, and the performance of the system was experimentally investigated. The heating capacity, compressor power consumption and COP were obtained. Warm-up experiments were performed to investigate the dynamic characteristics of the system with a heat load of 1.5 kW in the indoor chamber. For the heat pump system, the PTC heater and the combined system, the heating performance and efficiency were investigated to determine an optimal control method. The results of this study agree well with the experimental results available in literature. This study provides experimental data of good quality for heating system design and the development of electric vehicles.     

Development of an electric active rollcontrol (ARC) algorithm for a SUV

Cornering maneuvers with reduced body roll and without loss in comfort are leading requirements for car manufacturers. An electric active roll control (ARC) system controls body roll angle with motor-driven actuators installed in the centers of the front and rear stabilizer bars. A vehicle analysis model developed using a CarSim S/W was validated using vehicle test data. Two ARC algorithms for a sports utility vehicle (SUV) were designed using a sliding-mode control algorithm based on a nonlinear roll model and an estimated lateral acceleration based on a linearized roll model. Co-simulation with the Matlab simulink controller model and the CarSim vehicle model were conducted to evaluate the performance of two ARC control algorithms. To validate the ARC performance in a real vehicle, vehicle tests were conducted at KATECH proving ground using a small SUV equipped with two ARC actuators, upper and lower controllers and a few subsystems. From the simulation and vehicle validation test results, the proposed ARC control algorithm for the developed ARC actuator prototypes improves the vehicle’s dynamic performance.     

Cold performance of various biodiesel fuel blends at low temperature

This study examines the cold performance of biodiesel blends in a passenger car and a light duty truck at −16 °C and −20 °C. Six different types of biodiesels derived from soybean oil, waste cooking oil, rapeseed oil, cottonseed oil, palm oil and jatropha oil were blended with different volume ratios (B5 (5 vol. % biodiesel — 95 vol. % diesel), B10 and B20). The cold filter plugging point (CFPP) and the cloud point had an effect on the startability and driveability of both the passenger car and the light duty truck. The startability and driveability of the passenger car with all biodiesel blends (B5) were generally good at −20 °C. In the light duty truck, biodiesel blends (B10 and B20) of soybean, waste cooking, rapeseed and jatropha tended to be good at −20 °C in the startability and driveability tests than the biodiesel blends (B10 and B20) of cottonseed and palm. In particular, the palm biodiesel blend (B10) failed at −20 °C, and the palm biodiesel blend (B20) also failed at −16 °C in the startability test. The cold flow properties of biodiesel dictate that the length of the hydrocarbon chains and the presence of unsaturated structures significantly affect the low temperature properties of biodiesel.     

三维测量数据的钢结构虚拟装配过程仿真系统(英文)

The virtual erection simulation system was explained for a steel structure including ship and ocean plant blocks.The simulation system predicted the erection state to optimize any gap or overlap of blocks based on 3-D measurement data.The blocks were modified(cut) on the basis of the simulation result on the ground before erecting them by crane.The re-cutting process was not required and the blocks were erected into a mother ship speedily.Therefore,the erection time is reduced,increasing the dock turnover.