Range Extender Module Transmission Topology Study

Range extender modules are one option to compensate for short drive ranges of electric vehicles. The close interaction of combustion engine and generator poses new challenges in development. A key requirement for range extender systems is to be light and virtually imperceptible in operation. High-speed electrical machines aim at increasing power density. However, their introduction in a range extender requires a gearbox. The combustion engine torque fluctuations can lead to rattle in the gearbox. The rattle can be overcome by a dual mass flywheel. An interdisciplinary model is developed and used to analyse three different range extender systems: one with a low speed generator without gearbox, one with a high-speed generator, and one with a high-speed generator and a dual mass flywheel. The efficiency was found to be higher for the system with a low speed generator, whereas the power density and the costs are beneficial for the high-speed concept. A dual mass flywheel eliminates the changes of torque direction in the gearbox. It reduces the speed fluctuations of the gearbox and generator by over 90 % compared to the low speed setup. But it increases rolling moment and subsequently chassis excitation compared to a setup with only a gearbox.     

Design of Regenerative Anti-Lock Braking System Controller for 4 In-Wheel-Motor Drive Electric Vehicle with Road Surface Estimation

This paper presents a regenerative anti-lock braking system control method with road detection capability. The aim of the proposed methodology is to improve electric vehicle safety and energy economy during braking maneuvers. Vehicle body longitudinal deceleration is used to estimate a road surface. Based on the estimation results, the controller generates an appropriate braking torque to keep an optimal for various road surfaces wheel slip and to regenerate for a given motor the maximum possible amount of energy during vehicle deceleration. A fuzzy logic controller is applied to fulfill the task. The control method is tested on a four in-wheel-motor drive sport utility electric vehicle model. The model is constructed and parametrized according to the specifications provided by the vehicle manufacturer. The simulation results conducted on different road surfaces, including dry, wet and icy, are introduced.     

Effect of operating parameters on diesel/propane dual fuel premixed compression ignition in a diesel engine

In this research, the effects of three operating parameters (Diesel injection timing, propane ratio, and exhaust gas recirculation (EGR) rates) in a diesel-propane dual fuel combustion were investigated. The characteristics of dual-fuel combustion were analyzed by engine parameters, such as emission levels (Nitrogen oxides (NO_x) and particulate matter (PM)), gross indicated thermal efficiency (GIE) and gross IMEP Coefficient of Variance (CoV). Based on the results, improving operating strategies of the four main operating points were conducted for dual-fuel PCCI combustion with restrictions on the emissions and the maximum pressure rise rate. The NOx emission was restricted to below 0.21 g/kWh in terms of the indicated specific NO_x (ISNO_x), PM was restricted to under 0.2 FSN, and the maximum pressure rise rate (MPRR) was restricted to 10 bar/deg. Dual-fuel PCI combustion can be available with low NO_x, PM emission and the maximum pressure rise rate in relatively low load condition. However, exceeding of PM and MPRR regulation was occurred in high load condition, therefore, design of optimal piston shape for early diesel injection and modification of hardware optimizing for dual-fuel combustion should be taken into consideration.     

Design Optimization of the Cowl Cross Bar - Light Cowl Cross Bar Satisfying 5 Performances -

Nowadays, more lightweight designs is the key goal of all major automotive industries. One of the main sections for more lightweight automotive area is the Cowl cross bar (CCB) assemblies. A cowl cross bar supports a steering system, airbag module, audio, instrument panel and air conditioning system. The CCB integrates these components into the cockpit module and connects to the body. So the CCB must meet the 5 performance requirements, ① NVH requirement to minimize the vibration, ② Crash performance for less deflection, ③ Steering response requirement for steer predictability, ④ Durability performance like the fatigue life and ⑤ Supporting rigidity for the components. In this study, a new methodology for the optimum CCB design is proposed to obtain a more lightweight design considering 5 targeted requirements. At first, for NVH and Steering response performance, 3-steps of optimization was fulfilled in sequence of (1) Size optimization and mounting position, (2) Case studies about the various types of brackets and (3) Shape optimization using the topology. The proposed design and optimization framework was verified whether it could meet the crash, durability and stiffness requirements. The final optimal CCB would be applied to the new platforms of the Hyundai-Kia motors.     

Spatter rate estimation of GMAW-S based on partial least square regression

This paper analyzes the drop transfer process in gas metal arc welding in short-circuit transfer mode （GMAW-S） in order to develop an optimized spatter rate model that can be used on line. According to thermodynamic characters and practical behavior, a complete arcing process is divided into three sub-processes： arc re-ignition, energy output and shorting preparation. Shorting process is then divided as drop spread, bridge sustention and bridge destabilization. Nine process variables and their distribution are analyzed based on welding experiments with high-speed photos and synchronous current and voltage signals. Method of variation coefficient is used to reflect process consistency and to design characteristic parameters. Partial least square regression （PLSR） is utilized to set up spatter rate model because of severe correlativity among the above characteristic parameters. PLSR is a new multivariate statistical analysis method, in which regression modeling, data simplification and relativity analysis are included in a single algorithm. Experiment results show that the regression equation based on PLSR is effective for on-line predicting spatter rate of its corresponding welding condition.     

Relationship between quality and attributes of elliptical spot welds of high strength steel

More high strength steel(HSS) sheets are being applied in the automobile industry to improve safety and fuel efficiency.When HSS is spot welded, the strength of the welded-joint is usually determined by the attributes of the weld nugget.However, it is diffcult to obtain the circular nugget and to establish the relationship between the weld attributes and welding quality because of a large number of variables and experimental uncertainty.In the paper, the numerical analysis model of tensile-shear strength test for HSS spot welds was established.And the critical ellipticity of the elliptical spot weld was determined through finite element analysis.Quantitative relationship between elliptical weld attributes and weld strength was investigated statistically using the Latin hypercube and regression analysis method.The sheet thickness, nugget ellipticity, hardness radio and yield strength have the most influential attributes in affecting welding quality.The research results can be used as a guideline for HSS resistance spot welding design.     

A new black box analysis of hash functions based on block ciphers

For the 64 most basic ways to construct a hash function H:{0,1} → {0,1}n from a block cipher E:{0,1}n × {0,1}n → {0,1}n, Black et al.provided a formal and quantitative treatment of the 64 constructions, and proved that 20 schemes are collision resistant.This paper improves the upper and lower bounds and make contrast with a hash constructed from a random oracle.These 20 schemes have only one kind of collision resistance upper and lower bounds.In addition, we present new advantages for finding second preimages.     

Simulation of Chaos in Asymmetric Nonlinear Chua＇s Circuit

In order to describe practical chaotic systems exactly, we presented a simple modified Chua's circuit,which contains an asymmetric nonlinear resistive element. Mathematical analysis was made, and simulation study was performed by MATLAB. By varying the value of linear resistor in the circuit, rich variety dynamical behaviors were observed, such as DC equilibrium point, Hopf bifurcation, period-doubling bifurcation,single-scroll strange attractor, periodic windows, and asymmetric double-scroll strange attractor. The extreme sensitivity in the state trajectory with respect to the initial conditions was exhibited; the special characteristic of asymmetric nonlinear Chua's circuit was found also.     

A new method of transmission network flexible planning using the connection number

Because connection number can express and process synthetic uncertainties caused by various uncertainties in the transmission network planning, a connection number model (CNM) was presented to compare the values of connection number logically. This paper proposed a novel model for transmission network flexible planning with uncertainty. In the proposed planning model both certainty and uncertainty information were included, and the cost-benefit analysis method was used to evaluate the candidate schemes in the objective function. Its good adaptability and flexibility were illustrated through two examples.     

Distribution system optimization planning based on plant growth simulation algorithm

An approach for the integrated optimization of the construction/expansion capacity of high-voltage/medium-voltage (HV/MV) substations and the configuration of MV radial distribution network was presented using plant growth simulation algorithm (PGSA). In the optimization process, fixed costs correspondent to the investment in lines and substations and the variable costs associated to the operation of the system were considered under the constraints of branch capacity, substation capacity and bus voltage. The optimization variables considerably reduce the dimension of variables and speed up the process of optimizing. The effectiveness of the proposed approach was tested by a distribution system planning.