Table of Content

25 June 2018, Volume 40 Issue 6 Previous Issue    Next Issue

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A Study on Coordinated Optimization on Battery Capacity and Energy Management Strategy for a Plug in Hybrid Electric Bus Xie Shaobo, Xin Zongke, Li Huiling, Liu Tong & Wei Lang 2018, 40 (6):  625.  doi: 10.19562/j.chinasae.qcgc.2018.06.001 Abstract ( 257 )   Save In this paper, the selection of battery capacity and a coordinated optimization on energy management strategy are conducted for a plugin hybrid electric bus (PHEB) with minimizing the overall cost (consisting of battery purchase cost and energy consumption cost during operation) as objective. Firstly a biloop optimizing procedure is devised, in which the outer loop is for choosing battery with different capacities while the inner loop performs the energy management strategy based on Pontryagins minimum principle (PMP) with the battery pack chosen. Then a simulation is conducted based on Chinese typical urban citybus driving cycle and the results show that the optimal battery pack capacity of PHEB is affected by multiple factors including the required driving range and the unitprice of battery etc. Finally, with the battery pack chosen, a comparative simulation on energy management is carried out with strategies of PMP, dynamic programming, chargedepleting / chargingsustaining and equivalent energy consumption minimization strategy respectively, and the energy consumption characteristics of four strategies are obtained. Related Articles | Metrics

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A Study on the Effects of Low Viscosity Lubricating Oils on the Fuel Economy and Durability of Gasoline Engines Tang Chunqiu, Yin Kaifeng, Mo Yimin, Wang Jun, Lei Zhidan & Li Jialong 2018, 40 (6):  632.  doi: 10.19562/j.chinasae.qcgc.2018.06.002 Abstract ( 230 )   Save The effects of test oil SN 0W20 and reference oil SM 5W30 on the fuel economy of engine are compared by engine bench test. The results show that the use of lubricating oil with low viscosity can reduce the mechanical friction loss of engine by about 34% to 57%. The average specific fuel consumption in all conditions decreases by 1% to 35%. A durability test with the low viscosity lubricant SN 0W20 is conducted and after that the performances of engine is tested and the physical and chemical indexes and element contents of lubricating oil are analyzed. The results show that after the durability test of engine, the wear amounts of all friction pairs are relatively little, the extent of performance decline is within the normal range, indicating that the viscosity grade of SN0W20 can meet the requirements of engine durability. Related Articles | Metrics

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A Research on Thermal Decomposition Characteristics and Crystallization Law of Ammonium Salts for Solidstate SCR System in Diesel Engine Fan Luyan, Wang Andong, Qu Dawei, Li Jun & Ma Junyan 2018, 40 (6):  638.  doi: 10.19562/j.chinasae.qcgc.2018.06.003 Abstract ( 183 )   Save In view of that the aqueous urea solution used in traditional selective catalytic reduction (SCR) system is difficult to produce ammonia by thermal decomposition at low exhaust temperature in lowspeed and light load conditions of diesel engine and is easy to form sediments, leading to the blockingup of piping and hence lowering the conversion rate of NOx, two ammonium salts (ammonium carbonate and ammonium carbamate) are studied in this paper as candidate reductants of solidstate SCR system. Firstly the theoretical analysis of ammonia content and thermogravimetric experiments are conducted with the results showing that the obtainable masses of ammonia by thermal decomposition from ammonium carbonate and ammonium carbamate are 192 and 237 times as more as that from aqueous urea solution respectively, and both ammonium salts can completely decompose in 8 mins at 90°C, a temperature much lower than that of exhaust gas (150°C) in diesel engine at low speed/light load conditions. Then decomposition equilibrium pressure and recrystallization experiments are performed and the results indicate that in the normal range of working temperatures of coolant and lubricant oil in diesel engine, both ammonium salts can provide rather high injection pressure for injection system, and they do not tend to recrystallize So it is demonstrated that both ammonium salts meet all the requirements for reductants in solidstate SCR system, in which ammonium carbamate is slightly superior to ammonium carbonate in overall property. Finally isothermal and integral methods are used to calculate the decomposition kinetics parameters of ammonium salts, including their decomposition reaction orders, activation energies and apparent preexponential factors, to provide theoretical basis for the design of ammonia generation and supply devices in solid SCR system. Related Articles | Metrics

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A Research on the Effects of Different Data Processing Methods on the Results of DRE Test Zheng Sikai, Ge Yunshan, Chen Weicheng, Wang Xin, Song Bin & Yu Wenlin 2018, 40 (6):  646.  doi: 10.19562/j.chinasae.qcgc.2018.06.004 Abstract ( 262 )   Save Euro6 emission regulation for lightduty vehicles proposes two data processing methods for RDE test, i.e. power binning method and CO2 moving averaging window method. To explore the effects of two different processing methods on the analysis results of RDE test data, several RDE tests are conducted with portable emission measurement system according to the requirements of regulation, and the data are processed with power binning method and CO2 moving averaging window method respectively, which are then contrastively analyzed. The results show that the emission factors of all pollutants obtained by power binning method are larger than that by moving averaging window method. But when data in cold start, idling and misfire conditions are removed as same as with moving averaging window method, the emission factors obtained by power binning method are obviously lowered and basically the same as that with moving averaging window method. Thus a conclusion is drawn that data removal is the main cause of the difference   in pollutant emission factor with two different processing methods. Related Articles | Metrics

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Coordinated Control for Adaptive Cruise Control System of Distributed Drive Electric Vehicles Xie Laiqing, Luo Yugong, Li Shengbo & Li Keqiang 2018, 40 (6):  652.  doi: 10.19562/j.chinasae.qcgc.2018.06.005 Abstract ( 269 )   Save In view of the necessity and real time performance of multiobjective performance coordinated control in the longitudinal following movement of intelligent distributed drive electric vehicle, an adaptive cruise control algorithm based on model predictive control theory is proposed on the basis of the analysis on the structure and longitudinal kinetics characteristics of distributed drive electric vehicle. A method of reducing the scale of optimization problem is adopted to shorten the computing time of single step, with the computational efficiency enhanced in online optimization. For verifying the effectiveness of the algorithm, simulation platform is constructed and relevant simulation and hardwareintheloop test are carried out. The results of both simulation and test indicate that the algorithm proposed can achieve coordinated optimization of both safety and energy saving of that vehicle, and meet the requirements for real time control. Related Articles | Metrics

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Design and Implementation of the Control System for the Traction Motor of Electric Vehicles Based on AUTOSAR Qiu Meihan, Wang Xiaolin & Bian Hao 2018, 40 (6):  659.  doi: 10.19562/j.chinasae.qcgc.2018.06.006 Abstract ( 295 )   Save For the development of new energy vehicle software system，its objective is to enhance the reliability, transplantability and development efficiency of system software, and its trend is a hierarchical and modular development procedure. In this paper, based on AUTOSAR standard, the control system of electric vehicle traction motor is divided into different modules and software layers, and they are developed independently without coupling. Then with Infineon TC275 microprocessor as control platform, a measurement test is conducted on permanentmagnet synchronous motor. The results show that the control software can realize the normal control functions of motor with good speed and torque response characteristics, verifying the effectiveness and feasibility of the development procedure for motor control software architecture. Related Articles | Metrics

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A Research on the Factors Affecting the Consistency of Testing Results for Child Restraint Systems Zhang Xuerong, He Juan, Wang Haiye& Wu Miao 2018, 40 (6):  666.  doi: 10.19562/j.chinasae.qcgc.2018.06.007 Abstract ( 160 )   Save To explore the radical causes of deviations in dynamic test for child restraint systems in different laboratories, both simulation and test verification are conducted on universal and semi-universal child restraint systems with P3 dummy based on national standard GB27887, to quantitatively analyze the degree of effects of each factor on the deviations in dynamic tests.  The results show that the difference of impact waveform in different laboratories, the foam stiffness attenuation coefficient of sled cushion, the initial installation angle of supporting leg and the friction coefficient of safety belt guide have significant effects on the scatter of test data. In the process of subsequent national standard revision, it is necessary to have a quantitative control on key factors, to reduce the test discrepancy between laboratories, and enhance the consistency of tests. Related Articles | Metrics

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Simulation and Optimization of Vehicle Frontal Crashworthiness Based on Surrogate Model Chen Yuanyuan & Zheng Ling 2018, 40 (6):  673.  doi: 10.19562/j.chinasae.qcgc.2018.06.008 Abstract ( 172 )   Save In view of that traditional methods can not efficiently achieve multiobjective optimization, finite element method is combined with surrogate model technology, with vehicle mass, the peak acceleration of B pillar and the intrusion of firewall as the objectives of optimization and their surrogate models are constructed to study the influence of sample size on model accuracy, and an optimization on the thicknesses of panels is conducted by using NSGAII algorithm. The results show that increasing sample size can not necessarily enhance the accuracy of surrogate models effectively. The accuracy of test point evaluation method to a large extent depends on the number and location of test points, so it can not accurately evaluate the accuracy of surrogate models, while the adoption of cross verification method get a better results. After optimization based on surrogate models, significant improvements are achieved: vehicle mass decreases by 41kg, the peak acceleration of B pillar lowers by 844% and the intrusion of firewall reduces by 603%. Related Articles | Metrics

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A Study on the Influence of Braking Torque Control Method on the Energy Consumption Characteristics of Vehicle Eddy Current Retarder Hu Donghai, He Ren, Hu Nannan, Yi Fengyan & Xu Xiaoming 2018, 40 (6):  679.  doi: 10.19562/j.chinasae.qcgc.2018.06.009 Abstract ( 170 )   Save In view of the huge consumption of electric energy of batteries on vehicle during the braking process of eddy current retarder, the models for the braking characteristics and thermodynamic characteristics are established and the energy consumption characteristics of eddy current retarder with both hierarchical and stepless controls of braking torque are analyzed. The results of theoretical analysis and experimental study show that the electric energy consumption with hierarchical control is greater than that with stepless control. The main reason is the uneven allocation of braking task with hierarchical control, in which too more braking tasks are allocated to the less exciting windings, leading to rapid temperature rise and causing additional electricity consumption. With stepless control, the braking tasks are evenly allocated to all the field windings, ensuring a proper temperature of single winding and a reasonable energy consumption. Related Articles | Metrics

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Effects of Fitting Clearances in Balancing Axle Assembly on Vehicle Dynamics Huang Kang, Yang Yang, Zhen Shengchao & Yi Yong 2018, 40 (6):  687.  doi: 10.19562/j.chinasae.qcgc.2018.06.010 Abstract ( 193 )   Save For analyzing the effects of the fitting clearance in the balancing axle of multiaxis heavy truck on vehicle dynamics, taking a threeaxle heavy truck as an example, and a nonlinear kinematical model for balancing axle assembly with fitting clearances and a nonlinear vehicle kinetics model are established. With the real road excitations on three wheels as inputs, the dynamic characteristics of vehicle body pitching and the vertical displacements of vehicle body and driver are emphatically studied. By a simulation with Matlab, the dynamic characteristics curves under the excitation of Dgrade road are obtained, which are then compared with those based on ideal model. The results show that the fitting clearances in balancing axle will intensify the vibration of vehicle body. Related Articles | Metrics

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A Research on the Enhancement of Vehicle Lateral Stability by Applying Inerter to Suspension Shen Yujie, Chen Long, Yang Xiaofeng, Liu Yanling & Liu Changning 2018, 40 (6):  693.  doi: 10.19562/j.chinasae.qcgc.2018.06.011 Abstract ( 615 )   Save In order to explore the possibility of enhancing the lateral stability of vehicle by applying inerter to suspension, two different inerterspringdamper (ISD) suspension structures are studied. A seven DOF dynamics model for a car is built, and on the basis of an analysis on the lateral stability of vehicle and taking the typical fishhook steering input as test condition, an optimization on the element parameters of ISD suspension is conducted by using multiple population genetic algorithm with the peak value of time domain response of car body roll angle as optimization indicator, and the results of optimization are simulated. The results show that the peak values of car body roll angle of the vehicle with S1 and S2 ISD suspensions are significantly suppressed, improving by 386% and 486% respectively at different vehicle speeds compared with conventional passive suspension. And comparatively S2 suspension has more significant enhancement in vehicle lateral stability than S1 one so is more suitable for use in vehicle. Related Articles | Metrics

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A Study on Modeling Method of Stabilizer Rod Based on Nonlinear Characteristics of Suspension Li Xiaoshan, Wei Baolü, Zhang Qing, Qin Zaiwu, Ji Hao & Li Deyu 2018, 40 (6):  699.  doi: 10.19562/j.chinasae.qcgc.2018.06.012 Abstract ( 188 )   Save A finite element model for stabilizer rod is established based on nonlinear characteristics of suspension multibody system, the strength of stabilizer rod is analyzed with the wheel hop acquired in roadtest as input, and its modeling methods are evaluated through comparing the critical loads obtained by applying compression rod instability theory and bench test. The results of real vehicle verification show that the model for stabilizer rod based on nonlinear characteristics of suspension system can accurately predict the critical loads and the stress of stabilizer rod while the results of compression rod bench test have certain error, and the instability theory can not directly applied to strength check for stabilizer rod. Related Articles | Metrics

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A Study on Two Parameter Temperature Model for Main Clutch of Dry DCT Zheng Pengfei, Chen Li & Fang Chengliang 2018, 40 (6):  706.  doi: 10.19562/j.chinasae.qcgc.2018.06.013 Abstract ( 147 )   Save During clutch slipping phase of a dry dual clutch transmission, heat accumulation and intensive temperature rise seriously affect the torque transmitting capacity, friction and wear performance and durability of friction plates. Temperature model is the basis of temperature control and the traditional finite element temperature model can not be used for real time control due to tremendous computation efforts. According to the geometric and physical features of main clutch, an assumption of onedimension temperature field is put forward, energy balance equations are established and a timespace discrete model for unsteady heat conduction process under the action of internal heat source is derived, based on which temperature rise coefficient and heat dissipation coefficient are defined and a two parameter simplified model is built. The comparison with test results show that the relative error of simplified model is less than 10%. Related Articles | Metrics

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An Optimization on Whine Noise Characteristics of Transmission Based on Orthogonal Experimental Design Zang Mengyan, Dong Haozhe, Peng Guomin & Chen Yong 2018, 40 (6):  713.  doi: 10.19562/j.chinasae.qcgc.2018.06.014 Abstract ( 215 )   Save In order to tackle the whine noise problem of differential gear in an automotive transmission under third and fourth gear conditions, firstly a simulation on transmission model is conducted with the correctness of simulation model verified by comparing the simulation and test results of gear contact pitting spots and housing surface vibration response. Then on the basis of single factor analysis on the effects of microprofile correction parameters on the transmission error of differential gear, an orthogonal experiment optimization is performed with the weighted mean value of transmission error as evaluation indicator, and a combination of the microprofile correction parameters with minimum transmission error is obtained. Optimization results significantly reduce the transmission error of differential gear under third and fourth gear conditions and hence the corresponding whine noise. Related Articles | Metrics

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Nonlinear Optimal Sliding Mode Fuzzy Control for InWheel Active Vibration Damper of Electric Wheel Wang Juncheng & He Ren 2018, 40 (6):  719.  doi: 10.19562/j.chinasae.qcgc.2018.06.015 Abstract ( 169 )   Save Rigid connection of inwheel motor and wheel may increase the unsprung mass of electric vehicle and deteriorate the ride comfort of vehicle. To overcome the negative effects of vertical vibration of wheel, a nonlinear optimal sliding mode fuzzy control scheme is proposed for the inwheel active vibration damper in electric wheel. A quarter vehicle dynamics model is established with consideration of the generalized nonlinear characteristics of suspension, the control of inwheel active vibration damper is fulfilled by linearizing the nonlinear system, constructing an optimal sliding mode fuzzy controller, and delinearization. A comparative simulation is then conducted and the results show that the inwheel active vibration damper in electric wheel with nonlinear optimal sliding mode fuzzy control can effectively reduce the negative effects of vertical vibration of inwheel motor and ensure a better comprehensive ride comfort performance of electric vehicle. Related Articles | Metrics

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Concurrent Pedestrian and Cyclist Detection Based on Deep Neural Networks Chen Wenqiang, Xiong Hui, Li Keqiang, Li Xiaofei& Zhang Dezhao 2018, 40 (6):  726.  doi: 10.19562/j.chinasae.qcgc.2018.06.016 Abstract ( 232 )   Save In this paper, aiming at the defects of existing detection method, being unable to effectively distinguish two types of object: pedestrians and cyclists, a concurrent pedestrian and cyclist detection method is proposed based on deep neural network (DNN), while in view of the problems of frequent undetection and false detection in codetection of pedestrian and cyclist in road environment, the poor detection results for smalldimension targets and the complex and changeable background environment, several DNN modification schemes like difficult example extraction, multilayer feature fusion and multitarget candidate region input are devised to realize concurrent pedestrian and cyclist detection. The results of tests on the public database of pedestrian and cyclist show that the method proposed achieves high identification rate of pedestrian and cyclist and can distinguish each other, with its effectiveness validated. Related Articles | Metrics

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Rigidflexible Coupling Kinematics Analysis of Shifting Manipulator for Robot Driver Yu Shenlin & Chen Gang 2018, 40 (6):  733.  doi: 10.19562/j.chinasae.qcgc.2018.06.017 Abstract ( 163 )   Save For revealing the effects of the elastic deformations of linkages in the manipulator of robot driver on shifting displacement and velocity, a rigidflexible coupling kinematics analysis of shifting manipulator is conducted in this paper. Firstly, based on an analysis on the movement principle of shifting manipulator, a kinematics model for shifting manipulator is established, its kinematics equations are derived, and the displacements of gear selecting and gear shifting motor shafts are obtained by using the inverse solving technique of kinematics equations. Then both multirigid body kinematics model and rigidflexible coupling kinematics model for shifting manipulator are set up，on which a comparative simulation on the kinematics of shifting manipulator is conducted with the displacements of gear selecting and gear shifting motor shafts as inputs to analyze the motion trajectory and shift error of shifting manipulator. Finally both simulation and real vehicle test on the shifting displacements and velocities of manipulator are performed with a result showing they are consistent in tendency. Related Articles | Metrics

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A Research on Comfort Design of Driver Seat Based on Body Pressure Distribution Simulation Wang Guangbin, Ren Jindong & Liu Honghao 2018, 40 (6):  741.  doi: 10.19562/j.chinasae.qcgc.2018.06.018 Abstract ( 193 )   Save In this paper, the finite element model of HPoint Machine (HPM)II is constructed, the size and mass of each part, the lumbar support and torso kinematics attitude of the model are verified, the design parameters of seat are measured by the simulation on the attitude of HPM, and the interaction between driver and seat is simulated. Firstly, the geometric model of human body is built based on ANSUR human anthropometry database, the driving attitude is set by using cascade prediction model, and the finite element model of human body is set up based on its geometric model. Then a parametric finite element model for seat is established. Finally the finite element models for human body and seat are assembled together with corresponding boundary conditions set, and the body pressure distribution between human body and seat is simulated under different foam thickness, the position and protrusion of lumbar support, cushion angle and seatback angle, with the influences of these factors on pressure distribution obtained. The method adopted lays a foundation of seat design oriented towards ideal body pressure distribution and provides references for seat comfort design.   Related Articles | Metrics