Table of Content

25 September 2018, Volume 40 Issue 9 Previous Issue    Next Issue

Select

A Research on the Structural Innovative Design of Parallel Hybrid Powertrain System Deng Tao, Zhou Hao & Tang Peng 2018, 40 (9):  997-1004.  doi: 10.19562/j.chinasae.qcgc.2018.09.001 Abstract ( 654 )   PDF (1348KB) ( 770 )   Save In this paper, the mechanical innovative design method is applied to the structural analysis of single-motor parallel hybrid powertrain system for expanding the transmission system structure of hybrid electric vehicle. Firstly, two representative transmission structures of single-motor parallel hybrid electric vehicle are analysed with their mechanical topology structure obtained. With mechanical innovative design method, the kinematic chains of mechanical topology structure are obtained by applying generalization rules, and the generalized kinematic chains are acquired according to the members of kinematic chain links and kinematic pairs. By adopting specific program the feasible and specific kinematic chain map meeting design constraints is found from the generalized kinematic chain plots, and after eliminating those with same configurations, 12 feasible and specific kinematic chains are obtained, which are then converted into corresponding schematic diagram of plenary gear set by using concretization rules. Finally, through the analyses on power input/output distribution and operation modes, 132 feasible structures for the transmission system of single-motor parallel hybrid electric vehicle are obtained, from which a new configuration is chosen with its energy flows in six basic operation modes analyzed to get 15 combinations of clutch and brake state, verifying the feasibility of applying mechanical innovative design method to the structural design of hybrid powertrain system References | Related Articles | Metrics

Select

A Research on Equivalent Fuel Consumption Minimization Strategy Optimization#br# Based on Double-loop Multi-objective Particle Swarm Optimization Algorithm Shi Qin, Qiu Duoyang, Wu Bing, Liu Bingjiao & Chen Yikai 2018, 40 (9):  1005-1013.  doi: 10.19562/j.chinasae.qcgc.2018.09.002 Abstract ( 350 )   PDF (1213KB) ( 552 )   Save The optimal design of equivalent fuel consumption minimization strategy (ECMS) is for discontinuous and non-derivable multi-objective optimization. In order to improve the vehicle fuel economy and realize good power retention performance of the battery, a novel double-loop multi-objective particle swarm optimization (DL-MOPSO) algorithm is proposed to optimize the charging and discharging equivalent factor and power allocation mode simultaneously. Simulation results show that compared with the traditional exhaustion method, the ECMS obtained by the DL-MOPSO algorithm can improve the vehicle fuel economy by 10.28%, and the difference between the SOC final value and the target value is reduced to 0.0019, effectively maintaining power balance. Finally, the influence of the parameter β in penalty function on ECMS optimization is analyzed, which is of guiding significance to parameter selection References | Related Articles | Metrics

Select

A Study on the Effect of Stroke-to-Bore Ratio on Gasoline Engine's Flow Field Gao Ying, Xie Tianchi, Men Xin, Xu Yingjian & Fei Xiaoheng 2018, 40 (9):  1014-1020.  doi: 10.19562/j.chinasae.qcgc.2018.09.003 Abstract ( 392 )   PDF (2419KB) ( 534 )   Save To investigate the effect of stroke-to-bore ratio on in-cylinder flow field, the stroke-to-bore ratio of a three-cylinder port fuel injection gasoline engine model is changed to 0.7 and 0.9 (set as scheme 1 and scheme 2) with the other conditions the same, and the stroke-to-bore ratio of the original engine is 1.05 (set as scheme 3). Transient numerical simulation on the intake and combustion process of the three computational schemes at 2000r/min low load and 3800r/min full load is conducted using the software AVL-Fire. The velocity field, turbulent kinetic energy field and heat release rate of the three different computational schemes are compared. Results show that within reasonable limits, the appropriate increase of stroke-to-bore ratio can enhance the intensity of in-cylinder tumble, and hence improve the intensity and distribution of turbulence at ignition timing, achieving greater heat release rate and faster combustion References | Related Articles | Metrics

Select

Optimization of Dynamic Operations for Engine with CVVL System Han Benzhong, Zhang Lihua, Fu Yuansong & Li Liguang 2018, 40 (9):  1021-1031.  doi: 10.19562/j.chinasae.qcgc.2018.09.004 Abstract ( 539 )   PDF (1327KB) ( 460 )   Save Dynamic control and optimization for the engine with the CVVL system is studied in this paper to solve the problem of acceleration jerk, even engine stall and deceleration speed overshoot after the engine with CVVL is equipped on the vehicle. Engine tests reveal that the root cause of acceleration jerk and deceleration speed overshoot is the different dynamic control behaviors of CVVL system, throttle valve and variable valve timing (VVT) while intake air mass flow of the engine is the dynamic superposition result of the 3 control mechanism. During acceleration, CVVL responses quickly while VVT shows response delay. As a result, the intake air mass flow rises suddenly first and then drops, leading to intake fluctuation and engine jerk. During deceleration, CVVL acts slower than VVT. Intake air mass flow rises suddenly first when VVT is switched and then drops when CVVL goes back to a smaller lift. However, engine jerk during deceleration is not as obvious as acceleration. The problems have been effectively solved and smooth and fast switching at engine dynamic conditions is realized through the introduction of a time filter for CVVL and VVT response speed and the cooperative control of CVVL, VVT and throttle opening angle. References | Related Articles | Metrics

Select

A Research on Lateral Extendable Preview Switching Control System for Autonomous Vehicles Cai Yingfeng, Zang Yong, Sun Xiaoqiang, Chen Long, Wang Hai, Jiang Haobin & He Youguo 2018, 40 (9):  1032-1039.  doi: 10.19562/j.chinasae.qcgc.2018.09.005 Abstract ( 413 )   PDF (1420KB) ( 491 )   Save Aiming at the problem of poor adaptability and low control accuracy of lateral control system in autonomous driving vehicles under mixed road conditions with large curvature range, an extendable preview switching control method for the lateral control of autonomous vehicles is proposed in this paper. The control system, consisting of upper layer extendable controller and lower layer controller, realizes the switching control between the feedback control in classic domain and the feedback-forward control in extendable domain. The simulation results in Simulink show that the control method proposed reduce the control error on the road with large curvature while ensuring the control accuracy on the road with small curvature, having a good adaptability to time-varying conditions References | Related Articles | Metrics

Select

A Model Predictive Control-based Torque Coordinated Control Strategy for Hybrid Electric Vehicle During Mode Shifting Zhang Yuanbo, Wang Weida, Xiang Changle, Huang Kun, Ma Yue, Wei Chao & Li Zilong 2018, 40 (9):  1040-1047.  doi: 10.19562/j.chinasae.qcgc.2018.09.006 Abstract ( 499 )   PDF (1050KB) ( 525 )   Save Hybrid electric vehicle (HEV) has multiple working modes and due to the features of system discontinuity, the problems such as poor smoothness arise during mode switching. Accordingly, taking dual-mode series-parallel electromechanical compound transmission system as object, with improving mode switching quality as objective, the control strategy for clutch engagement process is emphatically studied in this paper. Firstly, the overall structure and characteristics of electromechanical compound transmission are analyzed, and the equivalent model for power coupling system is established. Then, a model predictive control-based control strategy for torque coordination is proposed with reducing vehicle jerk and the sliding-friction work of clutch as objective. Finally, the torque coordinated control strategy is verified with simulation model. The results indicate that with the mode switching control strategy proposed, the electromechanical compound transmission system can effectively reduce the torque ripple of output shaft and vehicle jerk, decrease the sliding friction loss of clutch, and hence greatly improve the quality of mode switching, while ensuring faster response of mode switching, having a certain reference value for engineering practice References | Related Articles | Metrics

Select

Decision-making Mechanism of Autonomous Lane-change for Intelligent Vehicles Based on Environment Situation Assessment He Yanxia, Yin Huilin & Xia Pengfei 2018, 40 (9):  1048-1053.  doi: 10.19562/j.chinasae.qcgc.2018.09.007 Abstract ( 234 )   PDF (1394KB) ( 403 )   Save Motor vehicles work in the complex and highly dynamic driving environment, with the information uncertainty of onboard sensors, so the correct situation assessment of dynamic environment is one of the key factors to the safety of motor vehicles, in particular, intelligent vehicles. In this paper, the mechanism of autonomous line-change decision-making for intelligent vehicle is studied based on environment situation assessment. Firstly a hierarchy analysis on vehicle environment situation assessment model is conducted based on human driving cognitive mechanism. Then the dynamic Bayesian network is used to fulfill situation assessment, and autonomous line-change decision-making is achieved with the principle of maximum expected utility. Finally, the effectiveness of the method proposed is verified by experiments. The results show that the method proposed can make correct and reasonable decision for lane change under complex dynamic environment and the condition of information uncertainty such as measured data deviation of onboard sensors References | Related Articles | Metrics

Select

Simulation and Experimental Study on Temperature Field Characteristics of Coated Gears in Automatic Transmission Zang Libin, Chen Yong, Chen Hua, Liu Hai, Zhou Huidong, Li Kai & Luo Daguo 2018, 40 (9):  1054-1061.  doi: 10.19562/j.chinasae.qcgc.2018.09.008 Abstract ( 233 )   PDF (3751KB) ( 351 )   Save Gear surface coating is an effective method to enhance the fatigue life of transmission gears. In this paper, based on nonlinear finite element method, heat generated by the friction between gears is regarded as heat source, friction and wear tester is used to obtain the friction factor of coating surface, and the frictional heat flux density and convection coefficient of coated gears under steady-state condition are accurately calculated. Then, a numerical simulation on the coated gear temperature field of a seven-speed dual-clutch automatic transmission under different coating thicknesses is conducted with ANSYS to reveal the effects of parameters such as the friction factor of coating and the rotation speed and torque of gear on the steady-state temperature field of gears. Finally infrared thermal imager is adopted to measure the gear surface temperature in different working conditions on gear dynamic cycle loading tester. The results verify the accuracy of simulation model and show that reducing the friction factor of coated gear can effectively lower the maximum bulk temperature of gears. The research provides reference basis for the anti-scuffing and surface modification design of transmission gears References | Related Articles | Metrics

Select

Estimation of Vehicle Mass and Road Slope Based on Steady-state Kalman Filter Hao Shengqiang, Luo Peipei & Xi Junqiang 2018, 40 (9):  1062-1067.  doi: 10.19562/j.chinasae.qcgc.2018.09.009 Abstract ( 455 )   PDF (1420KB) ( 670 )   Save In view of that the automatic transmission control system of vehicle is difficult to measure the vehicle mass and road slope, the longitudinal kinematic and dynamic models of vehicle are built, based on which discrete Kalman filter is used to estimate vehicle mass and road slope. The co-simulation with Carsim and Maltab/Simulink and the real vehicle test with proper acceleration sensor and steady-state Kalman filter verify that using the method proposed to estimate vehicle mass and road slope has better real-time performance and accuracy than those obtained from inertial navigator References | Related Articles | Metrics

Select

Clutch with Circumferential Intermittent Contact Li Heyan, Li Mingyang, Ma Biao, Du Qiu, Li Huizhu & Yu Liang 2018, 40 (9):  1068-1075.  doi: 10.19562/j.chinasae.qcgc.2018.09.010 Abstract ( 167 )   PDF (1686KB) ( 320 )   Save With consideration of the effects of temperature and sliding velocity on friction coefficient, an iterative model for calculating the temperature field of circumferential intermittent contact between friction elements of shifting clutch under macro-dimension is established to study the influence of intermittent contact, corresponding to the number of spline teeth, on temperature field and friction coefficient, and the model is validated by friction coefficient measuring experiments. The results show that intermittent contact may result in high temperature zones appear on the surface of friction disks, and the distribution of the high temperature regions corresponds to the number of spline teeth. The highest temperature and average temperature of friction disks lower with the increase of the number of spline teeth, and the temperature rise in friction disks exhibits nonlinear correlation with the number of spline teeth and sliding time. Under the same sliding condition, with the sliding time extending, the friction coefficients, corresponding to different number of spline teeth gradually increases to the same maximum value, and before the friction coefficient reaches the maximum value, the friction coefficient corresponding to fewer spline teeth is larger. Under shifting condition, the friction disks with less spline teeth quicker enter the state of dry friction and reach larger friction coefficient in shorter period of time. Under the long time sliding conditions such as when the vehicle creeps with foot on clutch, the friction disks with more spline teeth have less local temperature rise with better thermal safety References | Related Articles | Metrics

Select

Gear-shifting Control with Speed / Torque Double-synchronization for Hybrid Electric Vehicles Hu Yuhui, Yue Xinyu, Wu Hongzhen & Xi Junqiang 2018, 40 (9):  1076-1082.  doi: 10.19562/j.chinasae.qcgc.2018.09.011 Abstract ( 459 )   PDF (1941KB) ( 447 )   Save Aiming at the existing problems of synchronizing speed difference and shifting shock in conventional gear-shifting control for hybrid electric vehicle, a new way of gear-shifting control with speed / torque double-synchronization is proposed. During speed synchronization, the target speed is adjusted based on the speed change at driven end, and the output torque of motor is adjusted according to synchronizing speed difference so as to make the speeds at both driving and driven ends synchronize, with same moving tendency, for reducing shifting shock. To improve the performance of torque closed-loop PID control, fuzzy RBF neural network is adopted to tune the parameters of PID control, with the rapidity and accuracy of motor torque tracing enhanced. The results of experiment show that compared with conventional control, the gear-shifting control with speed/torque double-synchronization can not only shorten shifting time but also significantly reduce shifting shock References | Related Articles | Metrics

Select

Influence of Inertia Mass in Actuator on Amplitude-frequency Characteristics of Active Suspension System Wang Xingye, Zhang Jinqiu, Liu Yile, Zhang Jian & Peng Zhizhao 2018, 40 (9):  1083-1088.  doi: 10.19562/j.chinasae.qcgc.2018.09.012 Abstract ( 310 )   PDF (1120KB) ( 335 )   Save A rack-pinion type actuator for vehicle active suspension is designed, and the influence of actuator inertia mass on the amplitude-frequency characteristics of active suspension system is investigated. Firstly the calculation method of inertia mass is given and the effects of inertia mass on the natural frequency of suspension system are analyzed. Then the transfer characteristics of three evaluation indicators of suspension system in four situations, i.e. traditional passive suspension, suspension with inertia mass added, suspension with inertia mass and skyhook (SH) control and suspension with inertia mass and acceleration damping driven (ADD) control are compared. Finally bench tests are conducted for verification. The results show that the adding of inertia mass reduces the inherent frequency of car body and tire, and hence improves the vibration in middle-low frequency region but aggravates the vibration in high-frequency region. SH control can only improve the vibration suppression effects in middle-low frequency region but aggravate the vibration in high-frequency region, while ADD control can alleviate the aggravation of vibration and relatively better enhance vibration suppression effects in middle-high frequency region. Therefore the active suspension system with actuator inertia mass should select ADD control algorithm with better vibration suppression effects in middle-high frequency region References | Related Articles | Metrics

Select

A Research on the Estimation of Vehicle Rolling State Dong Mingming, Zhang Yu & Wang Zhenfeng 2018, 40 (9):  1089-1095.  doi: 10.19562/j.chinasae.qcgc.2018.09.013 Abstract ( 351 )   PDF (1213KB) ( 439 )   Save In view of the problem that under complex driving conditions the rolling state of vehicle cannot be accurately measured and hence vehicle roll cannot be effectively controlled, vehicle coupling dynamics and fuzzy T-S theory are used to design a model-based algorithm for T-S state observer, and fulfill the real-time and effective observation of vehicle rolling state in complex conditions in this paper. Firstly, vehicle vertical and lateral kinematic models under the conditions of different road excitations and steering wheel angles are constructed. Then, with consideration of the strong nonlinear features of tire forces, a tire T-S model based on T-S theory is proposed and then verified by simulation with “magic formula”. Next, based on tire T-S model and vehicle dynamics model, Bayesian theory is applied to the design of the algorithm for vehicle T-S observer. Finally, CarSim software is used to conduct simulation verification on the real-time estimation of vehicle roll angle and roll rate by vehicle T-S observer under standard-A/C road excitations. The results show that T-S observer can effectively estimate the rolling state of vehicle with the maximum standard deviation less than 12% References | Related Articles | Metrics

Select

Simulation Analysis and Evaluation of Body Pressure Distribution on Seat Shen Chongyang, Zhang Peng, Wang Qingzhong, Li Yang, Yang Ge & Gao Wei 2018, 40 (9):  1096-1100.  doi: 10.19562/j.chinasae.qcgc.2018.09.014 Abstract ( 296 )   PDF (2358KB) ( 514 )   Save Based on the H-point machine (HPM), a detailed simulation model of body pressure distribution on seat is established in this paper. The material parameters of foam and fabric closely related to the simulation analysis of body pressure distribution on seat are obtained through tensile and compression tests. The reliability of the model is validated by comparing the maximum pressure, average pressure, contact area and weight ratio in different regions. The results show that the established model can not only accurately reflect the general rule of body pressure distribution, but also can accurately reflect the body pressure distribution indexes of shoulder, waist and thigh of the H-point machine. The error between the simulation and test is less than 10%, and the seat simulation model is effective. References | Related Articles | Metrics

Select

Torsional Vibration Modeling and Analysis of Internal Combustion Engine as a Range Extender Zhang Lijun, Kan Yiran, Meng Dejian & Yu Zhuoping 2018, 40 (9):  1101-1109.  doi: 10.19562/j.chinasae.qcgc.2018.09.015 Abstract ( 230 )   PDF (3288KB) ( 484 )   Save A torsional vibration model consisting of the models of engine, clutch, torsional damper, generator and range extender controller is established for the range extender of a commercial vehicle, and the response states of system, excitation torque and the time-domain and frequency-domain characteristics of torsional vibration under typical conditions are emphatically analysed. The results show that the torsional vibration of range extender is mainly related to the fluctuation and abrupt change of excitation torque of engine and generator and the resonance in some conditions References | Related Articles | Metrics

Select

A Study on the Knocking Noise of Valve Timing System in a Turbocharged Engine During Cold Start Tang Ziqiang, Yang Jincai, Liu Gang, Liu Bin, Li Jian & Zhang Liang 2018, 40 (9):  1110-1117.  doi: 10.19562/j.chinasae.qcgc.2018.09.016 Abstract ( 242 )   PDF (3239KB) ( 378 )   Save Aiming at the problem of knocking noise in a turbo-charged engine under development during cold star after a long time out of service, based on the noise and vibration signals of engine in starting process, wavelet transform and angular domain analysis are adopted to identify the cause of knocking noise being the slapping of limiting clasp against the housing of hydraulic tensioner. The slapping mechanism of tensioner is systematically studied from the aspects of dynamic characteristics of lubrication system and valve timing system and sealing, based on which a scheme to increase the spring stiffness in tensioner for completely solving the abnormal noise problem of engine during start after a long time out of service References | Related Articles | Metrics

Select

The Optimized Gear Modification for Double-row Planetary Gear Train Zhang Rongchuan, Zhou Yunshan, Hu Xiaolan, Cheng Jianfei, Fu Bing & Zhang Feitie 2018, 40 (9):  1118-1124.  doi: 10.19562/j.chinasae.qcgc.2018.09.017 Abstract ( 313 )   PDF (1847KB) ( 666 )   Save Metal belt CVT uses planetary gear train (PGT) to fulfill the shifting between forward gear and reverse gear. Due to adding one row of planetary gear set, the degree-of-freedom of double-row PGT increases, leading to the intensification of excitation and the whine noise of CVT in reverse gear. In view of these, a metal-belt CVT is studied in this paper, and it can be inferred through noise measurement and order analysis that gear whine in reverse gear stems from PGT. In order to lower the gear whine in reverse gear, a kinetic analysis is conducted on double-row PGT. A nonlinear model for pure torsional vibration is developed with consideration of gear backlash, and an optimization on the magnitude of gear modification is performed using genetic algorithm with the vibration acceleration variance of planetary gears as objective function. The gears optimized are verified by tests with a result showing that the gear modification optimized enhances the sound quality of the CVT References | Related Articles | Metrics