Loading...
Welcome to Journal of Automotive Safety and Energy,

Current Issue

  • 2018, Vol. 9 No. 4 Published on:31 December 2018 Previous issue    Next issue
    Progress & Prospects
    Development and optimization of NVH for a 3-cylinder turbocharged gasoline direct injection engine
    SHEN Yuan, YANG Chen, DENG Xiaolong, et al
    2018, 9(4):  359-369.  doi:10.3969/j.issn.1674-8484.2018.04.001
    Abstract ( 252 )   PDF (2032KB) ( 838 )  

    Three-cylinder engines, which have small packaging size, have been a key player for major original design manufactures (OEMs) to meet more and more stringent fuel economy and emission regulations for internal combustion engines in the recent years. In this paper, vibration mechanism of 3-cylinders is illustrated, NVH (noise, vibration、harshness) issues associated with 3-cylinder engines are analyzed, and solutions presented by OEMs are summarized. The systematic analyses and optimizations on engine and transfer path, including crankshaft, balance shaft, dual-mode torsion vibration damper (TVD), engine mounts, and exhaust system, are applied to a 1-liter 3-cylinder turbocharged gasoline direct injection engine developed by Geely Auto. With the optimizations, the 3-cylinder engine delivers excellent NVH performance, along with good power and fuel economy, to provide superior driving experience to customers.

    Related Articles | Metrics
    Automotive Safety
    Loaded tooth contact analysis of spur gear considering edge relaxation effect
    CHEN Changliang, ZHOU Chi, WANG Qi, et al
    2018, 9(4):  370-378.  doi:10.3969/j.issn.1674-8484.2018.04.002
    Abstract ( 221 )   PDF (2479KB) ( 448 )  

    A loaded tooth contact analysis method (LTCA) was proposed for spur gears with considering the edge relaxation effect to improve the traditional analysis method for spur gears. Calculated tooth surface coordinates based on the tooth surface formula with the mesh paths calculated in a complete meshing period
    according to the mesh relationship. Used Newton-Raphson method to solve the mesh state of the gear teeth in the equilibrium state and to analyze the loaded tooth contact. Verified the load distribution coefficients, the contact stresses, the transmission errors and the calculation efficiencies in a complete meshing period based on the finite element method (FEM) with introducing the edge correction function and edge factor, and with considering the edge relaxation effect in a parabolic form by using a correction method for tooth width-edge contact-stiffness. The results show that this method can be used to analyze the loaded tooth contact of spur gears in equal width line.

    Related Articles | Metrics
    Occupant acceptability and its optimization for the integrated active pre-tensioning seatbelt
    WU Jun, SONG Zhiqiang, CAO Libo, et al
    2018, 9(4):  379-385.  doi:10.3969/j.issn.1674-8484.2018.04.003
    Abstract ( 241 )   PDF (1751KB) ( 426 )  

    Integrated active pretension seatbelt (IAPS) is an occupant restraint protection system integrated with several advanced driving assistance systems (ADAS). This paper investigated the occupant acceptance to IAPS, and gave some measures to improve the acceptance for developing and applying the IAPS. The bench test with a 50% th male dummy and the road test with 20 volunteers were carried out. The effects of three factors on occupant acceptability, i.e. the first-level pre-tensioning, the pre-tensioning frequency and the pre-tensioning noise value, analyzed. The results show that the minimum threshold of discomfort caused by the primary pre-tensioning is different among different volunteers, when the primary pre-tensioning is set at 124 N. Optimizing the TTC (time to crash) reduces the threshold value when original IAPS has a higher pre-tensioning frequency while the pre-tensioning noise value does not cause additional  interference to the occupants. Therefore, these optimization measures improve occupants' acceptability to the IAPS.

    Related Articles | Metrics
    Effect of foam energy absorption on protective performance of helmet under dynamic loadings
    HAN Yong, HE Wei, SHI Liangliang, et al
    2018, 9(4):  386-394.  doi:10.3969/j.issn.1674-8484.2018.04.004
    Abstract ( 218 )   PDF (2145KB) ( 387 )  

    For the safety design of motorcycle helmet, it is necessary to study the influence of the energy absorption capacity of the liner foam under the impact load on the protective performance of the motorcycle helmet. A finite element model of the helmet was established and the effectiveness of the model was verified
    according to the drop test in the regulation ECE R22.05 by the Economic Commission for European. Twelve drop test simulations were performed by changing the foam density corresponding to different test points. The results show that when the foam density increases at the test points of front, crown, and rear from 40 kg/m3 to 80 kg/m3, the energy absorption capacity of the foam increases, which makes the impact energy of the head decay faster. The risk of skull fracture at the three test points increases from 25%, 55%, and 39% to 53%, 96%, and 96%, respectively. However, there is not clear evidence of the relation between the skull fracture risk and foam density at the right lateral area of the helmet. Therefore, the safety design of the helmet should take into account both the density and size of the liner foam.

    Related Articles | Metrics
    Failure probability determination of automobile electric horn based on fuzzy set theory
    WANG Nan, WANG Yan, XIAO Lingyun,et al
    2018, 9(4):  395-400.  doi:10.3969/j.issn.1674-8484.2018.04.005
    Abstract ( 131 )   PDF (1241KB) ( 342 )  

    Defects of non-standard problem are judged by using risk assessment method for recalling of defective vehicle products in China. A method of combining fuzzy theory with fault tree was adopted to develop risk possibility analysis to ensure the rationality of risk possibility judgment. The probability of basic events was
    obtained by using trapezoidal fuzzy theory. A fault tree model for automobile electric horn was established to calculate the probability of electric horn failure in top events and in basic events. Analyzed the importance degrees, located the faults, and traced the causes in basic events. Compared the failure probability of electric horn with the Weibull distribution of fuzzy fault tree. The results show that the failure probability predicted by using the fuzzy fault tree is in good agreement with that by using Weibull failure probability distribution.Therefore, the fuzzy fault tree can be used to analyze the risk possibility. This method provides a new idea for the risk possibility quantitative calculation.

    Related Articles | Metrics
    Development and measurements of automotive autonomous emergency brake (AEB) pedestrian testing system
    WU Jun, XIANG Guoliang, YANG Junhui, et al
    2018, 9(4):  401-409.  doi:10.3969/j.issn.1674-8484.2018.04.006
    Abstract ( 466 )   PDF (1851KB) ( 1044 )  

    An automatic emergency braking (AEB) pedestrian detection system was developed for automotive active safety technology. The AEB pedestrian detection system includes a soft dummy target, a dummy driving device and a control system with driving the dummy to walk according to the requirements of the AEB pedestrian test scenario of the 2018 Chinese New Car Evaluation Procedure (C-NCAP), with real-time communicating a driving robot which controls the test vehicle. Some measurements were done for walking distances of the dummy target, walking speeds of the dummy target, and linkage experiments with the driving robot. The results show that the success rate of the system is more than 90%, while the accuracy of the dummy speed control is 96%, and the collision location accuracy is 96%. Therefore, the AEB pedestrian detection system can be used to conduct C-NCAP (2018) pedestrian test experiments both to evaluate a vehicle AEB system functions and to be a tool for related product developing since the system can accurately restore current hazardous conditions.

    Related Articles | Metrics
    Bionic design optimization and simulation analysis of bumper beam inspired by the structure of Bamboo Node
    LIN Yuncheng, SONG Jiafeng, LIU Shengfu,et al
    2018, 9(4):  410-417.  doi:10.3969/j.issn.1674-8484.2018.04.007
    Abstract ( 211 )   PDF (2581KB) ( 424 )  

    Based on the principles of engineering bionics and impact dynamics, 3 bionic design methods, which included 6 kinds of bumper beam, were introduced for enhancing the bumper’s crashworthiness to improve the crashworthiness and lightweight of bumpers. 5 mm / min compression test was carried out under
    quasi-static condition. The test and simulation load curve were basically consistent, and the peak force error was only 3.9%, which verified the effectiveness of simulation analysis; the 100% overlap front impact was simulated by the software of Hypermesh and LS-DYNA. The results show that the bionic bumper beam 1, which includes bionic ribs, has the higher specific energy absorption (SEA) than original bumper beam by 13.85%. And here is a mass reduction for bionic bumper beam by 23.82%. The better bionic design methods are bionic rib and bionic variable spacing among those bionic methods. The corresponding bumper beam has lower peak load, higher energy absorption and lower mass than normal bumper beam, which also has better deformation mode.

    Related Articles | Metrics
    Coordination control system for vehicle stability based on active tire force
    HUANG Kaiqi, WANG Xinjian, QU Guipeng
    2018, 9(4):  418-426.  doi:10.3969/j.issn.1674-8484.2018.04.008
    Abstract ( 200 )   PDF (2089KB) ( 371 )  

    An electronic stability program (ESP) and an active front steering (AFS) active tire force fuzzy coordination control strategy were proposed based on sideslip angle logic gate and yaw rate tracking. The control system adopted a hierarchical structure. The designed lower layer consisted of a single neuron adaptive
    proportion integration differentiation (PID) controller for the ESP and an ideal variable ratio feedforward with yaw rate feedback sliding mode controller for the AFS. The weight fuzzy coordinated control of each subsystem was decided to decoupling of vehicle dynamics integrated control system and global optimal allocation of the ESP and the AFS under different driving conditions in the upper layer of control system. The vehicle dynamics stability co-simulation model was established on the base of software ADMAS/Car and Simulink. The results show that the coordinate controller improves the vehicle tracking performance for the desired path and the global robustness of vehicle stability control system, compared with controller of the single control and the coexist control.

    Related Articles | Metrics
    Automotive Energy Efficiency & Environment Protection
    Low power consumption design of automobile TPMS based on synchronous serial communication
    OU Weiming, LING Yun, LI Shongqing
    2018, 9(4):  427-432.  doi:10.3969/j.issn.1674-8484.2018.04.009
    Abstract ( 184 )   PDF (1308KB) ( 312 )  

    The research on the tire pressure monitoring system (TPMS) synchronous serial communication technology was carried out to meet the low power consumption design requirement of TPMS. The special frame of information, which contained the data signal with an implicit synchronization signal, was constructed with the
    design scheme of TPMS hardware system and with the serial signal encoding method and decoding method of source. The results show that the wireless transmission efficiency of TPMS tire sensor transmitter is increased by 29.4% and the average power consumption is reduced by 2.62% compared with the universal asynchronous receiver/transmitter (UART) serial communication technology. The designed wireless synchronous serial communication technology is able to satisfy the demand of low power consumption design, and the wireless communication efficiency can be improved with low error rate. Therefore, it has good value of popularization and application.

    Related Articles | Metrics
    Traffic scene understanding using image semantic segmentation with an improved lightweight convolutional-neural-network
    BAI Jie, HAO Peihan, CHEN Sihan
    2018, 9(4):  433-440.  doi:10.3969/j.issn.1674-8484.2018.04.010
    Abstract ( 325 )   PDF (1798KB) ( 1009 )  

    A method of traffic scene understanding was proposed using image semantic segmentation method to improve the robustness of a visual perception model in an automotive autonomous driving system. A lightweight convolutional-neural-network was designed adopting semantic segmentation using deep learning
    with striking an optimal balance between efficiency and performance. The lightweight model, Mobile Net V2, was adopted in the feature-extraction section, and the convolution layers were replaced using stride = 2 with deformable convolution layers; In feature-decoder section, multi-scale Atrous deformable convolution module was designed and low-level features were also used to add more detail information. Augmented PASCAL VOC 2012 dataset was used to pre-train and evaluate the network and the traffic scene dataset, Cityscapes, was used to fine-tune and test. The results show that the new network achieves an accuracy of mean IoU (intersection over union) of 69.2%, and has better performances than that from DeepLab semantic segmentation networks with MobileNetV2. The new network takes only 127 ms per frame and 1.073 GB memory and is more efficient than that by the networks with VGG-16 and ResNet-101.

    Related Articles | Metrics
    Cooperative control of compound braking and active suspension for pure electric vehicles
    HUANG Chen, HONG Jun, LI Keqiang,et al
    2018, 9(4):  441-448.  doi:10.3969/j.issn.1674-8484.2018.04.011
    Abstract ( 153 )   PDF (2099KB) ( 552 )  

    A cooperative control method was proposed for the compound braking and the active suspension of pure electric vehicles (EV) with control objectives of both energy recovery performances and braking safety to improve the comprehensive performances of EV chassis. Completed some longitudinal mechanical
    characteristics tests for tires; established a tire longitudinal mechanical model and a vehicle dynamics model; designed a fuzzy cooperative control strategy. Verified the performances of the cooperative control by the joint simulation of the soft-wear Carsim and Simulink. The results show that the coordinated control increases the braking recovery energy by 13.11%, the battery state of charge (SOC) by 9.96%, and the comprehensive quadratic performance index of suspension by 8.61% when braking slightly on the road with low adhesion coefficient; and decreases the brake distance by 9.08%, and the comprehensive quadratic performance index of suspension by 5.93% when emergency braking on the road with high adhesion coefficient. Therefore, this control
    strategy improves the compound braking performances with less decreasing the suspension performance

    Related Articles | Metrics
    Path planning optimization-algorithm for a self-driving vehicle based on UTMD principle
    LI Xueyun
    2018, 9(4):  449-455.  doi:10.3969/j.issn.1674-8484.2018.04.012
    Abstract ( 186 )   PDF (1868KB) ( 289 )  

    A path-planning optimization-algorithm for self-driving vehicles was designed by using some bionic intelligent algorithms to take account of the real-time and the reliability in computation. The path planning algorithm based on the basic principles of ultrasound-targeted microbubble destruction (UTMD). Divided the
    iterative operation into target circle, microbubble iteration and micro-RNAs (miRNAs) iteration with the target delineation to reduce effectively the path search range. Verified the algorithm by using the Rastrigin function. Analyzed the setting of iteration numbers when they were set artificially. And used a self-test program to jump by itself. The algorithm was applied to 2-D path planning and simulated in Matlab. The results show that the path length planned by the UTMD algorithm is reduced by 4.52% compared with the length by Dijkstra algorithm. Therefore, the path-planning algorithm is effective for self-driving vehicles.

    Related Articles | Metrics
    Multidiscipline design optimization method for engine hood
    LIU Ying, YANG Xu, QIAO Xin
    2018, 9(4):  456-462.  doi:10.3969/j.issn.1674-8484.2018.04.013
    Abstract ( 189 )   PDF (2003KB) ( 468 )  

    A design optimization method was established for engine hood with multidisciplinary automatic calculation process including structure rigidity, NVH (noise-vibration-harshness) performances and pedestrian protection performances. An engine hood parametric model was built to optimize globally the engine hood
    by using a SFE Concept software with an implicit parametric method, with taking the position of the inner longitudinal beam of the engine hood and others as variables, using an iSight software platform, and with calling a simulation queue, based on the result of multidisciplinary Design Of Experiment (DOE) sample calculation. The results show that the improved engine hood improves pedestrian protection performance score from 7.42 to 7.72 according to the China New Car Assessment Program(C-NCAP) due to some small structural adjustments to obtain obvious optimization. Therefore, the design optimization method can be applied to due to the engine hood forward multidiscipline design optimization

    Related Articles | Metrics
    Simulation and validation test of 48 V hybrid control system
    ZHANG Yingbing, JIN Suhua, HUANG Wei, et al
    2018, 9(4):  463-468.  doi:10.3969/j.issn.1674-8484.2018.04.014
    Abstract ( 203 )   PDF (1909KB) ( 563 )  

    A 48 V hybrid system control model which included the core functions such as start-stop, fast engine start, torque assistant and braking energy recovery was built to investigate the technical routine and method of fuel consumption reduction for a multi-purpose vehicle (MPV). The hybrid system control model was test
    by hardware-in-the-loop (HIL), and the control strategy and data were validated and optimized at real vehicle. The results show that the 48 V hybrid system control model can decrease the fuel consumption by 14% under the New European Driving Cycle (NEDC) with a slight emission deterioration comparing with conventional configuration vehicles.

    Related Articles | Metrics
    Effects of excitation current on vibration characteristics of a hybrid excitation motor for electric vehicles
    FAN Ying,WU Zhanchuan, GAO Dawei,et al
    2018, 9(4):  469-476.  doi:10.3969/j.issn.1674-8484.2018.04.015
    Abstract ( 163 )   PDF (2022KB) ( 318 )  

    A dual-stator hybrid excitation permanent magnet (DSHEPM) motor with consequent-pole rotor structure was used to investigate the effects of AC excitation current on the electromagnetic force and vibration characteristics of the hybrid excitation motor. The magnetic flux distribution and air-gap magnetic density under different excitation conditions were analyzed by 2-dimensional finite element method. The Maxwell stress tensor method was employed to calculate the radial electromagnetic force. The electromagnetic force was decomposed using the 2-dimensional Fourier transformation (2DFFT) method. The vibration characteristic of the DSHEPM motor was analyzed by the mode superposition method based on multi-physics model. The results show that the phase angle of the excitation current has a significant impact on the electromagnetic force harmonics and the electromagnetic vibration can be decreased through the flux-weakening control. The research will contribute to the vibration suppression and optimization of the DSHEPM motor.

    Related Articles | Metrics