Current Issue

• 2021, Vol. 12 No. 4
  Published on:31 December 2021 Previous issue    Next issue
  Review, Progress and Prospects

  Low carbon and zero carbon technology paths and key technologies of ICEs under the background of carbon neutrality

  SHUAI Shijin, WANG Zhi, MA Xiao, XU Hongming, HE Xin, WANG Jianxin

  2021, 12(4):  417-439.  doi:10.3969/j.issn.1674-8484.2021.04.001

  Abstract ( 5744 )   HTML ( 699)   PDF (4021KB) ( 3930 )  

  Since China promised to “reach the carbon peak in 2030 and carbon neutrality in 2060” at the 75th United Nations General Assembly in September 2020, the Paris Agreement signed by major countries and regions in 2016 has controlled the rise of global temperature and accelerated carbon neutrality policies and actions. As the leading power of a large number of road and non-road mobile machinery and national defense equipment, internal combustion engine (ICE) not only undertakes the important mission of energy saving and emission reduction in the near and medium term, but also faces great challenges and important opportunities on how to achieve carbon neutrality in the future. Based on the analysis of carbon neutrality policies and actions in major European countries, America, Japan and China, this paper puts forward two technical paths and their feasibility of low-carbon and zero carbon of ICE in the near and medium term, as well as the key technologies to be solved for zero carbon ICE fueled by biomass fuel, green hydrogen, green ammonia and green electricity synthesized fuel (e-fuel). It aims to explore the road of sustainable development for the future of ICE. Existing research shows that ICE, as an efficient and high power density thermal engine for converting chemical energy into mechanical energy, still has a large room for energy saving through the combination of electrification and intelligent technologies. Compared with fuel cell power, ICE has a more complete industrial chain, higher technical maturity and lower cost. By utilizing zero carbon fuels, ICE can still be widely used in large-scale power equipment such as heavy trucks, construction machinery, ships and aviation, so as to promote the early realization of carbon peak and carbon neutrality in China’s energy and transportation field.

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  Overview of intelligent vehicle multi-target detection technology based on multi-sensor fusion

  WANG Hai, XU Yansong, CAI Yingfeng, CHEN Long

  2021, 12(4):  440-455.  doi:10.3969/j.issn.1674-8484.2021.04. 002

  Abstract ( 607 )   HTML ( 532)   PDF (2298KB) ( 1133 )  

  With the rapid rise of the field of artificial intelligence, the environment sensing technology of intelligent vehicles has also developed by leaps and bounds. The sensing system of intelligent vehicles is inseparable from the cooperative use of multiple sensors, and the multi-target detection technology of intelligent vehicles based on multi-sensor fusion has also become a hot research direction. Industry and academia have proposed different solutions. This paper summarizes the multi-target detection technology based on multi-sensor fusion in intelligent vehicles, indroduces the commonly used on-board sensors, data sets, methods and classification of multi-sensor fusion, and the recent multi-sensor detection algorithms, and finally summarizes the multi-target detection technology of intelligent vehicles based on multi-sensor fusion, It also puts forward analysis on the challenges and future development trend in this direction.

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  Automotive Safety

  Influence of pedestrian’s emergency posture on pedestrian injury in vehicle - pedestrian collision

  ZHANG Daowen, LIU Qi, QIU Jianbing, LIAO Wenjun, MU Yaoyao, JIN Siyu

  2021, 12(4):  456-466.  doi:10.3969/j.issn.1674-8484.2021.04.003

  Abstract ( 508 )   HTML ( 516)   PDF (1932KB) ( 249 )  

  A multi-rigid body model of frontal collision between pedestrians and vehicles was established by PC-Crash software to investigate the influence of pedestrian emergency posture on head, chest and lower limb injuries in frontal collision between vehicles and pedestrians. The accident reconstruction and model verification were carried out according to the real accident cases in the National Automobile Accident In-Depth Investigation System (NAIS). The simulation experiments were carried out to study the influence of different emergency postures and action amplitudes on pedestrian collision damage when vehicles collide at different speeds and steering angles. The weighted value was used to evaluate the comprehensive damage of pedestrians under different postures. The results show that the collision with vehicle speed higher than 50 km/h causes great damage to pedestrians. When the squat angle reaches 30°, the head injury decreases, and when the squat angle exceeds 50°, the pedestrian has the rolling risk. The tilt and jump postures are relatively dangerous postures leading to severe head and chest injuries. Head injury is the most serious when jumping height is 0.5 m. When the vehicle has emergency steering, pedestrian squatting and jumping cause greater chest injury, while head injury is the opposite.

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  Submarining injury mechanism and its protect measures for rear seat occupant under frontal impact

  WANG Donglin, HU Zichen, ZHAO Liang, JIN Pengfei, TANG Liang

  2021, 12(4):  467-474.  doi:10.3969/j.issn.1674-8484.2021.04.004

  Abstract ( 358 )   HTML ( 44)   PDF (7629KB) ( 785 )  

  The mechanism occurring occupant submarining was investigated to design an anti-submarining facilities of occupant restraint system. An finite element method (FEM) was used to compares the submarining tendency of different rear occupant FEMs (Hybrid III, FAST GHBMC and THUMS) in frontal crash, and found that the submarining trend of the occupant was related to the deformation of spine. The THUMS human model with high bio-realism was used to design submarining protection facilities for rear passengers with improving parameters of occupant restraint system to comparing the effects on the head, chest and other parts of human body. Six anti-submarining schemes are selected, such as increasing seat cushion angle, increasing seat cushion length and installing anti- submarining facilities under the condition that other occupant damage indexes meet the requirements of relevant laws and regulations. The results show that the optimal anti- submarining scheme is to install anti- submarining lever with a maximum safety-belt slip-distance of only 7 mm.

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  Biofidelity of current legform impactor in pedestrian safety test

  LONG Yongcheng, HAO Haizhou, LI Fan, FEI Jing

  2021, 12(4):  475-482.  doi:10.3969/j.issn.1674-8484.2021.04.005

  Abstract ( 444 )   HTML ( 34)   PDF (1527KB) ( 190 )  

  This paper explored the difference between the leg impactor for current pedestrian protection and the real human body in an actual vehicle structure collision. Selected the impactor with high biological fidelity and more scientific evaluation methods which reflect the human body injury in the actual collision accident. Analyzed the kinematic response and damage response for three leg impactors and human body models by using a finite element method on a sedan and a Sports Utility Vehicle (SUV). Compared the injury values of leg, thigh, knee and pelvis. The results show that the bio-fidelity of the Medial Collateral Ligament (MCL) of the Advanced Pedestrian Legform Impactor (aPLI) is better than that of the Flex Pedestrian Legform Impactor (Flex-PLI); and the thigh bending moment of the aPLI is better than that of the Transport Research Laboratory (TRL), but the aPLI cannot reflect the cover damage of the front edge of an SUV model to the pelvis. Therefore, the use of aPLI and TRL test in the evaluation of pedestrian lower limbs can more comprehensively evaluate the pedestrian’s injury.

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  Differences in head injuries between pedestrian and two-wheeler based on real-world accident reconstruction

  XU Hongzhen, WANG Fang, HU Lin, WANG Zhen, LI Fan

  2021, 12(4):  483-489.  doi:10.3969/j.issn.1674-8484.2021.04.006

  Abstract ( 213 )   HTML ( 30)   PDF (1054KB) ( 145 )  

  This paper reconstructed a series of collision boundary conditions of Vulnerable Road User (VRU); and some car collision accident cases from the In-depth Investigation of Vehicle Accident in Changsha (IVAC) database by using a multi-rigid body method to protect the VRUs to better protect the VRU. Numerically reproduced the head/brain injury occurred in the accident cases by using a finite element (FE) and a multi-rigid body coupling method. Investigated comprehensively the differences between head kinematics and injury responses of pedestrian and two-wheeler accidents. The results show that the two-wheelers’ head collision angle is 42.57° with a relative collision speed being 51.94 km/h; the pedestrian’s head collision angle is 50.23° with a relative collision speed being 72.54 km/h. These parameters are clearly different from the test boundary conditions (65° and 40 km/h) according current pedestrian safety regulations or programs. The overall head injury-risk of pedestrians is generally higher than that of two-wheelers. In particular, the brain injury-risk of pedestrians is significantly greater than that of two-wheelers.

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  Effectiveness of AEB system for head injury risk based on VRUs in-depth accident reconstruction

  HAN Yong, LI Yongqiang, XU Yonghong, WANG Bingyu, GAO Xiujing, HUANG Hongwu, NIE Bingbing

  2021, 12(4):  490-498.  doi:10.3969/j.issn.1674-8484.2021.04.007

  Abstract ( 422 )   HTML ( 42)   PDF (1887KB) ( 191 )  

  In order to provide a theoretical reference for the active-passive integrated safety vehicle design for Vulnerable Road Users (VRUs), which including pedestrians and two-wheelers, protection, this paper analyzed the protection effectiveness of some parameters such as the Field Of View in sensor detection (FOV), and the braking deceleration of automotive Automatic Emergency Braking (AEB) systems and the head injury risk for VRUs in accidents by using a high precision accident reproduction and some pre-crash scenario reconstruction methods. The results show that the accident avoidance rate is 45% when the FOV is 30°; The accident avoidance rate increases by 5%, 10% and 20% when the FOV is 40°, 50° and 90° respectively compared with the FOV of 30°; The average vehicle crash speed reduces significantly, up to 84%, for the Time To Collision (TTC) in 1 s, when the FOV reaches 90° at a deceleration of 0.8 g; There is uncertainty in the head landing damage although AEB intervention could reduce the damages caused by the impacts between VRUs and the vehicle front.

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  Influence of AEB for THOR 50th dummy seating position

  SUN Zhendong, ZHU Haitao, PENG Weiqiang

  2021, 12(4):  499-506.  doi:10.3969/j.issn.1674-8484.2021.04.008

  Abstract ( 189 )   HTML ( 33)   PDF (2003KB) ( 565 )  

  The test methods of three test cycles as CCRs(car to car rear stationary), CCRm (car to car rear moving) and CCRb (car to car rear braking) of AEB system were elaborated to investigate the posture change characteristics of the THOR 50^th dummy affected by the autonomous emergency braking(AEB) system and to obtain the typical braking waveform of AEB system similar to trapezoid. The typical waveform was constructed with the binomial fitting method to analyze the postural out-of-position characteristics of THOR 50^th dummy. The results show that when the initial speed is lower than 40 km/h, the forward leaning of the head and chest of THOR 50^th dummy increases as the deceleration increases, and the out-of-position of the dummy’s head and chest increases as the initial vehicle speed increases under the same braking acceleration; AEB emergency braking can cause the largest degree of the out-of-position of the head and chest at the initial speed of 40 km/h.

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  Correction for pulse number of indirect tire pressure monitoring system under vehicle turning condition

  WANG Baolin, XIA Huaicheng, DONG Qianqian

  2021, 12(4):  507-515.  doi:10.3969/j.issn.1674-8484.2021.04.009

  Abstract ( 212 )   HTML ( 28)   PDF (961KB) ( 193 )  

  This paper analyzed the reason why the indirect tire pressure monitoring system based on pulse method gives false alarm, because the vehicle outside wheel under normal tire pressure is misjudged as lack of air. Established a geometric relationship model of automobile turning by using the steering wheel angle as the correction parameter. Analyzed the effects of tire deflection, carriage roll and steering system deformation on the inner-lateral wheel pulse difference when the vehicle was turning. Proposed a Back-Propagation (BP) neural-network training method to modify the pulse number of the outside wheel under the turning condition. Constructed a three-layer BP neural network. The number of wheel pulses when turning was equivalent to that when driving in a straight line. The results show that the determination coefficient of the BP neural-network training method for the pulse difference fitting is 0.995, and the false alarm rate under the turning condition after correction is 0. Therefore, the correction method has a good effect.

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  Multiple object tracking algorithm integrated with attention mechanism for autonomous vehicles

  ZHANG Ping, CHI Zhicheng, CHEN Yifan, HUI Fei

  2021, 12(4):  516-521.  doi:10.3969/j.issn.1674-8484.2021.04.010

  Abstract ( 616 )   HTML ( 45)   PDF (2256KB) ( 412 )  

  This paper established a multiple-object tracking algorithm for autonomous-vehicles integrated with an attention mechanism to improve the tracking accuracy. The multiple-object tracking algorithm extracted object appearance features by using YOLOv3 neural network with attention mechanism that enhanced the performance of feature extraction network. The algorithm extracted discriminative features of the target or the background. A Long Short-Term Memory (LSTM) network extracted the target motion features, while the object tracking algorithm modeled the target trajectory dynamically. The algorithm accomplished a multiple object tracking through data matching and association based on tracked target similarity degree. Experiments were done on a multiple object tracking dataset MOT16. The results show that the object detection success rate increases 1.9% compared with YOLOv3 network, using the object detection algorithm with attention mechanism with a tracking accuracy of 53.9% and a tracking precision of 79.0%. Therefore, the algorithm achieves a stable target tracking.

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  Roadside multi-sensor fusion based on adaptive extended Kalman filter

  WU Yimin, ZHENG Kaiyuan, GAO Bolin, CHEN Ming, WANG Yifeng

  2021, 12(4):  522-527.  doi:10.3969/j.issn.1674-8484.2021.04.011

  Abstract ( 248 )   HTML ( 33)   PDF (831KB) ( 246 )  

  Roadside perception is a component of cloud control cooperative vehicle infrastructure perception. This paper proposed a fusion method for roadside multi-sensors based on measurement noise Adaptive Extended Kalman Filter (AEKF) to improve the perception accuracy and stability of roadside sensors. The fusion of target-level data from heterogeneous sensors was realized based on the sensing results of roadside cameras, lidars, and millimeter-wave radars. An online acquisition method of measurement noise was used to detect the stability of the sensor measurement value, to generate correction coefficients for the measurement noise, and to adjust adaptively the measurement noise. This method was tested in a real vehicle. The results show that this multi-sensor fusion method improves the accuracy of lateral distance estimation by 9.7%, the longitudinal distance estimation accuracy by 5.4%, and the speed estimation accuracy by 26.6%, compared with a single sensor; With the estimation accuracy of the traditional Extended Kalman Filter (EKF) algorithm being improved by 44.9% in the horizontal distance, by 21.3% in the longitudinal distance, and by 64.4% in the speed; Therefore, the AEKF algorithm estimation accuracy of this paper is higher than that of the traditional EKF algorithm.

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  Path planning and path tracking control for autonomous vehicle based on MPC with adaptive dual-horizon-parameters

  LI Yaohua, FAN Jikang, LIU Yang, HE Jie, LI Zetian, PAN Shaofei

  2021, 12(4):  528-539.  doi:10.3969/j.issn.1674-8484.2021.04.012

  Abstract ( 593 )   HTML ( 38)   PDF (1329KB) ( 1147 )  

  This paper designed a novel obstacle avoidance function by using the nonlinear model predictive control (MPC) algorithm to solve the problem of excessive obstacle avoidance. Established a series of comprehensive evaluation index of vehicle path tracking performance, obtained the optimal prediction time domain and the control time domain parameters, and designed the adaptive dual time domain MPC parameters path tracking controller. A joint simulation platform integrating the planning layer and the control layer was built for simulation. The results show that under the condition of 180 obstacle points, the obstacle avoidance function can avoid excessive obstacle avoidance, and the calculation time only increases by 0.294 ms; The maximum lateral error deviation is reduced by 0.169 m with the maximum yaw rate being reduced by 3.196 (°)/s when adopting the integrated structure of local obstacle avoidance path planning and path tracking control, in multiple static obstacle scenes and dynamic obstacle scenes, at the vehicle speed of 65 km/h.

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  Multi-modal dynamic traffic assignment model with the addition of electric vehicles

  ZHANG Rui, YAO Enjian, ZHANG Yongsheng

  2021, 12(4):  540-550.  doi:10.3969/j.issn.1674-8484.2021.04.013

  Abstract ( 211 )   HTML ( 35)   PDF (1456KB) ( 238 )  

  This paper proposed a multi-modal dynamic traffic assignment model based on travel behavior analysis to distinguish the transportation network status and to analyze the dynamic evolutionary process with the addition of electric vehicles (EVs). Established several travel behavior models for different travel groups based on a discrete choice theory. Proposed a multi-modal dynamic traffic assignment model and a corresponding algorithm based on the point queuing model, considering some factors like the network capacity, the battery surplus, and the charging-station service-level dynamically with doing a numerical example for verification. The results show that the factors, which impact transportation system significantly, include the EV State of Charge (SOC), the charging service fee, and the EV charging-pile number. The proposed scheme for public charging- facility capacity-allocation reduces the users’ cost by 3.61%, reduces the EV charging pile acquisition cost by 15.86%, reduces the CO₂ emission from transportation-system by 0.76%, increases the EV charging station operation income by 14.66%, and increases the level of service by 77.09%.

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  Automotive Energy Efficiency and Environment Protection

  Influence of the condensation conditions on PEMFC with ORC condenser using zeotropic fluids

  LI Qingshan, WANG Chunmei, WANG Chenfang, SHI Lining, ZHUGE Weilin, ZHANG Yangjun

  2021, 12(4):  551-556.  doi:10.3969/j.issn.1674-8484.2021.04.014

  Abstract ( 197 )   HTML ( 28)   PDF (783KB) ( 145 )  

  An organic Rankine cycle (ORC) with R245fa/R123 zeotropic mixture as cooling system to recover the waste heat of proton exchange membrane fuel cell (PEMFC) was proposed to improve the energy utilization factor. An ORC hybrid system was established using Aspen Plus software. The influence of the mass fraction of zeotropic fluids R245fa on ORC system performance was analyzed by fixing the condensing temperature and pressure etc. The results show that R245fa/R123 with mixing ratio of 0.6 / 0.4 has the highest waste heat recovery at winter and 101.3 kPa at fixed condensation pressure, which are 10.90% and 11.08%, respectively. Zeotropic mixtures have better working condition adaptability than pure components. By adjusting the mixing ratio, the waste heat of PEMFC can be fully recovered under different working conditions.

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  Model predictive control of super-mild hybrid electric vehicle based on Markov chain and Q-Learning

  YIN Yanli, MA Yongjuan, ZHOU Yawei, WANG Ruixin, ZHAN Sen, MA Shenpeng, HUANG Xuejiang, ZHANG Xinxin

  2021, 12(4):  557-569.  doi:10.3969/j.issn.1674-8484.2021.04.015

  Abstract ( 230 )   HTML ( 33)   PDF (25456KB) ( 81 )  

  A model predictive control energy management strategy for super-light hybrid electric vehicles (HEV) was proposed to take into account the global optimality of the energy management strategy and the real-time operation at the same time based on Markov chain and Q-Learning algorithm. The multi-step Markov model was used to predict the acceleration change process to calculate the future required power of HEV. An energy management strategy optimization model was established by taking the minimum equivalent fuel consumption and the local balance of the state of charge (SOC) of power battery as the objective function. The Q-learning algorithm was used to solve the optimization problem in the prediction time domain to obtain the optimal torque distribution sequence. The simulation analysis was carried out under the ECE_EUDC+UDDS cycle conditions on the base of MATLAB / Simulink platform. The results show that the control strategy solved by the Q-Learning solution reduces the simulation time by 4 s under the same fuel economy condition, comparing with the control strategy based on the dynamic programming (DP) solution. The proposed control strategy can significantly improve the operating efficiency and has better real-time performance.

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  Lithium plating identification based on electrochemical impedance spectra of lithium ion batteries

  DONG Peng, ZHANG Jianbo, WANG Zhenpo

  2021, 12(4):  570-579.  doi:10.3969/j.issn.1674-8484.2021.04.016

  Abstract ( 701 )   HTML ( 50)   PDF (1843KB) ( 620 )  

  The EIS-Ohm method and the EIS-SEI method were proposed based on the variation tendency of electrochemical impedance spectroscopy (EIS) in different temperatures for the lithium ion batteries with and without lithium plating, and the equivalent circuit model was applied to fit the Ohmic impedance and the solid-electrolyte interface impedance in the EIS respectively. With temperature increase, the EIS of the lithium plating batteries showed an increase and then a decrease in Ohmic impedance, while the impedance at the solid-electrolyte interface showed a smaller change. Scanning electron microscopy (SEM) and chemical methods were used to determine the morphology and chemical transformation of the plating lithium metal from the electrode surface. The feasibility of two lithium identification methods was discussed by combining the operating temperature (-10~60 °C) and detection time (> 21 min) of the battery. The results show that the two detection methods developed based on electrochemical impedance spectroscopy can clearly identify the lithium plating, and the rapid, non-dissembling identification methods have important applications for battery life and safety management.

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  Combustion and emissions characteristics of highly diluted gasoline mixture ignited by DME enabled micro-flame

  FU Xueqing, HE Bangquan, XU Sipeng, ZHAO Hua, GUO Wencui, YANG Jianjun, GAO Haiyang, LI Zhenguo

  2021, 12(4):  580-586.  doi:10.3969/j.issn.1674-8484.2021.04.017

  Abstract ( 287 )   HTML ( 27)   PDF (1163KB) ( 127 )  

  To improve combustion stability and shorten combustion duration in highly dilution conditions, the auto-ignition of a small amount of direct injection dimethyl ether (DME) only through compression formed multi-point micro-flame, aiming at regulating the combustion processes of highly diluted gasoline mixture formed by port fuel injection, which is known as micro-flame ignited (MFI) hybrid combustion. The effects of hot exhaust gases and air dilution on the combustion and emissions characteristics of MFI combustion were experimentally investigated at part loads in a single-cylinder four-stroke thermodynamic engine, and increasing intake pressure increased the excess air coefficient (λ) and lowered internal exhaust gases rate. The results show that ignition timing is slightly affected by λ, while combustion duration elongates at higher λ in the case of low amount of fuel. In the case of higher amount of fuel, ignition timing advances and combustion duration gradually increases at higher λ. Net indicated mean effective pressure (p_IMEPn) and indicated thermal efficiency increase firstly and then reduce with increased λ, and the indicated thermal efficiency can be reached at 35.4% at 0.32 MPa p_IMEPn and 42.3% at 0.56 MPa p_IMEPn, respectively. With λ increasing, unburned hydrocarbon emissions increase in the cose of low amount of fuel, while reduce in the cose of higher amount of fuel. In the meantime, CO emissions increase, and NO_x emissions which are lower than 15×10^-6 reduce.

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  Experiments on spray characteristics of diesel-biodiesel-pentanol fuels

  LI Li, LI Yanfei, QIN Song

  2021, 12(4):  587-595.  doi:10.3969/j.issn.1674-8484.2021.04.018

  Abstract ( 274 )   HTML ( 186)   PDF (1399KB) ( 219 )  

  This paper investigated the macroscopic and microscopic spray characteristics of diesel, bio-diesel, n-pentanol, and their oxygenated blends by using high-speed photography and Phase Doppler Particle Analyzer (PDPA) for fuel-engine co-optimization. Conducted some experiments in a constant volume vessel to investigate the effects of fuel property, injection pressure, ambient pressure, and ambient temperature. The results show that compared with diesel, bio-diesel has larger liquid phase penetration and smaller cone angle; And n-pentanol has the smallest liquid phase penetration; The Sauter mean diameter (SMD) of fuel sprays decreased with the increase of injection pressure from 40 to 120 MPa and the decrease of ambient pressure. Among all the fuels, bio-diesel has the largest SMD while n-pentanol exhibits the smallest SMD due to its low viscosity and surface tension. Density, viscosity, boiling point, and surface tension are identified as the key fuel properties affecting the spray characteristics, especially in high temperature conditions (830 K). Therefore the fuel physicochemical property complementation improves spray characteristics.

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  Application and reliability influence of low viscosity and energy saving engine oil for CN6 heavy duty diesel engines

  ZHAO Guoquan, DENG Jianlin

  2021, 12(4):  596-603.  doi:10.3969/j.issn.1674-8484.2021.04.019

  Abstract ( 274 )   HTML ( 191)   PDF (1325KB) ( 143 )  

  A research and development of low viscosity and energy saving engine oil (FA-4/5W-30) were carried out to further reduce the fuel consumption to enhance the market competitiveness of the new generation of CN6 heavy-duty diesel engine. The computer aided engineering (CAE) was employed to do the simulation analysis. The test on the bench and the bench reliability test were carried out for the fuel economy of the corresponding CN6 heavy duty diesel engine. The results show that the newly developed low viscosity energy saving engine oil can effectively improve fuel economy by about 1%, which can meet with the engine reliability requirement. This research makes full preparation and accumulates the data for the subsequent market application of lowviscosity energy saving engine oil (FA-4/5W-30).

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  -30 °C start-up of a PEFC stack based on alternate hydrogen pump method

  SI Dechun, JIAN Jiting, XU Haosen, WANG Shangshang, WANG Cheng, ZHANG Jianbo

  2021, 12(4):  604-612.  doi:10.3969/j.issn.1674-8484.2021.04.020

  Abstract ( 672 )   HTML ( 201)   PDF (2098KB) ( 470 )  

  Starting a fuel cell vehicle (FEV) under sub-zero temperature is one of the main obstacles to popularize FEVs in temperate and cold regions. This paper investigated the sub-zero start-up for a short stack of graphite-based bipolar plate polymer electrolyte fuel cells (PEFC) with 20 single cells and an active area of 285 cm². Developed a power supply system by using an alternate hydrogen pump based on a real vehicle, with supplying hydrogen to the anode and the cathode of a short stack at the same time in a low-temperature environment chamber to create a -30 °C start-up environment. The initial molecule-number content of membrane to water, the alternating electric amplitude and the frequency were three control parameters to achieve the -30°C start-up of the PEFC short stack. The polarization curves of the short stack were tested before and after the sub-zero start-up. The results show that the single cell reaches 0 °C in 80 s in the middle of a short PEFC stack, and rises to 0 °C in 200 s in the other places of the stack. There is basically no polarization attenuation in the stack before and after the sub-zero start-up.

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