Table of Content

25 August 2022, Volume 44 Issue 8 Previous Issue    Next Issue

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Safety Control Strategy for Adaptive Cruise Control System in Heavy Rainfall Scenes Chao Zhao,Dexu Bu,Lipeng Cao,Keqiang Li,Yugong Luo 2022, 44 (8):  1117-1125.  doi: 10.19562/j.chinasae.qcgc.2022.08.001 Abstract ( 388 )   HTML ( 41 )   PDF (2488KB) ( 445 )   Save Aiming at the issue of safety of intended functionality （SOTIF） of adaptive cruise control （ACC） system caused by the large unintended measurement error of target movement of millimeter wave radar in heavy rainfall scenes， a SOTIF safety control strategy for ACC system in heavy rainfall scenes is proposed in this paper. Firstly， double-state Chi-square is used to check the target information output by millimeter-wave radar to determine whether there exist SOTIF risks. Then the target information with safety risk is corrected by Kalman filter， with the target information corrected input into ACC controller to control vehicle motion state for achieving safety control. Finally， the Prescan/Simulink co-simulation platform is built to conduct verification simulation on the safety control strategy proposed. The results show that double-state Chi-square test can timely detect risk information with a detection time deviation within 1.31 s and a distance correction error of Kalman filter within 3.66 m， effectively ensuring the safe and stable operation of ACC system in heavy rainfall scenes. Figures and Tables | References | Related Articles | Metrics

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Robust Stability Control and Its Verification Test for All-Wheel Diagonal Steering of Unmanned Ground Vehicles Yue Zhao,Jibin Hu,Wei Wu,Chao Wei 2022, 44 (8):  1126-1135.  doi: 10.19562/j.chinasae.qcgc.2022.08.002 Abstract ( 229 )   HTML ( 17 )   PDF (3565KB) ( 377 )   Save The research and application of unmanned ground vehicles （UGVs） become more popular in both civilian and military fields. UGVs completely eliminate the human driving operating mechanisms， and adopt full X-by-wire control framework and distributed all-wheel independent drive/braking/steering techniques instead， with each wheel independently controlled to realize multi-steering modes and obtain high maneuver trajectory tracking ability which traditional vehicle cannot achieved. This paper aims to conduct a research on the all-wheel diagonal steering （vividly called crab walk steering） control of full X-by-wire controlled UGVs. Firstly， a stability robust control algorithm with a reconfigurable model is proposed， the robust control target and parameter perturbation dynamics model for diagonal maneuver are established， and a robust H2/H∞ stability controller is constructed to achieve a point-to-point yaw-less direct movement of UGVs. Then a decoupled control between body motion posture and movement trajectory is realized through comprehensive cooperated dynamics control， so significantly enhancing the trajectory tracking capability of UGVs in complex space. Finally， a test on a six-wheel UGV prototype is carried out to verify the control effects of the robust controller designed. Figures and Tables | References | Related Articles | Metrics

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Study on Coordinated Control of Speed Planning and Energy Management for Connected Hybrid Electric Truck in Vehicle Following Scene Shaobo Xie,Pengcheng Qu,Jiacheng Li,Huiqing Wang,Kun Lang 2022, 44 (8):  1136-1143.  doi: 10.19562/j.chinasae.qcgc.2022.08.003 Abstract ( 182 )   HTML ( 10 )   PDF (3896KB) ( 276 )   Save In view of that the following speed of network-connected hybrid electric truck in a fleet not only affects the driving safety， energy demand and distribution and battery aging rate， but also influence the aerodynamic drag and even the energy consumption through vehicle spacing， the speed planning and energy management strategy under vehicle following scenes are proposed in this paper with concurrent considerations of multi-objectives covering driving safety， energy consumption， aerodynamic drag and battery aging. Firstly， the vehicle following safety is quantified based on aerodynamics. Then， a real time control strategy based on model predictive control is constructed with minimizing the total equivalent cost consisting of safety cost， energy consumption cost and battery aging cost as objective function， in which the speed of front vehicle is predicted by using long- and short-term memory-based neural network， and the optimization problem in rolling time domain is solved with dynamic programming. The results show that the cooperative control strategy proposed can lower the battery aging cost via restraining the charging and discharging current， and reduce the aerodynamic drag and hence the energy cost by flexibly adjust following vehicle spacing. The results of comparison with human-driven-model-based following strategies verify the feasibility of cooperative control strategy proposed. Figures and Tables | References | Related Articles | Metrics

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Reservation Based Multi-Vehicle Cooperative Control at Traffic-Lightless Intersection Under Different Penetration of Mixed Traffic Flow Wenqin Zhong,Weiwei Kong,Zhiheng Li,Jie Yu,Yugong Luo 2022, 44 (8):  1144-1152.  doi: 10.19562/j.chinasae.qcgc.2022.08.004 Abstract ( 179 )   HTML ( 11 )   PDF (2727KB) ( 320 )   Save Reservation-based approach is a classical method of multi-vehicle cooperative controlling at traffic-lightless intersections. The traditional reservation-based approach usually assumes that only intelligent and connected vehicles （ICVs） exist at the intersection， which lacks discussion on the coexistence of human-driven vehicles （HDVs） and ICVs in this scenario. In this paper， based on the reservation-based approach， the cooperative control method for traffic-lightless intersections with mixed ICVs and HDVs is studied， and the impact of ICV penetration on traffic efficiency at traffice-lightless intersections is explored. Firstly， the functional zones of the traffic-lightless intersection under mixed traffic flow are divided， and the architecture of the reservation-based multi-vehicle cooperative control system for mixed traffic flow is proposed. Furthermore， the reservation-based multi-vehicle cooperative control strategy for mixed traffic flow is formulated， including the ICV cell reservation strategy and ICV speed control strategy considering the characteristics of HDVs. Finally， the SUMO/Python joint simulation platform is built to simulate the strategy under different traffic flows with the ICV penetration of 30%， 60%， 90% and 100% respectively， with the intersection passing rate and the average speed of the road section as the evaluation indicators. The results show that the proposed control strategy can ensure that all vehicles can pass the intersection safely， and the efficiency of traffic-lightless intersections increases with the increase of ICV penetration. Figures and Tables | References | Related Articles | Metrics

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Cooperated Adaptive Cruise Control for Mixed Autonomous Traffic Flow Liqun Peng,Yiting Wang,Yulin Ma,Xü Shucai 2022, 44 (8):  1153-1161.  doi: 10.19562/j.chinasae.qcgc.2022.08.005 Abstract ( 210 )   HTML ( 17 )   PDF (1871KB) ( 322 )   Save In the V2V environment of the internet of vehicles， the real-time movement status， driving conditions and road environment of the vehicle and its surrounding vehicles can be collected so as to provide more accurate information for vehicle adaptive cruise control （ACC） system. In order to eliminate the interference of headway fluctuation on longitudinal ACC under the mixed driving conditions of autonomous vehicles （AV） and manual vehicles （MV） ， a V2V based cooperative adaptive control method is proposed. Firstly， through V2V of the internet of Vehicles， the basic safety message （BSM） of the vehicle in the process of vehicle following is collected in real time so as to obtain the relative motion state and driving behavior sequence of the vehicles. Then， the linear quadratic regulator （LQR） is applied to infer the sequential driving maneuvers and short-term predict the vehicle motion state under the disturbance of traffic vehicle acceleration and deceleration. On this basis， a rolling optimization model and a cooperative adaptive control method for vehicle following distance are established to acquire the optimal equilibrium state of the headway of the mixed traffic flow. The test results show that under the acceleration/deceleration driving conditions of the preceding vehicle， the improved vehicle controller can respond faster to the change of the moving state of the preceding vehicle， and reduces the headway while ensuring the safe car-following distance and high traffic capacity. Figures and Tables | References | Related Articles | Metrics

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Longitudinal Control Method of Intelligent Vehicles Based on the Improved BP Neural Network Wang Liang,Zhaobo Qin,Liang Chen,Yougang Bian,Manjiang Hu 2022, 44 (8):  1162-1172.  doi: 10.19562/j.chinasae.qcgc.2022.08.006 Abstract ( 255 )   HTML ( 16 )   PDF (6990KB) ( 226 )   Save For the problem that the parameters of traditional PI control are fixed and difficult to be adjusted in the process of vehicle speed tracking， a longitudinal control method of intelligent vehicle based on the improved BP neural network is proposed. The BP neural network in drive mode and brake mode is established respectively. In view of the difficulty in selecting initial parameters of BP neural network and the problem of gradient disappearing in reverse self-learning， particle swarm optimization and batch normalization are used to improve the BP neural network. Finally， the dynamic self-tuning of PI parameters is realized. By Carsim/Simulink co-simulation and real vehicle test， the proposed method is verified. The results show that the proposed longitudinal control method can realize rapid adjustment of parameters based on error and improve the longitudinal control accuracy of the vehicle compared with the traditional PI control. Figures and Tables | References | Related Articles | Metrics

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Semantic Segmentation Method of LiDAR Point Cloud Based on 3D Conical Grid Runhui Huang,Likun Hu,Mingfang Su,Daye Xu,Aoran Chen 2022, 44 (8):  1173-1182.  doi: 10.19562/j.chinasae.qcgc.2022.08.007 Abstract ( 167 )   HTML ( 8 )   PDF (3392KB) ( 205 )   Save Semantic segmentation of LiDAR point cloud is an important branch of road scene perception in automatic driving system. Though the state-of-the-art methods convert point cloud into regular 2D images or Cartesian grid for processing， which reduces the computation efforts resulting from the unstructured point clouds， but the 2D image-based methods inevitably change the 3D geometric topology， while Cartesian grid-based methods ignore the density inconsistency of outdoor LiDAR point cloud， thus limiting their semantic segmentation ability， especially for small objects such as pedestrians and bicycles. Therefore， a semantic segmentation method for LiDAR point cloud base on 3D conical grid and sparse convolution network （Spconv3D） is proposed in this paper， in which conical grid partition is used to solve the problem of sparsity and density inconsistency of point cloud. The re-parameterized Spconv3D is designed to enhance the speed of model inference. Two large-scale datasets， i.e. SemanticKITTI and nuScenes are used to conduct an evaluation on the method proposed. The results show that compared with the state-of-the-art methods， the mIoU of the method proposed is 1.3% and 0.8% higher respectively， in particular with a significant rise in small object recognition. Figures and Tables | References | Related Articles | Metrics

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Design, Analysis and Validation of Novel Distributed Drive Liquid Hydrogen Fuel Cell Heavy Commercial Vehicles Hang Li,Zunyan Hu,Jiayi Hu,Jiachen Dong,Jianqiu Li,Liangfei Xu,Ouyang Minggao,Yu Bu,Lijun Wang,Zhidong Qin 2022, 44 (8):  1183-1198.  doi: 10.19562/j.chinasae.qcgc.2022.08.008 Abstract ( 491 )   HTML ( 27 )   PDF (9299KB) ( 478 )   Save According to the development requirements of high performance， long driving range and low cost for the powertrain of heavy commercial vehicles， a technical scheme for the distributed drive heavy commercial vehicles with liquid hydrogen fuel cell is proposed in this paper. In the scheme， many innovative technologies are applied， including high-power fuel cell system， large-capacity onboard liquid-hydrogen storage and supply system and distributed electric wheel drive system. Based on the design and matching techniques of fuel cell system， the first domestically publicized hundred-kilowatt-level fuel cell system （109 kW） is developed. Based on the breakthrough of key technologies such as onboard liquid hydrogen tank design， liquid hydrogen carburetor design and onboard liquid hydrogen BOG treatment and full system safety monitoring， the domestically first set on-board large-capacity liquid hydrogen storage and supply system （60 kg/110 kg） is developed. Based on the innovations in the magneto-thermal design， configuration design and integrated design of hub-motors， the electric wheels suitable for the double-tire assembled wheel for heavy vehicles are developed with a peak torque of single electric wheel of 16 000 N·m， a short-term peak torque of 18 000 N·m and a peak torque density of 60 N·m/kg. Based on the key technologies of components mentioned above， the world's first distributed drive liquid hydrogen fuel cell heavy commercial vehicle is developed， with a designed driving range of more than 1 000 km. The road tests on the 35 t and 49 t heavy commercial vehicle developed are carried out to verify the technical feasibility of liquid hydrogen storage， powertrain and distributed electric drive system， exploring the feasible direction of the electrification of heavy commercial vehicles. Figures and Tables | References | Related Articles | Metrics

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Analysis on Typical Modes of Thermal Runaway in Power Battery Pack with Uniformly Distributed Modules Jiqing Chen,Haolan Xian,Fengchong Lan 2022, 44 (8):  1199-1211.  doi: 10.19562/j.chinasae.qcgc.2022.08.009 Abstract ( 173 )   HTML ( 8 )   PDF (10154KB) ( 121 )   Save According to the structure of the widely used power battery pack with uniformly distributed modules， a thermal runaway propagation test platform for uniformly distributed modules is built， and the thermal runaway propagation test is carried out to analyze the thermal runaway propagation behavior characteristics and the law of heat flow transfer. The combination of the real cases of electric vehicle fire accident caused by the thermal runaway of power battery pack and the result of thermal runaway propagation test for the uniformly distributed battery modules verifies the propagation mode of thermal runaway for the battery pack. The results show that there are two propagation modes of thermal runaway for the battery pack： the thermal runaway propagation within the module and the thermal runaway propagation between different modules； The thermal runaway time interval within the module 1， where the thermal runaway occurs first， is 44， 34， 31 s respectively and that within the module 2， whose thermal runaway is caused by the effects of module 1， is significantly shortened， being 17， 15， 11 s respectively， with the thermal runaway time interval within the module getting smaller and smaller， the heat released by the thermal runaway of the battery cell that triggers the thermal runaway of the adjacent battery cells gradually reduces with the propagation of thermal runaway， and there exists an apparent time lag in the propagation of thermal runaway between modules， usually reaching the order of several minutes. There are two distinguish initial temperature of thermal runaway for the battery cell under thermal abuse conditions： the thermal runaway trigger temperature and the thermal runaway environment trigger temperature. The wall heat radiation and air heat conduction between modules increase the thermal runaway propagation speed in adjacent module， in which the maximum heat transferred by wall heat radiation can reach 95.18 kJ， while the maximum heat transferred by air heat conduction is 3.58 kJ， indicating the main way of heat transfer between modules being wall heat radiation. In order to prevent the thermal runaway from propagation within module， the protection measures for the propagation of thermal runaway between modules should be strengthened. Figures and Tables | References | Related Articles | Metrics

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Analysis on the Effects of User Behavior on Battery Aging of Electric Vehicles Based on Big Data Haiqiang Liang,Hongwen He,Kangwei Dai,Bo Pang 2022, 44 (8):  1212-1217.  doi: 10.19562/j.chinasae.qcgc.2022.08.010 Abstract ( 234 )   HTML ( 13 )   PDF (1671KB) ( 198 )   Save In order to explore the influence of users' behaviors on the battery aging of electric vehicles， a statistical analysis method based on big data is proposed to study the influence of the region user's vehicle located， the charging mode preference and driving style of users on battery aging， relying on a large number of high-quality user and vehicle data on the enterprise supervision platform. The results show that with the increase of the average operating temperature of battery， the attenuation of battery capacity reduces first and then increases. The battery aging degree of Beijing users is 10.59%~19.09% higher than that of Guangdong users. With the rise of fast charging frequency， the attenuation rate of battery capacity gradually increases， but with the increasing rate declining. The battery aging of the user preferring fast charging is 33.45%~56.24% faster than that of users preferring slow charging. Aggressive driving mode may accelerate battery aging， with an aging rate 1.73%~10.37% faster than gentle driving mode. The research results have reference significance for vehicle enterprises to optimize vehicle function design and guide the users to drive healthily. Figures and Tables | References | Related Articles | Metrics

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Torque Distribution Strategy Optimization of a Novel Dual-Motor Multi-Mode Drive System Using PSO Algorithm Xinyou Lin,Qiang Huang,Guangji Zhang 2022, 44 (8):  1218-1225.  doi: 10.19562/j.chinasae.qcgc.2022.08.011 Abstract ( 139 )   HTML ( 8 )   PDF (3611KB) ( 141 )   Save Torque distribution optimization is carried out for an electric vehicle equipped with a novel dual-motor multi-mode drive system in this paper. According to the features of the dual-motor multi-mode drive system， a vehicle model is established， with the working range of different modes divided. On the premise of meeting the requirements of power performance， the system efficiency oriented strategies for torque distribution and mode switching based on particle swarm optimization algorithm are formulated， and the offline and online methods are combined to enhance the real-time response speed of the system. The simulation model is established in Matlab / Simulink with a simulation conducted and a hardware-in-the-loop test is carried out for verification. The results show that the average efficiency of the system is 3% higher than that with the traditional mode switching strategy， and the energy consumption is 11.28% lower than that with the torque distribution strategy based on genetic algorithm. Figures and Tables | References | Related Articles | Metrics

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Peeling Model Establishment and Radial Magnetic Density Analysis of Motor Rotor Core Bing Du,Hailong Cui,Fenghua Liu,Maowei Zhou,Xiudong Huang,Canjun Yang,Chunhua Zou,Xiang Yan 2022, 44 (8):  1226-1236.  doi: 10.19562/j.chinasae.qcgc.2022.08.012 Abstract ( 122 )   HTML ( 2 )   PDF (3560KB) ( 109 )   Save To ensure that the rotor core of automotive permanent magnet synchronous motor （PMSM） has the ability to withstand large peeling forces， while avoiding destructive peeling test， two stacking processes， i.e. stacked riveting and adhesive process are modeled based on the principle of force-energy equivalence and the bilinear cohesion model introduced， with the peeling forces of rotor core obtained through simulation in this paper. Firstly， a peeling test platform for motor rotor core is constructed to compare the maximum peeling force of two stacking processes by test. Then the no-load radial magnetic density of PMSM under two processes is analyzed by simulation with ANASY Maxwell. The results show that the adhesive process adopted can greatly enhance the peel strength of the iron core， and meanwhile increase the operation efficiency of motor and the closeness of air-gap magnetic field to sine function， and reduce the operating current and losses of motor. Figures and Tables | References | Related Articles | Metrics

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State Estimation and Parameter Identification of Shifting Actuator of Automatic Transmission of Electric Vehicles Cheng Lin,Jiang Yi,Yu Tian 2022, 44 (8):  1237-1250.  doi: 10.19562/j.chinasae.qcgc.2022.08.013 Abstract ( 161 )   HTML ( 8 )   PDF (11622KB) ( 103 )   Save In order to improve the shifting performance when the parameters of the automatic transmission shifting actuator are time-varying， a hierarchical state estimation and parameter identification method based on the nonlinear H_{\mathrm{\infty }} algorithm is proposed， considering both the highly nonlinear system model and the unknown system noise characteristics. Firstly， the problem of time-varying parameters of the shifting actuator is found through experiments， and a nonlinear model is established for the shifting actuator. Then， the hierarchical state estimation layer and parameter identification layer are designed， both of which are based on the nonlinear H_{\mathrm{\infty }} algorithm. The upper estimation layer estimates the state of the actuator and transfers the result to the lower identification layer； the lower identification layer applies the state results as the measurement， and uses the system model as the measurement equation to identify the system parameters. Then， the cooperative operation of the two layers estimate the state of the shifting actuator， and identifies the structural and electrical performance parameters. Finally， a state estimation and parameter identification process based on automatic calibration is designed， which realizes the parameter identification of the shift actuator while calibrating and correcting the shift position value. The test results show that the hierarchical state estimation and parameter identification method proposed in this paper can accurately estimate and identify the state and parameters of the shifting actuator. After modifying the parameters， the shifting performance of the system is improved. Figures and Tables | References | Related Articles | Metrics

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Research on Driver Lateral Control Model Under Crosswind Conditions Based on Cognitive-Control Framework Yingshi Guo,Yahui Hu,Rui Fu,Chang Wang 2022, 44 (8):  1251-1261.  doi: 10.19562/j.chinasae.qcgc.2022.08.014 Abstract ( 156 )   HTML ( 10 )   PDF (2874KB) ( 137 )   Save In this paper， a driver lateral control model with cognitive-control as framework is proposed based on neuro-ergonomic cognitive theory and driver preview model. The lateral control model is verified by the co-simulation of Simulink and TruckSim software. The particle swarm optimization algorithm is used to optimize and calibrate the parameters of the proportional-derivative controller module in control framework. The results show that in crosswind condition， the driver lateral control model built with cognitive-control framework is effective （RMSE=0.09）， with higher accuracy and wider adaptability. In addition， from the perspective of cognitive-control， by changing the preview time tp，gain ratio kp and differential parameter kd， the behaviors of drivers with different driving style can be characterized. The research provides a reference thinking for enhancing the safety and comfort of advanced driving assisted systems and autonomous vehicles under crosswind conditions. Figures and Tables | References | Related Articles | Metrics

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The Wind Noise Source and Its Characteristic Analysis of HSM Standard Model Xingjun Hu,Jingming Mao,Yanghui Zhang,Yichen Liu,Jiayi Ma,Junxian Qiao,Tianming Yu 2022, 44 (8):  1262-1271.  doi: 10.19562/j.chinasae.qcgc.2022.08.015 Abstract ( 146 )   HTML ( 9 )   PDF (5988KB) ( 121 )   Save The interior noise source and its characteristics of HSM standard model are studied by wind tunnel test and flow field / sound field co-simulation. Five test conditions are devised to explore the effect of each noise source on interior noise， with the accuracy of simulation verified by test. The noise source components and their contributions are analyzed by pellicular mode decomposition （PMD）， with its difference mechanism revealed. The results show that with the increase of wind velocity， the changing frequency band of interior noise is different due to the effects of different noise sources. The interior noise is mainly induced by the separation vortex and its reattachment at the leading edge of the model， and the noise source excitation generated by the separation vortex is transmitted through windows， with the left window being the main contributor. The noise source excitation includes turbulent pressure fluctuation and acoustic pressure fluctuation， in which the former is the main component of the excitation， while the latter is the main source of interior noise. This difference stems from the different transfer efficiencies caused by the wavenumber relationship between the excitation and windows. Figures and Tables | References | Related Articles | Metrics

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Experimental Study on Transient Performance of Fuel Cell Air Compressor Based on Road Test Cycle Conditions Huanhuan Bao,Lei Zhang,Qi Liu,Jianqin Fu,Shuqian Wang,Quan Wu,Jingping Liu 2022, 44 (8):  1272-1279.  doi: 10.19562/j.chinasae.qcgc.2022.08.016 Abstract ( 138 )   HTML ( 7 )   PDF (4458KB) ( 140 )   Save The real operating performance of fuel cell system directly depends on the dynamic working characteristics of its air compressor. In order to systematically analyze the changing law of the transient performance of air compressor by testing， a dynamic performance test bench for the air compressor of fuel cell is built， and a transient test condition reflecting the real operating characteristics of air compressor is devised， with which the performance of air compressor and the changing characteristics of its operating parameters under a single transient test cycle are analyzed. The results show that the operating points of air compressor in transient condition are mainly located in the middle narrow band， i.e. a high-efficiency working zone in the steady-state performance map. The inlet and outlet flow-rate difference of air compressor fluctuates drastically due to the joint-influence of pressure ratio and temperature ratio， with a larger flow-rate difference of 3.5~8.5 m3/h in high speed zone. The maximum power consumed in high-speed zone is up to 5.6 kW， causing a large parasitic loss， but its sensibility to outlet temperature change is relatively low. When the speed of air compressor sharply lowers from 9 750 r/min to 4 450 r/min， the change of flow-rate has a time lag of about 2 s. Figures and Tables | References | Related Articles | Metrics

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Experimental Research on the Effect of Catalyzed Diesel Particulate Filter Active Regeneration on Selective Catalytic Reduction Performance Yinggang Shen,Weijie Shi,Huanrong Xiao,Ruimin Yang,Guisheng Chen,Kegang Bi 2022, 44 (8):  1280-1288.  doi: 10.19562/j.chinasae.qcgc.2022.08.017 Abstract ( 136 )   HTML ( 4 )   PDF (5071KB) ( 72 )   Save Based on the National 6 small-bore diesel engine loaded with a DOC+ CDPF+ SCR after-treatment test bench， the CDPF active regeneration and drop to idle（DTI） regeneration tests are carried out under the carbon load of 8 g/L， and the effect of CDPF active regeneration on operating characteristics of SCR coated with different catalysts is studied and analyzed. The results show that due to the action of the mixer， the active regeneration of CDPF has little influence on the uniformity of the temperature distribution at the inlet surface of the SCR， and the average inlet temperature of the SCR during the active regeneration is about 580 ℃. During the stabilization period of active regeneration， the NO x conversion efficiency is lower for both the two catalyst coating schemes， with the NO x conversion efficiency of Cu-zeolite SCR about 80.3%， and that of vanadia-based SCR about 32%. The stability of Cu-zeolite catalyst is relatively high. During the DTI active regeneration test， before the active regeneration， the NO x conversion efficiency gradually increases with the increase of the SCR inlet temperature. When the inlet temperature is 401 ℃， the NO x conversion efficiency reaches the highest value during this period， and its value is about 99.3%. After the active regeneration is stabilized， the NO x conversion efficiency decreases with the increase of temperature. When the working condition suddenly changes to the idle condition， the SCR inlet temperature reaches the highest value， which is about 582 ℃， and the conversion efficiency is 82.2%. At the same time， the oxygen concentration increases， resulting in the NO x conversion efficiency rising rapidly to the peak and then remaining stable， and the conversion efficiency is stabilized at 99.5%， which begins to decline when the temperature decreases. Figures and Tables | References | Related Articles | Metrics