Under the background of"Outstanding Engineer Education and Training Program"and ideology and politics teaching in course,it has become a training goal for colleges and universities to cultivate an engineer w...Under the background of"Outstanding Engineer Education and Training Program"and ideology and politics teaching in course,it has become a training goal for colleges and universities to cultivate an engineer with both political integrity and talent.However,it is necessary for colleges and universities to explore and practice how to combine the two skillfully without being abrupt and make students accept them.From the point of view of vehicle engineering experiment course and combining with the current situation of university teaching,this paper makes an in-depth exploration and practice on the ideological and political reform on vehicle engineering experiment course.展开更多
In view of the problem of the teaching effect of the vehicle specialty courses,this paper analyzes the training objectives of the courses,determines the teaching contents and relevant teaching methods,and provides spe...In view of the problem of the teaching effect of the vehicle specialty courses,this paper analyzes the training objectives of the courses,determines the teaching contents and relevant teaching methods,and provides specific teaching measures to improve the students'ability to solve practical problems and employment ability,so as to cultivate the application-oriented talents with innovation ability and practical ability that meet the needs of the society.展开更多
Under the situation of actively constructing the education pattern of ideological and political courses in our country,talents with excellent professional quality and excellent ideological and moral quality have becom...Under the situation of actively constructing the education pattern of ideological and political courses in our country,talents with excellent professional quality and excellent ideological and moral quality have become the training goal of current college education.However,what way should be adopted to better integrate ideological and political education with professional knowledge education will be the answer that colleges and universities need to constantly explore.This paper starts from the professional courses of vehicle engineering,combined with the current situation of China's automobile industry,to study practical reform methods,construct the pattern of whole curriculum education.展开更多
In order to overcome the limitation of vehicle engineering professional laboratory personnel and facilities,some of them is commonly used auxiliary software in the professional field for design,calculation and researc...In order to overcome the limitation of vehicle engineering professional laboratory personnel and facilities,some of them is commonly used auxiliary software in the professional field for design,calculation and research,including characteristics of software,application scope and methods are presented in this paper.Through these industries aided software powerful calculation,analysis functions and convenient visualization means,for the virtual simulation experiment,it can help to clearly illustrate the concept,deepen students' understanding level of vehicle professional course,improve the enthusiasm of the students,improve the ability of autonomous learning and improve students ' thinking ability and practice ability,and can effectively train highquality professionals with good quality.展开更多
New energy vehicles represent the inevitable trend of future development.Compared to traditional fuel vehicles,they are more energy-saving and environmentally friendly,effectively reducing air pollution and mitigating...New energy vehicles represent the inevitable trend of future development.Compared to traditional fuel vehicles,they are more energy-saving and environmentally friendly,effectively reducing air pollution and mitigating excessive exploitation of oil resources,a stance strongly supported by governments.However,new energy vehicles possess certain drawbacks in terms of price and usability compared to traditional counterparts.Therefore,external support is imperative for their development.This paper delineates four main sections:the background of new energy vehicle promotion and application,a comparative analysis of domestic and foreign promotion models,specific promotion suggestions,and future development prospects.By leveraging insights from economic analysis,the optimal promotion model for new energy vehicles is elucidated.展开更多
Aiming at the problems of low target image resolution,insufficient target feature extraction,low detection accuracy and poor real time in remote engineering vehicle detection,an improved CenterNet target detection mod...Aiming at the problems of low target image resolution,insufficient target feature extraction,low detection accuracy and poor real time in remote engineering vehicle detection,an improved CenterNet target detection model is proposed in this paper.Firstly,EfficientNet-B0 with Efficient Channel Attention(ECA)module is used as the basic network,which increases the quality and speed of feature extraction and reduces the number of model parameters.Then,the proposed Adaptive Fusion Bidirectional Feature Pyramid Network(AF-BiFPN)module is applied to fuse the features of different feature layers.Furthermore,the feature information of engineering vehicle targets is added by making full use of the high-level semantic and low-level fine-grained feature information of the target,which overcomes the problem that the original CenterNet network did not perform well in small target detection and improve the detection accuracy of the network.Finally,the tag coding strategy and bounding box regression method of CenterNet are optimized by introducing positioning quality loss.The accuracy of target prediction is increased by joint prediction of center position and target size.Experimental results show that the mean Average Precision(mAP)of the improved CenterNet model is 94.74%on the engineering vehicle dataset,and the detection rate is 29 FPS.Compared with the original CenterNet model based on ResNet-18,the detection accuracy of this model is improved by 16.29%,the detection speed is increased by 9 FPS,and the memory usage is reduced by 43 MB.Compared with YOLOv3 and YOLOv4,the mAP of this model is improved by 19.9%and 5.61%respectively.The proposed method can detect engineering vehicles more quickly and accurately in far distance.It has obvious advantages in target detection compared with traditional methods.展开更多
New energy vehicles have better clean and environmental protection characteristics than traditional fuel vehicles.The new energy engine cooling technology is critical in the design of new energy vehicles.This paper us...New energy vehicles have better clean and environmental protection characteristics than traditional fuel vehicles.The new energy engine cooling technology is critical in the design of new energy vehicles.This paper used oneand three-way joint simulation methods to simulate the refrigeration system of new energy vehicles.Firstly,a k-εturbulent flow model for the cooling pump flow field is established based on the principle of computational fluid dynamics.Then,the CFD commercial fluid analysis software FLUENT is used to simulate the flow field of the cooling pump under different inlet flow conditions.This paper proposes an optimization scheme for new energy vehicle engines’“boiling”phenomenon under high temperatures and long-time climbing conditions.The simulation results show that changing the radiator’s structure and adjusting the thermostat’s parameters can solve the problem of a“boiling pot.”The optimized new energy vehicle engine can maintain a better operating temperature range.The algorithm model can reference each cryogenic system component hardware selection and control strategy in the new energy vehicle’s engine.展开更多
In order to study the influence of thermal deformation of long-span cable- stayed bridge (LSCSB) on the dynamic characteristics of metro vehicle on the bridge, based on the theory of vehicle-track coupled dynamic...In order to study the influence of thermal deformation of long-span cable- stayed bridge (LSCSB) on the dynamic characteristics of metro vehicle on the bridge, based on the theory of vehicle-track coupled dynamics, the rigid-flexible coupled dynamic model of metro vehicle-track-LSCSB system is established by using finite element method and multi-rigid-body dynamics. Adopting this model, the deformation of LSCSB subject to temperature is analyzed, then the comprehensive effect of track random irregularity and rail deformation caused by temperature load is considered to study the dynamic characteristics of metro vehicle running through the bridge, and finally the influences of temperature increment and running speed on concerned dynamic indices of vehicle are studied. The results show that the LSCSB deforms obviously subject to temperature load, and the overall performance is that the cooling is arched, and the heating is bent, and the shape variable changes almost linearly with the temperature load. According to the parameters studied in this paper, the rail deformation caused by temperature load increases the wheel-rail vertical force, derailment coefficient and wheel load reduction rate by 1.5%, 3.1% and 5% respectively. The vertical acceleration of the vehicle body decreases by 2.4% under the cooling condition, while increases by 3.7% under the heating condition. The dynamic response of the bridge changes under temperature load. The maximum vertical and horizontal displacement in the middle of the main beam span are 6.24 mm and 2.19 mm respectively, and the maximum vertical and horizontal acceleration are 1.29 cm/s<sup>2</sup> and 2.54cm/s<sup>2</sup> respectively. The derailment coefficient and vertical acceleration of vehicle body are more affected by temperature load, and the wheel load reduction rate and wheel-rail vertical force are more affected by speed. The conclusion of this paper provides a reference for subsequent scholars to study the influence of thermal deformation on the dynamic response of vehicles on LSCSB.展开更多
Full frontal impact theory needs researching and exploring to satisfy the primary safety design of occupant restraint system,avoiding the increasingly "engineering"trend in order to develop and design safety...Full frontal impact theory needs researching and exploring to satisfy the primary safety design of occupant restraint system,avoiding the increasingly "engineering"trend in order to develop and design safety vehicle. After occupant restraint system is simulated by using linear elastic stiffness k,the occupant-vehicle frontal rigid barrier impact model is established. Dynamic equation of dummy chest coupling vehicle is built for full frontal impact based on ordinary vehicle deceleration by Hooke law,and the equation is solved by comparing coefficient and satisfying boundary qualifications. While relative vehicle characteristic parameters are kept unchanging,the actual vehicle deceleration is fitted to the simplified equivalent square wave( ESW),tipped equivalent square wave( TESW) and equivalent dual trapezoids wave( EDTW). Phase angle and amplitude A of dynamic equations based on ESW,TESW and EDTW are calculated and deduced. The results show that: the dynamic equation of dummy chest coupling vehicle can be well utilized to instruct the primary safety design of full frontal impact for objective vehicle to satisfy chest deceleration demands and the equation based on TESW is best for this design.展开更多
Engineering vehicles are widely used under various harsh working conditions.For many components in them,service loadings they suffered are usually random and nonstationary due to their remarkable characteristic called...Engineering vehicles are widely used under various harsh working conditions.For many components in them,service loadings they suffered are usually random and nonstationary due to their remarkable characteristic called cyclic operation.To deal with that,section method can be applied.However,this method will neglect those transition cycles caused by switching load section,which can contribute a lot to fatigue.In order to consider those transition cycles,this paper applied the model called“Switching Markov Chain of Turning Points”(SMCTP).Then the expected rain-flow matrix is compared with the overall rain-flow matrix conducted by section method.The comparison result shows that SMCTP can perform well in processing nonstationary loadings.As a result,the Switching Markov Chain method(SMC)was proved to be effective in stochastically characterizing the nonstationary switching loadings of engineering vehicles.展开更多
This paper presents an energy management optimization system based on an adaptive functional state model of battery aging for internal combustion engine vehicles(ICEVs).First,the functional characteristics of batterie...This paper presents an energy management optimization system based on an adaptive functional state model of battery aging for internal combustion engine vehicles(ICEVs).First,the functional characteristics of batteries in ICEVs are investigated.Then,an adaptive functional state model is proposed to represent battery aging throughout the entire battery service life.A battery protection scheme is developed,including over-discharge and graded over-current protection to improve battery safety.A model-based energy management strategy is synthesized to comprehensively optimize fuel economy,battery life preservation,and vehicle performance.The performance of the proposed scheme was examined under comprehensive test scenarios based on field and bench tests.The results show that the proposed energy management algorithm can effectively improve fuel economy.展开更多
With the rapid expansion of the global motor vehicle population,the transportation sector has taken up a growing proportion among all the carbon dioxide emissionrelated sectors.To contribute to solutions of the carbon...With the rapid expansion of the global motor vehicle population,the transportation sector has taken up a growing proportion among all the carbon dioxide emissionrelated sectors.To contribute to solutions of the carbon dioxide-oriented problem in transportation,this paper proposes the“ALL FREE”concept that applies partial oxidation process instead of the conventional complete oxidation to vehicle engines.In such an engine,the fuels are partially oxidized into corresponding chemical products,which,as a result,enable the process to be theoretically free of CO_(2),while the heat output of the partial oxidation could drive the vehicle.On the other hand,the resulting products are of great value,which could decrease or even counteract the cost of fuels in transportation.In this paper,the thermodynamic and kinetic data(e.g.,the heat output and heat release rate)of five selected partial oxidation reactions were calculated at length to demonstrate and exemplify the theoretical feasibility of the“ALL FREE”concept.It turned out that the partial oxidation of n-butane to maleic anhydride has the most potential to meet the basic requirements of this concept.To sum up,this design concept is of significant application potential for the reduction of CO_(2)emissions in the transportation industry,although there remain many technical challenges.展开更多
The diffusion of new energy vehicles(NEVs),such as battery electric vehicles(BEVs)and fuel cell vehicles(FCVs),is critical to the transportation sector's deep decarbonization.The cost of energy chains is an import...The diffusion of new energy vehicles(NEVs),such as battery electric vehicles(BEVs)and fuel cell vehicles(FCVs),is critical to the transportation sector's deep decarbonization.The cost of energy chains is an important factor in the diffusion of NEVs.Although researchers have addressed the technological learning effect of NEVs and the life cycle emissions associated with the diffusion of NEVs,little work has been conducted to analyze the life cycle costs of different energy chains associated with different NEVs in consideration of technological learning potential.Thus,relevant information on investment remains insufficient to promote the deployment of NEVs.This study proposes a systematic framework that includes various(competing or coordinated)energy chains of NEVs formed with different technologies of power generation and transmission,hydrogen production and transportation,power-to-liquid fuel,and fuel transportation.The levelized costs of three typical carbon-neutral energy chains are investigated using the life cycle cost model and considering the technological learning effect.Results show that the current well-to-pump levelized costs of the energy chains in China for BEVs,FCVs,and internal combustion engine vehicles(ICEVs)are approximately 3.60,4.31,and 2.21 yuan/GJ,respectively,and the well-to-wheel levelized costs are 4.50,6.15,and 7.51 yuan/GJ,respectively.These costs primarily include raw material costs and they vary greatly for BEVs and FCVs from resource and consumer costs.In consideration of the technological learning effect,the energy chains'well-to-wheel levelized costs are expected todecrease by 24.82%for BEVs,27.12%for FCVs,and 19.25%for ICEVs by 2060.This work also summarizes policy recommendations on developing energy chains to promote the diffusion of NEVs in China.展开更多
A new law on vehicle tax, to encourage the use of smaller engines to reduce pollution and oil dependence by collecting tax on the basis of engine capacity, is under consideration.
Ⅰ. Briefing domestic vehicle diesel engines Before the 1970s, domestic vehicle diesel engines were mainly applied to heavy vehicles, while medium and light vehicles were powered chiefly with gasoline engines.
Thanks to the import of various engine and advanced manufacturing technology from abroad, China’s vehicle engine sector has devel-oped into a one with higher technological and manufacturing levels. The dynamic property,
In view of the existence of uncertainties such as system model and disturbance signal in the electric power steering(EPS) sys-tem,and the demand for system dynamic performance,the mixed H2/H∞ controller based on gene...In view of the existence of uncertainties such as system model and disturbance signal in the electric power steering(EPS) sys-tem,and the demand for system dynamic performance,the mixed H2/H∞ controller based on genetic algorithm is proposed.In order to obtain satisfactory steering feel,robust performance and steering stability,models of EPS system and a two-degree-of-freedom car are set up,then the state space model and the augmented matrixes are built.The H∞ method is introduced to minimize the effect of disturbances on the outputs,and the H2 method is applied to optimizing the system performance based on genetic algorithm.The simulation results show that the modified mixed H2/H∞ controller,which synthesizes the advantage of H2 control and H∞ control,has better robust performance and robust stability.The designed controller can attenuate the noises and disturbances caused by road random motivation,torque sensor measurement and model parameter uncertainty,ena-bling the driver to obtain satisfactory road feel.展开更多
As one of the critical issues in operations management, spare parts planning classification systems based only on cost may not withstand the test of time because of continuing technological advancement or environmenta...As one of the critical issues in operations management, spare parts planning classification systems based only on cost may not withstand the test of time because of continuing technological advancement or environmental degradation. This study, however, emphasizes using failure mode effect and criticality analysis(FMECA) as a basis for designing an ABC classification system that is capable of more accurately determining critical equipment and making maintenance more efficient. In the proposed methodology, risk priority numbers(RPN) and criticality as an index of safety and reliability can be obtained using a structured failure analysis technique. These indexes can be added to the economic indicator of maintenance cost, and then a classification model of spare parts can be established according to a comprehensive scoring method. The model is calibrated by using case data from a bus braking system, and the components of the braking system are compared and analyzed. The results show that the improved ABC classification method reduces the proportion of key and main components. This method can make maintenance work more efficient, targeting the most critical components, and can reduce administrative costs for enterprises.展开更多
The seat-cabin system of fork lift trucks has a great influence on ride comfort.On the basis of the structure and characteristics of the seat-cabin system for a high-grade fork lift truck,a seat-cabin system vertical ...The seat-cabin system of fork lift trucks has a great influence on ride comfort.On the basis of the structure and characteristics of the seat-cabin system for a high-grade fork lift truck,a seat-cabin system vertical dynamic model was created.The vertical dynamic responses of the model under the random irregularities excitation were calculated.The calculated responses including the seat dynamic response and the cabin dynamic responses at the four corners are very close to the field measurement data and the relative deviations of the(root mean square)RMS acceleration responses are all less than 6.0%.The results show that the vertical dynamic model is acceptable and can truly describe the basic mechanical behavior of the seat-cabin system.The model provides a good basis for investigating the relations between the dynamic parameters and the vibration attenuation characteristics of the seat-cabin system to further improve ride comfort.展开更多
基金supported by Postgraduate Education and Teaching Reform Project of Harbin Institute of Technology(JGYJ-2019038)Postgraduate Education and Teaching Reform Project of Harbin Institute of Technology at Weihai(WH2019010)Teaching Research Project of Harbin Institute of Technology at Weihai(BKQN201905).
文摘Under the background of"Outstanding Engineer Education and Training Program"and ideology and politics teaching in course,it has become a training goal for colleges and universities to cultivate an engineer with both political integrity and talent.However,it is necessary for colleges and universities to explore and practice how to combine the two skillfully without being abrupt and make students accept them.From the point of view of vehicle engineering experiment course and combining with the current situation of university teaching,this paper makes an in-depth exploration and practice on the ideological and political reform on vehicle engineering experiment course.
基金supported by Postgraduate Education and Teaching Reform Project of Harbin Institute of Technology(JGYJ-2019038)Postgraduate Education and Teaching Reform Project of Harbin Institute of Technology at Weihai(WH2019010)Teaching Research Project of Harbin Institute of Technology at Weihai(BKQN201905).
文摘In view of the problem of the teaching effect of the vehicle specialty courses,this paper analyzes the training objectives of the courses,determines the teaching contents and relevant teaching methods,and provides specific teaching measures to improve the students'ability to solve practical problems and employment ability,so as to cultivate the application-oriented talents with innovation ability and practical ability that meet the needs of the society.
文摘Under the situation of actively constructing the education pattern of ideological and political courses in our country,talents with excellent professional quality and excellent ideological and moral quality have become the training goal of current college education.However,what way should be adopted to better integrate ideological and political education with professional knowledge education will be the answer that colleges and universities need to constantly explore.This paper starts from the professional courses of vehicle engineering,combined with the current situation of China's automobile industry,to study practical reform methods,construct the pattern of whole curriculum education.
基金supported by Henan Polytechnic University Education Teaching Reform Research Projects(No.2015JG034)
文摘In order to overcome the limitation of vehicle engineering professional laboratory personnel and facilities,some of them is commonly used auxiliary software in the professional field for design,calculation and research,including characteristics of software,application scope and methods are presented in this paper.Through these industries aided software powerful calculation,analysis functions and convenient visualization means,for the virtual simulation experiment,it can help to clearly illustrate the concept,deepen students' understanding level of vehicle professional course,improve the enthusiasm of the students,improve the ability of autonomous learning and improve students ' thinking ability and practice ability,and can effectively train highquality professionals with good quality.
文摘New energy vehicles represent the inevitable trend of future development.Compared to traditional fuel vehicles,they are more energy-saving and environmentally friendly,effectively reducing air pollution and mitigating excessive exploitation of oil resources,a stance strongly supported by governments.However,new energy vehicles possess certain drawbacks in terms of price and usability compared to traditional counterparts.Therefore,external support is imperative for their development.This paper delineates four main sections:the background of new energy vehicle promotion and application,a comparative analysis of domestic and foreign promotion models,specific promotion suggestions,and future development prospects.By leveraging insights from economic analysis,the optimal promotion model for new energy vehicles is elucidated.
基金This research was funded by College Student Innovation and Entrepreneurship Training Program,Grant Number 2021055Z and S202110082031the Special Project for Cultivating Scientific and Technological Innovation Ability of College and Middle School Students in Hebei Province,Grant Number 2021H011404.
文摘Aiming at the problems of low target image resolution,insufficient target feature extraction,low detection accuracy and poor real time in remote engineering vehicle detection,an improved CenterNet target detection model is proposed in this paper.Firstly,EfficientNet-B0 with Efficient Channel Attention(ECA)module is used as the basic network,which increases the quality and speed of feature extraction and reduces the number of model parameters.Then,the proposed Adaptive Fusion Bidirectional Feature Pyramid Network(AF-BiFPN)module is applied to fuse the features of different feature layers.Furthermore,the feature information of engineering vehicle targets is added by making full use of the high-level semantic and low-level fine-grained feature information of the target,which overcomes the problem that the original CenterNet network did not perform well in small target detection and improve the detection accuracy of the network.Finally,the tag coding strategy and bounding box regression method of CenterNet are optimized by introducing positioning quality loss.The accuracy of target prediction is increased by joint prediction of center position and target size.Experimental results show that the mean Average Precision(mAP)of the improved CenterNet model is 94.74%on the engineering vehicle dataset,and the detection rate is 29 FPS.Compared with the original CenterNet model based on ResNet-18,the detection accuracy of this model is improved by 16.29%,the detection speed is increased by 9 FPS,and the memory usage is reduced by 43 MB.Compared with YOLOv3 and YOLOv4,the mAP of this model is improved by 19.9%and 5.61%respectively.The proposed method can detect engineering vehicles more quickly and accurately in far distance.It has obvious advantages in target detection compared with traditional methods.
文摘New energy vehicles have better clean and environmental protection characteristics than traditional fuel vehicles.The new energy engine cooling technology is critical in the design of new energy vehicles.This paper used oneand three-way joint simulation methods to simulate the refrigeration system of new energy vehicles.Firstly,a k-εturbulent flow model for the cooling pump flow field is established based on the principle of computational fluid dynamics.Then,the CFD commercial fluid analysis software FLUENT is used to simulate the flow field of the cooling pump under different inlet flow conditions.This paper proposes an optimization scheme for new energy vehicle engines’“boiling”phenomenon under high temperatures and long-time climbing conditions.The simulation results show that changing the radiator’s structure and adjusting the thermostat’s parameters can solve the problem of a“boiling pot.”The optimized new energy vehicle engine can maintain a better operating temperature range.The algorithm model can reference each cryogenic system component hardware selection and control strategy in the new energy vehicle’s engine.
文摘In order to study the influence of thermal deformation of long-span cable- stayed bridge (LSCSB) on the dynamic characteristics of metro vehicle on the bridge, based on the theory of vehicle-track coupled dynamics, the rigid-flexible coupled dynamic model of metro vehicle-track-LSCSB system is established by using finite element method and multi-rigid-body dynamics. Adopting this model, the deformation of LSCSB subject to temperature is analyzed, then the comprehensive effect of track random irregularity and rail deformation caused by temperature load is considered to study the dynamic characteristics of metro vehicle running through the bridge, and finally the influences of temperature increment and running speed on concerned dynamic indices of vehicle are studied. The results show that the LSCSB deforms obviously subject to temperature load, and the overall performance is that the cooling is arched, and the heating is bent, and the shape variable changes almost linearly with the temperature load. According to the parameters studied in this paper, the rail deformation caused by temperature load increases the wheel-rail vertical force, derailment coefficient and wheel load reduction rate by 1.5%, 3.1% and 5% respectively. The vertical acceleration of the vehicle body decreases by 2.4% under the cooling condition, while increases by 3.7% under the heating condition. The dynamic response of the bridge changes under temperature load. The maximum vertical and horizontal displacement in the middle of the main beam span are 6.24 mm and 2.19 mm respectively, and the maximum vertical and horizontal acceleration are 1.29 cm/s<sup>2</sup> and 2.54cm/s<sup>2</sup> respectively. The derailment coefficient and vertical acceleration of vehicle body are more affected by temperature load, and the wheel load reduction rate and wheel-rail vertical force are more affected by speed. The conclusion of this paper provides a reference for subsequent scholars to study the influence of thermal deformation on the dynamic response of vehicles on LSCSB.
基金Sponsored by the National Science and Technology Support Program of China(Grant No.2011BAG02B02)
文摘Full frontal impact theory needs researching and exploring to satisfy the primary safety design of occupant restraint system,avoiding the increasingly "engineering"trend in order to develop and design safety vehicle. After occupant restraint system is simulated by using linear elastic stiffness k,the occupant-vehicle frontal rigid barrier impact model is established. Dynamic equation of dummy chest coupling vehicle is built for full frontal impact based on ordinary vehicle deceleration by Hooke law,and the equation is solved by comparing coefficient and satisfying boundary qualifications. While relative vehicle characteristic parameters are kept unchanging,the actual vehicle deceleration is fitted to the simplified equivalent square wave( ESW),tipped equivalent square wave( TESW) and equivalent dual trapezoids wave( EDTW). Phase angle and amplitude A of dynamic equations based on ESW,TESW and EDTW are calculated and deduced. The results show that: the dynamic equation of dummy chest coupling vehicle can be well utilized to instruct the primary safety design of full frontal impact for objective vehicle to satisfy chest deceleration demands and the equation based on TESW is best for this design.
基金National Natural Science Foundation of China(Grant No.51375202)National Natural science fund project(Grant No.51265020)Jilin Province Science and Technology Development Project(No.20160101285JC).
文摘Engineering vehicles are widely used under various harsh working conditions.For many components in them,service loadings they suffered are usually random and nonstationary due to their remarkable characteristic called cyclic operation.To deal with that,section method can be applied.However,this method will neglect those transition cycles caused by switching load section,which can contribute a lot to fatigue.In order to consider those transition cycles,this paper applied the model called“Switching Markov Chain of Turning Points”(SMCTP).Then the expected rain-flow matrix is compared with the overall rain-flow matrix conducted by section method.The comparison result shows that SMCTP can perform well in processing nonstationary loadings.As a result,the Switching Markov Chain method(SMC)was proved to be effective in stochastically characterizing the nonstationary switching loadings of engineering vehicles.
基金supported by National Natural Science Foundation of China(Grant No.52002209)Beijing Nova Program,and the State Key Laboratory of Automotive Safety and Energy(Grant No.KFY2210).
文摘This paper presents an energy management optimization system based on an adaptive functional state model of battery aging for internal combustion engine vehicles(ICEVs).First,the functional characteristics of batteries in ICEVs are investigated.Then,an adaptive functional state model is proposed to represent battery aging throughout the entire battery service life.A battery protection scheme is developed,including over-discharge and graded over-current protection to improve battery safety.A model-based energy management strategy is synthesized to comprehensively optimize fuel economy,battery life preservation,and vehicle performance.The performance of the proposed scheme was examined under comprehensive test scenarios based on field and bench tests.The results show that the proposed energy management algorithm can effectively improve fuel economy.
文摘With the rapid expansion of the global motor vehicle population,the transportation sector has taken up a growing proportion among all the carbon dioxide emissionrelated sectors.To contribute to solutions of the carbon dioxide-oriented problem in transportation,this paper proposes the“ALL FREE”concept that applies partial oxidation process instead of the conventional complete oxidation to vehicle engines.In such an engine,the fuels are partially oxidized into corresponding chemical products,which,as a result,enable the process to be theoretically free of CO_(2),while the heat output of the partial oxidation could drive the vehicle.On the other hand,the resulting products are of great value,which could decrease or even counteract the cost of fuels in transportation.In this paper,the thermodynamic and kinetic data(e.g.,the heat output and heat release rate)of five selected partial oxidation reactions were calculated at length to demonstrate and exemplify the theoretical feasibility of the“ALL FREE”concept.It turned out that the partial oxidation of n-butane to maleic anhydride has the most potential to meet the basic requirements of this concept.To sum up,this design concept is of significant application potential for the reduction of CO_(2)emissions in the transportation industry,although there remain many technical challenges.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.72131007,7214006,and 72074077)Open access funding provided by International Institute for Applied Systems Analysis(IIASA).
文摘The diffusion of new energy vehicles(NEVs),such as battery electric vehicles(BEVs)and fuel cell vehicles(FCVs),is critical to the transportation sector's deep decarbonization.The cost of energy chains is an important factor in the diffusion of NEVs.Although researchers have addressed the technological learning effect of NEVs and the life cycle emissions associated with the diffusion of NEVs,little work has been conducted to analyze the life cycle costs of different energy chains associated with different NEVs in consideration of technological learning potential.Thus,relevant information on investment remains insufficient to promote the deployment of NEVs.This study proposes a systematic framework that includes various(competing or coordinated)energy chains of NEVs formed with different technologies of power generation and transmission,hydrogen production and transportation,power-to-liquid fuel,and fuel transportation.The levelized costs of three typical carbon-neutral energy chains are investigated using the life cycle cost model and considering the technological learning effect.Results show that the current well-to-pump levelized costs of the energy chains in China for BEVs,FCVs,and internal combustion engine vehicles(ICEVs)are approximately 3.60,4.31,and 2.21 yuan/GJ,respectively,and the well-to-wheel levelized costs are 4.50,6.15,and 7.51 yuan/GJ,respectively.These costs primarily include raw material costs and they vary greatly for BEVs and FCVs from resource and consumer costs.In consideration of the technological learning effect,the energy chains'well-to-wheel levelized costs are expected todecrease by 24.82%for BEVs,27.12%for FCVs,and 19.25%for ICEVs by 2060.This work also summarizes policy recommendations on developing energy chains to promote the diffusion of NEVs in China.
文摘A new law on vehicle tax, to encourage the use of smaller engines to reduce pollution and oil dependence by collecting tax on the basis of engine capacity, is under consideration.
文摘Ⅰ. Briefing domestic vehicle diesel engines Before the 1970s, domestic vehicle diesel engines were mainly applied to heavy vehicles, while medium and light vehicles were powered chiefly with gasoline engines.
文摘Thanks to the import of various engine and advanced manufacturing technology from abroad, China’s vehicle engine sector has devel-oped into a one with higher technological and manufacturing levels. The dynamic property,
基金supported by the National Natural Science Foundation of China (Grant Nos.51005115 and 51005248)the Science Fund of State Key Laboratory of Automotive Safety and Energy (Grant No.KF11201)
文摘In view of the existence of uncertainties such as system model and disturbance signal in the electric power steering(EPS) sys-tem,and the demand for system dynamic performance,the mixed H2/H∞ controller based on genetic algorithm is proposed.In order to obtain satisfactory steering feel,robust performance and steering stability,models of EPS system and a two-degree-of-freedom car are set up,then the state space model and the augmented matrixes are built.The H∞ method is introduced to minimize the effect of disturbances on the outputs,and the H2 method is applied to optimizing the system performance based on genetic algorithm.The simulation results show that the modified mixed H2/H∞ controller,which synthesizes the advantage of H2 control and H∞ control,has better robust performance and robust stability.The designed controller can attenuate the noises and disturbances caused by road random motivation,torque sensor measurement and model parameter uncertainty,ena-bling the driver to obtain satisfactory road feel.
基金supported by the Opening Project of the Key Laboratory of Operation Safety Technology on Transportation Vehicles,Ministry of Transport,PRC (No.KFKT2016-03)the Basic Science Research Plan of Shaanxi Province (No.2020JM225)the Fundamental Research Funds for the Central Universities (No.310822173702)。
文摘As one of the critical issues in operations management, spare parts planning classification systems based only on cost may not withstand the test of time because of continuing technological advancement or environmental degradation. This study, however, emphasizes using failure mode effect and criticality analysis(FMECA) as a basis for designing an ABC classification system that is capable of more accurately determining critical equipment and making maintenance more efficient. In the proposed methodology, risk priority numbers(RPN) and criticality as an index of safety and reliability can be obtained using a structured failure analysis technique. These indexes can be added to the economic indicator of maintenance cost, and then a classification model of spare parts can be established according to a comprehensive scoring method. The model is calibrated by using case data from a bus braking system, and the components of the braking system are compared and analyzed. The results show that the improved ABC classification method reduces the proportion of key and main components. This method can make maintenance work more efficient, targeting the most critical components, and can reduce administrative costs for enterprises.
文摘The seat-cabin system of fork lift trucks has a great influence on ride comfort.On the basis of the structure and characteristics of the seat-cabin system for a high-grade fork lift truck,a seat-cabin system vertical dynamic model was created.The vertical dynamic responses of the model under the random irregularities excitation were calculated.The calculated responses including the seat dynamic response and the cabin dynamic responses at the four corners are very close to the field measurement data and the relative deviations of the(root mean square)RMS acceleration responses are all less than 6.0%.The results show that the vertical dynamic model is acceptable and can truly describe the basic mechanical behavior of the seat-cabin system.The model provides a good basis for investigating the relations between the dynamic parameters and the vibration attenuation characteristics of the seat-cabin system to further improve ride comfort.
