Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)...Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)_2CO_(3))as an efficient CO_(2)NO_(3)RR electrocatalyst with an impressive urea Faradaic efficiency of45.2%±2.1%and a high yield rate of 1564.5±145.2μg h~(-1)mg_(cat)~(-1).More importantly,H_(2) evolution is fully inhibited on this electrocatalyst over a wide potential range between-0.3 and-0.8 V versus reversible hydrogen electrode.Our thermodynamic simulation reveals that the first C-N coupling follows a unique pathway on Cu_2(OH)_2CO_(3) by combining the two intermediates,~*COOH and~*NHO.This work demonstrates that high selectivity and yield rate of urea can be simultaneously achieved on simple Cu-based electrocatalysts in CO_(2)NO_(3)RR,and provide guidance for rational design of more advanced catalysts.展开更多
Dear Editor,This letter deals with a real-world problem regarding chaotic time series prediction, where a driver-centric velocity prediction model is presented for vehicle intelligent control and advanced driver assis...Dear Editor,This letter deals with a real-world problem regarding chaotic time series prediction, where a driver-centric velocity prediction model is presented for vehicle intelligent control and advanced driver assistance,i.e., multi-dimension fuzzy predictor. Inspired by fuzzy granulation technology, a finite-state Markov chain(MC) is reinforced to capture probabilities of the transitions between velocity and acceleration and present signals that vary in a continuous range.展开更多
The work presented in this paper is a progression to previous research which developed an overcurrent-tolerant prediction model. This paper presents some of the modelling and development techniques used for the previo...The work presented in this paper is a progression to previous research which developed an overcurrent-tolerant prediction model. This paper presents some of the modelling and development techniques used for the previous research, but more emphasis is placed on the requirements of the case study;whereby an aeroplane pushback tug is converted into a series Hybrid Electric Vehicle (HEV). An iterative design process enabled the traction motor, transmission, generator and battery pack parameters to be tailored for this vehicle’s unique duty cycle. A MATLAB/Simulink model was developed to simulate the existing internal combustion engine powertrain as well as the series HEV equivalent for comparative analysis and validation purposes. The HEV design was validated by comparing the simulation results to recorded real-world data collected from the existing vehicle (torque, speeds etc.). The HEV simulations provided greater fuel savings and reduced emissions over the daily duty cycle in comparison to the existing vehicle.展开更多
Gasoline direct injection(GDI)engines are currently the dominant powertrains for passenger cars.With the implementation of increasingly stringent fuel consumption and emission regulationsworldwide,GDI engines are faci...Gasoline direct injection(GDI)engines are currently the dominant powertrains for passenger cars.With the implementation of increasingly stringent fuel consumption and emission regulationsworldwide,GDI engines are facing challenges owing to high particulate matter emissions and a tendency to knock,leading to a change in the research and design(R&D)issues compared with those in the twentieth century.This paper reviews the progress in research regarding GDI engine technologies over the past 20 years,focusing on combustion system configurations,and also highlights common issues in GDI R&D,including pre-ignition and deto-knock,soot formation and PM emissions,injector deposits and gasoline compression ignition(GCI).First,an overview of recent developments in the field as driven by regulations is provided,following which progress in injection and combustion systems is examined.Third,the review addresses the occurrence and mechanism of deto-knock and considers means of suppressing this phenomenon.The fourth section discusses soot formation mechanisms and particulate matter emission characteristics of GDI engines and describes the application of gasoline particulate filter(GPF)after-treatment.The subsequent section summarizes studies regarding injector deposit formation,as well as pioneering research into GCI combustion modes.Finally,a summary and future prospects for GDI engine technologies are provided.展开更多
Biofuels have extensive available resources and have an immense potential as promising alternative fuels for automobile.The application advantages of biofuels are mainly reflected as particulate matter(PM)reduction,ca...Biofuels have extensive available resources and have an immense potential as promising alternative fuels for automobile.The application advantages of biofuels are mainly reflected as particulate matter(PM)reduction,carbon neutral,greenhouse gases reduction,waste utilization,energy and economic security,and fuel pluralism.Based on the understanding of molecular structure effects of biofuels on soot formation and particles morphology,the effects of alcohols,ethers,esters and biodiesel on spray and combustion process in constant volume bomb in recent years are retrospectively analyzed in this paper.For the mixture,macromolecular ester fuels and polyoxymethylene dimethyl ether(PODE)are conducive to the improvement of liquid spray,while biodiesel,small molecules,dimethyl ether(DME)and alcohols are reversed.Alcohols are advantageous to the extension of mixing time and the increasing of vapor-phase mixture.Through the influence integrated assessment,alcohols show the best performance on the spray,atomization and combustion,while biodiesels show the worst.But in terms of combustion,PODE is the best choice without considering spray and atomization.For binary alternative-diesel fuel blends,methanol or butanol is the best additive based on synthetically considerations on spray,atomization and combustion.To meet the requirements of the fuel application of diesel engine,ternary fuel or even quaternary fuel have been proposed and explored.This review can help to form a systematic understanding on fuel recombining and obtain the guide of clean and efficient fuel formulation for diesel engine.展开更多
In the usage phase,diesel engines fuelled with diesel-biodiesel blends produced lower soot,HC and CO emissions.However,the environmental effects should include the greenhouse gas(GHG)emissions.GHG variations of biodie...In the usage phase,diesel engines fuelled with diesel-biodiesel blends produced lower soot,HC and CO emissions.However,the environmental effects should include the greenhouse gas(GHG)emissions.GHG variations of biodiesel production from three generation feedstocks were analyzed based on the land use change(LUC).Adequate land use change could keep the biodiversity and did not cause the increase of GHG emissions.The choice for feedstocks of biodiesel in China was comprehensively analyzed based on the land use type,the precipitation and the oil contents and the cultivation conditions of plants.Then,the suggestions for biodiesel development in China were given.Results showed that China should thoroughly abandon the first generation feedstocks due to the lack of arable land.Jatropha curcas(J.curcas),Pistacia chinensis Bunge(P.chinensis),Comus wilsoniana(C.wilsoniana)and Xanthoceras sorbifolium Bunge(X.sorbifolium)were considered as the most promising feedstocks for biodiesel production.It is suggested to plant X.sorbifolium in sand lands in the north and northwest of China with less natural rainfall and the others in south and southwest of China.The concern for microalgae should be transmitted to engineering microalgae cultivated in wastewater.The microalgae biodiesel refinery should be developed together with wastewater proposal industry and coal fired power plants.Lastly,only natural gas-based or biomass-based methanol can be used for biodiesel production.展开更多
Injection-induced rail pressure fluctuations are proven to cause nonuniform spray development.These fluctuations are also responsible for generating lower injection pressures,to the detriment of jet penetration length...Injection-induced rail pressure fluctuations are proven to cause nonuniform spray development.These fluctuations are also responsible for generating lower injection pressures,to the detriment of jet penetration length and break-up timing.Despite the vast literature dealing with such issues,several aspects of rail pressure fluctuations remain unclear.Additionally,the need for compliance with the emission legislation has shed light on the potential of alternative fuels,which represent a pathway for sustainable mobility.This scenario has motivated the present study dealing with the assessment of the time history of rail pressure correlated with fuel properties.Tests have been performed using a last-generation common rail injection equipment under various injection settings,employing diesel and 2-methylfuran-diesel blend.This paper describes the research activity and aims to provide new insights into the correlation of rail pressure fluctuations with fuel properties.展开更多
基金supported by the Research Grants Council(26206115,16304821 and 16309418)the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(SMSEGL20SC01)+2 种基金the Innovation and Technology Commission(grant no.ITC-CNERC14EG03)of the Hong Kong Special Administrative Regionthe Hong Kong Postdoctoral Fellowship Scheme(HKUST PDFS2021-4S12 and HKUST PDFS2021-6S08)the support from the Shenzhen fundamental research funding(JCYJ20210324115809026,20200925154115001,JCYJ20200109141216566)。
文摘Urea generation through electrochemical CO_(2) and NO_(3)~-co-reduction reaction(CO_(2)NO_(3)RR)is still limited by either the low selectivity or yield rate of urea.Herein,we report copper carbonate hydroxide(Cu_2(OH)_2CO_(3))as an efficient CO_(2)NO_(3)RR electrocatalyst with an impressive urea Faradaic efficiency of45.2%±2.1%and a high yield rate of 1564.5±145.2μg h~(-1)mg_(cat)~(-1).More importantly,H_(2) evolution is fully inhibited on this electrocatalyst over a wide potential range between-0.3 and-0.8 V versus reversible hydrogen electrode.Our thermodynamic simulation reveals that the first C-N coupling follows a unique pathway on Cu_2(OH)_2CO_(3) by combining the two intermediates,~*COOH and~*NHO.This work demonstrates that high selectivity and yield rate of urea can be simultaneously achieved on simple Cu-based electrocatalysts in CO_(2)NO_(3)RR,and provide guidance for rational design of more advanced catalysts.
文摘Dear Editor,This letter deals with a real-world problem regarding chaotic time series prediction, where a driver-centric velocity prediction model is presented for vehicle intelligent control and advanced driver assistance,i.e., multi-dimension fuzzy predictor. Inspired by fuzzy granulation technology, a finite-state Markov chain(MC) is reinforced to capture probabilities of the transitions between velocity and acceleration and present signals that vary in a continuous range.
文摘The work presented in this paper is a progression to previous research which developed an overcurrent-tolerant prediction model. This paper presents some of the modelling and development techniques used for the previous research, but more emphasis is placed on the requirements of the case study;whereby an aeroplane pushback tug is converted into a series Hybrid Electric Vehicle (HEV). An iterative design process enabled the traction motor, transmission, generator and battery pack parameters to be tailored for this vehicle’s unique duty cycle. A MATLAB/Simulink model was developed to simulate the existing internal combustion engine powertrain as well as the series HEV equivalent for comparative analysis and validation purposes. The HEV design was validated by comparing the simulation results to recorded real-world data collected from the existing vehicle (torque, speeds etc.). The HEV simulations provided greater fuel savings and reduced emissions over the daily duty cycle in comparison to the existing vehicle.
基金The authors acknowledge theChina NationalNat-ural Science Foundation Project“Formation and Evolution of PM from GDI Engines:From Primary Particles to Secondary Aerosols”(Grant No.51636003)the National Key R&D Plan Project“Integration Technology of PM Capture and Clean Emissions for GDI Vehicles”(Grant No.2017YFC02110004).
文摘Gasoline direct injection(GDI)engines are currently the dominant powertrains for passenger cars.With the implementation of increasingly stringent fuel consumption and emission regulationsworldwide,GDI engines are facing challenges owing to high particulate matter emissions and a tendency to knock,leading to a change in the research and design(R&D)issues compared with those in the twentieth century.This paper reviews the progress in research regarding GDI engine technologies over the past 20 years,focusing on combustion system configurations,and also highlights common issues in GDI R&D,including pre-ignition and deto-knock,soot formation and PM emissions,injector deposits and gasoline compression ignition(GCI).First,an overview of recent developments in the field as driven by regulations is provided,following which progress in injection and combustion systems is examined.Third,the review addresses the occurrence and mechanism of deto-knock and considers means of suppressing this phenomenon.The fourth section discusses soot formation mechanisms and particulate matter emission characteristics of GDI engines and describes the application of gasoline particulate filter(GPF)after-treatment.The subsequent section summarizes studies regarding injector deposit formation,as well as pioneering research into GCI combustion modes.Finally,a summary and future prospects for GDI engine technologies are provided.
基金supported by the Key Research and Development Program of Shaanxi Province(2019ZDLGY15-07)the National Natural Science Foundation of China(51806020)+1 种基金the Youth Innovation Team of Shaanxi Universities(Energy Saving and New Energy Vehicles)the Special Fund for Basic Scientific Research of Central Colleges,Chang’an University(300102229104)。
文摘Biofuels have extensive available resources and have an immense potential as promising alternative fuels for automobile.The application advantages of biofuels are mainly reflected as particulate matter(PM)reduction,carbon neutral,greenhouse gases reduction,waste utilization,energy and economic security,and fuel pluralism.Based on the understanding of molecular structure effects of biofuels on soot formation and particles morphology,the effects of alcohols,ethers,esters and biodiesel on spray and combustion process in constant volume bomb in recent years are retrospectively analyzed in this paper.For the mixture,macromolecular ester fuels and polyoxymethylene dimethyl ether(PODE)are conducive to the improvement of liquid spray,while biodiesel,small molecules,dimethyl ether(DME)and alcohols are reversed.Alcohols are advantageous to the extension of mixing time and the increasing of vapor-phase mixture.Through the influence integrated assessment,alcohols show the best performance on the spray,atomization and combustion,while biodiesels show the worst.But in terms of combustion,PODE is the best choice without considering spray and atomization.For binary alternative-diesel fuel blends,methanol or butanol is the best additive based on synthetically considerations on spray,atomization and combustion.To meet the requirements of the fuel application of diesel engine,ternary fuel or even quaternary fuel have been proposed and explored.This review can help to form a systematic understanding on fuel recombining and obtain the guide of clean and efficient fuel formulation for diesel engine.
基金supported by the Key Research and Development Program of Shaanxi Province(2019ZDLGY15-07)the Youth Innovation Team of Shaanxi Universities,and National Engineering Laboratory for Mobile Source Emission Control Technology(NELMS2017B02)。
文摘In the usage phase,diesel engines fuelled with diesel-biodiesel blends produced lower soot,HC and CO emissions.However,the environmental effects should include the greenhouse gas(GHG)emissions.GHG variations of biodiesel production from three generation feedstocks were analyzed based on the land use change(LUC).Adequate land use change could keep the biodiversity and did not cause the increase of GHG emissions.The choice for feedstocks of biodiesel in China was comprehensively analyzed based on the land use type,the precipitation and the oil contents and the cultivation conditions of plants.Then,the suggestions for biodiesel development in China were given.Results showed that China should thoroughly abandon the first generation feedstocks due to the lack of arable land.Jatropha curcas(J.curcas),Pistacia chinensis Bunge(P.chinensis),Comus wilsoniana(C.wilsoniana)and Xanthoceras sorbifolium Bunge(X.sorbifolium)were considered as the most promising feedstocks for biodiesel production.It is suggested to plant X.sorbifolium in sand lands in the north and northwest of China with less natural rainfall and the others in south and southwest of China.The concern for microalgae should be transmitted to engineering microalgae cultivated in wastewater.The microalgae biodiesel refinery should be developed together with wastewater proposal industry and coal fired power plants.Lastly,only natural gas-based or biomass-based methanol can be used for biodiesel production.
基金The present work is part of a 3-year research project sponsored by the Engineering and Physical Sciences Research Council(EPSRC)under Grant EP/N021746/1 and the National Natural Science Foundation of China(NSFC)under Grant 51.
文摘Injection-induced rail pressure fluctuations are proven to cause nonuniform spray development.These fluctuations are also responsible for generating lower injection pressures,to the detriment of jet penetration length and break-up timing.Despite the vast literature dealing with such issues,several aspects of rail pressure fluctuations remain unclear.Additionally,the need for compliance with the emission legislation has shed light on the potential of alternative fuels,which represent a pathway for sustainable mobility.This scenario has motivated the present study dealing with the assessment of the time history of rail pressure correlated with fuel properties.Tests have been performed using a last-generation common rail injection equipment under various injection settings,employing diesel and 2-methylfuran-diesel blend.This paper describes the research activity and aims to provide new insights into the correlation of rail pressure fluctuations with fuel properties.