针对某2级增压车用柴油机的废气再循环(exhaust gas recirculation,EGR)系统,试验研究不同EGR率对发动机经济性和排放性的影响,以及利用EGR实现进气旁通后对发动机性能的影响。试验结果表明:随着EGR率升高,柴油机燃油消耗率和噪声降低;...针对某2级增压车用柴油机的废气再循环(exhaust gas recirculation,EGR)系统,试验研究不同EGR率对发动机经济性和排放性的影响,以及利用EGR实现进气旁通后对发动机性能的影响。试验结果表明:随着EGR率升高,柴油机燃油消耗率和噪声降低;排气温度升高,有助于提高选择性催化还原后处理效率;降低缸内压力,可以提高发动机可靠性。随着EGR率升高,NO x和HC排放明显减低,但会导致CO和烟度排放升高;EGR率低于23%时,CO和烟度排放升高缓慢,EGR率高于23%时,CO和烟度排放升高趋势明显。超低排放发动机应选择高EGR系统,当中冷后进气压力比涡前排气压力高时,EGR阀可作为旁通阀,将进气旁通到增压器涡端,提高增压器的效率和发动机缸内进气量,增加低速时的过量空气系数和低速扭矩。展开更多
Resettlement is considered a major policy measure in two major Chinese policy programs,the "Great Development of the West" and poverty alleviation in the new century,and the "New Countryside Development...Resettlement is considered a major policy measure in two major Chinese policy programs,the "Great Development of the West" and poverty alleviation in the new century,and the "New Countryside Development".The selection of the target location of resettlement sites for poverty-stricken villages is of critical importance to the success of resettlement projects,yet the selection process is challenged by the need for analyzing a variety of contributing factors,and the need for many rounds of tedious data processing.So in this paper we present an in-depth analysis of the major factors and data processing model concerning mountainous povertystricken villages,which also takes a major part of China's poor villages.Our analysis shows the following factors bear the most importance in resettlement selection:1) topography:candidate areas should have slope less than 25 degrees and altitude less than 2400 meters.2) accessibility:close to market conventions places and transportation facilities.3) farming resources:with abundant land and water resources.4) non-intrusiveness:interests of receiving villages should be considered and negative impact minimized.A simple measure could be having the candidate area 1000 m away from the receiving residents.5) Minimal ecological and political footprint:candidate areas shall not conflict with nature conservation areas or nationally planned key land use projects.6) Social and cultural compatibility:residents will better off if relocated in the same county,considering language,religion,ethnic culture and other factors.Taking Makuadi,Lushui County of Nujiang Prefecture as a case study,we demonstrate how GIS analysis and modeling tools can be used in the selection process of resettlement projects in mountainous areas.展开更多
基金supported by the National Natural Science Foundation of China(11974110,61974041)the ‘The Six Top Talents’ of Jiangsu Pro-vince(XCL-052)the Qing Lan Project of Jiangsu Province。
文摘针对某2级增压车用柴油机的废气再循环(exhaust gas recirculation,EGR)系统,试验研究不同EGR率对发动机经济性和排放性的影响,以及利用EGR实现进气旁通后对发动机性能的影响。试验结果表明:随着EGR率升高,柴油机燃油消耗率和噪声降低;排气温度升高,有助于提高选择性催化还原后处理效率;降低缸内压力,可以提高发动机可靠性。随着EGR率升高,NO x和HC排放明显减低,但会导致CO和烟度排放升高;EGR率低于23%时,CO和烟度排放升高缓慢,EGR率高于23%时,CO和烟度排放升高趋势明显。超低排放发动机应选择高EGR系统,当中冷后进气压力比涡前排气压力高时,EGR阀可作为旁通阀,将进气旁通到增压器涡端,提高增压器的效率和发动机缸内进气量,增加低速时的过量空气系数和低速扭矩。
基金supported by the National Natural Science Foundation of China (Grant No.40761019)National Natural Science Foundation of Yunnan (Grant No.2007D157M)
文摘Resettlement is considered a major policy measure in two major Chinese policy programs,the "Great Development of the West" and poverty alleviation in the new century,and the "New Countryside Development".The selection of the target location of resettlement sites for poverty-stricken villages is of critical importance to the success of resettlement projects,yet the selection process is challenged by the need for analyzing a variety of contributing factors,and the need for many rounds of tedious data processing.So in this paper we present an in-depth analysis of the major factors and data processing model concerning mountainous povertystricken villages,which also takes a major part of China's poor villages.Our analysis shows the following factors bear the most importance in resettlement selection:1) topography:candidate areas should have slope less than 25 degrees and altitude less than 2400 meters.2) accessibility:close to market conventions places and transportation facilities.3) farming resources:with abundant land and water resources.4) non-intrusiveness:interests of receiving villages should be considered and negative impact minimized.A simple measure could be having the candidate area 1000 m away from the receiving residents.5) Minimal ecological and political footprint:candidate areas shall not conflict with nature conservation areas or nationally planned key land use projects.6) Social and cultural compatibility:residents will better off if relocated in the same county,considering language,religion,ethnic culture and other factors.Taking Makuadi,Lushui County of Nujiang Prefecture as a case study,we demonstrate how GIS analysis and modeling tools can be used in the selection process of resettlement projects in mountainous areas.
