环球扫描

美国再投4800万助推环保汽车发展 为提高燃油效率、降低交通成本、保护环境,美国政府将再次投入4800万美元资金,对38个汽车技术研发项目进行支持。美国能源部长欧内斯特·莫尼兹表示,通过与大学、私营企业、国家实验室合作,美国能源部致力于建设强大的交通运输部门,此举不仅削减有害排放,创造就业机会,还有助于美国走向可持续的能源未来。     

机动车碳排放管理国际经验与启示

随着机动车保有量的快速增长,机动车已成为CO2排放最重要和增长最快的领域之一.美国、欧盟、日本等主要经济体研究制定了机动车CO2排放标准及管理制度,对有效降低机动车CO2排放发挥了重要作用.本文通过梳理国外机动车碳排放管理经验,针对我国机动车CO2排放标准及管理体系不健全、温室气体与大气污染物管控缺乏有效协同、现有油耗...     

On-road pollutant emission and fuel consumption characteristics of buses in Beijing

On-road emission and fuel consumption (FC) levels for Euro III and IV buses fueled on diesel and compressed natural gas (CNG) were compared, and emission and FC characteristics of buses were analyzed based on approximately 28,700 groups of instantaneous data obtained in Beijing using a portable emissions measurement system (PEMS). The experimental results revealed that NOx and PM emissions from CNG buses were decreased by 72.0% and 82.3% respectively, compared with Euro IV diesel buses. Similarly, these emissions were reduced by 75.2% and 96.3% respectively, compared with Euro III diesel buses. In addition, CO2, CO, HC, NOx, PM emissions and FC of Euro IV diesel buses were reduced by 26.4%, 75.2%, 73.6%, 11.4%, 79.1%, and 26.0%, respectively, relative to Euro III diesel buses. The CO2, CO, HC, NOx, PM emissions and FC factors all decreased with bus speed increased, while increased as bus acceleration increased. At the same time, the emission/FC rates as well as the emission/FC factors exhibited a strong positive correlation with the vehicle specific power (VSP). They all were the lowest when VSP < 0, and then rapidly increased as VSP increased. Furthermore, both the emission/FC rates and emission/FC factors were the highest at accelerations, higher at cruise speeds, and the lowest at decelerations for non-idling buses. These results can provide a base reference to further estimate bus emission and FC inventories in Beijing.     

材料声学特性的典型参数测试技术研究进展

吸声系数和隔声量是描述材料声学特性的典型参数,首先分析了材料吸声系数和隔声量测试技术的研究意义,指出提高材料吸声系数和隔声量测试技术符合我国先进武器装备的发展需求。梳理了国内外吸声系数和隔声量的主要实验室测试方法及标准,具体介绍了阻抗管法、混响室法、Alpha舱法测量材料吸声系数,阻抗管法、混响室-混响室法、混响室-消声室法、Alpha舱法测量材料隔声量的研究进展,分析了各种测试方法的优缺点,最后展望了该领域的发展趋势。