JS250沙滩车的排放治理

对于JS250沙滩车采用新型号化油器优化 催化剂 二次补气的排放治理方案后和原车相比,可使CO降幅62％;HC降幅61％,基本满足了欧标法规要求,此方法是国内外应用研究的少有案例。     

Impacts of traffic-flows on vehicular-exhaust emissions at traffic junctions

This paper examines the impact of traffic-flow on CO, NO₂ and PM emissions at two distinct traffic junctions and evaluates the use of emission factors. The study includes three scenarios regarding pollutant emissions, which combine a field, experimental and semi-empirically estimated traffic parameters for free, interrupted and congested traffic-flow conditions. It evaluates the emission patterns for heterogeneity in traffic characteristics of both junctions. The results suggest the corrections to be made to emission factors at traffic junctions for better forecast of air quality.     

Does traffic-related calibration of car-following models provide accurate estimations of vehicle emissions?

Fuel consumption or pollutant emissions can be assessed by coupling a microscopic traffic flow model with an instantaneous emission model. Traffic models are usually calibrated using goodness of fit indicators related to the traffic behavior. Thus, this paper investigates how such a calibration influences the accuracy of fuel consumption and NOx and PM estimations. Two traffic models are investigated: Newell and Gipps. It appears that the Gipps model provides the closest simulated trajectories when compared to real ones. Interestingly, a reverse ranking is observed for fuel consumption, NOx and PM emissions. For both models, the emissions of single vehicles are very sensitive to the calibration. This is confirmed by a global sensitivity analysis of the Gipps model that shows that non-optimal parameters significantly increase the variance of the outputs. Fortunately, this is no longer the case when emissions are calculated for a group of many vehicles. Indeed, the mean errors for platoons are close to 10% for the Gipps model and always lower than 4% for the Newell model. Another interesting property is that optimal parameters for each vehicle can be replaced by the mean values with no discrepancy for the Newell model and low discrepancies for the Gipps model when calculating the different emission outputs. Finally, this study presents preliminary results that show that multi-objective calibration methods are certainly the best direction for future works on the Gipps model. Indeed, the accuracy of vehicle emissions can be highly improved with negligible counterparts on the traffic model accuracy.     

A model for evaluating the environmental and functional benefits of “innovative” roundabouts

This study looks at the singling out of a multi-parameter criterion for choosing conventional or innovative roundabout layouts, by taking functional, environmental and economic aspects into consideration. The performances of three conventional roundabouts (with different lane number at entries and through the ring), turbo-roundabouts and roundabouts with right-turn bypass lane on all the arms (flower roundabouts) have been compared in terms of vehicle delays and pollutant (carbon dioxide, nitrogen oxides, particle pollution (PM₁₀ and PM_2.5)) emissions. By means of closed-form capacity models and with the help of COPERT IV^© software, several traffic simulations have been carried out, referred to yearly peak flow values Q_max and ranging between 1300 and 3300 veh/h, starting from a typical annual traffic demand curve in urban areas. The estimation of cumulative vehicle delays and annual pollutant emissions, together with construction and maintenance costs has allowed working out overall costs for each roundabout under consideration, depending on the traffic demand. Thus, the proposed model allows finding the most cost-effective geometric solution as to overall costs for a comprehensive case record of traffic values.     

Closed-loop Inventory Routing Problem for returnable transport items

Increasing concerns on supply chain sustainability have given birth to the concept of closed-loop supply chain. Closed-loop supply chains include the return processes besides forward flows to recover the value from the customers or end-users. Vendor Managed Inventory (VMI) systems ensure collaborative relationships between a vendor and a set of customers. In such systems, the vendor takes on the responsibility of product deliveries and inventory management at customers. Product deliveries also include reverse flows of returnable transport items. The execution of the VMI policy requires vendor to deal with a Closed-loop Inventory Routing Problem (CIRP) consisting of its own forward and backward routing decisions, and inventory decisions of customers. In CIRP literature, traditional assumptions of disregarding reverse logistic operations, knowing beforehand distribution costs between nodes and customers demand, and managing single product restrict the usage of the proposed models in current food logistics systems. From this point of view, the aim of this research is to enhance the traditional models for the CIRP to make them more useful for the decision makers in closed-loop supply chains. Therefore, we propose a probabilistic mixed-integer linear programming model for the CIRP that accounts for forward and reverse logistics operations, explicit fuel consumption, demand uncertainty and multiple products. A case study on the distribution operations of a soft drink company shows the applicability of the model to a real-life problem. The results suggest that the proposed model can achieve significant savings in total cost and thus offers better support to decision makers.     

Real world vehicle emissions: Their correlation with driving parameters

Vehicular population in developing countries is expected to proliferate in the coming decade, centred on Tier II and Tier III cities rather than large metropolis. WLTP is being introduced as a global instrument for emission regulation to reduce gap between standard test procedures and actual road conditions. This work aims at quantifying and discernment of the gap between WLTC and real-world conditions in an urban city in a developing country on the basis of driving cycle parameters and simulated emissions for gasoline fuelled light passenger cars. Real world driving patterns were recorded on different routes and varying traffic conditions using car-chasing technique integrated with GPS monitoring and speed sensors. Real-world driving patterns and ambient conditions were used to simulate emissions using International Vehicle Emissions model for average rate (g/km) and Comprehensive Modal Emissions Model for instantaneous emission (g/s) analysis. Cycle parameters were mathematically calculated to compare WLTC and road trips. The analyses revealed a large gap between WLTC and road conditions. CO emissions were predicted to be 155% higher than WLTC and HC and NOx emissions were estimated to be 63% and 64% higher respectively. These gaps were correlated to different driving cycle parameters. It was observed that road driving occurs at lower average speeds with higher frequency and magnitudes of accelerations. The positive kinetic energy required by road cycles, was 100% higher than WLTC and the Relative Positive Acceleration (RPA) demanded by road cycles, was found to be 60% higher in real-world driving patterns and thereby contribute to higher emissions.     

Modelling greenhouse gas emissions from cars in Great Britain

This paper outlines the issues involved in the problem of global warming. The road transport sector's contributions to this problem are then detailed and various policy options to reduce greenhouse gas emissions from private cars are discussed. The paper then describes a model which forecasts greenhouse gas emissions from cars. The effects of various policy options are then modelled and the results compared. Policies considered include: raising fuel prices in terms of the UK government's commitment to increase road fuel duties; subsidising public transport in terms of reduced public transport fares; and a tax differentiated by engine size.     

Abatement cost functions for incentive-based policies in the automobile market

This paper compares the outcomes of policies that target vehicle holdings with those that target vehicle usage using data from the US Consumer Expenditure Survey. Results show that a higher price of gasoline shifts vehicle holdings towards more fuel efficient vehicles and reduces the annual demand for miles, whereas imposing a fee on vehicles or a feebate program only shifts vehicle holdings towards more fuel efficient vehicles and has little to no impact on the demand for miles. While it is relatively expensive to reduce CO₂ emission through incentive-based policies, achieving any abatement level is more expensive through imposing fees on vehicles than gasoline taxes. In addition, the maximum amount of abatement attainable by a feebate program is relatively small and the same amount could be achieved by imposing a $0.73 gasoline tax per gallon.     

国际船舶温室气体法规对船舶改造市场的影响研究

该文针对船舶改造市场因国际海事组织（international maritime organization,IMO）的温室气体减排新战略所受影响开展了评估,通过对现有船舶法规履约情况以及国内外船舶修造资源禀赋分析,详细研究了实施新战略对船舶改造市场规模、市场结构、区域差异、市场特性和船舶修造企业战略等方面的影响。研究表明:IMO新战略的实施将促进全球扩大基于绿色改造的船舶修造市场,且预计市场规模达40亿至400亿美元;同时将有力加速船舶改造市场结构向水动力、新燃料和后处理等领域调整,并推动船舶修造业多元化、差异化和个性化的发展趋势,为全球船舶修造企业市场布局、战略调整和资源购置提供数据基础。     

绿色通航视域下过坝船舶预约调度双目标优化研究

针对船舶到达不均衡和供需时空不匹配导致的水利枢纽通航拥堵问题,建立过坝船舶预约的双目标决策模型,优化船舶平均等待时间和到达调整率,探讨两者之间的权衡关系;进一步考虑船舶的失约情形,设计过坝预约的重调度规则。然后,利用非支配排序遗传算法的gamultiobj函数求解模型,并探讨预约机制实施前后的碳减排效果。最后,以三峡枢纽为例,验证模型的有效性。结果表明：该模型在平均等待时间和到达调整率的权衡中,得到了多样化的预约调度方案,并通过合理分配预约份额,有序管理船舶到达。同时,与原调度方案相比,理想和失约情形下的预约调度方案,可分别带来27.51 t和20.04 t的最大碳减排量;且重调度策略使到达调整率的均值降低了2.7%,减少了失约的干扰影响。