Development of simulated driving cycles for light,medium, and heavy duty trucks: Case of the Toronto Waterfront Area

Driving cycles are an important input for state-of-the-art vehicle emission models. Development of a driving cycle requires second-by-second vehicle speed for a representative set of vehicles. Current standard driving cycles cannot reflect or forecast changes in traffic conditions. This paper introduces a method to develop representative driving cycles using simulated data from a calibrated microscopic traffic simulation model of the Toronto Waterfront Area. The simulation model is calibrated to reflect road counts, link speeds, and accelerations using a multi-objective genetic algorithm. The simulation is validated by comparing simulated vs. observed passenger freeway cycles. The simulation method is applied to develop AM peak hour driving cycles for light, medium and heavy duty trucks. The demonstration reveals differences in speed, acceleration, and driver aggressiveness between driving cycles for different vehicle types. These driving cycles are compared against a range of available driving cycles, showing different traffic conditions and driving behaviors, and suggesting a need for city-specific driving cycles. Emissions from the simulated driving cycles are also compared with EPA’s Heavy Duty Urban Dynamometer Driving Schedule showing higher emission factors for the Toronto Waterfront cycles.     

Particulate matter in marine diesel engines exhausts: Emissions and control strategies

Marine diesel engines emit particles that have a complex nature, being composed by carbonaceous particles, with size spanning from few nanometres to less than one micron, and inorganic particles of micron size mainly made by ashes and sulphates.On a global scale, international shipping is responsible for few percentages of the particulate matter emissions, which also affect climate, but the regional distribution of naval traffic suggests the insurgence of significant exposure risk for population living along the coastal areas, due to chronic exposure effects. Specific strategies should be implemented to reduce the emissions of all the components of particulate matter. This paper aims to present a survey on the current and innovative strategies to remove particles from marine diesel engine exhausts, along with a critical review of the most recent findings on ships emitted particles. Evidences on physical–chemical properties, toxicology and emission factors of the particles were reported. This survey indicates that several strategies can provide a significant reduction of particulate matter emissions from ships and integration between innovative after-treatment systems, ships design and operation procedures can potentially lead to overall reduction of more than 99% even with parallel fuel savings.     

The endogeneity of OECD gasoline taxes: Evidence from pair-wise,heterogeneous panel long-run causality tests

Despite the current interest in using fuel taxes as an instrument for climate policy, there has been little study of current automotive fuel tax regimes. We expand on two earlier cross-sectional studies on why fuel taxes differ across countries by using OECD panel data and employing heterogeneous panel cointegration and long-run panel Granger-causality techniques. We confirm some of those earlier studies’ conclusions. Further, we find that governments that rely on consumption-based taxes for revenues will have higher gasoline tax rates (than governments that rely on income and wealth/property-based taxes). But more significantly, we determine that higher gasoline demand among consumers “causes” democratic governments to set lower gasoline taxes—a finding with important implications for today’s climate/energy policy debate.     

Market introduction strategies for alternative powertrains in long-range passenger cars under competition

Alternative powertrains are considered as a promising option to significantly reduce CO₂ emissions from passenger cars. One major prerequisite is their successful market introduction. In this paper, we present a system dynamics model that allows for the evaluation of strategies for the market introduction of alternative powertrain technologies in long-range passenger cars (⩾400 km) under competition. The model considers two competing manufacturers, one first-mover and one follower, each introducing plug-in hybrids and fuel cell electric vehicles according to exogenously defined strategies, which comprise timing, pricing, and technology parameters. The manufacturers can learn from each other due to technology spillover, leading to cost reductions of the powertrains. We use an exemplary dataset for the German car market to study the manufacturers’ influence on the market success of alternative powertrains as well as the underlying mechanisms. The results indicate that in general more competition leads to higher market shares of alternatively powered vehicles and thus allows for a higher reduction of emissions. However, this might cause decreasing profits for both manufacturers, especially if the follower pursues an aggressive pricing strategy when entering the market to gain market shares from its competitor. Also, technology spillover has a positive effect on the market penetration. This particularly holds true for a low level of technology experience where high cost reductions can be achieved and for fuel cell electric vehicles where the costs of the powertrain are much higher compared to plug-in hybrids.     

Analysis of fuel consumption and pollutant emissions of regulated and alternative driving cycles based on real-world measurements

Discrepancies between real-world use of vehicles and certification cycles are a known issue. This paper presents an analysis of vehicle fuel consumption and pollutant emissions of the European certification cycle (NEDC) and the proposed worldwide harmonized light vehicles test procedure (WLTP) Class 3 cycle using data collected on-road. Sixteen light duty vehicles equipped with different propulsion technologies (spark-ignition engine, compression-ignition engine, parallel hybrid and full hybrid) were monitored using a portable emission measurement system under real-world driving conditions. The on-road data obtained, combined with the Vehicle Specific Power (VSP) methodology, was used to recreate the dynamic conditions of the NEDC and WLTP Class 3 cycle. Individual vehicle certification values of fuel consumption, CO₂, HC and NO_x emissions were compared with test cycle estimates based on road measurements. The fuel consumption calculated from on-road data is, on average, 23.9% and 16.3% higher than certification values for the recreated NEDC and WLTP Class 3 cycle, respectively. Estimated HC emissions are lower in gasoline and hybrid vehicles than certification values. Diesel vehicles present higher estimated NO_x emissions compared to current certification values (322% and 326% higher for NO_x and 244% and 247% higher for HC + NO_x for NEDC and WLTP Class 3 cycle, respectively).     

Have Emission Control Areas (ECAs) harmed port efficiency in Europe?

Ports in the European Union and North America have enforced environmental regulations on controlling SO_x and NOx emissions from ships in their coastal areas known as Emission Control Areas (ECAs). This study uses two-stage approaches to examine whether ECA regulations impact the efficiency of ports operating in such areas. First, port efficiencies are estimated using non-radial slacks-based measure (SBM) Data Envelopment Analysis (DEA) models. The efficiency scores estimated by the SBM DEA models are then regressed on explanatory variables, including the ECA factor, and macroeconomic indicators using bootstrapped truncated regression (BTR) models. Panel data is collected on countries in EU ECAs and non-ECAs regarding such input variables as capital and labor, with cargo as an output variable. The results indicate that ECA regulations can harm port efficiency, reflecting concerns of policy-makers and industrial managers: the average efficiency loss from an ECA designation amounts to 0.058–0.066 on a scale of 0–1, accounting for a 15–18% loss from ECA ports’ average efficiency scores.     

Real-time route diversion control in a model predictive control framework with multiple objectives: Traffic efficiency,emission reduction and fuel economy

In this paper, the route recommendation provided by the traffic management authority, rather than the uncontrollable bifurcation splitting rate, is directly considered as the control variable in the route guidance system; a real-time en-route diversion control strategy with multiple objectives is designed in a Model Predictive Control (MPC) framework with regard to system uncertainties and disturbances. The objectives include not only traffic efficiency, but also emission reduction and fuel economy, which respectively correspond to minimizing the total time spent (TTS), total amount of emissions and fuel consumption for all vehicles moving through a network. In the MPC framework, the routing control problem is transformed to be a constrained combinational optimization, which is solved by the parallel Tabu Search algorithm. Two representative traffic scenarios are tested, and the simulation results show: (1) The room for improvement in each objective by means of route diversion control is not consistent with each other and varies with the utilized traffic scenario. In the peak hour, the routing control can lead to significant improvements in TTS and fuel economy, while a relatively small improvement in emission reduction is achieved; in the off-peak hour, however, it is opposite, which indicates that routing is possibly dispensable from the aspect of improving traffic efficiency, but is required from the aspect of emission reduction. (2) The conflict among the multiple objectives varies with the utilized traffic scenario in route diversion control. Improving traffic efficiency often conflicts with emission reduction in both scenarios. For the objectives of traffic efficiency and fuel economy, they are not conflicting in peak hour, while in the off-peak hour, the two objectives are likely conflicting, and the improvement in one objective can lead to the degradation in the other objective. (3) Regardless of the scenarios of peak hour or off-peak hour, the proposed control strategy can result in a proper trade-off among the three chosen objectives.     

Using a chassis dynamometer to determine the influencing factors for the emissions of Euro VI vehicles

In order to explore the influence of different factors on the emissions of heavy diesel vehicles, a chassis dynamometer was used to test and analyze a Euro VI standard heavy-duty diesel vehicle under different load, fuel, driving conditions, and resistance conditions. The full load condition was found to increase NOx emissions by about 0.107 g/km (30%) and the particulate matter (PM) by 0.003 g/km (18%) compared to the empty load condition. Compared with the China V diesel, the NOx emissions of the Beijing VI diesel were reduced by 0.065 g/km (18%), and PM decreased by 0.004 g/km (25%). The HC, CO, PM, and NOx emissions measured during the Chinese World Harmonized Transient Cycle (C-WHTC) were 0.002 g/km (27%), 0.0005 g/km (14%), 0.0024 g/km (15%), and 0.092 g/km (25%) higher, respectively, than those measured during the European Transient Cycle (ETC). The HC, CO, PM, and NOx emissions measured by using the test resistance were 0.002 g/km (28%), 0.001 g/km (25%), 0.003 g/km (18.7%), and 0.09 g/km (25.7%) higher, respectively, than those calculated with the recommended formula.     

The effects of emission control area regulations on cruise shipping

To control SOx, NOx and particulate matter emission from ships, including cruise ships, emission control areas (ECAs) have been defined by the International Maritime Organization (IMO), which influences cruise planning. This paper investigates a mixed integer programming model to reschedule voyage plans by optimizing speeds, sailing patterns and ports-of-call sequences, hence reducing fuel costs. A tabu search based solution method is developed to solve the model. Computational tests on real-world data of cruise lines are conducted in order to explore the effects of ECA regulations on cruise shipping. The results show that the proposed model can save fuel costs under ECA regulations, and the designed solution method is efficient.     

基于模型的船用柴油机多目标优化

在船用发动机第一阶段排放法规将要实施的情况下,为兼顾发动机的经济性和排放性,采用基于模型的多目标优化标定方法对船用发动机进行优化。根据排放法规的要求并结合船用发动机的推进特性和工况点,采用混合试验设计(Do E)设计试验工况点,在发动机台架上收集发动机试验数据,通过对试验数据进行分析建立优化标定模型,以经济性最好及满足氮氧化物(NOX)和碳氢化合物(HC)排放要求为目标,以其他排放物和排温为约束条件,应用基于Pareto概念的遗传算法进行优化求解。验证结果表明:法规排放点满足船用发动机一阶段排放法规的要求,氮氧化物(NOX)和碳氢化合物(HC)排放、油耗分别比原机降低12.34%、3.65%,一氧化碳(CO)和颗粒物(PM)排放分别比原机降低33.29%、13.21%;推进特性下工况点得到了较好的优化效果。