Fuel price elasticities for single-unit truck operations in the United States

This paper provides fuel price elasticity estimates for single-unit truck activity, where single-unit trucks are defined as vehicles on a single frame with either (1) at least two axles and six tires; or (2) a gross vehicle weight greater than 10,000 lb. Using data from 1980 to 2012, this paper applies first-difference and error correction models and finds that single-unit truck activity is sensitive to certain macroeconomic and infrastructure factors (gross domestic product, lane miles expansion, and housing construction), but is not sensitive to diesel fuel prices. These results suggest that fuel price elasticities of single unit truck activity are inelastic. These results may be used by policymakers in considering policies that have a direct impact on fuel prices, or policies whose effects may be equivalent to fuel price adjustments.     

Eco-driving training of professional bus drivers – Does it work?

The drive to reduce fuel consumption and greenhouse gas emissions is one shared by both businesses and governments. Although many businesses in the European Union undertake interventions, such as driver training, there is relatively little research which has tested the efficacy of this approach and that which does exist has methodological limitations. One emerging technology employed to deliver eco-driving training is driver training using a simulator. The present study investigated whether bus drivers trained in eco-driving techniques were able to implement this learning in a simulator and whether this training would also transfer into the workplace. A total of 29 bus drivers attended an all-day eco-driving course and their driving was tested using a simulator both before and after the course. A further 18 bus drivers comprised the control group, and they attended first aid courses as well as completing the same simulator drives (before-after training). The bus drivers who were given the eco-driving training significantly improved fuel economy figures in the simulator, while there was no change in fuel economy for the control group. Actual fuel economy figures were also provided by the bus companies immediately before the training, immediately after the training and six months after the training. As expected there were no significant changes in fuel economy for the control group. However, fuel economy for the treatment group improved significantly immediately after the eco-driving training (11.6%) and this improvement was even larger six months after the training (16.9%). This study shows that simulator-based training in eco-driving techniques has the potential to significantly reduce fuel consumption and greenhouse gas emissions in the road transport sector.     

基于PTC材料加热的柴油喷油器模拟

文章选用居里温度为60℃的陶瓷基PTC材料作为加热元件,利用流体力学计算软件Fluent模拟了两种不同燃油流量下用PTC材料加热柴油的温度场变化。仿真结果表明,利用PTC材料加热可有效提高燃油温度,改善冷启动性能,且随着燃油流量的增加,喷油器出口温度呈下降趋势。     

质子交换膜燃料电池催化剂研究进展

降低催化剂成本、提高催化剂性能是燃料电池汽车实现商业化的前提。本文结合质子交换膜燃料电池关键材料催化剂的现状,主要从铂基催化剂、其他贵金属催化剂和非铂基催化剂对质子交换膜燃料电池催化剂研究进展和热点进行分析及展望。     

Analysis of three independent real-world driving studies: A data driven and expert analysis approach to determining parameters affecting fuel economy

It is well established that individual variations in driving style have a significant impact on vehicle energy efficiency. The literature shows certain parameters have been linked to good fuel economy, specifically acceleration, throttle use, number of stop/starts and gear change behaviours. The primary aim of this study was to examine what driving parameters are specifically related to good fuel economy using a non-homogeneous extended data set of vehicles and drivers over real-world driving scenarios spanning two countries. The analysis presented in this paper shows how three completely independent studies looking at the same factor (i.e., the influence of driver behaviour on fuel efficiency) can be evaluated, and, despite their notable differences in location, environment, route, vehicle and drivers, can be compared on broadly similar terms. The data from the three studies were analysed in two ways; firstly, using expert analysis and the second a purely data driven approach. The various models and experts concurred that a combination of at least one factor from the each of the categories of vehicle speed, engine speed, acceleration and throttle position were required to accurately predict the impact on fuel economy. The identification of standard deviation of speed as the primary contributing factor to fuel economy, as identified by both the expert and data driven analysis, is also an important finding. Finally, this study has illustrated how various seemingly independent studies can be brought together, analysed as a whole and meaningful conclusions extracted from the combined data set.     

Stop-and-go traffic analysis: Theoretical properties,environmental impacts and oscillation mitigation

This study aims (i) to analyze theoretical properties of a recently proposed describing-function (DF) based approach (Li and Ouyang, 2011; Li et al., 2012) for traffic oscillation quantification, (ii) to adapt it for estimating fuel consumption and emission from traffic oscillation and (iii) to explore vehicle control strategies of smoothing traffic with advanced technologies. The DF approach was developed to predict traffic oscillation propagation across a platoon of vehicles following each other by a nonlinear car-following law with only the leading vehicle’s input. We first simplify the DF approach and prove a set of properties (e.g., existence and uniqueness of its solution) that assure its prediction is always consistent with observed traffic oscillation patterns. Then we integrate the DF approach with existing estimation models of fuel consumption and emission to analytically predict environmental impacts (i.e., unit-distance fuel consumption and emission) from traffic oscillation. The prediction results by the DF approach are validated with both computer simulation and field measurements. Further, we explore how to utilize advantageous features of emerging sensing, communication and control technologies, such as fast response and information sharing, to smooth traffic oscillation and reduce its environmental impacts. We extend the studied car-following law to incorporate these features and apply the DF approach to demonstrate how these features can help dampen the growth of oscillation and environmental impact measurements. For information sharing, we convert the corresponding extended car-following law into a new fixed point problem and propose a simple bisecting based algorithm to efficiently solve it. Numerical experiments show that these new car-following control strategies can effectively suppress development of oscillation amplitude and consequently mitigate fuel consumption and emission.     

高速布置型船舶的风帆设计及综合效能分析

针对国内研究较少的高速布置型船舶的风帆助航问题,基于船舶特点及风帆升阻力特性选定了帆型,设计了一套风帆加装方案。在结合历史气象统计数据的基础上,对风帆长期综合效能进行了分析。以一艘大连-烟台航线上高速客滚船为例,结合实船统计得到的此航线上的历史风场资源时空分布,对该船加帆后长期综合效能进行了计算,结果表明,所设计的风帆可较为显著地降低耗能并减少温室气体排放,具有良好的推广应用前景。     

基于模糊神经网络的水火弯板双臂系统控制与研究

研究了水火弯板双机械臂的非线性控制问题,采用一种模糊神经网络算法,利用神经网络的学习能力和模糊控制的模糊信息处理能力,调整优化双机械臂运动的位置偏差,得到该控制体系下的最佳驱动参数,仿真结果表明,该控制策略提高了水火弯板双机械臂的控制精度,并且使系统具有较好的动、静态性能。     

基于热电技术的发动机排气余热回收

本文介绍了热电技术的基本原理,并以宝马汽车公司的热电发电机为例论述了热电技术在发动机排气余热回收过程中的应用,包括热电发电机的结构设计、系统集成、系统建模、实用效果及发展潜能。     

基于燃油经济性的汽车动力传动系匹配优化

传统的汽车传动系匹配研究方法,都是以汽车的动力性或经济性指标为优化目标的单目标优化。为了实现真正意义上的多目标优化,文章利用modeFRONTIER软件和遗传算法的组合优化策略,结合某5挡手动变速车传动系匹配,进行了基于燃油经济性的传动系参数优化设计,达到了降低汽车燃油消耗的效果,为汽车开发设计中传动系匹配优化提供了参考。