Recent Advancements in PEM Fuel Cell Technologies for Electrified Transportation

The interest in developing clean and environmentally-friendly energy devices to be used on vehicles is intensifying because of emissions from conventional internal combustion engines considered as one of the significant contributors to the rapidly changing climate. Fuel cell energy devices, especially the proton exchange membrane (PEM) type, are the solid contender to replace the conventional vehicle propulsion technology in the transport sector. The PEM fuel cell technology needs a lot of efforts to overcome some existing problems such as durability, hydrogen storage, and cost for its successful worldwide commercialisation. This chapter deals with the durability, cost, and performance challenges related to the utilization of PEM fuel cell technology in electrified transportation. Recent advancements concerning the current challenges have been discussed. Moreover, issues of hydrogen storage and infrastructure are outlined.

Effect of connected and autonomous vehicles on traffic flow at a bidirectional road

The objective of this study was to investigate the impact of connected and autonomous vehicles (CAVs) on traffic flow under various parameters. For this purpose, we propose a mixed CAV and conventional vehicle (CV) model to investigate a bidirectional two-lane traffic flow under the periodic boundary condition. The traffic flux and the phase diagrams of the system in the ([Formula: see text]) area are constructed in both cases: with and without CAVs. The overtaking frequency is also calculated. The simulation findings show that the traffic capacity is greatly enhanced with the increase in the CAV penetration ratio. Owing to the cooperative driving strategy, with the increase in penetration ratio of the CAV, the portion of smooth overtaking is boosted. Furthermore, it is found that the traffic throughput is positively correlated to the speed limit of the fast vehicle where the flux increases as [Formula: see text] increases. Also, even if there is a low rate of slow moving vehicles in the system, it will have an appreciable and a significant negative influence.

Optimal Integrated Emission Management through Variable Engine Calibration

In this work, the potential for improving the trade-off between fuel consumption and tailpipe NOx emissions through variable engine calibration (VEC) is demonstrated for both conventional and hybrid electric vehicles (HEV). First, a preoptimization procedure for the engine operation is proposed to address the challenge posed by the large number of engine control inputs. By excluding infeasible and suboptimal operation offline, an engine model is developed that can be evaluated efficiently during online optimization. Next, dynamic programming is used to find the optimal trade-off between fuel consumption and tailpipe NOx emissions for various vehicle configurations and driving missions. Simulation results show that for a conventional vehicle equipped with VEC and gear optimization run on the worldwide harmonized light vehicles test cycle (WLTC), the fuel consumption can be reduced by 5.4% at equivalent NOx emissions. At equivalent fuel consumption, the NOx emissions can be reduced by 80%. For an HEV, the introduction of VEC, in addition to the optimization of the torque split and the gear selection, drastically extended the achievable trade-off between fuel consumption and tailpipe NOx emissions in simulations. Most notably, the region with very low NOx emissions could only be reached with VEC.

Calibrating Wiedemann-99 Model Parameters to Trajectory Data of Mixed Vehicular Traffic

We propose a new methodology for calibrating Wiedemann-99 vehicle-following parameters for mixed traffic (different conventional vehicle classes) based on trajectory data. The existing acceleration equations of the Wiedemann model are modified to represent more realistic driving behavior. Exploratory analysis of simulation data revealed that different Wiedemann-99 model parameters could lead to similar macroscopic behavior, highlighting the importance of calibration at the microscopic level. Therefore, the proposed methodology is based on optimizing performance measures at the microscopic level (acceleration, speed, and trajectory profiles) to estimate suitable calibration parameters. Further, the goodness of fit for the observed data is sensitive to the numerical integration method used to compute vehicles’ velocity and position. We found that the calibrated parameters using the proposed methodology perform better than other approaches for calibrating mixed traffic. The results reveal that the calibrated parameter values and, consequently, the thresholds that delineate closing, following, emergency braking, and opening regimes, vary between two-wheelers and cars. The window (in the relative speed versus gap plot) for the unconscious following is larger for cars while the free-flow regime is more extensive for two-wheelers. Moreover, under the same relative speed and gap stimulus, two-wheelers and cars may be in different regimes and display different acceleration responses. Thus, accurate calibration of each vehicle’s parameters is essential for developing micro-simulation models for mixed traffic. The calibration analysis results of strict and overlapping staggered car following signify an impact of staggered car following compared with strict car following which demands separate calibration for strict and staggered following.

A Review on Mechanical Motion Rectifier for Energy Harvesting

The conventional vehicle suspension dissipates the mechanical vibration energy in the form of heat which waste considerable energy. The regenerative suspensions have attracted much attention in recent years for the improvement of vibration attenuating performance as well as the reduction of energy dissipation. In fact, the vibrations in some situations can be very large, for example, the vibrations of tall buildings, long vehicle systems, railroads and ocean waves. With the global concern on energy and environmental issues, energy harvesting from large-scale vibrations is more attractive. This paper introduces the existing research and significance of regenerative shock absorbers and reviews the potential of automotive vibration energy recovery techniques; then, it classifies and summarizes the general classifications of regenerative shock absorbers. Keywords: Mechanical vibration, regenerative suspension, energy dissipation, railroads, ocean waves, vehicle.

Evaluation of the CO2 emission from motor vehicles in the context of sustainable transport development

Greenhouse gases emission is an important element in the development of the automotive industry. The unceasing trend of reducing the negative impact of vehicles on the environment is a determinant of setting directions for the improvement of their production and operation. One of the solutions in this regard are low-emission vehicles. However, this area requires continuous research and analyses, the results of which are partially presented in this article. The aim of the study was to evaluate the CO2 emission from the selected types of vehicles as in traffic driving, measured based on the standardised type-approval tests. This method allows to easily reproduce the obtained results, reliably compare and also extend it with further tests in a completely independent manner. The CO2 emission in the production process of the vehicle and its fuel, was also evaluated. It was assumed (research hypothesis) that CO2 emission changes significantly with the development of production technology and the use of various vehicle power sources. Based on their own research, the authors also analysed the feasibility/reliability of the assumptions about the benefits associated with emissions, obtained by replacing the classic vehicle with the hydrogen one. They estimated the time and intensity of using a hydrogen-powered vehicle that guarantees a benefit in terms of CO2 emissions compared to a conventional vehicle.

Evaluation of Traffic Signal Systems Effectiveness in Connected Vehicle Environments Using Trajectory Analytics

One of the ways to design more effective signal control strategies is to leverage and synthesize connected vehicle generated (CVG) information to identify traffic states for the controller to operate in a predictive, yet vehicle-actuated manner. The contribution of this paper is twofold: (1) it presents a framework for an advanced, online, signal control logic in a connected environment that utilizes information from connected vehicles (CVs) to augment high-resolution controller and/or sensor data, and (2) it applies the trajectory analytics to compare the performance of the new controller schemes with CVG data and functionalities relative to conventional, vehicle-actuated, control. The framework puts forward a predictive control logic that schedules phases in an acyclic manner over a variable planning horizon. Phase duration is continually evaluated in response to updated requests for service distributed among equipped vehicles and associated performance indicators. Within the same connected control setup, two measures of effectiveness of a decision were compared to determine the upper bound on the potential effectiveness of a more responsive control strategy. Finally, trajectory analytics was used to evaluate the effectiveness of the CV technology-based control scheme against the conventional one. The findings indicate that both control system performance assessment and optimization objectives should change with access to CVG data. Unlike current state of the practice controllers, the developed method is able to handle high and low demand states equally well. The designed connected controller is shown to be robust in handling varying traffic conditions and demand levels.

Metro Stations as Crowd-shipping Catalysts: An Empirical and Computational Study

Crowd-shipping is a promising shared mobility service that involves the delivery of goods using non-professional shippers. This service is mainly intended to reduce congestion and pollution in city centers but, as some authors observe, in most crowd-shipping initiatives the crowd rely on private motorized vehicles and hence the environmental benefits could be small, if not negative. Conversely, a crowd-shipping service relying on public transport should maximize the environmental benefits. Motivated by this observation, in this study we assess the potentials of crowd-shipping based on metro commuters in the city of Brescia, Italy. Our contribution is twofold. First, we analyze the results of a survey conducted among metro users to assess their willingness to act as crowd-shippers. The main result is that most young commuters and retirees are willing to be crowd-shippers even for a null reward. Second, we assess the potential economic impact of using metro-based crowd-shipping coupled with a traditional home delivery service. To this end, we formulate a variant of the VRP model where the customers closest to the metro stations may be served either by a conventional vehicle or by a crowd-shipper. The model is implemented using Python with Gurobi solver. A computational study based on the Brescia case is performed to get insights on the economic advantages that a metro-based crowd delivery option may have for a retailing company.

Management of urban air logistics with unmanned aerial vehicles: The case of medicine supply in Aveiro, Portugal

Purpose: This research aims to investigate the relation between urban logistics and all delivery systems used. The unmanned aerial vehicle (UAV) and the unmanned aerial system (UAS) have been under investigation in the world of logistics, having been pointed as the next logistic technology. For that reason, this article proposes the use of UAV in urban logistics.Design/methodology/approach: We set for the methodology study the current state of this system and analyze what lies ahead soon. Based on this information, we intend to implement a scenario of deliveries in an urban environment. This scenario will be in the city of Aveiro and consists of the delivery of medicines into pharmacies located in an urban environment. With this study, we pretend to find the best current and future solution to operate in an urban environment, with the conventional vehicle or the UAV/UAS.Findings: The legal implications for the use of UAV/UAS are one important factor that can set back the use of these technologies due to the lack of legislation. Although this technology has some limitations in endurance and payload, this investigation reached a consensus in the use of UAV for logistics in urban areas, in small payloads (around 15 kg), and low endurance (around 25 min). The UAV/UAS brings excellent advantages that the conventional vehicle cannot overcome: direct routes; traffic congestion; and environmental legislation.Practical implications: This study brings an overview of a possible scenario for urban logistics. Although this is currently not possible, soon, this scenario could be implemented. This would bring a reduction in operation costs and reduce the congestion in the urban cores of the cities.Originality/value: Based on this research, this delivery system could, in the future, help and be the starting point for UAV/UAS logistics, specifically in the delivery of medicines.

An examination of alternative schemes for active and semi-active control of vertical car-body vibration to improve ride comfort

The recent tendency to reduce the weight of car bodies is posing a new challenge to vertical ride quality, since the vibrations related to car-body vertical bending modes affect heavily passengers’ comfort and cannot be fully mitigated by conventional vehicle suspensions. In this work, four mechatronic suspensions, considering active and semi-active technologies in secondary and primary suspensions, are compared to show their relative merits. LQG and H∞ model-based control strategies are established in a consistent way for each suspension scheme to perform a comparative assessment of the four concepts on objective grounds. A two-dimensional 9-DOF vehicle model is firstly built, using a simplified representation of car-body bending modes; this model is also used to design the model-based controllers. The comparison of the four mechatronic suspension schemes based on the 9-DOF model shows that full-active secondary suspension is the most effective solution whilst semi-active primary suspension is also effective in terms of mitigating car-body bending vibration. Then, a three-dimensional flexible multibody system (FMBS) vehicle model integrated with a finite-element car-body is considered to allow a more detailed consideration of the vehicle’s vibrating behaviour. The results of the FMBS model show a good agreement to the results of the 9-DOF model and the relative merits of the four mechatronic suspension schemes as found from the previous analysis are basically confirmed, although the FMBS model is more suited for a quantitative assessment of ride quality.