This paper evaluates the energy consumption and battery performance of city transit electric buses operating on real day-today routes and standardized bus drive cycles, based on a developed framework tool that links bus electrification feasibility with real-world vehicle performance, city transit bus service reliability, battery sizing and charging infrastructure. The impacts of battery capacity combined with regular and ultrafast charging over different routes have been analyzed in terms of the ability to maintain city transit bus service reliability like conventional buses. The results show that ultrafast charging via frequent short-time boost charging events, for example at a designated bus stop after completing each circuit of an assigned route, can play a significant role in reducing the battery size and can eliminate the need for longer duration charging events that would cause schedule delays. The analysis presented shows that significant benefits can be realized by employing multiple battery configurations and flexible battery swapping practices in electric buses. These flexible design and use options will allow electric buses to service routes of varying city driving patterns and can therefore enable meaningful reductions to the cost of the vehicle and battery while ensuring service that is as reliable as conventional buses.

Many vehicle systems simulations utilize engine maps constructed from steadystate dynamometer measurements to estimate exhaust temperature and emissions as functions of engine speed and load. Unfortunately, steady-state engine behaviour is often significantly different from actual behaviour under transient driving conditions. This is particularly true for vehicles that undergo repeated engine shutdown and restart (e.g. electric hybrids). The authors propose a methodology for estimating transient engine exhaust properties and fuel economy based on corrections to steady-state maps. The suggested methodology has been implemented in the Powertrain Systems Analysis Toolkit (PSAT) and this implementation is used to demonstrate good agreement with experimental measurements for both a light-duty diesel and a flex-fuel gasoline/ethanol engine. Specific procedures are also recommended for setting key parameters required by the proposed methodology and possible directions for further improvements are suggested.

An analysis of three‐dimensional computational fluid dynamics (CFD) is conducted to investigate the coupled cooling process involved in fluid flow and heat transfer between the solid plate and the coolant flow for optimization of the cooling design of a fuel cell stack. A conception of IUT (Index of Uniform Temperature) across the entire area is presented to evaluate the degree of uniform temperature profile across the cooling plates. Six cooling modes, including three serpentine‐type modes and another three parallel‐type modes, are presented and analyzed for optimization of the cooling mode of fuel cells. The prediction finds that the cooling effect of serpentine‐type cooling modes could be better than that of parallel‐type cooling modes.

No abstract

No abstract

public-access-plan). *Revised Manuscript with No Changes Marked Click here to download Revised Manuscript with No Changes Marked: AEJ_revision_R2_notmarked_03_2015.docx

A pair of tri-band multiple-input-multiple-output (MIMO) antennas with high isolation is investigated in this paper. The proposed antenna consists of two monopole antenna elements with an edge to edge spacing of 4 mm (0.03 λ 0 at 2.3 GHz). The monopole antenna element chose the bending line structure that can operate in tri-band and realize miniaturization. To achieve compact dimension and high isolation, symmetrical distribution layout is adopted to decouple the low frequency band, the U-shaped neutralization line (NL) contacting with two microstrip lines, and it can to improve the isolation in high frequency band, and the inverted U-shaped NL contacting with two radiation patch can decoupling in the middle frequency band. And then study the envelope correlation coefficient is lower, and the radiation pattern in operation bands is quasi-omnidirectional. It indicates that the antenna has obtained a satisfactory diversity performance within the whole operation bands which can be a good candidate for some portable MIMO applications. INDEX TERMS Multiple-input-multiple-output, tri-band, high isolation, neutralization line.

No abstract