Personal transportation in urban areas is characterised by different transportation technologies with significantly varying properties regarding usability, infrastructural requirements and environmental impacts. This characterisation motivates the objective evaluation of mobility solutions, based on different criteria. State of the art evaluations in the scientific literature mainly focus on one specific criterion at a time. The most common criteria investigated are found in energy demand or equivalent fuel consumption. Other parameters include the traffic space demand or mean velocity as a reference for the user-related criterion “travel time”. Since different modes of transport show various potentials in different criteria, an interesting point for scientific research is consideration of the different criteria in a more comprehensive evaluation approach. To address this issue, the aim of this study is to present a new approach for an objective evaluation and comparison of different transport technologies under consideration of pre-defined range of criteria and defined boundary conditions and requirements for personal mobility in cities. Besides technical-oriented aspects like driving range, transport capability and life cycle-related consumption of resources, additional factors influencing user-behaviour and traffic density are reflected. The evaluation method is presented, based on a generated exemplary data collection regarding technical and in-use characteristics of different modes of transport, mainly investigated in the city of Graz, Austria. The study focuses on different means of transport, in particular walking, bicycling, the use of powered two-wheelers, passenger cars with different propulsion systems and public transport systems. It is based on the determination of selected criteria, considering ecologic, infrastructural and user-related aspects. With respect to ecologic criteria, the study considers resources and energy consumption as also the resulting CO2 equivalent emissions. The mean velocity and transport capacity are considered in the context of user-related criteria. Traffic space demand is an important and limited resource, especially in urban areas. The present study thus includes the determination and comparison of the relative traffic and parking space demands for the different modes of transport. The evaluation is based on a specifically developed evaluation methodology, considering weighted traffic performance indices, which are also proposed and discussed. Within the present study, a database providing specific mobility-related criteria and parameters has been generated, representing technical characteristics and the effects of the use of different vehicles and means of transportation in urban areas. The illustrated results allow an objective evaluation of a broad range of different means of transportation and vehicles, based on introduced “weighted traffic performance indices” (WTPI). The study contributes to a discussion of transportation technologies and allows a derivation of measures for further research topics to face future intra-urban mobility demands. This represents a basis for decision making on the priorisation of the most suitable transport systems for urban areas. It is shown that the motorised individual passenger transport as dominated by the use of private passenger cars in particular represents today the most inefficient form of inner-urban mobility.
As an important trend in the automotive industry, electrification of propulsion systems has potential to significantly reduce greenhouse-gas emissions of the transportation sector. Whereas electric vehicles do not produce exhaust emissions during driving, the impact of electricity provision for charging batteries, as well as the impact of vehicle production play an essential role in a holistic consideration of the carbon footprint. The paper introduces a comprehensive evaluation of greenhouse gas-emission-related factors of cars driven by different propulsion technologies, considering the entire product life cycle. This comprises vehicle production, including battery system, electric powertrain and other relevant components, the car’s use phase under consideration of different electricity mixes and the end-of-life phase. The results of the study give insights of influencing factors on life-cycle-related carbon-dioxide-equivalent emissions of cars driven by combustion engines, hybrid powertrains and battery-electric propulsion systems. In addition, a comparison of actual mass-production cars is made and the total life-cycle carbon footprints are discussed under different boundary conditions of electric power supply. In this way, the article comprehensively introduces an automotive life-cycle assessment and provides fundamental information, contributing to an objective discussion of different propulsion technologies.
With the rising number of electric and hybrid vehicles the demand for customerfriendly and innovative solutions for the charging infrastructure is growing steadily. Furthermore, future autonomous driving and parking vehicles are calling for new approaches regarding to battery charging. Nowadays electric vehicles have to be charged by hand. In other words, someone has to connect the charging cable with the charging socket of the vehicle. This paper deals with automated charging systems for electric vehicles. In order to realize tethered charging a fully automated system supports the complete process. The first part of work explains advantages of automated conductive charging systems regarding to other automated concepts and why such systems are needed. The second part deals with an investigation of the state of art. Thereby it is evidenced which systems are already developed and published. Afterwards, challenges and problems behind automated conductive systems are shown. Thereby the individual problems are analysed and illustrated. Finally, an initial concept for automated charging station is presented and discussed as a solution charging multiple and various types of vehicles at public parking facilities.
Rotor shaft position sensors are required to ensure the efficient and reliable control of Permanent Magnet Synchronous Machines (PMSM), which are often applied as traction motors in electrified automotive powertrains. In general, various sensor principles are available, e.g., resolvers and inductive- or magnetoresistive sensors. Each technology is characterized by strengths and weaknesses in terms of measurement accuracy, space demands, disturbing factors and costs, etc. Since the most frequently applied technology, the resolver, shows some weaknesses and is relatively costly, alternative technologies have been introduced during the past years. This paper investigates state-of-the-art position sensor technologies and compares their potentials for use in PMSM in automotive powertrain systems. The corresponding evaluation criteria are defined according to the typical requirements of automotive electric powertrains, and include the provided sensor accuracy under the influence of mechanical tolerances and deviations, integration size, and different electrical- and signal processing-related parameters. The study presents a mapping of the potentials of different rotor position sensor technologies with the target to support the selection of suitable sensor technologies for specified powertrain control applications, addressing both system design and components development.
In the design process of electric powertrains, consisting of electric machine, gearbox and power electronics, the requirements regarding performance, package and costs are typically set on system level. This imposes that deduction of component requirements is not unique and component properties interfere with each other. As a component of the powertrain system, the gearbox represents a linking element between the electric machine and drive shafts to the wheels. Through this the available installation space of the gearbox shows manifold characteristics due to multiple possible motor- and power electronics variants as also versatile system installation positions and angles. This space can be utilized by different gearbox variants, which are characterized by gearbox-internal design parameters. They affect gear ratio, configuration of gear wheels, outer shape of the gearbox and therefore the package as well as efficiency and production costs. The high variability of gearbox design parameters and packaging-related aspects lead to a complex problem in the design process. In this context, the present contribution introduces a gearbox design optimization process to support decision-making in the early development phase. For given load-, lifetime- and package-requirements, the introduced differential-evolution-based process delivers design parameters for shafts, gears, bearings and their arrangement to handle efficiency, package and costs in a multi-objective manner. The results are represented by a Pareto front of gearbox designs variants, from which decision makers are able to choose the best and most suitable trade-off. The new approach is exemplarily demonstrated on a single-speed, two-stage helical gearbox with an integrated differential drive, which represents a common gearbox topology for xEV-axle drives.