Vehicle Roof Research Articles

Design of a 16‐beam pattern‐reconfigurable antenna for vehicular environment

This article presents the design of a multipattern antenna with pattern switching for vehicular communications. The proposed antenna has four triangular patches integrated onto a split square ring (SR) resonator to operate at two distinct frequencies, viz. 2.4 and 3.5 GHz. The proposed antenna is designed with a view to enhancing the link reliability of Wireless Local Area Network (WLAN), WiMax, and vehicle to vehicle communication frequencies. Each triangular patch is separately excited using a microstrip line feed to enable beam steering. The ground plane of the antenna is embedded with two SR slots to improve the bandwidth and radiation performance. Further gain enhancement is achieved by loading the antenna with a plane reflector located at a distance of 20 mm from the antenna's ground surface. In reality, this reflector is realized using the vehicle's roof which provides gain enhancement up to 5.2 dBi at 2.4 GHz and 4 dBi at 3.5 GHz. By exciting single to multiple ports sequentially 16 different radiation patterns are obtained, which provides high-gain omnidirectional coverage. The prototype antenna is fabricated and the simulation results are verified using experimental measurements. From the results, it is evident that the proposed antenna is suitable for vehicular communication applications.

Thin, stretchable, universal wireless power transfer system for electric vehicle charging.

Wireless power transfer technology has emerged as a new class of prospective components for electric vehicle charging. However, conventional wireless power transfer systems often suffer from unsatisfactory charging efficiency due to the comparatively longer recharge range and insufficient universality for various car models. Here, we present a stretchable wireless power transfer (SWPT) system that consists of thin and stretchable inductive coupling coils designed in serpentine shapes to provide stretchablility for the charging of any model. The receiving coil is adhered to the vehicle roof, and the transmitting coil hung over the vehicle is used to adjust the transmission distance. In order to improve the capability of coils, the design of windings is optimized to enhance stretchability and decrease the resistance via fabricating treble strand serpentine copper traces. The results show that the charging efficiencies of the SWPT remain stable even though the coils are under bending and stretching. As an application demonstration, the SWPT system is installed on the roofs of two different model cars, respectively, and the results demonstrate that the charging efficiencies remain stable. Thus, this work paves a novel way to develop a stretchable, convenient, universal, and high-performance wireless power transfer system.

Design of High-Gain Circularly Polarized Antennas Based on Vehicle Application Environment

In this paper, a novel circularly polarized (CP) antenna that achieves high gain by maximizing the radiation aperture utilization is proposed for vehicle applications. The realization of increasing the radiation aperture is based on the application environment, making full utilization of the vehicle roof, a large metal reflector beneath the antenna, which is indispensable in the vehicle application. Developed from the structure of typical microstrip patch antenna, the design extends the radiation patch to cover the side of the dielectric substrate, which increases the size of the radiating patch without increasing the antenna's outline size. To make CP antennas more suitable for special working environments with large reflecting surface, a sequential rotation feeding structure with 90° progressive phase difference is uniquely designed based on the active port impedance of the four-ended radiation structure. This co-design method introducing the active port impedance of a multi-port radiator into the design of feeding network as the loads can effectively guarantee the CP performance of the antenna, and can greatly simplify the optimization work in the subsequent stage. Based on this design idea, a prototype working at 1.48 GHz with a 50-MHz bandwidth is designed for vehicle satellite broadcasting application. Experimental results show that the antenna achieves a high CP gain greater than 7 dBic with a compact size of $50 \times 50 \times 10\,\,mm^{3}$ ($0.247\lambda _{0} \times 0.247\lambda _{0} \times 0.05\lambda _{0}$ , $\lambda _{0} $ is the wavelength of working frequency in free space).

Design and analysis of a polyamide – steel hybrid A-pillar for increased vehicle roof structural integrity in rollover accident scenarios

In a world where motor vehicles are the primary means of personal transportation, accidents have become common. One of the accident modes of note are rollover accidents which in most instances deals with the roof crush scenario. In roof crush, the A-pillar structures would have failed to a certain degree if not completely. In this research ways to strengthen the roof structure, in particular the A-pillar structure are sought through the application of Polymer-Metal Hybrid materials to the A-pillar design. The Polymer-Metal Hybrid Material is designed from material selection to configuration optimisation using design parameters derived from rollover accident scenario information as well as vehicle Body-in-White manufacturing processes. The hybrid material designed was constituted of directly bonded 43% glass filled polyamide 6/6 and dual phase 980 High Strength Steel. Analyses on the application of the design material and effectiveness of its optimised configuration are carried out through non-linear stress analysis simulations and Multi-Objective Genetic Algorithm optimisation techniques. Results point to the assertion that application of the hybrid material design can attain up to a 15% weight saving and attains with marginal stiffness performance gains. However, the strength performance of the hybrid material design shows that the design excels in withstanding forces stresses greater than the All-steel member by an order of nearly 2.

교류 전동차 주회로 차단기 동작특성 연구

This paper presents an analysis of the operating characteristics of MCB in the power system of EMU powered by AC 25kV. The MCB is installed on the roof of the EMU vehicle and it performs on and off operations in poor environments conditions depending on the external environment, such as vibration and temperature changes due to operation. In the Shinbundang-Line driverless EMU vehicle system, as MCB’s operation failures occurred at outdoor temperature range of –1℃~ -11℃. It is analyzed the operate characteristic and the hypothesis theory of operation failure was established. It is verified experimentally and an applicable system is proposed that can operate smoothly under service environment condition. Finally, the results of the verification were applied to the train and the results of the proposed system were verified through long-term and follow-up observation.

Impact of Nonplanar Panels on Photovoltaic Power Generation in the Case of Vehicles

We investigate the impact of nonplanar panels on power generation in the case of photovoltaic panels mounted on vehicles. The power generation of nonplanar photovoltaic panels on vehicles is analyzed using the numerical geometric model, comprising the incident angle distribution of irradiation. We calculated power generated by the photovoltaic panels equipped on the roof, side, and tilted surfaces of vehicles, showing that even the panels on the side, which are fitted vertically to the ground, generate more than a quarter of the total power as that generated by the panel horizontal to the ground. Furthermore, we evaluated the curve correction factor that reflects the relative power generation of nonplanar panels with respect to the reference flat panels on vehicles. The geometrical model reproduces a simple relationship between the curve correction factor and effective surface ratio between the nonplanar and reference flat panels. Our findings indicate that the curve correction factor is useful to estimate power generation for nonplanar photovoltaic devices on vehicles; this provides a guiding principle for designing nonplanar photovoltaic devices for vehicles.

Research on Lightweight Carbon Fiber Roof of a Blade Electric Vehicle

The static collapse model of carbon fiber composite material and steel roof of a domestic blade electric vehicle was established respectively through the finite element software--Hyperworks. The relationship between the pressure of the pressure plate and the collapse depth of the roof was calculated by using the ls-dyna solver. The results show that the carbon fiber composite has better protection to passengers than the steel roof, and has achieved obvious lightweight effect. In order to obtain the optimal protective layer method for the occupant, the static crushing simulation comparison was carried out on the composite roof of four classical layer methods [0/45/-45/90]2s, [0/90/45/- 45]2s, [45/45/0/90]2s and [45/45 /90/0]2s, the results showed that the [45/-45/90/0]2s method is superior to others as adopted in the layer mode.

Implementation of Dual-Circuit System for Additional Power Supply Based on Photovoltaic Converters for Electric Vehicles

The article presents a process of designing the photovoltaic (PHV) converters system for an electric vehicle, shows the scheme of photovoltaic converters usage, the results of electric vehicle motion modeling with photovoltaic converters, and the results of road tests of an electric vehicle with an additional power source based on photovoltaic converters. The photovoltaic converters system and low-voltage system of an electric vehicle have a shared low-voltage battery, which allows the implementation of two schemes of electric vehicle power supply. Initially, the aggregate base was selected, then, taking into account the efficiency of each device included in the design of the new electric vehicle, mathematical modeling was carried out and showed good efficiency results of the photovoltaic converters system. Then, the prototype was manufactured and tested. The aggregate base included the battery of photovoltaic converters assembled in a certain way on the vehicle roof, the MPPT (maximum power point tracking) controller, the buffer storage device in the form of a 12 V battery, and the DC (direct current) converter that allows transmitting electricity from the buffer battery to the high-voltage system. Modeling of the electric vehicle motion considered typical operating modes, including energy costs for the operation of assistant systems of the electric vehicle, as well as including the consumption of low-voltage components. The tests were carried out according to the NEDC (New European Driving Cycle). As a result, implementation of photovoltaic converters with 21% efficiency allowed for the power reserve of the electric vehicle to be increased by up to 9%.

Prospective Life Cycle Assessment of a Structural Battery

With increasing interest in reducing fossil fuel emissions, more and more development is focused on electric mobility. For electric vehicles, the main challenge is the mass of the batteries, which significantly increase the mass of the vehicles and limits their range. One possible concept to solve this is incorporating structural batteries; a structural material that both stores electrical energy and carries mechanical load. The concept envisions constructing the body of an electric vehicle with this material and thus reducing the need for further energy storage. This research is investigating a future structural battery that is incorporated in the roof of an electric vehicle. The structural battery is replacing the original steel roof of the vehicle, and part of the original traction battery. The environmental implications of this structural battery roof are investigated with a life cycle assessment, which shows that a structural battery roof can avoid climate impacts in substantive quantities. The main emissions for the structural battery stem from its production and efforts should be focused there to further improve the environmental benefits of the structural battery. Toxicity is investigated with a novel chemical risk assessment from a life cycle perspective, which shows that two chemicals should be targeted for substitution.

ANN Based Improved Regenerative Braking System on PV/Battery Powered Electric Vehicles with Single Stage Interaction Converter

Hybrid features batteriesand photovoltaic (PV) module located on the roof of electric Vehicles (EV) can be effectively used by a single stage interaction converter (SSIC). SSIC is introduced for directing the energy flow amid the PV panel, battery and BLDC machine.In this paper a novel braking system is used for charing electrical vehicles using solar battery system (PV) integrated with BLDC motor. It is called as RBS (Regenerative Braking System). During the RB process, generator function is provided by BLDC motor. In order to boost the BLDC-Back-EMF, a suitable switching algorithm is used. By boosting the inverter and SSIC converter the DC-Link voltage reference is reduced to charge the battery. It increases the efficiency of the RB system. In this paper Aritifical Neural Network is used to provide a smooth and reliable brake with distributed force. This proposed BLDC-Back-EMF is experimented in MATLAB Simulink software and the results are verified. Speed, Breaking-Force, torque and front-RB force, rearmeachnical-RB force and other voltage, power are verified.

Study of the influenceof the «climate control» installation on fuel consumption and emissions of harmful substances by cars at idle with a running enginee

The article is devoted to the issue of improving fuel efficiency and environmental friendliness of cars serving the administrative and management personnel of the oil and gas complex. It is established that the effective ambient temperature, the color of opaque body elements, the power of the internal combustion engine and the passenger compartment volume of the car affects the fuel consumption and the number of specific emissions of harmful substances with exhaust gases when using the «climate control» installation. However, the simplest controllable factor is the color of the opaque body elements, which is characterized by light reflectance. In the course of experimental studies, the dependences of the change in fuel consumption and the share of reducing emissions of harmful substances from exhaust gases of passenger cars with the «climate control» installation on the light reflectance were established. A method has been developed to reduce fuel consumption and the number of specific emissions of harmful substances from exhaust gases of passenger cars with the «climate control» installation, which consists in imparting white color to the vehicle roof and allows reducing fuel consumption by 5.5–10.3 %, and specific emissions of harmful substances by 0.8–2.3 %.

A novel inverse procedure for load identification based on improved artificial tree algorithm

This paper presents an accurate and effective method, namely, the improved artificial tree algorithm based on the Green’s kernel function method (IAT-GKFM), to identify the load in time domain. The forward problem of load identification is constructed by using the Green’s kernel function method. The forward problem is discretized using the time domain Galerkin method, where a matrix form for load identification is formed. The IAT algorithm is proposed to solve the inverse multi-dimensions problem in the inverse stage, which aims to minimize the measuring dispersion between the calculated response and the actual response. Several numerical examples are conducted. It is demonstrated that the IAT with high performance can provide more optimum results than those of other compared algorithms. Using this optimized strategy, the loads acting on a simple plate and a vehicle roof are reconstructed successfully. The superiority of IAT-GKFM may motivate the improvement of the other inverse problems.

Flat concentrator photovoltaic system for automotive applications

In this paper, we present a novel design and an optical simulation of a flat concentrator photovoltaic (CPV) system for electric vehicle application. The sunlight concentration component is comprised of a planar waveguide integrated dichroic mirror-coated cone prisms and a mirror-coated lens array. Sunlight reflects firstly at the mirror-coated lens array and then strikes the cone prism of the planar waveguide. The prisms are coated by the dichroic mirrors to divide the solar spectrum into two bands. The low-energy band is transmitted and reaches the GaInAsP/GaInAs dual-junction solar cells. The mid-energy band is reflected at the prism surface and coupled inside the waveguide. The exit port of the waveguide is attached with GaInP/GaAs dual-junction solar cells. The simulation results demonstrated a maximum electricity conversion efficiency of 32.88% at the high concentration ratio. The system thickness is 35 mm, which is as thin as the conventional flat photovoltaic panel and system allow for a lateral sun-tracking mechanism. This is suitable for installation on the vehicle's roof. The results showed that the presented flat CPV system is a new approach for a highly efficient application of solar energy to the electrical vehicle.

Towards Holistic Energy-Efficient Vehicle Product System Design: The Case for a Penalized Continuous End-of-Life Model in the Life Cycle Energy Optimisation Methodology

AbstractThe Life Cycle Energy Optimisation (LCEO) methodology aims at finding a design solution that uses a minimum amount of cumulative energy demand over the different phases of the vehicle's life cycle, while complying with a set of functional constraints. This effectively balances trade-offs, and therewith avoids sub-optimal shifting between the energy demand for the cradle-to-production of materials, operation of the vehicle, and end-of-life phases. The present work describes the extension of the LCEO methodology to perform holistic product system optimisation. The constrained design of an automotive component and the design of a subset of the processes which are applied to it during its life cycle are simultaneously optimised to achieve a minimal product system life cycle energy. A subset of the processes of the end-of-life phase of a vehicle's roof are modeled through a continuous formulation. The roof is modeled as a sandwich structure with its design variables being the material compositions and the thicknesses of the different layers. The results show the applicability of the LCEO methodology to product system design and the use of penalization to ensure solution feasibility.

Optimization study on the compressive strength of a passenger vehicle roof

In order to improve the compressive strength of a passenger vehicle roof, in accordance with the Roof Crush Resistance of Passenger Cars (GB26134-2010), the paper rematches the main parts of the roof thickness parameters and optimizes the maximum compressive resistance using finite element analysis, experimental design, the establishment of approximate model and optimization. The results show that, by optimizat ion and rematch, the maximum compressive resistance of roof increased by 3564N and improved the roof safety performance in the case of constant vehicle weight.

A new methodology to study the pantograph–catenary dynamics in curved railway tracks

The pantograph–catenary system is responsible to provide an uninterrupted energy supply to power electric traction railway vehicles. The analysis of the dynamic behaviour of the catenary and pantograph, as well as its interaction, has been the objective of active research to improve energy collection quality. This work proposes an approach for the fully three-dimensional dynamic analysis of pantograph–catenary interaction in general railway tracks including curves. The catenary model and the trajectory of the pantograph base are defined with respect to the track geometry considering the conventional definition used by the rail industry, i.e. the track curvature, cross-level and vertical position. The pantograph is modelled using a multibody formulation being its base motion constrained to follow the generalised trajectory from the railway vehicle roof. The finite element method is used to model the catenary. A co-simulation procedure is set to establish the coupled dynamics of the two systems. In order to demonstrate the methodology, setup models for curved catenaries, analyse modelling implications and highlight applicability, realistic case studies of pantograph–catenary interaction in high-speed rail operations are presented and discussed. In the process, significant differences are found in the dynamic response of the catenary in curved and straight tracks.

Parked electric car's cabin heat management using photovoltaic powered ventilation system

This paper explores the use of electric car roof mounted photovoltaic (PV) powered ventilation for cabin heat management/ventilation. A fully-functional Renault Zoe electric car has been used for performance evaluation of parked electric car ventilation directly powered by PV. This work has been part of a research project of testing electric cars in the urban environment and it has been conducted at the Edinburgh Napier University’s Transport Research Institute. In this work, parked electric car ventilation has been reported, when roof-mounted PV modules were used to operate DC powered fans for ventilation. It has been found that the DC motor-fan selection for removing the hot air from cabin space is of important (i.e. operating characteristics of motor-fan have been very close to the maximum power points locus of the PV modules at different solar insolation). The electric car cabin temperature models with reference to solar radiation have been presented and it will be useful for knowing the parked car cabin temperature variations and designing the car roof mounted PV powered ventilation system. In this paper, performance evaluation of parked electric car’s cabin heat management is presented and analysed. Results from this work will be helpful for designing electric car ventilation system (operating at parking time), when powered by vehicle roof integrated PV modules.

Aeroacoustic analysis of automotive roof crossbars through on-track acoustic measurements

This work concerns the noise radiated by crossbars installed on the roof of automotive vehicles. The Reynolds numbers analyzed range between 98,000 and 147,000 based on the crossbar chord. Through a comparison of results obtained in an aeroacoustic wind-tunnel, we demonstrate that on-track sound pressure measurements from a single in-flow microphone are suitable to study the aeroacoustics of crossbars under realistic operational conditions. The current investigation presents noise measurements by reference profiles such as elliptic and circular crossbars, as well as a NACA 0012 airfoil. Results from the elliptical crossbar show both tonal and broadband components in the noise spectra, combining features observed for the circular bar and the airfoil. For higher Reynolds numbers, the tones observed in the elliptical profile are broad and free of harmonics, similar to those observed for the NACA 0012. The influences of the leading and trailing-edge shapes of the elliptical crossbar on the radiated noise are presented together with the effects of the angle of attack. A thinner trailing edge leads to a reduction in the tonal noise followed by an increase in the broadband content. On the other hand, a blunter leading edge reduces the broadband noise, especially for higher frequencies. Positive angles of attack provide a reduction in both tonal and broadband noise components for the elliptical crossbar, particularly at lower Reynolds numbers.

A Fundamental Consideration of Active Noise Control System by Small Actuator for Ultra-Compact EV

The ultra-compact electric vehicle has recently experienced increasing popularity for short-distance travel. However, one of the issues with ultra-compact electric vehicles is that although the engine is silent, exterior road and wind noise have a significant impact on the occupant’s comfort in the interior space. We propose an ANC system whereby a kind of small actuator is installed on the roof of an ultra-compact electric vehicle. In this paper, we consider the noise control effects of using a giant magnetostrictive actuator and conduct an experimental study on feed-forward and feedback control systems.

Design of Conformal Microstrip Patch Antenna for Vehicle Tracking

The road accidents have increased in the urban areas to the level which is alarming. The accidents cause loss of human life which can be avoided if the accident victim is rescued at the earliest and given the necessary treatment. This paper involves the designing of an antenna unit for the purpose of tracking the vehicles met with the accidents. The tracking unit placed in vehicles requires a low profile antenna to be placed on top of the roof of vehicle. The simulation study of this antenna is performed in Feko Suite and validated in CST.