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Viewing 1 to 30 of 907
2011-04-12
Technical Paper
2011-01-0090
Wei Liu, Wenku Shi Sr
In this paper, a Magneto-Rheological (MR) fluid semi-active suspension system was tested on a commercial vehicle, a domestic light bus, to determine the performance improvements compared to passive suspensions. MR fluid is a material that responds to an applied magnetic field with a significant change in its rheological behavior. When the magnetic field is applied, the properties of such a fluid can change from a free-flowing, low viscosity fluid to a near solid, and this change in properties takes place in a few milliseconds and is fully reversible. A quarter suspension test rig was built out to test the nonlinear performance of MR damper. Based on a large number of experimental data, a phenomenological model of MR damper based on the Bouc-Wen hysteresis model was adopted to predict both the force-displacement behavior and the complex nonlinear force-velocity response.
2013-09-24
Technical Paper
2013-01-2418
Sreedhar Reddy, Vignesh T Shekar
There have always been different approaches when it comes to ‘Bus body architecture’. The design approach has gone through different phases namely, chassis based, semi integral, integral and monocoque. Equally varied is the choice of material for bus super structure. The predominantly used ones are - mild steel with galvanization, stainless steel (SS) and aluminum. This paper discusses the rationale behind choosing stainless steel for the complete bus structure. With rapid development in infrastructure and public mass transit system, it has become imperative to have a robust structure for buses that is durable and crash worthy. Among the family of stainless steels, ferritic stainless steel exhibits excellent mechanical properties with corrosion resistance and better strength to weight ratio compared to the galvanized mild steel.
2013-09-24
Technical Paper
2013-01-2378
Manimaran Krishnamoorthy, Mathew Sam Paul Albert
In this work, durability of the bus structure is evaluated with a Virtual Test Model (VTM).Full vehicle Multi Body Dynamics (MBD) model of the bus is built, with inclusion of flexibility of the bus structure to capture structural modes. Component mode synthesis method is used for creation of flexible model for use in MBD. Load extraction is done by performing MBD analysis with measured wheel inputs. Modal Superposition Method (MSM) is employed in FE along with these extracted loads for calculation of modal transient dynamic stress response of the structure. e-N based fatigue life is estimated. The estimated fatigue life from the modal superposition method show good correlation with the physical test results done in 6-poster test rig.
2013-01-09
Technical Paper
2013-26-0043
Vignesh S, Vijay Ram C, Sachin P
Non air-conditioned buses constitute a major portion of public transportation facilities in many countries across the world. Inadequate cabin air circulation is a major cause of passenger discomfort in these buses. The aim of this study is to model the air flow pattern inside the passenger compartment of a bus and to establish the effect of solutions such as roof vents in improving the air circulation. RANS based CFD simulations with Shear Stress Transport (SST) turbulence model have been carried out using a commercial CFD solver. The CFD methodology has been verified by comparing results with experimentally validated LES simulation results available in literature. The vehicle model used in this study was the shell structure of a bus with an overall length of 7 m and a wheel base of 3.9 m. Simulations were carried out for a four vent configuration which showed an increase of 131% in the average in-cabin air velocity over the baseline model without any roof-vents.
2013-01-09
Technical Paper
2013-26-0038
S. R. Nigade, S. S. Dandge, R. S. Mahajan, H. V. Vankudre
Automotive Industry Standard (AIS)-031 specifies the requirement of strength of large passenger vehicles in case of rollover. In India the certificate is granted after the successful completion of rollover test of the vehicle as per AIS-031. Complete vehicle is used for rollover test in which the vehicle is tilted laterally in the ditch of 800 mm. Such tests with complete vehicle are costly and unaffordable to small bus body builders. So according to Annex 2 of AIS-031, manufacture can carryout rollover on body sections of the vehicle. This is an equivalent approval method which is less costly compared to rollover test on complete vehicle. It requires detailed study of superstructure and selection of weakest body sections from the given superstructure of bus, which in turn requires mass and energy calculation of body section. For doing rollover analysis using body section, bus is selected which has already passed a full-rollover test.
2013-01-09
Technical Paper
2013-26-0100
J. Sai Prasad, N. Chollangi Damodar, T. Sudhakara Naidu
The acceptable noise and vibration performance is one of the most important requirements in a passenger bus as it is intended for widest spectrum of passengers covering all age groups. Gear rattle, being one of the critical factors for NVH and durability, plays a vital role in passenger comfort inside vehicle. The phenomenon of gear rattle happens due to irregularity in engine torque, causing impacts between the teeth of unloaded gear pairs of a gearbox which produce vibrations giving rise to this unacceptable acoustic response. In depth assessment of the dynamic behavior of systems and related components required to eliminate gear rattle. During normal running conditions, abnormal in-cab noise was perceived in a bus. Initial subjective evaluation revealed that the intensity was high during acceleration and deceleration. Objective measurements and analysis of the in-cab noise and vibration measurements had indicated that the noise is mainly due to gear rattling.
2013-01-09
Technical Paper
2013-26-0139
Sathish Kumar P, Vikram Suryavanshi, Manikandan M, Bollishetty Sreedhar
Evaluation of vehicle structural durability is one of the key requirements in design and development of today's automobiles. Computer simulations are used to estimate vehicle durability to save the cost and time required for building and testing the prototype vehicles. The objective of this work was to find the service life of automotive structures like passenger commercial vehicle (bus) and truck's cabin by calculating cumulative fatigue life for operation under actual road conditions. Stresses in the bus and cabin are derived by means of performing finite element analysis using inertia relief method. Multi body dynamics simulation software ADAMS was used to obtain the load history at the bus and cabin mount locations - using measured load data as input. Strain based fatigue life analysis was carried out in MSC-Fatigue using static stresses from Nastran and extracted force histories from ADAMS. The estimated fatigue life was compared with the physical test results.
2013-10-07
Technical Paper
2013-36-0270
Fábio Coelho Barbosa
Intensive use of fossil fuels in densely populated areas has caused adverse environmental effects in cities all over the world. This has fostered the evaluation of alternative technologies for transit applications, like hydrogen fuel cells - electrochemical energy conversion devices that operate with zero emission, quieter and with higher efficiencies than internal combustion engines, specially at part load regimes. Transit bus market is particularly well suited to technology innovations because they are i) centrally fueled and maintained, ii) professionally operated on fixed routes and schedules, iii) tolerate weight and volume requirement of new technologies and, finally, whenever necessary, iv) can be subsidized by government. In this scenario, considerable research, development and testing effort has been dedicated to hydrogen fuel cell bus technology, with the engagement of governments and transit authorities, bus industry and operators.
2013-10-07
Technical Paper
2013-36-0208
Anibal Godoy Machado, Nilton Mitsuro Shiraiwa
With focus on reducing the Green House Gases emissions, the use of biodiesel as an alternative fuel, in special for buses that runs on the Brazilian metropolitan areas has been even higher. Additionally, with the introduction of the new legislation for diesel engines in 2012, CONAMA PROCONVE P7, that in order to attempt to its requirements uses different kinds of exhaust gases after treatment systems, the necessity of knowing the behavior of those “P7 engines” operating with different biodiesel contents on blends with regular fossil fuel or even pure biodiesel has been an important issue to ensure the benefits of using such alternative fuel. On this evaluation, blends of 5%, 10%, 20%, 30%, 50%, 75% and 100% of biodiesel content in ANP65/2011 A_S50 Diesel Fuel (50ppm Sulfur content) was experimented in a Mercedes-Benz OM926LA E5 engine with SCR (Selective Catalyst Reaction) exhaust gases after treatment system.
2013-10-07
Technical Paper
2013-36-0312
I. Coutinho, A. Pereira, C. Sanches, M. Mottin
The internal combustion engine air intake manifold is subjected to continuous dynamic excitation due to unbalanced firing sequence and alternated movement of the pistons. An elastic anchoring for the intake manifold of Iveco's new bus was developed based on two criteria: 1. increase the natural frequency of the system to avoid coupling with engine's NEF 6 idle input and 2. minimize the vibration transmitted to the chassis. In order to solve this duality an optimization algorithm was used to fit cushion stiffness to both requirements. The system behavior is evaluated virtually in frequency domain through FRFs and its modal mode shapes and natural frequencies (eigenvectors and eigenvalues) extracted with Lanczos method.
2013-09-08
Technical Paper
2013-24-0081
Federico Millo, Rocco Fuso, Luciano Rolando, Jianning Zhao, Andrea Benedetto, Filippo Cappadona, Paolo Seglie
Nowadays the increasing demand for sustainable mobility has fostered the introduction of innovative propulsion systems also in the public transport sector in order to achieve a significant reduction of pollutant emissions in highly congested urban areas. Within this context this paper describes the development of the HYBUS, an environmental friendly hybrid bus for on-road urban transportation, which was jointly carried out by Pininfarina and Politecnico di Torino in the framework of the AMPERE project. The first prototype of the bus was built by integrating an innovative hybrid propulsion system featuring a plug-in series architecture into the chassis of an old IVECO 490 TURBOCITY. The bus is 12 meters long and has a capacity of up to 116 passengers in the original layout. The project relied on a modular approach where the powertrain could be easily customized for size and power depending on the specific application.
2011-04-12
Technical Paper
2011-01-0801
Bong-Ha Hwang
Professional bus drivers are highly exposed to physical fatigue and work-related injuries because driving task includes complicated actions that require a variety of ability and cause extreme concentration or strain. For this reason, there has always been some sense of concern regarding driver fatigue, especially for drivers of commercial vehicles. In this study, we have tried to analyze quantitative fatigue degree of urban bus drivers by measuring their physiological signals. The investigation is made up of the following approaches: a traditional questionnaire survey and video-ethnographic method with 4-way cameras. The close-circuit cameras are installed to observe the upper and lower body of real drivers when they are in driving or even resting. This approach can help to understand urban bus drivers' behaviors and fatigue-related issues. Based on the video-ethnographic investigation results above, we have got certain patterns of drivers.
2011-08-30
Technical Paper
2011-01-1965
Reijo Makinen, Nils-Olof Nylund, Kimmo Erkkilä lng, Pirjo Saikkonen, Arno Amberla
Helsinki Region Transport, Neste Oil, Proventia Emission Control and VTT Technical Research Centre of Finland carried out a 3.5 year PPP venture “OPTIBIO” to demonstrate the use of paraffinic renewable diesel (hydrotreated vegetable oil HVO) in city buses. The fleet test in Metropolitan Helsinki involving some 300 buses is the largest one in the world to demonstrate this new fuel. The fuels were a 30 % blend of renewable diesel and 100 % renewable diesel. This paper describes the overall set-up of the project, gives an overview of the emission results as well as presents experience from the field.
2011-08-30
Technical Paper
2011-01-1966
Kimmo Erkkilä, Nils-Olof Nylund, Tuomo Hulkkonen, Aki Tilli, Seppo Mikkonen, Pirjo Saikkonen, Reijo Makinen, Arno Amberla
When switching from regular diesel fuel (sulfur free) to paraffinic hydrotreated vegetable oil (HVO), the changes in fuel chemistry and physical properties will affect emission characteristics in a very positive way. The effects also depend on the technology, after-treatment and sophistication of the engine. To determine the real effects in the case of city buses, 17 typical buses, representing emission classes from Euro II to EEV, were measured with HVO, regular diesel and several blended fuels. The average reduction was 10% for nitrogen oxides (NOx) and 30% for particulate matter (PM). Also some engine tests were performed to demonstrate the potential for additional performance benefits when fuel injection timing was optimized for HVO.
1999-08-17
Technical Paper
1999-01-2906
W. D. Jacobs, L. K. Heung, T. Motyka, W. A. Summers, J. M. Morrison
The H2Fuel Bus is the world's first hydrogen-fueled electric hybrid transit bus (see Figure1.). It was a project developed through a public/private partnership involving several leading technological and industrial organizations, with primary funding by the Department of Energy (DOE). The primary goals of the project were to gain valuable information on the technical readiness and economic viability of hydrogen fueled buses and to enhance the public awareness and acceptance of emerging hydrogen technologies. The bus completed its field-testing and was placed into public service on September 4, 1998 by Augusta Public Transit in Augusta, Georgia. The bus employs a hybrid Internal Combustion (IC) engine/generator and battery powered electric drive system, with onboard storage of hydrogen in metal hydride beds.
1999-11-15
Technical Paper
1999-01-3781
Ragnar Ledesma, Shan Shih
The uniqueness and challenge of heavy and medium duty vehicle manufacturing is that the vehicle&s subsystems and major components are procured from different suppliers. As a consequence, engineering task coordination for total vehicle performance optimization is required even if the intended design modification is only on one component. In the case of suspension design, related subsystems such as the drive axle, driveline, brake system, steering system, and engine mounts should all be included for review. The related potential problems for study fall into three categories, namely: function, durability, and NVH. The effective approach in addressing all these issues early in the design stage is through computer modeling and dynamic system simulation of the suspension system and related subsystems.
2012-06-01
Technical Paper
2011-01-2469
Nigel Clark, David L. McKain, W Wayne, Daniel Carder, Mridul Gautam
West Virginia University characterized the emissions and fuel economy performance of a 30-foot 2010 transit bus equipped with urea selective catalytic reduction (u-SCR) exhaust aftertreatment. The bus was exercised over speed-time driving schedules representative of both urban and on-highway activity using a chassis dynamometer while the exhaust was routed to a full-scale dilution tunnel with research grade emissions analyzers. The Paris speed-time driving schedule was used to represent slow urban transit bus activity while the Cruise driving schedule was used to represent on-highway activity. Vehicle weights representative of both one-half and empty passenger loading were evaluated. Fuel economy observed during testing with the urban driving schedule was significantly lower (55%) than testing performed with the on-highway driving schedule.
2011-10-06
Technical Paper
2011-28-0066
Stanislav N. Florentsev, Dmitry B. Izosimov, Sergey B. Baida, Alexander A. Belousov, Andrey N. Sibirtsev, Sergei V. Zhuravljov
A city bus LIAZ 5292XX is a result of teamwork of "RUSELPROM" Corp. and the "Likino Bus Works." By the results of the International Automobile Forum, Moscow, Russia, 2008 the bus has been recognized as the best bus of year in Russia. LIAZ 5292XX with hybrid power train provides the following values: bus length is 12 m; maximum (peak) traction power is about 250 kW; maximum speed 90 km/h; movement on 20% (12°) grade is possible. The bus carries ICE; electric traction IM; generator IM; buffer super capacitor. Parameters and block diagrams of the traction electric equipment set (TEES) of the city bus are presented in the article. The control algorithm of power flows which provides the main fuel economy is considered. Results of benchmark tests are given. The special software - Service Computing System visualizes parameters of TEES operating variables; presents and processes of the graphic information; loads, saves and views in graphic and table form the files of emergency logs.
2011-10-06
Technical Paper
2011-28-0067
Arghya Sardar, Sajid Mubashir
Emission reduction and fuel economy are the primary drivers for public transport authorities. Electric propulsion is efficient, and do not produce any local emissions. However, achieving range similar to IC engine vehicles would require large battery pack, and considering this plug-in hybrid technology may be attractive options for public transport buses. Advances in battery technology and power electronics have enhanced the possibility of plug-in hybrid vehicles penetrating market in near future. Rising fuel prices and concerns over green house gases as well as other emissions have made it essential to consider such options seriously. Globally there are many efforts towards development of plug-in hybrid vehicles and Indian vehicle manufacturers have also demonstrated plug-in hybrid buses. Such vehicles can offer higher benefits in Indian congested traffic. However, it is required to evaluate the comparative environmental performance of plug-in hybrid vehicles in life-cycle analysis.
2011-10-06
Technical Paper
2011-28-0065
Yongrae Kim, Yonggu Lee, Kyonam Choi, Dongsoo Jeong
High-powered vehicles offer an advantage of superior fuel economy through use of regenerative braking and lowered transient emissions by reducing the operating portion of the engine to follow load as closely as in a conventional bus. A hybrid bus was designed and a prototype was developed. It has a parallel-type hybrid powertrain system and uses a 6-liter diesel engine which satisfy Euro-5 emission standard. 44-kW-electric motor, AMT (automated manual transmission) and Li-ion-type batteries were applied to this hybrid bus. Total 8 hybrid buses are test-running in 6 cities and the driving performances are monitored in terms of fuel efficiency, emission and convenience. This paper presents the performance, major component features and calibration procedures of hybrid powertrain systems. Test run monitoring result showed a benefit of fuel economy at least 36% by comparing to a conventional diesel-powered bus.
2011-10-06
Technical Paper
2011-28-0054
Suresh Babu Muttana, Arghya Sardar, Sajid Mubashir
Sustainable mobility has become priority in the wake of environmental concerns viz. emissions and depletion of fossil fuels. The growing demand for more fuel-efficient vehicles to reduce energy consumption and air pollution is a challenge for the automotive industry. Significant improvements in fuel economy can be obtained by weight reduction of vehicle as well as by improvements in engine and powertrain efficiency. If the vehicle body mass is reduced, there will be secondary mass reductions at the component level, particularly in the powertrain. Globally, automotive manufacturers have been engaged in efforts to develop lighter alternatives using aluminium alloys and other light weight materials, so as to reduce the energy requirement, improve the fuel consumption and reduce vehicular emissions. While the growth in mobility is growing rapidly in India, the installed base is still comparatively small, compared to the developed countries.
2011-09-11
Technical Paper
2011-24-0083
Laura Tribioli, Fabrizio Martini, Giovanni Pede, Carlo Villante
Hybrid electric vehicles (HEVs) are worldwide recognized as one of the best and most immediate opportunities to solve the problems of fuel consumption, pollutant emissions and fossil fuels depletion, thanks to the high reliability of engines and the high efficiencies of motors. Moreover, as transport policy is becoming day by day stricter all over the world, moving people or goods efficiently and cheaply is the goal that all the main automobile manufacturers are trying to reach. In this context, the municipalities are performing their own action plans for public transport and the efforts in realizing high efficiency hybrid electric buses, could be supported by the local policies. For these reasons, the authors intend to propose an efficient control strategy for a hybrid electric bus, with a series architecture for the power-train.
2011-01-19
Technical Paper
2011-26-0092
Vikas Yadav, Gerardo Olivares
Public transportation system and specifically transit bus systems are key element of the national transportation network in United States. Buses are one of the safest forms of transportation. Nonetheless, bus crashes resulting in operator injuries and fatalities do occur. According to National Transportation Statistics from 1990-2002, the number of transit motor buses in the U.S. has increased by 30% [1]. The majority of fatal crashes involving transit buses result from frontal crashes which could be fatal for bus operators. Therefore, crashworthiness research is a continuing effort. Research has been performed to analyze and improve the safety of transit bus operators. This paper describes the design, analysis and testing of an inflatable restraint system for a bus operator. At present a three point restraint is the only safety feature implemented on transit buses. The primary objective was to study the level of safety provided by the present safety system.
2011-01-19
Technical Paper
2011-26-0093
Chandrashekhar K. Thorbole, David A. Renfroe, Stephen A. Batzer, Digvijay S. Tanwar
The necessity for avoiding the occupant ejection from their seats during motor coach rollover accidents is of supreme importance. The seat belt as a safety device is the best practical way of achieving this task. As per the motorcoach Enhanced Safety Act of 2009 passed in the United States senate, requires new motorcoaches to be installed with safety belts for each seating position. This bill also suggests the possibility of retrofitting seat belts on the existing motorcoaches. The use of portable seatbelt to restraint occupant is more economical as compared to retrofit the seat belt. This fact motivates the further research on portable restraint device. This paper demonstrates the evaluation of the first version of the Portable Restraint Device (PRD) using full scale bus rollover test. This test identified the shortcoming of this current device in securing to the bus seat and its non user friendly design.
2004-11-16
Technical Paper
2004-01-3257
Ivan Roger Scansani Gregori
1. SUMMARY There is a large variation in the results of the durability of friction facings in field applications and in most cases there is very little information about the conditions in which the vehicle operated and therefore it was decided to developed a test procedure capable of containing all the different conditions of a vehicle. For this works statistical applications such as DOE (Experimental Design for Experiment) were used to help in planning and to obtain of equations of the tests results and Weibull curves for statistical analysis and comparison of failure mode. By this mean, it was possible to determine a correlation of the results on wear between the bench test and mileage covered on vehicle up to total wear. Therefore it is new possible to estimate the durability of friction facing on vehicles based on bench tests and also obtain knowledge about the behave of the material relative to energy and working temperature.
2012-04-16
Technical Paper
2012-01-0651
Caixia Yang, Eric Bibeau, G Paul Zanetel
Public transit bus fuel consumption is a function of the duty cycle, power demand when driving and idling, and the efficiency of the bus. Accurate evaluation of fuel consumption is best assessed by comparative testing over relevant drive cycles. Generally, in transit service, a bus serves along predetermined route and bus stops. To increase the accuracy of fuel consumption estimation to simulate buses electrification scenarios, a fuel consumption simulation model for transit buses is carried out based on the analysis of a large number of transit bus journeys composed of 82 buses tested along 124 testing routes. The bus fuel consumption simulation is executed using Matlab. The estimation fuel consumptions for representative service routes with different passenger loads and bus model year are obtained. The simulation results on transit bus fuel consumption are compared with values available from testing reports and fuel consumption estimated by Winnipeg Transit.
2012-11-25
Technical Paper
2012-36-0632
Guilherme Zardo Selbach, Celso Cruz, Rafael Mazzorana, Gustavo Bastchen, Andre Piekarski, Rodrigo Martins, Gustavo Hindi
Health related problems in over populated areas are a major concern and as such, there are specific legislations for noise generated by transport vehicles. In diesel powered commercial vehicles, the source for noise are mainly related to rolling, transmission, aerodynamics and engine. Considering internal combustion engine, three factors can be highlighted as major noise source: combustion, mechanical and tailpipe. The tailpipe noise is considered as the noise radiated from the open terminations of intake and exhaust systems, caused by both pressure pulses propagating to the open ends of the duct systems, and by vortex shedding as the burst leaves the tailpipe (flow generated noise). In order to reduce noise generated by vehicles, it is important to investigate the gas interactions and what can be improved in exhaust line design during the product development phase.
2012-10-02
Technical Paper
2012-36-0540
Silvia M. S. G. Velazquez, Jose Roberto Moreira, Sandra M. Apolinario
This work has as its purpose to evaluate the greenhouse effect gases (GHGs) emissions from ethanol-powered buses, which were introduced in the urban transportation system of the city of São Paulo, in 2007, by means of Project BEST - BioEthanol for Sustainable Transport with the goal of promoting ethanol usage in substitution to diesel in public transportation, aiming at the reduction of atmospheric pollution in great urban centers and at the reduction of global warming. The engine is advanced even for the strict European emission standards, because it meets the EURO 5 specifications and the Enhanced Environmental Vehicle (EEV), besides surpassing the limits imposed by the P-7 stage of PROCONVE. Today, ethanol-powered buses became a reality, because the chassis and the engine, then imported, as well as the additive for the ethanol, are already manufactured in Brazil.
2013-04-08
Technical Paper
2013-01-0212
Aaron Jones, Nicole Schimpf, Normand Dube
Buses often combine high occupancy loads, limited pathways for egress, and the involvement of passengers with limited mobility. In the event of a fire, the potential for passenger injury and loss of life is significant. Additionally, there can be substantial financial losses due to equipment loss and service interruption. In order to prevent future occurrences, it is critical to thoroughly investigate bus fires and develop an understanding of their causes. The causes of non-arson bus fires typically can be categorized as electrical, friction at the wheel level, or engine component failures. This paper examines actual fire occurrences, their root cause investigation, and the measures that were taken to prevent future incidents.
2013-04-08
Journal Article
2013-01-0210
Marty Ahrens
Automobile fires account for the majority of vehicle fires and vehicle fire deaths. Fires involving larger trucks resulted in a disproportionate share of vehicle fire losses. Although bus fires are less common, they have a much higher rate of fire based on distance driven. Bus fires have the potential to endanger a larger number of passengers. Any efforts to evaluate the merits of proposed fire safety improvements require an understanding of how many fires and deaths are presently occurring and how many might be prevented with the proposed improvements. Data from the U.S. Fire Administration's National Fire Incident Reporting System (NFIRS) and the National Fire Protection Association's (NFPA's) fire department survey were used to estimate the frequency and associated losses of such fires attended by local U.S. fire departments, and the major factors in these fires and losses.
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