Your Selections

Buses
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Committees

Events

Magazine

Series

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Formula SAE Data Acquisition and Detailed Analysis of a Lap

Georgia Southern University-Connor M. Ashford, Aniruddha Mitra
  • Technical Paper
  • 2020-01-0544
To be published on 2020-04-14 by SAE International in United States
Formula Society of Automotive Engineers (FSAE) International is a student design competition organized by SAE. The student design involves engineering and manufacturing a formula style racecar and evaluating its performance. Testing and validation of the vehicle is an integral part of the design and performance during the competition. At the collegiate level the drivers are at the amateur level. As a result, the human factor plays a significant role in the outcome of the dynamic events. In order to reduce the uncertainty factor and improve the general performance, driver training is necessary. Instead of overall performance of the driver based on individual lap, our current research focuses on the more detailed components of the driver’s actions throughout different sections of the lap. A complete lap consists of several components, such as, straight line acceleration and braking, max and min radius cornering, slalom or “S” movements, and bus stops or quick braking and turning. In order to evaluate the performance of each driver in each of these components, an AiM data acquisition system is mounted in…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Hydrogen Fuel Cell Buses: Modelling and Analysing Suitability from an Operator and Environmental Perspective

Queen's University Belfast-Darryl Doyle, Andrew Harris, Steve Chege, Lucinda Douglas, Juliana Early
Wrightbus-Robert Best
  • Technical Paper
  • 2020-01-1172
To be published on 2020-04-14 by SAE International in United States
Global commitments to decrease greenhouse gas emissions have led to a shift to alternative powertrains in the transport sector. In addition to this, stricter controls on air quality within cities has seen the introduction of zero emission zones, requiring vehicles with full zero emission capabilities. As a result, there is growing interest in hydrogen fuel cell electric buses (FCEBs) as a zero local emission vehicle with superior range, operational flexibility and refuelling time than other clean alternatives e.g. battery electric buses (BEBs). This is illustrated in increased investment through projects such as JIVE/JIVE2, which are deploying nearly 300 FCEBs and refuelling infrastructure in Europe by the early 2020s. This paper details the performance and suitability analysis of a proposed FCEB, using a quasistatic backwards-facing Simulink powertrain model. The model is validated against existing vehicle data (Mk1), allowing it to be further leveraged for predictions of an advanced future production vehicle (Mk2) with next generation motors and fuel cell stack. The modelled outputs are used for a comparison of the FCEB performance to an equivalent BEB…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Study of thermal efficiency improvement by multi-hole nozzle

Hino Motors Ltd.-Kazunori Yoshitomi, Yoshihiro Funayama, Mori Ishii, Hiroshi Nakajima
  • Technical Paper
  • 2020-01-0304
To be published on 2020-04-14 by SAE International in United States
A truck and bus transportation which support logistics and people, diesel engines are highly expected to have high thermal efficiency and low exhaust emissions over the next few decades. Effective methods to achieve even higher thermal efficiency are to reduce a cooling loss from combustion chamber wall. A multi-hole diesel injector has a significant impact on improving engine thermal efficiency by enhancing a combustion activity and reducing a cooling loss. In this study, two types of diesel injectors – 8-hole and 14-hole - with the same flow rate were tested under heavy-duty diesel engine condition. Heat release rate, energy balance and engine emissions were investigated using the single-cylinder engine with displacement of 1,478 cc. Furthermore, an optical engine was used to observe quantitative spray penetration and flame development from shadowgraph imaging and analyze flame temperature by a two-color method. The results of the single-cylinder engine showed that the 14-hole injector exhibited higher indicated thermal efficiency thanks to lower cooling loss than 8-hole results. However, we observed a slightly higher exhaust loss in the case of…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Statistical Analysis of City Bus Driving Cycle Features for the Purpose of Multidimensional Driving Cycle Synthesis

University of Zagreb-Jakov Topić, Branimir Skugor, Josko Deur
  • Technical Paper
  • 2020-01-1288
To be published on 2020-04-14 by SAE International in United States
Driving cycles are typically defined as time profiles of vehicle velocity, and as such they reflect basic driving characteristics. They have a wide application from the perspective of both conventional and electric road vehicles, ranging from prediction of fuel/energy consumption (e.g. for certification purposes), estimation of greenhouse gas and pollutant emissions to selection of optimal vehicle powertrain configuration and design of its control strategy. In the case of electric vehicles, the driving cycles are also applied to determine effective vehicle range, battery life period, and charging management strategy. Nowadays, in most applications artificial certification driving cycles are used. As they do not represent realistic driving conditions, their application results in generally unreliable estimates and analyses. Therefore, recent research efforts have been directed towards development of statistically representative synthetic driving cycles derived from recorded GPS driving data. The state-of-the-art synthesis approach is based on Markov chains, typically including vehicle velocity and acceleration as Markov chain states. However, apart from the vehicle velocity and acceleration, a road slope and vehicle mass are also shown to significantly impact…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

An Electric Motor Thermal Bus Cooling System for Vehicle Propulsion – Design and Test

CCDC Ground Vehicle Systems Center-Katherine Sebeck
Clemson University-Shervin Shoai Naini, Richard Miller, John Wagner
  • Technical Paper
  • 2020-01-0745
To be published on 2020-04-14 by SAE International in United States
Automotive and truck manufacturers are introducing electric propulsion systems into their ground vehicles to reduce fossil fuel consumption and harmful tailpipe emissions. The mobility shift to electric motors requires a compact thermal management system that can accommodate heat dissipation demands with minimum energy consumption in a confined space. An innovative cooling system design, emphasizing passive cooling methods coupled with a small liquid system, using a thermal bus architecture will be explored. The laboratory experiment features an emulated electric motor interfaced to a thermal cradle and multiple heat rejection pathways to evaluate the transfer of generated heat to the ambient surroundings. The thermal response of passive (e.g., carbon fiber, high thermal conductivity material, thermosyphon) and active cooling systems are investigated for two operating scenarios. The test results demonstrate significant improvements can be achieved in cooling system energy consumption while maintaining a target e-motor temperature of 70℃. The governing thermal system dynamics will be reviewed in discussion of the experimental observations.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Dyno-in-the-Loop: An Innovative Hardware-in-the-Loop Development and Testing Platform for Emerging Mobility Technologies

Oak Ridge National Laboratory-Zhiming Gao, Tim LaClair
University of California Riverside-Guoyuan Wu, Dylan Brown, Zhouqiao Zhao, Peng Hao, Michael Todd, Kanok Boriboonsomsin, Matthew Barth
  • Technical Paper
  • 2020-01-1057
To be published on 2020-04-14 by SAE International in United States
Today’s transportation is quickly transforming with the advent of shared-mobility, vehicle electrification, connected vehicle technology, and vehicle automation. These technologies will not only affect our safety and mobility, but also our energy consumption, air pollution, and climate change. As a result, it is of unprecedented importance to understand the overall system impacts, as a result of introducing these emerging technologies and concepts. However, existing modeling tools are not able to properly capture the implications of these technologies, not to mention accurately and reliably evaluating their effectiveness with a reasonable scope. For example, it is quite challenging to calibrate state-of-the-art microscopic traffic simulators to properly model the behavior of automated vehicles or to address potential cyber-security issues in a Connected Vehicle (CV) environment. It is even more difficult to scale up the assessment on a larger spatial scale (e.g., statewide, nationwide) or to project these impacts over a longer temporal span. To address these gaps, we have developed a Dyno-in-the-Loop (DiL) development and testing approach which integrates a test vehicle, a chassis dynamometer, and high fidelity…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Deep Learning-based Queue-aware Eco-Approach and Departure system for Plug-in Hybrid Electric Bus at signalized intersections: a simulation study

Oak Ridge National Laboratory-Zhiming Gao, Tim LaClair
University of California-Fei Ye, Peng Hao, Guoyuan Wu, Danial Esaid, Kanok Boriboonsomsin, Matthew Barth
  • Technical Paper
  • 2020-01-0584
To be published on 2020-04-14 by SAE International in United States
Eco-Approach and Departure (EAD) has been considered as a promising eco-driving strategy for vehicles traveling in an urban environment, where signal phase and timing (SPaT) and geometric intersection description (GID) information are well utilized to guide the vehicles passing through the intersection in a most energy efficient manner. Previous studies by the authors formulated the optimal trajectory planning problem as finding the shortest path on a graph model where the nodes define the reachable states of the host vehicle (e.g., speed, location) at each time step, the links govern the state reachability from previous time step, and the link costs represent the energy consumption rate due to state transition. This method is effective in energy saving, but its computation efficiency can be enhanced by machine learning techniques. In this paper, we propose an innovative Deep Learning-based Queue-aware Eco-Approach and Departure (DLQ-EAD) System for a Plug-in Hybrid Electric Bus (PHEB), to provide an online optimal vehicle trajectory considering both the downstream traffic conditions (i.e. traffic lights, queues) and vehicle powertrain efficiency. Based on the optimal solutions…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Advanced Driver-Assistance Systems for City Bus Applications

Kowloon Motor Bus Co.-Chun Yi Lo
Queen's University Belfast-Luke Blades, Roy Douglas, Juliana Early
  • Technical Paper
  • 2020-01-1208
To be published on 2020-04-14 by SAE International in United States
In 2018 there were over 1,700 fatalities on Great Britain roads, with over 25,000 people seriously injured. With vehicle miles increasing each year it is important that there is improved on-road safety, both for passenger cars and for public transport. Nowadays, advanced driver-assistance systems (ADAS) are widely utilized, with the EU Commission mandating ADAS such as autonomous emergency braking (AEB), lane-keeping assistance and reversing cameras on all new cars from 2021. Transport for London have introduced the Bus Safety Standard, within which is the requirement for ADAS systems, many of which are due to become mandatory from 2021. This study uses statistical analysis of bus accidents that have occurred across Great Britain in order to determine which ADAS technologies may result in the largest reduction of potential bus accidents. It discusses the technologies available for bus applications and compares those that are appropriate with those utilized on cars. Police reported traffic accident data for Great Britain, over the period 2011-2017, was filtered down to over 30,000 injuries caused by accidents involving buses. From this data…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Variability of driving conditions and its effect on charging time for urban battery electric buses

University of Michigan-Anshul Paunikar, Rasoul Salehi
  • Technical Paper
  • 2020-01-0598
To be published on 2020-04-14 by SAE International in United States
Due to growing environmental concerns and stringent vehicle emissions regulations, there is a constant urge in the automotive industry to move towards electrified propulsion systems. Public transportation plays a major role in contributing towards lowering the emission level. Battery electric buses are regarded as a type of promising green mass transportation as they provide the advantage of less greenhouse gas emissions per passenger. However, the electric bus poses a threat of limited range and is not able to drive throughout the day without being charged again. This research focuses on the current bus transit systems in the city of Ann Arbor and investigates the impact of different electrification levels on the final CO2 reduction. Utilizing models of a conventional diesel bus, hybrid electric bus, and battery electric bus, the CO2 emission for each type of transportation bus is estimated. Measured vehicle speed data from various routes under different driving conditions are used to investigate the variability of performance metrics. Finally, recommendations are made for charge requirements of battery electric bus considering the variation in drive…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Improving the design and analysis of commercial bus structures using vehicle performance envelopes

Queen's University Belfast-Michelle McIlroy, Adrian Murphy, Damian Quinn, Trevor Robinson
  • Technical Paper
  • 2020-01-0207
To be published on 2020-04-14 by SAE International in United States
A challenge in structural design is the inability to quickly assess how a change in use can affect the structural performance of the system. This is particularly important in the bus industry with multiple variations of one base product type for many customers. Thus for a single design there can be frequent changes to mission profiles or customer constraints, which must be considered within short time periods before production commences for a particular customer. This can often limit full understanding of the structural performance, key structural features or critical failure modes, ultimately limiting the potential for producing buses with minimum structural mass. The proposed method in this paper aims to develop a design tool capable of rapidly informing structural design engineers with respect to the structural limitations of various vehicle components using performance envelopes. Vehicle performance envelopes define the combination of global vehicle accelerations (lateral, vertical and longitudinal) that cause structural failure of any feature or component included in the envelope. Additionally, envelopes will enable definition of the critical (non-redundant) and redundant structural failure modes…