Modeling and Simulation for Advanced Technology Vehicles
There is a critical need for improved vehicle performance simulation tools in order to optimize the design and selection of drive components for electric and hybrid electric transit vehicles. CETE has developed a Topographical Inertial Energy Simulator (TIES) has been developed as a design tool that incorporates topography and curvature of the planned route, vehicle weight, requirements for acceleration and instantaneous speed, aerodynamic drag and rolling resistance, and overall energy efficiencies for each of the components that make up the drive train of a hybrid transit vehicle. When used in conjunction with models of the energy conversion processes required to charge and discharge electrical components (batteries and ultracapacitors) and models of the overall “well to wheel” efficiency characteristics of petroleum based fuels, TIES can be used to compare predicted performance of hybrid electric transit vehicles that use various combinations of internal combustion engines, fuel cells, ultracapacitors, and batteries.
Data Acquisition System for Electric and Hybrid Electric Vehicles
The Data Acquisition System (DAS) developed by the Center for Energy, Transportation and the Environment (CETE) at the University of Tennessee at Chattanooga (UTC) permits operating agencies to understand, in real time, the impact that an operator and/or service requirement has on the entire electric- or hybrid-electric propulsion system and, more specifically, the batteries. It can be used to increase the utility and successful implementation of a electric- or hybrid-electric bus fleet by providing data on driving techniques, energy consumption versus road/load conditions and the energy requirements of existing and potential routes. In essence, this operational mode of the DAS system performs the functions of a digital storage oscilloscope, thereby enabling sophisticated evaluation and diagnosis. Three prototype DAS units were developed, fabricated, and installed on battery-electric buses operating in Santa Barbara, California, and Emory University in Atlanta, Georgia, and on a hybrid-electric bus operating in Sevierville, Tennessee.
Dynamic Message Sign (DMS) System for Transit Bus Stops
In conjunction with the Chattanooga Area Regional Transportation Authority (CARTA), a Dynamic Message Sign (DMS) system was deployed that involved the installation of real-time electronic passenger information signs on the UT Chattanooga campus and at other strategic locations important to university passengers. Implementation of the DMS system supports CETE’s “Smart and Clean” approach to campus transit by deploying ITS technologies on advanced technology and clean fuel vehicles. The need for improved passenger information at bus stops was identified as a top priority during the development of the UTC Campus Transit Plan and this project provided a near-term remedy for addressing this issue.
The real-time passenger information system, or dynamic message sign (DMS) system, is intended to improve customer satisfaction in such a manner as to lead to increased ridership on campus-related transit services. DMS communicates real-time arrival and departure information to passengers via electronic bus stop signs, the internet and wireless hand-held devices such as mobile phones and Personal Digital Assistants (PDAs). The system greatly increases customer access to real-time information by allowing for user-defined views and automated notification of bus arrival times on hand-held devices. This real-time system not only communicates precise arrival and departure times, but also provides passengers with critical information regarding service interruptions, emergencies and other important public service announcements and campus-related event notices. DMS utilizes Global Positioning Satellite (GPS) technology to identify bus locations as well as provides for predictive modeling. The system calculates the arrival time of buses for specific routes and stops and provides definitive information for passengers addressing the uncertainty that often exists at bus stops for passengers.