Project. Emissions measurement

Principal investigator. Hesham Rakha, Virginia Polytechnic Institute and State University, 540-231-1505, Rakha@vtti.vt.edu

Project objective. This project aims to refine the practice of measuring vehicle emissions, by supporting the Virginia Department of Environmental Quality on three tasks: 1) converting emissions concentration measurements to emissions rates; and 2) devising techniques to account for the lag between speed/acceleration measurements and tailpipe emission measurements, and 3) devising techniques for screening high emitting vehicles.

Project abstract
Task 1. Converting emissions concentration measurements to emission rates. A 1998 study in Houston, Texas, used linear relationships convert measured emissions to emission rates, but this methodology has raised questions. This task attempts to develop a new conversion methodology from emission concentrations to emission rates based on emission data collected from on-board emission measurements as well as remote sensing concentration measurements. On-road Emission Measurement (OEM) systems are portable emission measurement units that measure tailpipe emissions during actual on-road driving. The state-of-practice relationships will be extended to include other emissions such as CO2, NOx, and PM. Our models will consider a number of factors, including the engine displacement and the Vehicle Specific Power (VSP).

Task 2. Devising techniques to account for the lag between speed/acceleration measurements and tailpipe emission measurements. This task will involve devising techniques to estimate the lag and make multiple speed recordings in order to associate emissions with the correct speed/acceleration levels.

Task 3. Devising techniques for screening of high emitting vehicles. This task will involve looking at the Remote Sensing emission data from data gathered in 2004 to data gathered in 2002. Techniques of identifying high emitting vehicles will be devised and tested for the screening of high emitting vehicles.

Tasks
Task 1. Converting emissions concentration measurements to emission rates.
Task 2. Devising techniques to account for the lag between speed/acceleration measurements and tailpipe emission measurements.
Task 3. Devising techniques for screening of high emitting vehicles.

Milestones
Task 1. Completion by Dec. 31, 2005.
Task 2. Completion by March 31, 2006.
Task 3. Completion by June 30, 2006.
Student involvement. One GRA

Budget. FY 06
Faculty 40,000
GRA 10,000
Match 30,000 (Virginia Department of Environmental Quality)

Relation to other research. This research effort extends the research that is currently being done as part of the ITS Implementation project "Modeling Energy and Environmental Impacts of ITS." Specifically, the energy and environmental models that were developed in the "Modeling Energy and Environmental Impacts of ITS" will be used to screen high emitting vehicles.

Technology Transfer. Technology transfer will be conducted via conference presentations and journal publications and the potential application of the developed procedures for the screening of high emitting vehicles by the Virginia Department of Environmental Quality.

Potential Benefits. Enhancing the environment through the removal of high emitting vehicles from the vehicle fleet. Studies have shown that between 5 to 10% of the vehicle fleet are responsible for 50% of the vehicle emissions, so the application of these improved techniques to a small percentage of the Commonwealth's total number of vehicles could yield substantial improvements to the environment.

TRB Keywords. Energy and emission modeling, high emitting vehicle screening, remote sensing, and emission inventories.