SWUTC Research Project Description

Title of Project: Comparisons Between Vehicular Emissions Of Real-World In-Use And Regulatory Dynamometer Driving

Project Number:  476660-00021

Principal Investigator:
Doh-Won Lee
(979) 862-2232
P.I. Affiliation:  Texas A&M University

Project Monitor:
John M. E. Storey, Ph.D.
Oak Ridge National Laboratory
Distinguished Research Staff
Fuels, Engines, and Emissions Research Center
P.O. Box 2008 MS6472
Oak Ridge, TN 37831-6472
(865) 946-1232

Project Status:  Active

Date Started:  9/1/09

Estimation Completion Date:  8/31/10

Estimated Cost - Current Fiscal:  $65,475

Estimated Cost - Total Planned:  $65,475

Project Summary:
Project Abstract:
Currently, mandatory vehicular exhaust emission tests are performed on chassis or engine dynamometers using drive or duty cycles. Although there have been many real-world in-use vehicular emissions studies, none can directly compare the dynamometer emissions tests in laboratories and in-use emissions tests under real-world conditions because it is not possible to follow the cycles in real-world using normal vehicles. (During real-world driving, a driver cannot steer the vehicle, handle the brake and accelerator at the same time while watching a screen to follow the speed profiles of the drive cycles.)

TTI researchers will modify a TTI test vehicle by adding slave acceleration and brake pedals, which will allow two drivers to maneuver the vehicle simultaneously to follow the drive cycles while driving on a test track. The vehicle will be tested while following the drive cycles on a test track as well as on a chassis dynamometer. The collected data while driving on the test track will be directly compared to the data on the chassis dynamometer. This research will examine if current EPA vehicular emissions testing results are realistic under real-world driving conditions. In addition, this research will develop a procedure on how to collect emission data that is directly comparable to laboratory testing.

Project Objectives:
The research project will focus on the following four objectives:

• Modification of a TTI’s test vehicle to perform real-world vehicle emissions measurement while following FTP drive cycles
• Development of a methodology for emissions measurement tests
• Regulatory chassis dyno and real-world emissions measurements
• Comparison and analysis of the measured vehicle emissions data

Task Descriptions:
Task 1: Literature Review.
Current EPA and CARB vehicular emissions standards and test procedures will be reviewed. Existing reports and articles pertaining to regulatory dynamometer and in-use real-world vehicular emissions tests will be examined.

Task 2: Test Methodology & Plan Development.
TTI researchers will develop a testing methodology for real-world emissions measurement while following FTP drive cycles in order to make the measured results directly comparable to regulatory testing results. Also, a detailed test plan will be developed.

Based on preliminary investigation, TTI researchers are planning to perform regulatory chassis dyno testing at Oak Ridge National Laboratory (ORNL), Knoxville, TN in order to accommodate with the project budget. The estimated cost for testing at ORNL, including chassis dyno testing fee, test vehicle transportation, and travel, is about $6,500 (excluding indirect costs), which is much lower than $21,000, the estimate for testing at Southwest Research Institute (the only laboratory providing gasoline vehicle dyno testing in Texas). For real-world emissions testing, TTI researchers are planning to perform the testing on 9 mile circular tracks at Pecos Research & Testing Center, Pecos, TX where FTP drive cycles can be followed much safer than at a 3 mile rectangular track at TTI’s Riverside Campus (RC), Bryan, TX. (TTI researchers examined the track at TTI’s RC and concluded that turning maneuver at corners of the rectangular track while following FTP drive cycles is highly unsafe and should be avoided. The detailed test plan will include:  
-           Coordination of real-world in-use testing on a test track
-           Coordination of chassis dynamometer testing
-           Train drivers to follow the FTP drive cycles using the modified TTI test vehicle
-           TTI test vehicle transportation and TTI researchers’ travel for testing

Task 3: Test Vehicle Modification.
A TTI test vehicle (a light-duty gasoline vehicle) will be modified for real-world in-use vehicle emissions testing. Slave acceleration and brake pedals will be added in the vehicle to allow the vehicle to follow the drive cycles on a test track. After the modification, the modified vehicle’s drivability on a test track for the emissions testing will be examined prior to the actual emissions testing.

Task 4: Emissions Testing.
Regulatory and real-world emissions testing will be performed. The vehicle will be tested while following the drive cycles on a test track as well as on a chassis dynamometer. The drive cycles will be repeated at least three times to obtain statistically meaningful data. For cold start testing, which can be done once a day, however, only two tests will be conducted for each of dyno and real-world testing due to the limited budget. For both testing, TTI’s portable emissions measurement systems (PEMS) will be used to collect emissions data.

Task 5: Emission Result Comparisons and Analysis.
The measured emissions data collected from the chassis dynamometer and the test track testing will be compared and analyzed. Direct comparisons between the measured emissions data tested on a dynamometer and real-world driving will provide information of effectiveness of current emissions tests using dynamometers.

Task 6: Preparation of Final Report and PowerPoint Presentation.
A final report, including an executive summary, will be prepared documenting the findings and developed methodology. A PowerPoint presentation summarizing research findings and conclusions will also be prepared. The presentation will be designed to be delivered on-line or in person to any interested parties.

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