EPA-600/R-05/090a August 2005 Heavy-Duty Diesel Vehicle Modal Emission Model (HDDV-MEM) Volume I: Modal Emission Modeling Framework EPA-600/R-05/090a August 2005 Heavy-Duty Diesel Vehicle Modal Emission Model (HDDV-MEM) Volume I: Modal Emission Modeling Framework by Randall Guensler Seungju Yoon Chunxia Feng Hainan Li Jungwook Jun School of Civil and Environmental Engineering Georgia Institute of Technology Atlanta, GA Contract No: 4C-R022-NAEX EPA Project Officer: Sue Kimbrough U.S. Environmental Protection Agency National Risk Management Research Laboratory Air Pollution Prevention and Control Division Research Triangle Park, NC 27711 U.S. Environmental Protection Agency Office of Research and Development Washington, DC 20460 Abstract The research reported in this document outlines a proposed heavy-duty Diesel vehicle modal emission modeling framework (HDDV-MEMF) for heavy-duty diesel-powered trucks and buses. The heavy-duty vehicle modal modules being developed under this research effort, although different from the structure within the motor vehicle emissions simulator (MOVES) model, should be compatible with it. In the proposed HDDV-MEMF, emissions from heavy-duty vehicles are predicted as a function of hours of on-road operation at specific engine horsepower loads. Hence, the basic algorithms and matrix calculations in the new heavy-duty diesel vehicle modeling framework should be transferable to MOVES. The specific implementation approach employed by the research team to test the model in Atlanta is somewhat different from other approaches in that an existing geographic information system (GIS) based modeling tool is being adapted to the task. The new model implementation is similar in general structure to the previous modal emission rate model known as the Mobile Assessment System for Urban and Regional Evaluation (MEASURE) model. Sponsored by the U.S. Environmental Protection Agency, this exploratory framework is designed to be applied to a variety of policy assessments. The model can be used to evaluate policies aimed at reducing the emission rates from heavy-duty vehicles as well as policies designed to change the on-road operating characteristics to reduce emissions. ii Foreword The U.S. Environmental Protection Agency (EPA) is charged by Congress with protecting the Nation’s land, air, and water resources. Under a mandate of national environmental laws, the Agency strives to formulate and implement actions leading to a compatible balance between human activities and the ability of natural systems to support and nurture life. To meet this mandate, EPA’s research program is providing data and technical support for solving environmental problems today and building a science knowledge base necessary to manage our ecological resources wisely, understand how pollutants affect our health, and prevent or reduce environmental risks in the future. The National Risk Management Research Laboratory (NRMRL) is the Agency’s center for investigation of technological and management approaches for preventing and reducing risks from pollution that threaten human health and the environment. The focus of the Laboratory’s research program is on methods and their cost-effectiveness for prevention and control of pollution to air, land, water, and subsurface resources; protection of water quality in public water systems; remediation of contaminated sites, sediments and ground water; prevention and control of indoor air pollution; and restoration of ecosystems. NRMRL collaborates with both public and private sector partners to foster technologies that reduce the cost of compliance and to anticipate emerging problems. NRMRL’s research provides solutions to environmental problems by: developing and promoting technologies that protect and improve the environment; advancing scientific and engineering information to support regulatory and policy decisions; and providing the technical support and information transfer to ensure implementation of environmental regulations and strategies at the national, state, and community levels. This publication has been produced as part of the Laboratory’s strategic long-term research plan. It is published and made available by EPA’s Office of Research and Development to assist the user community and to link researchers with their clients. Sally Gutierrez, Director National Risk Management Research Laboratory iii EPA Review Notice This report has been peer and administratively reviewed by the U.S. Environmental Protection Agency and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. This document is available to the public through the National Technical Information Service, Springfield, Virginia 22161. iv Table of Contents Section Page Abstract.................................................................ii Foreword............................................................... iii List of Figures.......................................................... viii List of Tables ........................................................... ix Acronyms ...............................................................x Acknowledgments ...................................................... xiii Executive Summary .......................................................1 Introduction .............................................................5 Modeling Parameters ......................................................7 Goals and Objectives ...................................................7 Pollutants Modeled.....................................................7 Approach.............................................................8 The Geographic Information System.........................................13 GIS Spatial Analysis Framework.........................................13 Infrastructure ........................................................14 Operating Environment ................................................14 Subfleet Characterization and Traffic Volumes.................................17 Vehicle Technology Groups .............................................17 Emitter Classifications .................................................19 On-Road Traffic Volumes ..............................................19 Emissions Rate Differences .............................................20 Transit Buses ........................................................21 Off-road Activity .....................................................21 Freight and Passenger Loads ...............................................23 Truck Loads .........................................................23 Transit Passenger Loads................................................25 On-Road Operating Characteristics ..........................................27 Engine Power Functions...................................................29 Accessory Power Loss .................................................31 Drive Train Power Loss................................................32 Mechanical Friction ...................................................32 Torque Converter Losses ...............................................32 Axle Bearing Friction..................................................33 Inertial Losses........................................................33 Driver Behavior ......................................................34 v Table of Contents (continued) Section Page Drive Train Power Loss Modeling Approach............................... 35 Drive Train Efficiency.............................................. 35 Rotational Moment of Inertia Losses................................... 35 Axle Horsepower Relationships ...................................... 36 System Monitors ..................................................... 36 Road Load Power Functions ............................................... 37 Rolling Resistance Force (FR) ........................................... 37 Gravitational Weight Force (FW) ......................................... 38 Aerodynamic Drag Force (FD)........................................... 39 Aerodynamic Lift Adjustment ........................................... 40 Curve Resistance Force (FC) ............................................ 40 Payload Inertial Resistance (FP) ......................................... 41 Available Tractive Force (FT) ........................................... 41 Emission Rate Functions.................................................. 43 Emitter Category ..................................................... 44 Commanded Fuel-Lean Operations....................................... 44 Correction Factors and Environmental Factors.............................. 45 Deterioration Rates ................................................ 45 Temperature...................................................... 46 Humidity ........................................................ 46 Altitude ......................................................... 46 Inventory Assembly and Model Output....................................... 49 Emission Matrix Calculations........................................... 49 Integration of Link-Based Emissions ..................................... 50 Case Study of Two MARTA Transit Bus Routes ............................... 53 References............................................................. 63 Bibliography ........................................................... 65 Appendix A Model Equation Parameters ..................................... 67 Appendix B Potential