THE EFFECTS OF DRIVE CYCLE ACCESSORY LOAD AND DEGREE OF HYBRIDIZATION ON ...

152 Pages·2010·3.88 MB·English

THE EFFECTS OF DRIVE CYCLE ACCESSORY LOAD AND DEGREE OF
HYBRIDIZATION ON FUEL ECONOMY AND EMISSIONS
FOR HYBRID ELECTRIC BUSES

by
DENNIS CHEN

A THESIS

Submitted in partial fulfillment of the requirements
for the degree of Master of Science in the
Department of Mechanical Engineering
in the Graduate School of
The University of Alabama

TUSCALOOSA, ALABAMA

2010
Copyright Dennis Chen 2010
ALL RIGHTS RESERVED
ABSTRACT
Hybrid Electric Vehicles (HEVs) have gained much attention in recent years. This is
mainly due to rising fuel prices and increasing environmental awareness. By implementing
electricity as one of the power sources, a HEV can not only reduce fuel consumption but can also
decrease tailpipe emissions.
In this thesis, the software package Powertrain Systems Analysis Toolkit (PSAT) was
chosen as the simulation tool to model several bus powertrain configurations – conventional,
three different degrees of hybridization parallel hybrid electric (PHEB), and a series hybrid
electric (SHEB) to predict fuel economy and emissions level. The simulations were run with a
typical accessory load, 15 kW, for a 40-foot transit bus as well as for no accessory load. The
effect of accessory load on fuel economy was identified. Four different drive cycles – Manhattan,
UDDS, CBD, and WVU City cycles – that covered a wide range of driving conditions were
chosen as the testing cycles for the simulations.
For no accessory load, it was found that the PHEB1, which had the highest degree of
hybridization, yielded the best fuel economy improvement on all four drive cycles. The highest
fuel economy improvement without accessory load, 121.9%, was found for the Manhattan cycle.
The maximum fuel economy improvement, 51.8%, for a 15 kW accessory load also occurred
running the Manhattan cycle, and was achieved by the PHEB1 as well. The maximum fuel
economy reduction with a 15 kW accessory load was 48.9%.
The largest emissions reductions with a 15 kW of accessory load were achieved by the
PHEB1 operated in the Manhattan cycle, with NOx and PM emissions reductions of 73.4% and
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45.9% over the conventional bus, respectively. Based on the emissions analysis, a bus with better
fuel economy tends to have lower emissions and a bus with lower gas mileage usually produces
more emissions, although there were some exceptions in the inverse relationship between gas
mileage and emissions level.
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DEDICATION
I dedicate this work to my father, James Chen, my mother, Sophia Shen, and my sister,
Tsu-Mei Chen, for their support and encouragement.

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LIST OF ABBREVIATIONS
AC Alternating current
ADVISOR Advanced vehicle simulator
Ah Amp hours
ANL Argonne National Laboratory
BAE British Aerospace Engineering
bhp Brake horsepower
BRT Bus Rapid Transit
BSFC Brake specific fuel consumption
CAFE Corporate average fuel economy
CARB California Air Resources Board
CBD Central business district
cc Cubic centimeter
CO Carbon monoxide
CVT Continuous variable transmission
DC Direct current
DOE Department of Energy
DPF Diesel particulate filter
DPIM Dual power inverter module
EIA Energy Information Administration
EPA Environmental Protection Agency
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ESC European Stationary Cycle
EV Electric vehicle
ft-lb Foot-pound
g Gram
GUI Graphical user-interface
GVWR Gross vehicle weight rating
HC Hydrocarbon
HEB Hybrid electric bus
HEV Hybrid electric vehicle
hr hour
HV Hybrid vehicle
ICE Internal combustion engine
kW Kilowatt
mpg Miles per gallon
mph Miles per hour
MTA Metropolitan Transportation Authority
NHTSA National Highway Traffic Safety Administration
NiMH Nickel metal hydride
N-m Newton-meter
NOx Nitrogen oxides
NREL National Renewable Energy Laboratory
NYC New York City
OAPEC Organization of Arab Petroleum Exporting Countries
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Pb-acid Lead acid
PM Particulate matter
PMF Particulate matter filter
PNGV Partnership for a New Generation of Vehicles
PSAT Powertrain systems analysis toolkit
RITA Research and Innovative Technology Administration
SAE Society of Automotive Engineers
SCR Selective catalytic reduction
SHEB Series hybrid electric bus
SOC State of charge
UDDS Urban dynamometer driving schedule
ULSD Ultra low sulfur diesel
WVU West Virginia University
ZEV Zero emission vehicle
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ACKNOWLEDGMENTS
First I would like to thank my graduate advisor and mentor, Dr. Clark Midkiff, for his
professional direction, assistance, and support. I would also like to thank Dr. Keith Williams and
Dr. Eric Carlson for serving on the thesis committee, as well as Dr. Robert Taylor, the
department head of Mechanical Engineering. I also want to express my appreciation to Mr.
Aymeric Rousseau from Argonne National Laboratory for his technical support on PSAT.
I also want to express gratitude to my father, James Chen, my mother, Sophia Shen, and
my sister, Tsu-Mei Chen, for their continuous financial support, mental encouragement, and
unconditional love.
I would like to express my thankfulness to Dr. Der San Chen and Dr. Hannah Chen for
their support, care, and consideration.
A special appreciation needs to be presented to Matthew Breshears, my office mate, for
helping me revise my thesis.
Finally, I would like to thank all the professors who have taught me throughout the time,
six years, I have studied at UA.

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CONTENTS
ABSTRACT………………………………………………………………………………………ii
DEDICATION………………………………………..…………………………….……...…..iv
LIST OF ABBREVIATIONS……………………………………………….…………………….v
ACKNOWLEDGMENTS……………………………………………………………………....viii
LIST OF TABLES………………………………………………………………….……………xii
LIST OF FIGURES……………………………………………………………………………..xiv
1. INTRODUCTION…………………….………………………………………………………1
Background……………………………………..……………………………………………..1
Objective………………………………………………………………...…………...………..8
Organization of Thesis……………………………………………………………...…………9
2. LITERATURE REVIEW……………………………………………………………………10
History………………………………………………………………………………………..10
Vehicle Configuration………………………………………………………………………..14
Conventional Vehicles…………………………………………………………....…….14
Electric Vehicles…………………………………………………….………………..15
Parallel HEV……………………………………………………………………………..16
Series HEV……………………………………………………………………………….18
Series-parallel HEV……………………………………………………………………...19
Existing Design………………………………………………………………………………20
GM Allison System…………………………………………………………………...20
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