Proposal to Implement a Vehicle Electric Load Leveling System

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Nov 15, 2013 (3 years and 4 months ago)

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Proposal to Implement a

Vehicle Electric Load Leveling System










Submitted to:

National Science Foundation (NSF)



Submitted by:

Erin Davis

Fred Jessup

Benton O’Neil



October 1
8
, 2004


Davis, Jessup, O’Neil

2

1
.
0

Introduction


1.1

Background



Internal combu
stion vehicles are inherently inefficient
[1]

leading to avoidable expenses for the
consumer. Therefore,
a
ny decrease in the cost of driving a vehicle
would be

beneficial.
In order to
reduce costs, engineers around the world are working towards e
fficiency

improvements in transportation
technology
which
will translate directly to consumer savings. The
American Trucking Association

(ATA)
is supporting our research and development of vehicle efficiency improvements. The ATA requires
our
research to provide

a
proof of concept to increase battery life and fuel efficiency on tractor trailers.




1.2 Problem


Today’s vehicles do not manage the flow of power through their electrical systems for maximum
fuel economy and battery life. Large current spikes during

engine starting and constantly varying electric
loads shorten the life of the battery
[2]
.
This is significant due to the negative environmental impact of
automotive battery disposal
[3]
. Another problem is that

the vehicle’s alternator supplies current r
egardless
of engine mechanical load. This additional mechanical load presented by the alternator reduces fuel
economy. These two electrical system inefficiencies result in heightened operating costs.



1.3 Prior Research




The objectives, scope, and s
pecifications for our project were not supplied by the ATA. We were
given the freedom to determine these independently. The platform for our proof of concept is a 2001 Ford
Explorer. Prior research performed for this project included measurement of batt
ery and alternator current
in both static and dynamic states. This primary research has allowed us to form initial designs and
specific
ations as discussed in S
ection 2.2
, Technical A
pproach.



1.4 Objectives


Our goal in this project is to achieve a pay
back period of
three

years when applied to a 2001 Ford
Explorer
. Our experimental results will provide a basis for application of this system to a wide variety of
vehicles.
We aim to extend battery life to at least that of the manufacturer’s specificatio
n. Though it is not
the emphasis of our design, increased fuel efficiency will be an additional benefit. The combination of
these two improvements will
allow us to achieve the desired

payback period.


1.5 Scope


The project deliverables are as follows: d
esign description report, physical implementation of
system on 2001 Ford Explorer, technical report, and trade show presentation. At the completion of the
project we will have demonstrated the feasibility of an ultracapacitor system that normalizes

batter
y and
alternator current.


A possible future improvement to the electrical system for this vehicle is the control of the output
of the alternator. A switching algorithm could be designed to limit alternator output during times of high
mechanical engine l
oad, to further improve engine efficiency


1.6 Methods



The project described in this proposal will continue throughout the year

under the guidelines of
the ECE 480 senior capstone design course
[3]
. The
fina
l report
will
be composed of the
work performe
d

during the Fall 2004 semester including

initial research and design, final design, and preliminary
construction.

The following Spring semester is reserved for final construction, testing, and
implementation.




Davis, Jessup, O’Neil

3

2
.
0

Project
Overview


2
.1
Project Descripti
on



All motor vehicles contain an electric system that consists of three main parts; a battery, an
alternator, and an electric load. The battery stores large amounts of energy and is responsible for starting
the engine. The alternator is powered by the
engine and supplies electric energy while the vehicle is
running. Finally, the electric load consists of all vehicle accessories that require electric power, from the
headlights to the sparkplugs.


Automobiles present highly varying loads to their alte
rnator and battery during operation. These
loads, in addition to large currents drawn during engine starting, shorten the life of the battery and place
unnecessarily large mechanical loads on the engine
[2]
.
This additional mechanical load presented by th
e
alternator reduces fuel economy.
The decreased battery life due to large and irregular loads leads to an
increase in battery disposal and an adverse effect on the environment
[3]
.



Our proposed design will improve fuel efficiency and increase battery l
ife. During engine starting,
an ultracapacitor bank will supply necessary current. The DC
-
DC converter will regulate the charging and
discharging of the battery for maximum life. A switch will isolate the alternator from the system during
high mechanica
l engine loading and enable it during times of low mechanical engine loading. This will
improve engine efficiency by leveling engine mechanical load. Further detail of battery life extension and
alternator efficiency control wi
ll be discussed below. Fig
ure 2
.1 illustrates the proposed design.



DC
/
DC Converter
Battery
Cap Bank
Vehicle
Load
Alternator


Figure 2
.1





2
.1a

Battery Life Extension


An electric load in a vehicle draws current from either the battery or the alternator. For example,
when the key is turned in the igni
tion, an extremely high current is drawn from the battery into the starter
motor, which converts the electrical energy into torque to turn the engine. Our initial data shown in Figure
2
.2, taken from a 2001 Ford Explorer, shows the current drawn from the
vehicle’s battery and alternator
during a normal engine start. This battery current is represented as a blue line.


Davis, Jessup, O’Neil

4

Starting Engine - Stock and Desired Battery Currents
-100
0
100
200
300
400
500
0
1
2
3
4
5
6
7
8
9
10
Time (s)
Current (A)
Stock Battery Current
Desired Battery Current

Figure 2
.2


Figure
2
.2 illustrates the first of the two problems our proposed design will address. The current
drawn from the battery du
ring this partic
ular start was greater than 500 Amps (A).
Ultracapacitors

are
built specifically for high current loads. They are used in our design to limit the current seen by the
battery, thus ensuring that the battery’s rated charge and discharge lev
els are constantly maintained, and
thereby increasing its lifespan. The red line shown in Figure
2
.2
represents

the
expected

current load on
the battery after our design has been implemented. This current is much more regulated and is less
damaging to th
e battery.
As addressed in the introduction, b
attery replacement and disposal is costly,
time intensive, and harmful to the environment
[3
]
.
Due to our system, the resulting

increase in a battery’s
useful life will translate to a
n additional
sa
vings in ve
hicle operating cost
.



2
.1b

Alternator
Output

Control



After a vehicle is started, the majority of electrical loads are supplied by the alternator. The
alternator is a significant mechanical load on the engine. There are many other mechanical loads on
an
engine such as an air conditioner, the water pump, or even a steep incline which translates through the
tires to the engine. When a vehicle is climbing a steep grade or accelerating from a stop sign, the engine
is working very hard. Each additional me
chanical load presented to the engine decreases its power and
its efficiency. If for some reason the alternator is heavily loaded, it too will present an increased
mechanical load to the engine. Figure 2.3 shows the increase in current draw on the altern
ator of a Ford
Explorer when its high
-
beam lights are turned on.

Davis, Jessup, O’Neil

5

Total Load Seen by Alternator During Light Cycling
Stock Alternator Current and Desired Alternator Current
25
35
45
55
65
1
3
5
7
9
11
13
Time (s)
Current (A)
Stock Alternator Current
Desired Alternator Current
Parking
Lights
Low
Beams
High
Beams
Low
Beams
Parking
Lights
OFF

Figure 2
.3



The

blue line
shows
that there is a significant increase in load on the alternator, especially in the
spikes of current when lights are first switched on. This increased curre
nt draw on the alternator
translates to an increased mechanical load on the engine at a time when it is already running inefficiently.
Our design uses Ultracapacitors to limit the spikes in current seen by the alternator, reducing the electrical
load on t
he alternator. The control system for our design would consider the mechanical load on the
engine and would limit large alternator current draw to times when the engine is loaded the
least. The red
line in Figure 2
.3 illustrates the desired current draw
during times of high engine mechanical load.
Reducing mechanical load on the engine at opportune times in the driving cycle will improve the efficiency
of the vehicle and decrease fuel consumption, another benefit of this design.



2.1c

Expected Outcomes


This system will be designed and built for a 2001 Ford Explorer. It is a proof of design showing
the benefits of electric load leveling on batter
y life and vehicle efficiency.
We will continue to characterize
the Ford Explorer’s electrical system to det
ermine necessary design specifications. Once design, system
modeling, and component specific
ations are set, we will build

the
resultant

system
. This

system will

then

be installed in the Ford Explorer and tested for performance.
Finally, we
will prepare
a
conclusive repo
rt
of the costs and benefits of electric load leveling.




The driving force behind this system
is

the
three year
payback period.

Throughout the design
and analysis, b
oth
monetary and environmental cost
s and benefits must be taken into co
nsideration
.

We
expect that with our ultracapacitor electric load leveling system installed
,

we will observe a regulated
charging and discharging of the battery and a decrease in the peak electrical loads seen by the alternator.
Battery life will increas
e and the battery itself may be downsized. The alternator will be loaded more
efficiently and also may be downsized. Fuel efficiency will increase and emissions will decrease. The
system will pay for itself in less than three years with savings in fuel

cost and battery replacement
following the payback period. An analysis of the automotive market, with emphasis in larger vehicles, will
show that electric load leveling is feasible and profitable in many applications.





Davis, Jessup, O’Neil

6

2
.2

Technical Approach


Our pr
oposed project will consist of the following seven phases. The first three phases will be
completed before November 29
th
, 2004 with the remaining phases to be completed in the Spring of 2005.


Phase I:

Data Collection



The system parameters are defined b
y the energy requirements of the Ford Explorer. We
measured current loads on the battery and alternator in both static and dynamic testing. This data
enables us to appropriately size the system to the vehicle.


The tools used for data collection includ
e: current clamps, compact FieldPoint analog input
module, Labview software, 2001 Ford Explorer, and a laptop computer. Each current clamp measures a
current and sends this value to separate compact FieldPoint channel. One current clamp measures the
cu
rrent supplied by the battery while the other measures current supplied by the alternator. We wrote a
program using Labview software that records data points every 85 milliseconds on both channels. These
values are fed into a Microsoft Excel file on the
laptop computer. The spreadsheet contains current
versus time for both the battery and the alternator. This gives us a graphical and numerical interpretation
of the current drawn by the load. The program can be run for any amount of time. This method o
f testing
was used to acquire current data for both starting and driving the vehicle.


Phase II:

Specifications



The three main components that we will be designing are the ultracapacitor bank, the DC/DC
converter, and the digital control system. These
components can
be found in Figure 2
.1 above. From our
initial data acquisition, we are able to determine the following specifications.


Ultracapacitor
Bank


Supply 600 amps for 2 seconds to start the engine


Fit within a volume of 225in
3



Weigh less th
an 10lbs.


Comply with Federal
Motor Vehicle
Safety Standards

and Regulations
[4]



DC/DC Converter


Bidirectional

Capable of currents no greater than 50A

Pulse Width Modulation (PWM) controlled


Digital Control System


PWM output

Voltage and current analog

input

External step
-
down circuitry

Standby battery charge monitoring

Software programmable



The system will be designed

to

these specifications with constant consideration of cost, space,
weight, safety, and feasibility.




Phase III:

System Design and M
odeling



The digital control system will monitor the charge of the battery and ultracapacitor bank. It will
also monitor the current flowing out of the battery and the ultracapacitor bank. The current allowed to flow
through the DC/DC converter will be
determined by the charge of the ultracapacitor bank and the
magnitude of the electrical load. A maximum of 50A will be allowed to flow into or out of the battery at any
given time. All remaining current will be supplied by ultracapacitor bank and alterna
tor.

Davis, Jessup, O’Neil

7


System modeling will be performed using Matlab and MathCAD software. Modeling results will
provide indication of design errors before components are purchased or built.


Phase IV:

Construction


Off the shelf components will be purchased for

DC/DC converter construction, microcontroller,
and ultracapacitor bank. The microcontroller and DC/DC converter will be assembled on a printed circuit
board out of house. Ultracapacitor bank and all other construction will be performed at the University

of
Idaho in the Advanced Vehicle Concept Team’s garage and in the Gauss Johnson Mechanical
Engineering shop.



Phase V:

Testing



Tools similar to those used in initial data ac
quisition will be used in bench testing for a starter
motor and a generator.
P
latform testing will be performed after system installation into the Ford Explorer.
Results w
ill be compared to initial data and modeling.



Phase VI:

Implementation



System will be physically installed on Ford Explorer to meet Federal
Motor Vehicle Safe
ty
Standards and Regulations
[4]
.


Phase VII:

Final Analysis



Cost analysis will be performed to determine feasibility and payback period. Factors such as
system cost, increased battery life, fuel efficiency improvement, environmental effects, and weight,

will be
considered in this analysis. Payback period will be used to determine the market feasibility of the system.

National Institute for Advanced Transportation Technology (NIATT) requires a final report that will
cover the entirety of our projec
t. Our designs, methods, testing, and results will be described in detail and
presented at a national transportation conference.



3
.
0

Work Plan




Task








Completion Date


On
-
site customer interview





Completed


DC converter and battery research




Completed


English 317 project proposal





10/18/2004


Project web page






10/22/2004


Compilation and analysis of converter and



10/27/2004

battery research


Capacitor sizing calculations





10/27/2004


Develop method for component selection



10/
28/2004


Preliminary budget estimate





10/29/2004


Conceptual design review meeting




11/05/2004


English 317 Final Report





11/29/2004


Design description report





11/30/2004


English 317 Oral Report






12/01/2004


Resolution of design review iss
ues




12/03/2004


System level DFMEA






12/06/2004


Finalized budget and work plan





12/08/2004


Approved design proposal





12/11/2004


Purchase orders prepared and issued




01/24/2005



Assembly drawings, detailed parts list,




02/03/2005



compo
nent drawings






Davis, Jessup, O’Neil

8


Fabrication review, shop plan and schedule



02/08/2005


Approved drawing package and manufacturing plan


02/10/2005


Part acquisition, part creation in shop




03/05/2005


Demonstration of working hardware




03/06/2005




Collection o
f performance data, data analysis,



04/04/2005



design evaluation (DFMEA)


Approved outline for final report





03/06/2005

Final report and hardware delivery plan




03/25/2005


NIATT technical report delivery





04/30/2005


Presentation at trade show





05/04/2005



4
.
0

Budget



Item







Budgeted


Ultracapacitors X6






$240

Lincoln LS Starter Motor
X2





$388

12V/35Ah Sealed Lead Acid Battery X2




$110

Test Equipment







$350

DC/DC Converter X2






$110

Rabbit 54MHz Microcontroller

X2




$29

Miscellaneous Circuitry






$50

Travel Expenses






$1000

Other








$1723







Total Budget


$4000













5
.
0

Works Cited


[1]

Cordon
,
Dan
. (Speaker). (
2004
).
AVCT hybrid vehicle presentation
.

Basic Engine Function: Energy Flow and
Emerging Technologies
.

Oral Presentation September 21, 2004.

[2]

“Panasonic VRLA Battery Overview” Panasonic, Specification Sheet.

[Online].
http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_VRLA_Overview.pdf

[3]

"Lead Acid Batteries


Hazards
and Responsible Use
"
Integrated Waste Management Board
,

Publication #612
-
00
-
002
.

Mar 2000
.

[Online]. http://www.ci.poway.ca.us/env/lead_acid_batteries.pdf

[4]

“Federal Motor Vehicle Safety Standards and Regulations” U.S. Department of Transportation.
DOT publi
cation. Dec 1998. [Online]
http://www.nhtsa.dot.gov/cars/rules/import/FMVSS/

[5]

“Design Proposal Guidelines” Steve Beyerlein et al. Course Documentation.

[Online].
http://seniordesign.engr.uidaho.edu/Course_Docs/Documentation/Design%20Proposal%20Guide
lines.do
c

[6]

“BOOSTCAP Ultracapacitor Specification Sheet” Maxwell Technologies, Document #1006292
Rev #4. [Online]
http://www.maxwell.com/pdf/uc/datasheets/BCAP_Series.pdf









Davis, Jessup, O’Neil

9

6
.
0

Statement of Qualifications


Erin Davis
is c
urrently pursuing a Bachelor of Scienc
e degree in Electrical Engineering at the University of
Idaho.
Since the Fall of 2003, s
he
has been involved with the Advanced Vehicle Concepts Team at the
University of Idaho, gaining
experience with ultracapacitive systems on a 2001 Ford Explorer. Alth
ough
this above system was a hybrid electric assist, it used the high power density capabilities of
Ultracapacitors which initiated the idea of Ultracapacitors in an electric load leveling system. Erin brings
to the team a natural aptitude for mathematica
l computation and practical experience in the application of
ultracapacitive systems.


Fred Jessup
is currently pursuing a Bachelor of Science degree in Electrical Engineering. He will
complete his degree in the Spring of 2005
at the University of Idaho w
ith a
focus in electronics and
semiconductor devices. As the team leader for the 2004 Future Truck electrics team he cultivated
methods for team organization and effective project completion. He gained valuable experience with
digital control systems as
a student of Dr. Richard Wall in the Fall of 2003. Fred brings to the team
knowledge of small scale electronics and digital control systems, and an ability to lead and organize.


Benton O’Neil
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