Clean%20Snowmobile%20Team

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PIGGYBACK DIVISION MATTHEW MENARD CRAIG
FORTIER NOISE VIBRATION AND HARSHNESS
DIVISION JOSHUA AYERS DANIELLE MCCAFFERTY NOAH
WRIGHT DUSTIN MCCANN COMPOSITE COWLING
DEVELOPMENT DIVISION MATTHEW BODWELL EVAN
MERRIT CHRISTOPHER HILL JESSE MORIN CONCEPT
CHASSIS DEVELOPMENT DIVISION COMPOSITE CONCEPT
CHASSIS THOMAS LAMONTAGNE MICHAEL BOWERS TUBULAR
METALLIC CONCEPT CHASSIS DARRELL FLAGG OTIS
CLAPP BRIAN WILD MATTHEW WYATT
Clean Snowmobile Team
SLED BEAR
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PIGGY BACK DIVISION
During the first year in the Clean Snowmobile
Challege in 2004 the emissions team decided to
add a catalytic converter to the 4 stroke 660cc
Arctic Cat engine that they were using. Last year
the emissions team decided after a serious of
tests to leave the catalytic converter intact and
try to improve the sled through a microcontroller
unit. This first microcontroller unit only used a
single reading from a wide band O2 sensor to
control the Air Inlet Temperature (AIT). AIT was
altered inside the piggyback depending on the
single input to change the AIT that the sled ECU
was reading. This in turn controlled the Air to
Fuel ratio (A/F). When the A/F ratio is running
at a rich mixture the amount of CO, and HC are
reduced. When the mixture is running at a lean
mixture the amount of NOx emissions are reduced.
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PIGGY BACK DIVISION
This year we took the piggyback a step further.
We went ahead and added a throttle position
sensor (TPS) as the second input to the piggyback
in hopes to better control the A/F ratio from
idle to wide open throttle.
The control of the A/F mixture can be
accomplished through the use of a piggyback
electronics system with the help of analyzers
such as a wideband O2 sensor, throttle position
sensor, dynamometer, and exhaust gas analyzer.
This system will change information going into
the Engine Control Unit or ECU. The main purpose
of the ECU is to determine the pulse width of the
fuel injectors. Pulse width is defined as how
long the injectors stay on. The pulse width is
determined by sensors which act as inputs to the
ECU. The ECU looks at the incoming signals, then
through programming logic and data tables
determines the appropriate pulse width for the
situation
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PIGGY BACK DIVISION
The 2006 Piggyback control unit success achieved
the goals of reducing the emissions of the 2003
Arctic Cat 4 stroke snowmobile. Although it was
not able to provide significant reductions that
exceeded the 2005 piggyback, for the full
throttle range, it did greatly reduce the
emissions that were being produced during the
sled idling. These were the highest emissions of
the sled during the competition last year. With
the proper inputs this piggyback would make for a
quality addition to any stock sled in order to
consistently with lower emissions, making it an
excellent addition to a Snowmobile Conversion
Kit.
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NOISE VIBRATION AND HARSHNESS DIVISION
This project focuses on the improvements to this
sled in the noise vibration and harshness area. 
Initial benchmarking of the performance of our
sled will be required, along with testing of the
effect of a range of standard and new
modifications.  Exhaust modifications will not
necessarily be emphasized, instead the drive
train, mechanical noise, induction and other
noise sources will be most likely to be the
source of significant gains in noise reduction.
This test apparatus was built to analyze
insulating material. A six-inch diameter speaker
is attached to a PVC tube one meter in length.
The insulating material to be tested is inserted
at the opposite end of the tube and a microphone
(shown in picture) or sound level meter is
mounted in a PVC shell immediately after the
material. A frequency generator provides the
signal to the speaker that emits a single
frequency. The material response is then
displayed by either the sound level meter or an
oscilloscope.
Five materials were chosen from the material
matrix and a one third octave band analysis was
performed. A sample of each material was put
into the acoustic test tube and bombarded with
sound at each individual frequency. An
A-weighted sound level meter recorded the sound
pressure level at each frequency. From this
analysis, it was determined that the best
material to use for our cowling insulation was
material 7, Cotton Echo Eliminator with High
Density Layer, made by Acoustical Surfaces, Inc.
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NOISE VIBRATION AND HARSHNESS DIVISION
During baseline sound runs for the sled, it was
determined that the left side of the sled was
consistently louder than the right side. Since
the left side of the sled is the clutch side, the
clutch was designated a significant noise source.
To combat this problem, an enclosure was
designed and built to acoustically isolate the
clutch compartment. Complete isolation brought
up the problem of possible overheating and
failure of the clutch belt and so a dedicated
blower and ducting system were added. The blower
is controlled by an adjustable temperature
control unit and provides 60 cubic feet per
minute of air directly to the clutch compartment.
This flow is circulated through the clutch case
and is then ported to the back of the engine
compartment to provide auxiliary engine cooling.
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NOISE VIBRATION AND HARSHNESS DIVISION
Several modifications were made to the rear
suspension system. Arctic Cat suspensions use
one of the runner cross-members as the rebound
stop for the rear arm of the rear shock. This
metal-on-metal contact is a significant noise
source. A bumper made of a high durometer
motor mount material has been added to this
system to transform the high frequency vibration
of this contact point into very low frequencies
and heat energy.  Another significant noise
source on the suspension is the friction contact
of the track on the runners. To decrease this
noise source and help decrease wear on the
runners, a total of eight idler wheels were added
in two sets of four. Each of these sets spans
the full width of the track and together they
provide an even quieter alternative to the
already quiet Arctic Cat Quiet Track.
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COMPOSITE COWLING DEVELOPMENT DIVISION
University of Maine Mechanical Engineering
M
Senior Design 05-06
Goals
Motivation

• Improve quality of hood
• Decrease overall weight of hood
• Improve rigidity and optimize fiber orientation
• Increase hood clearance over previous years

The original cowling no longer fits due to under
hood clearance issues brought on by the addition
of emission control hardware. Two replacement
hoods have been built previously and yielded
mixed results. Neither hood looked particularly
appealing and both had fitment and performance
issues. And, needless to say, neither hood was
satisfactory to represent the Maine Clean
Snowmobile Team.
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COMPOSITE COWLING DEVELOPMENT DIVISION
University of Maine Mechanical Engineering
This Years Achievements
M
Senior Design 05-06
It can be seen in the pictures that this years
cowling is a drastic improvement over previous
years and even over the original stock cowling.
This years hood was designed to better clear the
muffler under the hood while simultaneously
improving looks and bettering the fitment. The
new cowling has a far more impressive appearance,
boasting the carbon fiber look. As expected,
overall rigidity is up due to the material
strength gained by choosing carbon fiber over
glass fiber, and the increase in the total amount
of material that makes up the cowling. This years
hood did not show a significant weight decrease
because most of the time had to be spent on
creating the mold and learning the proper
fabrication procedures. Learning the proper
procedures helped ensure professional quality.
The team built this first pass cowling on the
safe side, figuring it is better to have cowling
that could be depended on rather than ending up
with a few pieces that once were a cowling.
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COMPOSITE COWLING DEVELOPMENT DIVISION
Future Work
The developments made this year will allow future
teams to concentrate on performing a more in
depth stress analysis and lay-up optimization.
This, more in depth design approach and better
utilization of various core materials will allow
the overall strength and rigidity to remain at
their current levels while weight is reduced.
Gaining overall efficiency thorough weight
reduction by using modern engineering materials
is and will be a focus of the Maine Clean Snow
Mobile Team.