Momentum - October 2019 - 16

STUDENT
GENERATION

ENGINEERING THE FUTURE OF
TWO-STROKE
WITH LONG WINTERS, plenty of sledheads, and a thriving
engineering program-Montana State University needed
the SAE Clean Snowmobile Challenge. After establishing
as a non-profit and gaining a snowmobile sponsorship
from Polaris, our new team set out to compete in the 2019
SAE Clean Snowmobile Challenge in Michigan.
As a first-year team, we learned countless lessons
ranging from technical design, to complying with
competition constraints, to growing in our teamwork
abilities while working under pressure. During our
original design and planning phase, we concluded that
our team of 10 engineering students had the ability to
focus on innovating one or two major modifications to
the snowmobile for the 2018-2019 season. To achieve this
goal, we acquired a lab space at the college, fundraised
and gained local sponsors, met several times a week, and
pushed ourselves to apply engineering principles beyond
our previous experiences. 

PLANNING 
After compiling our team and identifying skills and
strengths, we broke into small design groups that
underwent their own process to pitch a primary sled

How a snowmobile team is formed
With the sensitive ecosystem of Yellowstone National Park less
than 100 miles away from Bozeman, the Clean Snowmobile
Challenge Team at Montana State University directly benefits the
use of snowmobiles in national parks and the continuous
improvement of automotive engineering. I had the idea to start
the SAE Clean Snowmobile Challenge team at Montana State
University due to my passion for internal combustion engineering,
the snowmobiling culture around Bozeman, and my drive to help
college students acquire real-world engineering experience.
Many other engineering students at Montana State
University have interests that parallel the objectives of the Clean
Snowmobile Challenge in the automotive engineering discipline.
I saw the opportunity for our school to compete in a difficult
competition that focused more on the modern issues
encountered in automotive engineering such as improving
combustion emissions, reducing noise pollution, and increasing
internal combustion engine efficiency.
After consulting with different professors and students in the
Mechanical Engineering Department, the vision for starting the
club was confirmed. I had the goal to enroll in the SAE Clean
Snowmobile Challenge to not only benefit myself, but to
provide an opportunity for current and future engineering
students to develop real-world engineering and leadership skills,
primarily before their final Capstone project.
By Aaron Juntunen

16 October 2019

Photo credit: Keweenaw
Research Institute/Michigan
Technological University

The Montana State University sled streaks down the Acceleration Event course at the
2019 SAE Clean Snowmobile Challenge.
modification to the group. This process expanded our experience with
engineering design, research and development, and teamwork. After
pitching potential designs to all teammates, a design matrix was used
to identify the best primary modifications to engineer and build as a
functional prototype.
We chose our design ideas based on ease of implementation, innovation,
and the potential for scoring points at the snowmobile competition. For
example, resulting in one of the highest point values was a custom catalytic
converter apparatus for our two-stroke engine. This modification fit into
the competition category of emissions reduction. This process led us
to successfully compete at the 2019 Clean Snowmobile Challenge with
original ideas and innovative system integration.

DESIGN
In addition to developing a custom catalytic converter, it was decided
we would implement a flex-fuel system and adjust for competition
compliance. We also spent time considering design ideas for 2020, as
demonstrated during our conceptual presentation at the competition.
These concepts are still in development and consist of both a dualexpansion chamber and noise cancellation system. 
The engine of our sled is a Polaris Cleanfire 600-cc two-stroke,
driving a Switchback Assault chassis. The major initial conditions of this
setup included large amounts of unburned hydrocarbons and carbon
monoxide emitted by the two-stoke motor, lack of versatility with
ethanol levels beyond regular gasoline, and missing safety features
required under competition rules. To address these conditions, our
group used engineering design principles to gain understanding of
oxidation catalyst methods to reduce carbon outputs, conversion from
regular to flex-fuel potential, and the SAE Clean Snowmobile Challenge
MOMENTUM
Momentum - October 2019

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