University of Idaho Senior Design Project
For
National Institute for Advanced Transportation Technology/ Hush Power
Snowmobile Muffler
August 17, 2010
Scope
To design and develop a muffler for the University of Idaho’s Clean Snowmobile Challenge (CSC) team’s two-stroke snowmobile. The muffler must be designed to fit in place of the snowmobile’s standard muffler without significant modifications to the chassis. The muffler must integrate an emissions catalyst and reduce noise emissions to National Park Standards.
Background
The University of Idaho CSC team has shown it can make a two-stroke snowmobile meet National Park Standards for noise emissions of 73 dBA in achieving the award for quietest snowmobile at the CSC in 2008. To do this, the team relied on detuning the engine and on adding sound insulation, which required larger body panels and added weight to the snowmobile. These detract from the attractiveness of the snowmobile to the average rider and make the solution impracticable.
Design Requirements
The system must be able to fit in place of the stock muffler space with only minor modifications to the chassis.
The system must not drastically increase the weight of the snowmobile.
The system must integrate a removable emissions catalyst.
The packing quality must appear to be OEM in fit and finish
The system must decrease noise emissions to National Park Standards of 73 dBA when measured according to SAE Standard J192 (full-throttle at a distance of fifty feet).