University of Idaho's Clean Snowmobile Design Using a Direct-Injection Two-Stroke Engine 2008-32-0031

The University of Idaho's (UI's) entry into the 2007 SAE Clean Snowmobile Challenge (CSC) was a third-generation gasoline direct-injection (GDI) two-stroke powered snowmobile. The modulated and battery-less direct-injection system fully met the competition goals of “improved emissions and noise while maintaining or improving the performance characteristics of the original snowmobile.” The students designed and manufactured a new head for a stock two-stroke 600cc snowmobile engine. The head was designed to use direct fuel injection to control fuel quantity and timing to reduce fuel short-circuiting. Performance was refined through the use of precise engine mapping. The emissions output was further reduced by a reduction catalyst located in the exhaust silencer. Noise from the engine compartment was reduced by using sound absorbing materials and a sealed hood.

The UICSC team consisted of students from freshmen through graduate students. Educational aspects of the competition are central to the team's structure and success, as experienced team members teach and mentor new members.

The UICSC team achieved first place in the 2007 competition, and eight other awards, including Best Fuel Economy, Best Handling, Best Design, Best Value, Best Ride, Best Design Paper and Best Oral Presentation. The 2007 UI snowmobile averaged 19.6 miles per gallon in fuel economy, maintained stock power, exceeded 2012 snowmobile emissions standards with an EPA five-mode emissions score of 177 and achieved National Park Service sound reduction requirements for park admission with a J192 sound magnitude of 73 dBA.