Integration of Hybrid-Electric Strategy to Enhance Clean Snowmobile Performance

Abstract

The University of Wisconsin-Madison Snowmobile Team has engineered and constructed a hybrid-electric entry for the 2004 Society of Automotive Engineers' Clean Snowmobile Challenge. Built on a 2003 crosscountry touring chassis, this machine features a 784 cc. fuel injected four-stroke engine in parallel with a 48-volt electric golf cart motor. This 12 kg electric motor increases powertrain torque as much as 40% under acceleration and recharges the batteries during cruising. Air pollution from the gasoline engine is reduced to levels far below those of the snowmobile industry's current best available technology. The 4stroke's closed-loop EFI system maintains stoichiometric or slightly rich combustion while an electric secondary air injection pump is cycled to modulate between rich and lean, feeding a 3-way catalyst to reduce NOx, HC and CO emissions by up to 90%. The entire hybrid drivetrain including battery pack and a two-stage muffler are packaged in a manner that maintains the snowmobile's aggressive OEM appearance. Autos RVs Snowmobiles Buses Total HC 58 19 780 4 861 CO 483 337 939 15 1774 Estimated average annual emissions in tons. Snowmobile Emission Factor: University of Denver Automobile Emission Factor: EPA FTP Given this negative publicity and the recent scrutiny over National Park recreational vehicle policies, the need for cleaner, quieter snowmobile has become absolutely clear. Longevity of the sport and the survival of winter tourism economies are dependent on new technologies which must maintain the performance that snowmobile riders demand while drastically reducing environmental impact. Recognizing the difficulty in this challenge, the Society of Automotive Engineers (SAE) developed the "Clean Snowmobile Challenge" (CSC) as an engineering design competition among colleges and universities geared toward research and development of environmentally friendly snowmobiles. Competition entries are redesigns of original equipment manufacturer (OEM) snowmobiles and are expected to significantly reduce unburned hydrocarbons, carbon monoxide, and noise emissions. Successful CSC entries will also emphasize reliability, efficiency, and cost effectiveness. The 2004 CSC will be held in Michigan's Keweenaw Peninsula from March 15-20, where the University of Wisconsin-Madison will return for its third consecutive year of competition. The following paper discusses how the University of Wisconsin-Madison Team engineered a snowmobile for the 2004 CSC that fundamentally challenges conventional snowmobile powertrain design. First, the paper addresses performance characteristics, considerations and results achieved through the use of a parallel hybrid electric design. The section also describes how various components interact to achieve