Development of an In-Service Snowmobile Emission Test Procedure for the SAE Clean Snowmobile Challenge

As concerns over air pollution continue to increase, all vehicles are subject to greater scrutiny for their emissions levels. Snowmobiles and other off-road recreational vehicles are now required to meet emissions regulations enacted by the United States Environmental Protection Agency (EPA). Currently these vehicles are certified using a stationary test procedure with the engine operating attached to a dynamometer and following a five-mode test cycle. The five modes range from idle to wide open throttle and are chosen to represent the typical operation regime of a vehicle. In addition, the EPA five-mode stationary emissions test has been traditionally used for scoring competition snowmobiles at the SAE Clean Snowmobile Challenge (CSC). For the 2009 CSC, in-service emission testing was added to the competition to score the teams on actual, in-use emissions during operation of their competition snowmobile operated on a controlled test course. The testing was done using a Semtech-DS mobile emissions analyzer that was installed in an enclosed sleigh and pulled behind the snowmobile. This paper discusses the development of the in-service test procedure that was used to score the competition snowmobiles during the 2009 CSC and presents preliminary data collected during this development. The results from the In-Service Emission Event at the 2009 CSC are also presented and discussed along with the results from the stationary, five-mode emissions test. Future development plans for in-service emission measurements include improving accuracy and incorporating real-time fuel flow measurement to permit truly dynamic vehicle operation during emissions sampling.