Emissions From Snowmobile Engines Using Bio-based Fuels and Lubricants

Snowmobile engine emissions are of concern in environmentally sensitive areas, such as Yellowstone National Park (YNP). A program was undertaken to determine potential emission benefits of use of bio-based fuels and lubricants in snowmobile engines. Candidate fuels and lubricants were evaluated using a fan-cooled 488-cc Polaris engine, and a liquid-cooled 440-cc Arctco engine. Fuels tested include a reference gasoline, gasohol (10% ethanol), and an aliphatic gasoline. Lubricants evaluated include a bio-based lubricant, a fully synthetic lubricant, a high polyisobutylene (PIB) lubricant, as well as a conventional, mineral-based lubricant. Emissions and fuel consumption were measured using a five-mode test cycle that was developed from analysis of snowmobile field operating data. Emissions measured include total hydrocarbons (THC), carbon monoxide (CO), nitrogen oxides (NO_x), carbon dioxide (CO₂), particulate matter (PM), polycyclic aromatic hydrocarbons (PAH, both particulate bound and vapor-phase), and individual hydrocarbon species (C₁-C₁₂). Emissions and fuel consumption using bio-based fuels and lubricants were compared to results using a conventional fuel and lubricant. Promising candidates were identified and recommended for further study in a field demonstration in Yellowstone National Park.