Solutions - Fuels and Lubricants
Overview
The use of oxygenated fuels and cleaner lubricants in snowmobiles has been touted as a partial solution to the problem of snowmobile emissions.
In 1997, the Montana Department of Environmental Quality completed laboratory emissions tests at Southwest Research Institute (SwRI) in cooperation with the U.S. Department of Energy, the snowmobile manufacturers industry, the community of West Yellowstone, the National Park Service, and others.
The testing used two of the most common snowmobile engines operated in the Yellowstone region: a fan-cooled 500cc Polaris engine, and a liquid-cooled 440cc Arctic Cat engine. The tests used a 5-mode steady state test procedure developed by the International Snowmobile Manufacturers Association (ISMA) from field data collected by SwRI. The laboratory emissions tests showed ethanol blend fuel (10 percent ethanol, 90 percent unleaded gasoline) reduced carbon monoxide (CO) emissions by 9 to 38 percent, unburned hydrocarbons (HC) by 16 percent, and (PM) particulate matter by 25 percent.
Tests of emissions done in the field by the University of Denver showed that each 1 percent of ethanol in the gasoline blend would reduce carbon monoxide (CO) emissions by a little more than 1 percent so that roughly, a 7 percent blend of ethanol fuel reduced CO emissions by 7 percent. The Yellowstone National Park staff has operated the Park's fleet of 100 snowmobiles with E-10 and bio-based lube oil since 1997.
The laboratory tests showed that lubrication oils affected particulate emissions of snowmobiles. Different lubrication oils were found to increase particulate matter as much as 140 percent or to decrease it as much as 65 percent compared engines using conventional fuel and mineral lubrication oil. The particulate matter analyzed in the laboratory was found to be small enough to seep into lung tissue, with a toxicity similar to that of diesel exhaust. Samples taken in the field in cold temperatures at the West Entrance to Yellowstone Park confirmed that the aerosols from snowmobiles were the same size as those in the laboratory. California lists diesel exhaust as a known human carcinogen.
To better evaluate the cancer potential of snowmobile engine particulate, a modified Ames test called a bioassay was conducted. The test measures the amount of genetic change of the culture over a set period of time. The greater the amount of change or kill, the greater the toxicity of the particulate emissions being tested, or genotoxicity. The test does not confirm that the emissions will cause cancer without further testing, but all known human carcinogens have high genotoxicity potential.
For these tests, the biodegradable lube oils (bio-based) were found to decrease the genotoxicity potential by 30 percent on average, and possibly reduce the toxicity potential by 60 percent for particulate matter produced at the lower engine speeds used in Yellowstone National Park.
Project findings caused West Yellowstone snowmobile and snowcoach rental agencies to voluntarily use E-10 and bio-based lube oils to reduce emissions and increase power. The fleet operators experienced a 60 percent reduction in required maintenance calls, avoided carburetor freezing, and had better power and fuel economy. Project results persuaded Outboard Motor Company to produce and supply a highly biodegradable lube oil for NPS to use in high-horsepower direct-injection marine engines on Yellowstone Lake. These engines are certified to meet EPA's emission requirements for 2006. The bio-based lube oil improves fuel economy, reduces pollution, reduces the persistence of the emissions in the environment, and reduces cancer risk from emissions by 30 percent to 60 percent. This project received awards for environmental stewardship from EPA Region VIII (1996), the Conoco President's Award for the Environment (1997), and the DuPont President's Award for Safety and the Environment (1997) and a Department of Energy Outstanding Achievement Award (2000). It has fostered other environmental stewardship projects with Conoco in Montana.
